moving the viewbox

moving the viewbox

@private type my_custom_shaderProgram = {
  program: Webgl.WebGLProgram;
  vertexPositionAttribute: Webgl.GLint;
  vertexNormalAttribute: Webgl.GLint;
  pMatrixUniform: Webgl.WebGLUniformLocation;
  mvMatrixUniform: Webgl.WebGLUniformLocation;
  nMatrixUniform: Webgl.WebGLUniformLocation;
  ambientColorUniform: Webgl.WebGLUniformLocation;
  lightingDirectionUniform: Webgl.WebGLUniformLocation;
  useLightingUniform: Webgl.WebGLUniformLocation
};

@private type static_buffer = {
  positions: Webgl.WebGLBuffer;
  itemSize: int; numItems: int;
  normals: Webgl.WebGLBuffer
};

@private type engine.scene = list(object);

@private type engine = {
  context: Webgl.Context.private;
  canvas: { selector:dom; width: int; height: int };
  shaderProgram: my_custom_shaderProgram
  static_buffers: { repcoords: { x:static_buffer; y:static_buffer; z:static_buffer } };
  framePickBuffer: Webgl.WebGLFramebuffer;
  scene: engine.scene;
  selector: dom;
  last_coord_fixer: option(Dom.dimensions -> vec3);
} ;

@client initPickBuffer(eng) =
  gl = eng.context;
  framePickBuffer = Webgl.createFramebuffer(gl);
  renderPickBuffer = Webgl.createRenderbuffer(gl);
  pickTexture = Webgl.createTexture(gl);
  do Webgl.bindTexture(gl, Webgl.TEXTURE_2D(gl), Option.some(pickTexture));
  tex = Webgl.Uint8Array.from_int_list([0, 0, 0]);
  do Webgl.texImage2D(gl, Webgl.TEXTURE_2D(gl), 0, Webgl.RGB(gl), eng.canvas.width, eng.canvas.height, 0, Webgl.RGB(gl), Webgl.UNSIGNED_BYTE(gl), Webgl.Uint8Array.to_ArrayBuffer(tex));
  do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.some(framePickBuffer));
  do Webgl.bindRenderbuffer(gl, Webgl.RENDERBUFFER(gl), Option.some(renderPickBuffer));
  do Webgl.renderbufferStorage(gl, Webgl.RENDERBUFFER(gl), Webgl.DEPTH_COMPONENT16(gl), eng.canvas.width, eng.canvas.height);
  do Webgl.bindRenderbuffer(gl, Webgl.RENDERBUFFER(gl), Option.none);

  do Webgl.framebufferTexture2D(gl, Webgl.FRAMEBUFFER(gl), Webgl.COLOR_ATTACHMENT0(gl), Webgl.TEXTURE_2D(gl), pickTexture, 0);
  do Webgl.framebufferRenderbuffer(gl, Webgl.FRAMEBUFFER(gl), Webgl.DEPTH_ATTACHMENT(gl), Webgl.RENDERBUFFER(gl), renderPickBuffer);
  do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.none);
  do Webgl.bindTexture(gl, Webgl.TEXTURE_2D(gl), Option.none);
  framePickBuffer
;

initShaders(gl) =
  f(e, str) =
    shader = Webgl.createShader(gl, e);
    do Webgl.shaderSource(gl, shader, str);
    do Webgl.compileShader(gl, shader);
    shader;
  fragmentShader = f(Webgl.FRAGMENT_SHADER(gl), CustomShaders.shader_fs);
  vertexShader = f(Webgl.VERTEX_SHADER(gl), CustomShaders.shader_vs);
  // TODO getShaderParameter
  shaderProgram = Webgl.createProgram(gl);
  do Webgl.attachShader(gl, shaderProgram, vertexShader);
  do Webgl.attachShader(gl, shaderProgram, fragmentShader);
  do Webgl.linkProgram(gl, shaderProgram);
  // TODO : getProgramParameter(shaderProgram, gl.LINK_STATUS)) {
  do Webgl.useProgram(gl, shaderProgram);
  shaderProgram =
    vertexPositionAttribute = Webgl.getAttribLocation(gl, shaderProgram, "aVertexPosition");
    vertexNormalAttribute = Webgl.getAttribLocation(gl, shaderProgram, "aVertexNormal");
    do Webgl.enableVertexAttribArray(gl, vertexPositionAttribute);
    do Webgl.enableVertexAttribArray(gl, vertexNormalAttribute);
    { program = shaderProgram;
      ~vertexPositionAttribute;
      ~vertexNormalAttribute;
      pMatrixUniform = Webgl.getUniformLocation(gl, shaderProgram, "uPMatrix");
      mvMatrixUniform = Webgl.getUniformLocation(gl, shaderProgram, "uMVMatrix");
      nMatrixUniform = Webgl.getUniformLocation(gl, shaderProgram, "uNMatrix");
      ambientColorUniform = Webgl.getUniformLocation(gl, shaderProgram, "uAmbientColor");
      lightingDirectionUniform = Webgl.getUniformLocation(gl, shaderProgram, "uLightingDirection");
      useLightingUniform = Webgl.getUniformLocation(gl, shaderProgram, "uUseLighting");
    };
  shaderProgram
;

initLineXBuffers(gl, orient) =
  (vertices, vertexNormals) = match orient with
    | {x} -> ([ 0.0, 0.0, 0.0, 5.0, 0.0, 0.0 ], [ 2.5, 0.0, 0.0,        2.5, -1.0, 0.0 ])
    | {y} -> ([ 0.0, 0.0, 0.0, 0.0, 5.0, 0.0 ], [ 0.0, 2.5, 0.0,        -1.0, 2.5, 0.0 ])
    | {z} -> ([ 0.0, 0.0, 0.0, 0.0, 0.0, 5.0 ], [ 0.0, 0.0, 2.5,        0.0, -1.0, 2.5 ])
    end ;
  vertexPositionBuffer = Webgl.createBuffer(gl);
  do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), vertexPositionBuffer);
  do Webgl.bufferData(gl, Webgl.ARRAY_BUFFER(gl),
    Webgl.Float32Array.to_ArrayBuffer(Webgl.Float32Array.from_float_list(vertices)),
    Webgl.STATIC_DRAW(gl));
  vertexNormalBuffer = Webgl.createBuffer(gl);
  do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), vertexNormalBuffer);
  do Webgl.bufferData(gl, Webgl.ARRAY_BUFFER(gl),
    Webgl.Float32Array.to_ArrayBuffer(Webgl.Float32Array.from_float_list(vertexNormals)),
    Webgl.STATIC_DRAW(gl));
  { positions=vertexPositionBuffer; itemSize=3; numItems=2; normals=vertexNormalBuffer }
;

setMatrixUniforms(gl, shaderProgram, pMatrix, mvMatrix) =
  a =
    b = mat4.to_list(pMatrix);
    c = Webgl.Float32Array.from_float_list(b);
    c;
  e =
    f = mat4.to_list(mvMatrix);
    g = Webgl.Float32Array.from_float_list(f);
    g;
  do Webgl.uniformMatrix4fv(gl, shaderProgram.pMatrixUniform, false, a);
  do Webgl.uniformMatrix4fv(gl, shaderProgram.mvMatrixUniform, false, e);
  normalMatrix = mat3.create();
  do mat4.toInverseMat3(mvMatrix, normalMatrix);
  do mat3.transpose(normalMatrix, normalMatrix);
  do Webgl.uniformMatrix3fv(gl, shaderProgram.nMatrixUniform, false, Webgl.Float32Array.from_float_list(mat3.to_list(normalMatrix)));
  void
;

setup_boxes(eng) =
  g(x:int, y:int, w:int, h:int) =
    inbox(pos) = (pos.x_px >= x) && (pos.y_px >= y) && (pos.x_px < (w + x)) && (pos.y_px < (h + y));
    { ~x; ~y; ~w; ~h; ~inbox } ;
  compute_left_right(x) = if ((mod(x, 2)) == 0) then
      a = (x / 2);
      ((a, a), 0)
    else
      b = (x / 2);
      ((b, b+1), 0);
  ((w_l, w_r), e_w) = compute_left_right(eng.canvas.width);
  ((h_u, h_d), e_h) = compute_left_right(eng.canvas.height);
  { _YX=g(0, h_d+e_h, w_l, h_u); _YZ=g(w_l+e_w, h_d+e_h, w_r, h_u);
    _ZX=g(0, 0, w_l, h_d);       _3D=g(w_l+e_w, 0, w_r, h_d) }
;

which_box(b, pos) =
  if b._YX.inbox(pos) then {_YX}
  else if b._YZ.inbox(pos) then {_YZ}
  else if b._ZX.inbox(pos) then {_ZX}
  else if b._3D.inbox(pos) then {_3D}
  else {out}
;

fetch_box(b, who) = match who with
  | {_YX} -> b._YX
  | {_YZ} -> b._YZ
  | {_ZX} -> b._ZX
  | {_3D} -> b._3D
  end ;

rel_pos_in_box(this_viewbox, pos) =
  x = (float_of_int(pos.x_px - this_viewbox.x) / float_of_int(this_viewbox.w)) * 2.0 - 1.0;
  y = (float_of_int(pos.y_px - this_viewbox.y) / float_of_int(this_viewbox.h)) * 2.0 - 1.0;
  (x, y);

drawScene_for_a_viewport(eng, who, viewport, camera_setting : mat4, up, scene, mode) =
  gl = eng.context; shaderProgram = eng.shaderProgram; repcoords = eng.static_buffers.repcoords;
  do Webgl.viewport(gl, viewport.x, viewport.y, viewport.w, viewport.h);
  pMatrix = camera_setting;
  mvMatrix =
    tmp_mvMatrix = mat4.create();
    do mat4.identity(tmp_mvMatrix);
    Stack.push(Stack.create(), tmp_mvMatrix);
  do setMatrixUniforms(gl, shaderProgram, pMatrix, Stack.peek(mvMatrix));
  draw_rep(r, g, b, rep) =
    do Webgl.uniform3f(gl, shaderProgram.ambientColorUniform, r, g, b);
    do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), rep.positions);
    do Webgl.vertexAttribPointer(gl, shaderProgram.vertexPositionAttribute, rep.itemSize, Webgl.FLOAT(gl), false, 0, 0);
    do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), rep.normals);
    do Webgl.vertexAttribPointer(gl, shaderProgram.vertexNormalAttribute, rep.itemSize, Webgl.FLOAT(gl), false, 0, 0);
    do Webgl.drawArrays(gl, Webgl.LINES(gl), 0, rep.numItems);
    void ;

  _ =
    match mode with
    | {normal} ->
      do Webgl.uniform1i(gl, shaderProgram.useLightingUniform, 0); // 0 = false
      do draw_rep(1.0, 0.0, 0.0, repcoords.x);
      do draw_rep(0.0, 1.0, 0.0, repcoords.y);
      do draw_rep(0.0, 0.0, 1.0, repcoords.z);
      do match who with
        | {_3D} ->
          do Webgl.uniform1i(gl, shaderProgram.useLightingUniform, 1); // 1 = true
          Webgl.uniform3f(gl, shaderProgram.lightingDirectionUniform, 0.85, 0.8, 0.75)
        | _ -> void end;
      List.iter((object -> display(eng, pMatrix, mvMatrix, object, false)), scene)
    | {pick} ->
      do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.some(eng.framePickBuffer));
      do Webgl.clear(gl, Webgl.GLbitfield_OR(Webgl.COLOR_BUFFER_BIT(gl), Webgl.DEPTH_BUFFER_BIT(gl)));
      do Webgl.uniform1i(gl, shaderProgram.useLightingUniform, 0); // 0 = false;
      do List.iter((object -> display(eng, pMatrix, mvMatrix, object, true)), scene);
      void
    end ;

  (pMatrix, mvMatrix)
;

@private drawScene_and_register(org_eng, viewbox, get_scene : (->Scene.Client.scene), get_camera_setting : (->Modeler.views), get_mode, get_pending_mouseup_and_clean) =
  last_viewbox = Mutable.make(Option.none);
  to_be_pick = Mutable.make(List.empty);
  rec aux(eng:engine) =
    gl = eng.context;
    (eng, scene) =
      f(is_selected, p) =
        match List.find((z_in_mem -> z_in_mem.id == p.id), eng.scene) with
        | { some=in_mem } -> { in_mem with position=p.cube; ~is_selected; color=p.color }
        | { none } -> Cube.create(gl, p, is_selected)
        end;
      scene : engine.scene =
        tmp = get_scene();
        others_scene = List.map(f(false, _), tmp.others.objs);
        selection_scene = Option.switch((the -> [ f(true, the) ]), List.empty, tmp.selection);
        List.append(selection_scene, others_scene);
      ({ eng with ~scene }, scene);
    views = get_camera_setting();
    eng =
      match get_mode() with
      | {pick=pos; ~cont} -> (
        match which_box(viewbox, pos) with
        | {out} -> eng
        | {_YX} as who | {_YZ} as who | {_ZX} as who | {_3D} as who ->
          //do Log.debug("Picking", "in box: '{who}' \t {viewbox}");
          this_viewbox = fetch_box(viewbox, who);
          some_settings = fetch_box(views, who);
          mvMatrix = mat4.copy(some_settings.m) ;
          _ = drawScene_for_a_viewport(eng, who, this_viewbox, mvMatrix, (0.0, 1.0, 0.0), scene, {pick});
          do mat4.inverse(mvMatrix, mvMatrix);
          g(pos : Dom.dimensions) : vec3 =
            x = (float_of_int(pos.x_px - this_viewbox.x) / float_of_int(this_viewbox.w)) * 2.0 - 1.0;
            y = (float_of_int(pos.y_px - this_viewbox.y) / float_of_int(this_viewbox.h)) * 2.0 - 1.0;
            vstart = vec4.from_public((x, y, 1.0, 1.0));
            vtmp = vec4.from_public((9.9, 9.9, 9.9, 9.9));
            do mat4.multiplyVec4(mvMatrix, vstart, vtmp);
            vpreres = vec4.to_public(vtmp);
            vres = (vpreres.f1 / vpreres.f4, vpreres.f2 / vpreres.f4, vpreres.f3 / vpreres.f4);
            do Log.debug("Converting coord", "vstart={ vec4.str(vstart) }, \t vres={ vres }");
            vres;
          pos_result = g(pos);
          possible_target =
            pickedColor =
              data = Webgl.Uint8Array.from_int_list(List.init((_->123), 4));
              do Webgl.readPixels(gl, pos.x_px, pos.y_px, 1, 1, Webgl.RGBA(gl), Webgl.UNSIGNED_BYTE(gl), Webgl.Uint8Array.to_ArrayBuffer(data));
              match Webgl.Uint8Array.to_int_list(data) with
              | [r, g, b, _] -> (r, g, b)
              | _ -> error("Picking failure")
              end ;
            do Log.debug("Picking", "Color is: { pickedColor }");
            f =
              (r, g, b) = pickedColor;
              (z -> (z.picking_color == (float_of_int(r) / 255., float_of_int(g) / 255., float_of_int(b) / 255.))) ;
            Option.map((u -> u.id), List.find(f, eng.scene));
          do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.none);
          _ = cont({ mousedown; pos=vec3.apply(pos_result, some_settings.clear_near_far, (_-> 0.0)); ~possible_target; coord_fixer=Option.some(g) });
          do last_viewbox.set(Option.some((this_viewbox, some_settings.clear_near_far, who)));
          { eng with last_coord_fixer=Option.some(g) }
        end)
      | {normal} ->
        do Webgl.clear(gl, Webgl.GLbitfield_OR(Webgl.COLOR_BUFFER_BIT(gl), Webgl.DEPTH_BUFFER_BIT(gl)));
        _ = drawScene_for_a_viewport(eng, {_YX}, viewbox._YX, views._YX.m, (0.0, 1.0, 0.0), scene, {normal});
        _ = drawScene_for_a_viewport(eng, {_YZ}, viewbox._YZ, views._YZ.m, (0.0, 1.0, 0.0), scene, {normal});
        _ = drawScene_for_a_viewport(eng, {_ZX}, viewbox._ZX, views._ZX.m, (0.0, 0.0, 1.0), scene, {normal});
        _ = drawScene_for_a_viewport(eng, {_3D}, viewbox._3D, views._3D.m, (0.0, 1.0, 0.0), scene, {normal});
        eng
      end ;
    do
      todo : list = get_pending_mouseup_and_clean();
      f((bad_pos, cont)) : void =
        g(last_coord_fixer) =
          with_v((this_viewbox, this_clear_near_far, this_who)) =
            match this_who with
            | {out} | {_3D} -> void
            | _ ->
              if this_viewbox.inbox(bad_pos) then
                cont(vec3.apply(last_coord_fixer(bad_pos), this_clear_near_far, (_-> 0.0)), this_clear_near_far)
              else
                Log.warning("Incorrect mouseup", "at bad_pos={bad_pos}")
            end;
          Option.iter(with_v, last_viewbox.get());
        Option.iter(g, eng.last_coord_fixer);
      List.iter(f, todo);
    do RequestAnimationFrame.request((_ -> aux(eng)), eng.selector);
    void
    ;
  do aux(org_eng);
  (a -> to_be_pick.set(List.cons(a, to_be_pick.get())))
;

initGL(canvas_sel, width, height, get_scene, get_camera_setting, mouse_listener, support_gpu_picking) : outcome =
  match WebGLUtils.setupWebGL_with_custom_failure(Dom.of_selection(canvas_sel)) with
  | { ok=context } ->
    mode = Mutable.make({normal});
    pending_mouseup = Mutable.make(List.empty);
    is_picking(m) = match m with | { pick=_; cont=_ } -> true | _ -> false end;
    gl = context;
    eng : engine =
      start = @openrecord({ context=gl; canvas={ selector=canvas_sel; ~width; ~height }; scene=List.empty; selector=canvas_sel;
        last_coord_fixer=Option.none });
      start = { start with shaderProgram=initShaders(gl) };
      start = { start with framePickBuffer=initPickBuffer(start) } ;
      { start with static_buffers.repcoords=
        { x=initLineXBuffers(gl, {x}); y=initLineXBuffers(gl, {y}); z=initLineXBuffers(gl, {z}) } };
    viewbox = setup_boxes(eng) ;
    {} =
      recompute_pos(rel_mouse_position_on_page) =
        m_pos = // we transform the pos to be relative to the upper leftcorner of the canvas
          c_pos = Dom.get_offset(canvas_sel);
          rel = rel_mouse_position_on_page;
          { x_px=max(rel.x_px - c_pos.x_px, 0); y_px=max(rel.y_px - c_pos.y_px, 0) };
        // now with gl the origin will be at the lower left corner
        gl_pos = { x_px=min(max(m_pos.x_px,0), width-1); y_px=min(max(height - 1 - m_pos.y_px, 0), height-1) };
        do Log.debug("P", "[({m_pos.x_px},{m_pos.y_px})] {gl_pos.x_px}, {gl_pos.y_px}");
        gl_pos;
      handler_mousedown(e) =
        gl_pos = recompute_pos(e.mouse_position_on_page);
        cont(e) =
          do mode.set({normal});
          mouse_listener(e);
        if not(is_picking(mode.get())) then mode.set({pick=gl_pos; ~cont}) else void;
      _ = Dom.bind(canvas_sel, { mousedown }, handler_mousedown);
      handler_mouseup(e) =
        gl_pos = recompute_pos(e.mouse_position_on_page);
        cont(x, switch) = mouse_listener({mouseup; pos=x; ~switch});
        pending_mouseup.set(List.cons((gl_pos, cont), pending_mouseup.get()));
      _ = Dom.bind(canvas_sel, { mouseup }, handler_mouseup);
      void;
    //Clear screen and make everything light gray // disabled to show png grid
    //do Webgl.clearColor(gl, 0.875, 0.875, 0.875, 1.0);
    //we should do depth testing so that things drawn behind other
    //things should be hidden by the things in front of them).
    do Webgl.clearDepth(gl, 1.0);
    do Webgl.enable(gl, Webgl.DEPTH_TEST(gl));
    do Webgl.depthFunc(gl, Webgl.LEQUAL(gl));
    do
      get_pending_mouseup_and_clean() =
        tmp = List.rev(pending_mouseup.get());
        do pending_mouseup.set(List.empty);
        tmp;
      gpu_picker_register = drawScene_and_register(eng, viewbox, get_scene, get_camera_setting, mode.get, get_pending_mouseup_and_clean);
      do support_gpu_picking.set(Option.some(gpu_picker_register));
      void
    { success }
  | { ~ko } -> { failure=ko }
  end ;

@private type my_custom_shaderProgram = {
  program: Webgl.WebGLProgram;
  vertexPositionAttribute: Webgl.GLint;
  vertexNormalAttribute: Webgl.GLint;
  pMatrixUniform: Webgl.WebGLUniformLocation;
  mvMatrixUniform: Webgl.WebGLUniformLocation;
  nMatrixUniform: Webgl.WebGLUniformLocation;
  ambientColorUniform: Webgl.WebGLUniformLocation;
  lightingDirectionUniform: Webgl.WebGLUniformLocation;
  useLightingUniform: Webgl.WebGLUniformLocation
};

@private type static_buffer = {
  positions: Webgl.WebGLBuffer;
  itemSize: int; numItems: int;
  normals: Webgl.WebGLBuffer
};

@private type engine.scene = list(object);

@private type engine = {
  context: Webgl.Context.private;
  canvas: { selector:dom; width: int; height: int };
  shaderProgram: my_custom_shaderProgram
  static_buffers: { repcoords: { x:static_buffer; y:static_buffer; z:static_buffer } };
  framePickBuffer: Webgl.WebGLFramebuffer;
  scene: engine.scene;
  selector: dom;
  last_coord_fixer: option(Dom.dimensions -> vec3);
} ;

@client initPickBuffer(eng) =
  gl = eng.context;
  framePickBuffer = Webgl.createFramebuffer(gl);
  renderPickBuffer = Webgl.createRenderbuffer(gl);
  pickTexture = Webgl.createTexture(gl);
  do Webgl.bindTexture(gl, Webgl.TEXTURE_2D(gl), Option.some(pickTexture));
  tex = Webgl.Uint8Array.from_int_list([0, 0, 0]);
  do Webgl.texImage2D(gl, Webgl.TEXTURE_2D(gl), 0, Webgl.RGB(gl), eng.canvas.width, eng.canvas.height, 0, Webgl.RGB(gl), Webgl.UNSIGNED_BYTE(gl), Webgl.Uint8Array.to_ArrayBuffer(tex));
  do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.some(framePickBuffer));
  do Webgl.bindRenderbuffer(gl, Webgl.RENDERBUFFER(gl), Option.some(renderPickBuffer));
  do Webgl.renderbufferStorage(gl, Webgl.RENDERBUFFER(gl), Webgl.DEPTH_COMPONENT16(gl), eng.canvas.width, eng.canvas.height);
  do Webgl.bindRenderbuffer(gl, Webgl.RENDERBUFFER(gl), Option.none);

  do Webgl.framebufferTexture2D(gl, Webgl.FRAMEBUFFER(gl), Webgl.COLOR_ATTACHMENT0(gl), Webgl.TEXTURE_2D(gl), pickTexture, 0);
  do Webgl.framebufferRenderbuffer(gl, Webgl.FRAMEBUFFER(gl), Webgl.DEPTH_ATTACHMENT(gl), Webgl.RENDERBUFFER(gl), renderPickBuffer);
  do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.none);
  do Webgl.bindTexture(gl, Webgl.TEXTURE_2D(gl), Option.none);
  framePickBuffer
;

initShaders(gl) =
  f(e, str) =
    shader = Webgl.createShader(gl, e);
    do Webgl.shaderSource(gl, shader, str);
    do Webgl.compileShader(gl, shader);
    shader;
  fragmentShader = f(Webgl.FRAGMENT_SHADER(gl), CustomShaders.shader_fs);
  vertexShader = f(Webgl.VERTEX_SHADER(gl), CustomShaders.shader_vs);
  // TODO getShaderParameter
  shaderProgram = Webgl.createProgram(gl);
  do Webgl.attachShader(gl, shaderProgram, vertexShader);
  do Webgl.attachShader(gl, shaderProgram, fragmentShader);
  do Webgl.linkProgram(gl, shaderProgram);
  // TODO : getProgramParameter(shaderProgram, gl.LINK_STATUS)) {
  do Webgl.useProgram(gl, shaderProgram);
  shaderProgram =
    vertexPositionAttribute = Webgl.getAttribLocation(gl, shaderProgram, "aVertexPosition");
    vertexNormalAttribute = Webgl.getAttribLocation(gl, shaderProgram, "aVertexNormal");
    do Webgl.enableVertexAttribArray(gl, vertexPositionAttribute);
    do Webgl.enableVertexAttribArray(gl, vertexNormalAttribute);
    { program = shaderProgram;
      ~vertexPositionAttribute;
      ~vertexNormalAttribute;
      pMatrixUniform = Webgl.getUniformLocation(gl, shaderProgram, "uPMatrix");
      mvMatrixUniform = Webgl.getUniformLocation(gl, shaderProgram, "uMVMatrix");
      nMatrixUniform = Webgl.getUniformLocation(gl, shaderProgram, "uNMatrix");
      ambientColorUniform = Webgl.getUniformLocation(gl, shaderProgram, "uAmbientColor");
      lightingDirectionUniform = Webgl.getUniformLocation(gl, shaderProgram, "uLightingDirection");
      useLightingUniform = Webgl.getUniformLocation(gl, shaderProgram, "uUseLighting");
    };
  shaderProgram
;

initLineXBuffers(gl, orient) =
  (vertices, vertexNormals) = match orient with
    | {x} -> ([ 0.0, 0.0, 0.0, 5.0, 0.0, 0.0 ], [ 2.5, 0.0, 0.0,        2.5, -1.0, 0.0 ])
    | {y} -> ([ 0.0, 0.0, 0.0, 0.0, 5.0, 0.0 ], [ 0.0, 2.5, 0.0,        -1.0, 2.5, 0.0 ])
    | {z} -> ([ 0.0, 0.0, 0.0, 0.0, 0.0, 5.0 ], [ 0.0, 0.0, 2.5,        0.0, -1.0, 2.5 ])
    end ;
  vertexPositionBuffer = Webgl.createBuffer(gl);
  do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), vertexPositionBuffer);
  do Webgl.bufferData(gl, Webgl.ARRAY_BUFFER(gl),
    Webgl.Float32Array.to_ArrayBuffer(Webgl.Float32Array.from_float_list(vertices)),
    Webgl.STATIC_DRAW(gl));
  vertexNormalBuffer = Webgl.createBuffer(gl);
  do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), vertexNormalBuffer);
  do Webgl.bufferData(gl, Webgl.ARRAY_BUFFER(gl),
    Webgl.Float32Array.to_ArrayBuffer(Webgl.Float32Array.from_float_list(vertexNormals)),
    Webgl.STATIC_DRAW(gl));
  { positions=vertexPositionBuffer; itemSize=3; numItems=2; normals=vertexNormalBuffer }
;

setMatrixUniforms(gl, shaderProgram, pMatrix, mvMatrix) =
  a =
    b = mat4.to_list(pMatrix);
    c = Webgl.Float32Array.from_float_list(b);
    c;
  e =
    f = mat4.to_list(mvMatrix);
    g = Webgl.Float32Array.from_float_list(f);
    g;
  do Webgl.uniformMatrix4fv(gl, shaderProgram.pMatrixUniform, false, a);
  do Webgl.uniformMatrix4fv(gl, shaderProgram.mvMatrixUniform, false, e);
  normalMatrix = mat3.create();
  do mat4.toInverseMat3(mvMatrix, normalMatrix);
  do mat3.transpose(normalMatrix, normalMatrix);
  do Webgl.uniformMatrix3fv(gl, shaderProgram.nMatrixUniform, false, Webgl.Float32Array.from_float_list(mat3.to_list(normalMatrix)));
  void
;

setup_boxes(eng) =
  g(x:int, y:int, w:int, h:int) =
    inbox(pos) = (pos.x_px >= x) && (pos.y_px >= y) && (pos.x_px < (w + x)) && (pos.y_px < (h + y));
    { ~x; ~y; ~w; ~h; ~inbox } ;
  compute_left_right(x) = if ((mod(x, 2)) == 0) then
      a = (x / 2);
      ((a, a), 0)
    else
      b = (x / 2);
      ((b, b+1), 0);
  ((w_l, w_r), e_w) = compute_left_right(eng.canvas.width);
  ((h_u, h_d), e_h) = compute_left_right(eng.canvas.height);
  { _YX=g(0, h_d+e_h, w_l, h_u); _YZ=g(w_l+e_w, h_d+e_h, w_r, h_u);
    _ZX=g(0, 0, w_l, h_d);       _3D=g(w_l+e_w, 0, w_r, h_d) }
;

which_box(b, pos) =
  if b._YX.inbox(pos) then {_YX}
  else if b._YZ.inbox(pos) then {_YZ}
  else if b._ZX.inbox(pos) then {_ZX}
  else if b._3D.inbox(pos) then {_3D}
  else {out}
;

fetch_box(b, who) = match who with
  | {_YX} -> b._YX
  | {_YZ} -> b._YZ
  | {_ZX} -> b._ZX
  | {_3D} -> b._3D
  end ;

drawScene_for_a_viewport(eng, who, viewport, camera_setting : mat4, up, scene, mode) =
  gl = eng.context; shaderProgram = eng.shaderProgram; repcoords = eng.static_buffers.repcoords;
  do Webgl.viewport(gl, viewport.x, viewport.y, viewport.w, viewport.h);
  pMatrix = camera_setting;
  mvMatrix =
    tmp_mvMatrix = mat4.create();
    do mat4.identity(tmp_mvMatrix);
    Stack.push(Stack.create(), tmp_mvMatrix);
  do setMatrixUniforms(gl, shaderProgram, pMatrix, Stack.peek(mvMatrix));
  draw_rep(r, g, b, rep) =
    do Webgl.uniform3f(gl, shaderProgram.ambientColorUniform, r, g, b);
    do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), rep.positions);
    do Webgl.vertexAttribPointer(gl, shaderProgram.vertexPositionAttribute, rep.itemSize, Webgl.FLOAT(gl), false, 0, 0);
    do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), rep.normals);
    do Webgl.vertexAttribPointer(gl, shaderProgram.vertexNormalAttribute, rep.itemSize, Webgl.FLOAT(gl), false, 0, 0);
    do Webgl.drawArrays(gl, Webgl.LINES(gl), 0, rep.numItems);
    void ;

  _ =
    match mode with
    | {normal} ->
      do Webgl.uniform1i(gl, shaderProgram.useLightingUniform, 0); // 0 = false
      do draw_rep(1.0, 0.0, 0.0, repcoords.x);
      do draw_rep(0.0, 1.0, 0.0, repcoords.y);
      do draw_rep(0.0, 0.0, 1.0, repcoords.z);
      do match who with
        | {_3D} ->
          do Webgl.uniform1i(gl, shaderProgram.useLightingUniform, 1); // 1 = true
          Webgl.uniform3f(gl, shaderProgram.lightingDirectionUniform, 0.85, 0.8, 0.75)
        | _ -> void end;
      List.iter((object -> display(eng, pMatrix, mvMatrix, object, false)), scene)
    | {pick} ->
      do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.some(eng.framePickBuffer));
      do Webgl.clear(gl, Webgl.GLbitfield_OR(Webgl.COLOR_BUFFER_BIT(gl), Webgl.DEPTH_BUFFER_BIT(gl)));
      do Webgl.uniform1i(gl, shaderProgram.useLightingUniform, 0); // 0 = false;
      do List.iter((object -> display(eng, pMatrix, mvMatrix, object, true)), scene);
      void
    end ;

  (pMatrix, mvMatrix)
;

@private drawScene_and_register(org_eng, get_scene : (->Scene.Client.scene), get_camera_setting : (->Modeler.views), get_mode, get_pending_mouseup_and_clean) =
  viewbox = setup_boxes(org_eng) ;
  last_viewbox = Mutable.make(Option.none);
  to_be_pick = Mutable.make(List.empty);
  rec aux(eng:engine) =
    gl = eng.context;
    (eng, scene) =
      f(is_selected, p) =
        match List.find((z_in_mem -> z_in_mem.id == p.id), eng.scene) with
        | { some=in_mem } -> { in_mem with position=p.cube; ~is_selected; color=p.color }
        | { none } -> Cube.create(gl, p, is_selected)
        end;
      scene : engine.scene =
        tmp = get_scene();
        others_scene = List.map(f(false, _), tmp.others.objs);
        selection_scene = Option.switch((the -> [ f(true, the) ]), List.empty, tmp.selection);
        List.append(selection_scene, others_scene);
      ({ eng with ~scene }, scene);
    views = get_camera_setting();
    eng =
      match get_mode() with
      | {pick=pos; ~cont} -> (
        match which_box(viewbox, pos) with
        | {out} -> eng
        | {_YX} as who | {_YZ} as who | {_ZX} as who | {_3D} as who ->
          //do Log.debug("Picking", "in box: '{who}' \t {viewbox}");
          this_viewbox = fetch_box(viewbox, who);
          some_settings = fetch_box(views, who);
          mvMatrix = mat4.copy(some_settings.m) ;
          _ = drawScene_for_a_viewport(eng, who, this_viewbox, mvMatrix, (0.0, 1.0, 0.0), scene, {pick});
          do mat4.inverse(mvMatrix, mvMatrix);
          g(pos : Dom.dimensions) : vec3 =
            x = (float_of_int(pos.x_px - this_viewbox.x) / float_of_int(this_viewbox.w)) * 2.0 - 1.0;
            y = (float_of_int(pos.y_px - this_viewbox.y) / float_of_int(this_viewbox.h)) * 2.0 - 1.0;
            vstart = vec4.from_public((x, y, 1.0, 1.0));
            vtmp = vec4.from_public((9.9, 9.9, 9.9, 9.9));
            do mat4.multiplyVec4(mvMatrix, vstart, vtmp);
            vpreres = vec4.to_public(vtmp);
            vres = (vpreres.f1 / vpreres.f4, vpreres.f2 / vpreres.f4, vpreres.f3 / vpreres.f4);
            do Log.debug("Converting coord", "vstart={ vec4.str(vstart) }, \t vres={ vres }");
            vres;
          pos_result = g(pos);
          possible_target =
            pickedColor =
              data = Webgl.Uint8Array.from_int_list(List.init((_->123), 4));
              do Webgl.readPixels(gl, pos.x_px, pos.y_px, 1, 1, Webgl.RGBA(gl), Webgl.UNSIGNED_BYTE(gl), Webgl.Uint8Array.to_ArrayBuffer(data));
              match Webgl.Uint8Array.to_int_list(data) with
              | [r, g, b, _] -> (r, g, b)
              | _ -> error("Picking failure")
              end ;
            do Log.debug("Picking", "Color is: { pickedColor }");
            f =
              (r, g, b) = pickedColor;
              (z -> (z.picking_color == (float_of_int(r) / 255., float_of_int(g) / 255., float_of_int(b) / 255.))) ;
            Option.map((u -> u.id), List.find(f, eng.scene));
          do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.none);
          _ = cont({ mousedown; pos=vec3.apply(pos_result, some_settings.clear_near_far, (_-> 0.0)); ~possible_target; coord_fixer=Option.some(g) });
          do last_viewbox.set(Option.some((this_viewbox, some_settings.clear_near_far, who)));
          { eng with last_coord_fixer=Option.some(g) }
        end)
      | {normal} ->
        do Webgl.clear(gl, Webgl.GLbitfield_OR(Webgl.COLOR_BUFFER_BIT(gl), Webgl.DEPTH_BUFFER_BIT(gl)));
        _ = drawScene_for_a_viewport(eng, {_YX}, viewbox._YX, views._YX.m, (0.0, 1.0, 0.0), scene, {normal});
        _ = drawScene_for_a_viewport(eng, {_YZ}, viewbox._YZ, views._YZ.m, (0.0, 1.0, 0.0), scene, {normal});
        _ = drawScene_for_a_viewport(eng, {_ZX}, viewbox._ZX, views._ZX.m, (0.0, 0.0, 1.0), scene, {normal});
        _ = drawScene_for_a_viewport(eng, {_3D}, viewbox._3D, views._3D.m, (0.0, 1.0, 0.0), scene, {normal});
        eng
      end ;
    do
      todo : list = get_pending_mouseup_and_clean();
      f((bad_pos, cont)) : void =
        g(last_coord_fixer) =
          with_v((this_viewbox, this_clear_near_far, this_who)) =
            match this_who with
            | {out} | {_3D} -> void
            | _ ->
              if this_viewbox.inbox(bad_pos) then
                cont(vec3.apply(last_coord_fixer(bad_pos), this_clear_near_far, (_-> 0.0)), this_clear_near_far)
              else
                Log.warning("Incorrect mouseup", "at bad_pos={bad_pos}")
            end;
          Option.iter(with_v, last_viewbox.get());
        Option.iter(g, eng.last_coord_fixer);
      List.iter(f, todo);
    do RequestAnimationFrame.request((_ -> aux(eng)), eng.selector);
    void
    ;
  do aux(org_eng);
  (a -> to_be_pick.set(List.cons(a, to_be_pick.get())))
;

initGL(canvas_sel, width, height, get_scene, get_camera_setting, mouse_listener, support_gpu_picking) : outcome =
  match WebGLUtils.setupWebGL_with_custom_failure(Dom.of_selection(canvas_sel)) with
  | { ok=context } ->
    mode = Mutable.make({normal});
    pending_mouseup = Mutable.make(List.empty);
    is_picking(m) = match m with | { pick=_; cont=_ } -> true | _ -> false end;
    _ =
      recompute_pos(rel_mouse_position_on_page) =
        m_pos = // we transform the pos to be relative to the upper leftcorner of the canvas
          c_pos = Dom.get_offset(canvas_sel);
          rel = rel_mouse_position_on_page;
          { x_px=max(rel.x_px - c_pos.x_px, 0); y_px=max(rel.y_px - c_pos.y_px, 0) };
        // now with gl the origin will be at the lower left corner
        gl_pos = { x_px=min(max(m_pos.x_px,0), width-1); y_px=min(max(height - 1 - m_pos.y_px, 0), height-1) };
        do Log.debug("P", "[({m_pos.x_px},{m_pos.y_px})] {gl_pos.x_px}, {gl_pos.y_px}");
        gl_pos;
      handler_mousedown(e) =
        gl_pos = recompute_pos(e.mouse_position_on_page);
        cont(e) =
          do mode.set({normal});
          mouse_listener(e);
        if not(is_picking(mode.get())) then mode.set({pick=gl_pos; ~cont}) else void;
      _ = Dom.bind(canvas_sel, { mousedown }, handler_mousedown);
      handler_mouseup(e) =
        gl_pos = recompute_pos(e.mouse_position_on_page);
        cont(x, switch) = mouse_listener({mouseup; pos=x; ~switch});
        pending_mouseup.set(List.cons((gl_pos, cont), pending_mouseup.get()));
      _ = Dom.bind(canvas_sel, { mouseup }, handler_mouseup);
      void;
    gl = context;
    eng : engine =
      start = @openrecord({ context=gl; canvas={ selector=canvas_sel; ~width; ~height }; scene=List.empty; selector=canvas_sel;
        last_coord_fixer=Option.none });
      start = { start with shaderProgram=initShaders(gl) };
      start = { start with framePickBuffer=initPickBuffer(start) } ;
      { start with static_buffers.repcoords=
        { x=initLineXBuffers(gl, {x}); y=initLineXBuffers(gl, {y}); z=initLineXBuffers(gl, {z}) } };
    //Clear screen and make everything light gray // disabled to show png grid
    //do Webgl.clearColor(gl, 0.875, 0.875, 0.875, 1.0);
    //we should do depth testing so that things drawn behind other
    //things should be hidden by the things in front of them).
    do Webgl.clearDepth(gl, 1.0);
    do Webgl.enable(gl, Webgl.DEPTH_TEST(gl));
    do Webgl.depthFunc(gl, Webgl.LEQUAL(gl));
    do
      get_pending_mouseup_and_clean() =
        tmp = List.rev(pending_mouseup.get());
        do pending_mouseup.set(List.empty);
        tmp;
      gpu_picker_register = drawScene_and_register(eng, get_scene, get_camera_setting, mode.get, get_pending_mouseup_and_clean);
      do support_gpu_picking.set(Option.some(gpu_picker_register));
      void
    { success }
  | { ~ko } -> { failure=ko }
  end ;


moving some vars

moving some vars

@private type my_custom_shaderProgram = {
  program: Webgl.WebGLProgram;
  vertexPositionAttribute: Webgl.GLint;
  vertexNormalAttribute: Webgl.GLint;
  pMatrixUniform: Webgl.WebGLUniformLocation;
  mvMatrixUniform: Webgl.WebGLUniformLocation;
  nMatrixUniform: Webgl.WebGLUniformLocation;
  ambientColorUniform: Webgl.WebGLUniformLocation;
  lightingDirectionUniform: Webgl.WebGLUniformLocation;
  useLightingUniform: Webgl.WebGLUniformLocation
};

@private type static_buffer = {
  positions: Webgl.WebGLBuffer;
  itemSize: int; numItems: int;
  normals: Webgl.WebGLBuffer
};

@private type engine.scene = list(object);

@private type engine = {
  context: Webgl.Context.private;
  canvas: { selector:dom; width: int; height: int };
  shaderProgram: my_custom_shaderProgram
  static_buffers: { repcoords: { x:static_buffer; y:static_buffer; z:static_buffer } };
  framePickBuffer: Webgl.WebGLFramebuffer;
  scene: engine.scene
  selector: dom
} ;

@client initPickBuffer(eng) =
  gl = eng.context;
  framePickBuffer = Webgl.createFramebuffer(gl);
  renderPickBuffer = Webgl.createRenderbuffer(gl);
  pickTexture = Webgl.createTexture(gl);
  do Webgl.bindTexture(gl, Webgl.TEXTURE_2D(gl), Option.some(pickTexture));
  tex = Webgl.Uint8Array.from_int_list([0, 0, 0]);
  do Webgl.texImage2D(gl, Webgl.TEXTURE_2D(gl), 0, Webgl.RGB(gl), eng.canvas.width, eng.canvas.height, 0, Webgl.RGB(gl), Webgl.UNSIGNED_BYTE(gl), Webgl.Uint8Array.to_ArrayBuffer(tex));
  do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.some(framePickBuffer));
  do Webgl.bindRenderbuffer(gl, Webgl.RENDERBUFFER(gl), Option.some(renderPickBuffer));
  do Webgl.renderbufferStorage(gl, Webgl.RENDERBUFFER(gl), Webgl.DEPTH_COMPONENT16(gl), eng.canvas.width, eng.canvas.height);
  do Webgl.bindRenderbuffer(gl, Webgl.RENDERBUFFER(gl), Option.none);

  do Webgl.framebufferTexture2D(gl, Webgl.FRAMEBUFFER(gl), Webgl.COLOR_ATTACHMENT0(gl), Webgl.TEXTURE_2D(gl), pickTexture, 0);
  do Webgl.framebufferRenderbuffer(gl, Webgl.FRAMEBUFFER(gl), Webgl.DEPTH_ATTACHMENT(gl), Webgl.RENDERBUFFER(gl), renderPickBuffer);
  do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.none);
  do Webgl.bindTexture(gl, Webgl.TEXTURE_2D(gl), Option.none);
  framePickBuffer
;

initShaders(gl) =
  f(e, str) =
    shader = Webgl.createShader(gl, e);
    do Webgl.shaderSource(gl, shader, str);
    do Webgl.compileShader(gl, shader);
    shader;
  fragmentShader = f(Webgl.FRAGMENT_SHADER(gl), CustomShaders.shader_fs);
  vertexShader = f(Webgl.VERTEX_SHADER(gl), CustomShaders.shader_vs);
  // TODO getShaderParameter
  shaderProgram = Webgl.createProgram(gl);
  do Webgl.attachShader(gl, shaderProgram, vertexShader);
  do Webgl.attachShader(gl, shaderProgram, fragmentShader);
  do Webgl.linkProgram(gl, shaderProgram);
  // TODO : getProgramParameter(shaderProgram, gl.LINK_STATUS)) {
  do Webgl.useProgram(gl, shaderProgram);
  shaderProgram =
    vertexPositionAttribute = Webgl.getAttribLocation(gl, shaderProgram, "aVertexPosition");
    vertexNormalAttribute = Webgl.getAttribLocation(gl, shaderProgram, "aVertexNormal");
    do Webgl.enableVertexAttribArray(gl, vertexPositionAttribute);
    do Webgl.enableVertexAttribArray(gl, vertexNormalAttribute);
    { program = shaderProgram;
      ~vertexPositionAttribute;
      ~vertexNormalAttribute;
      pMatrixUniform = Webgl.getUniformLocation(gl, shaderProgram, "uPMatrix");
      mvMatrixUniform = Webgl.getUniformLocation(gl, shaderProgram, "uMVMatrix");
      nMatrixUniform = Webgl.getUniformLocation(gl, shaderProgram, "uNMatrix");
      ambientColorUniform = Webgl.getUniformLocation(gl, shaderProgram, "uAmbientColor");
      lightingDirectionUniform = Webgl.getUniformLocation(gl, shaderProgram, "uLightingDirection");
      useLightingUniform = Webgl.getUniformLocation(gl, shaderProgram, "uUseLighting");
    };
  shaderProgram
;

initLineXBuffers(gl, orient) =
  (vertices, vertexNormals) = match orient with
    | {x} -> ([ 0.0, 0.0, 0.0, 5.0, 0.0, 0.0 ], [ 2.5, 0.0, 0.0,        2.5, -1.0, 0.0 ])
    | {y} -> ([ 0.0, 0.0, 0.0, 0.0, 5.0, 0.0 ], [ 0.0, 2.5, 0.0,        -1.0, 2.5, 0.0 ])
    | {z} -> ([ 0.0, 0.0, 0.0, 0.0, 0.0, 5.0 ], [ 0.0, 0.0, 2.5,        0.0, -1.0, 2.5 ])
    end ;
  vertexPositionBuffer = Webgl.createBuffer(gl);
  do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), vertexPositionBuffer);
  do Webgl.bufferData(gl, Webgl.ARRAY_BUFFER(gl),
    Webgl.Float32Array.to_ArrayBuffer(Webgl.Float32Array.from_float_list(vertices)),
    Webgl.STATIC_DRAW(gl));
  vertexNormalBuffer = Webgl.createBuffer(gl);
  do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), vertexNormalBuffer);
  do Webgl.bufferData(gl, Webgl.ARRAY_BUFFER(gl),
    Webgl.Float32Array.to_ArrayBuffer(Webgl.Float32Array.from_float_list(vertexNormals)),
    Webgl.STATIC_DRAW(gl));
  { positions=vertexPositionBuffer; itemSize=3; numItems=2; normals=vertexNormalBuffer }
;

setMatrixUniforms(gl, shaderProgram, pMatrix, mvMatrix) =
  a =
    b = mat4.to_list(pMatrix);
    c = Webgl.Float32Array.from_float_list(b);
    c;
  e =
    f = mat4.to_list(mvMatrix);
    g = Webgl.Float32Array.from_float_list(f);
    g;
  do Webgl.uniformMatrix4fv(gl, shaderProgram.pMatrixUniform, false, a);
  do Webgl.uniformMatrix4fv(gl, shaderProgram.mvMatrixUniform, false, e);
  normalMatrix = mat3.create();
  do mat4.toInverseMat3(mvMatrix, normalMatrix);
  do mat3.transpose(normalMatrix, normalMatrix);
  do Webgl.uniformMatrix3fv(gl, shaderProgram.nMatrixUniform, false, Webgl.Float32Array.from_float_list(mat3.to_list(normalMatrix)));
  void
;

setup_boxes(eng) =
  cnf_x(pos) = { pos with f1=0.0 }; cnf_y(pos) = { pos with f2=0.0 }; cnf_z(pos) = { pos with f3=0.0 };
  g(x:int, y:int, w:int, h:int, clear_near_far) =
    inbox(pos) = (pos.x_px >= x) && (pos.y_px >= y) && (pos.x_px < (w + x)) && (pos.y_px < (h + y));
    { ~x; ~y; ~w; ~h; ~inbox; ~clear_near_far } ;
  compute_left_right(x) = if ((mod(x, 2)) == 0) then
      a = (x / 2);
      ((a, a), 0)
    else
      b = (x / 2);
      ((b, b+1), 0);
  ((w_l, w_r), e_w) = compute_left_right(eng.canvas.width);
  ((h_u, h_d), e_h) = compute_left_right(eng.canvas.height);
  { _YX=g(0, h_d+e_h, w_l, h_u, cnf_z); _YZ=g(w_l+e_w, h_d+e_h, w_r, h_u, cnf_x);
    _ZX=g(0, 0, w_l, h_d, cnf_y);       _3D=g(w_l+e_w, 0, w_r, h_d, cnf_y) }
;

which_box(b, pos) =
  if b._YX.inbox(pos) then {_YX}
  else if b._YZ.inbox(pos) then {_YZ}
  else if b._ZX.inbox(pos) then {_ZX}
  else if b._3D.inbox(pos) then {_3D}
  else {out}
;

fetch_box(b, who) = match who with
  | {_YX} -> b._YX
  | {_YZ} -> b._YZ
  | {_ZX} -> b._ZX
  | {_3D} -> b._3D
  end ;

drawScene_for_a_viewport(eng, who, viewport, eye, up, scene, mode) =
  gl = eng.context; shaderProgram = eng.shaderProgram; repcoords = eng.static_buffers.repcoords;
  do Webgl.viewport(gl, viewport.x, viewport.y, viewport.w, viewport.h);
  pMatrix =
    tmp_pMatrix = mat4.create();
    tmp_x = Float.of_int(viewport.w / 40)
    tmp_y = Float.of_int(viewport.h / 40)
    match who with
    | {_YX} ->
      do mat4.ortho(-tmp_x, tmp_x, -tmp_y, tmp_y, -10., 10., tmp_pMatrix);
      tmp_pMatrix
    | {_YZ} ->
      do mat4.ortho(-tmp_x, tmp_x, -tmp_y, tmp_y, -10., 10., tmp_pMatrix);
      mat4.rotateY(tmp_pMatrix, (90. * Math.PI / 180.), tmp_pMatrix)
    | {_ZX} ->
      do mat4.ortho(-tmp_x, tmp_x, -tmp_y, tmp_y, -10., 10., tmp_pMatrix);
      mat4.rotateX(tmp_pMatrix, (90. * Math.PI / 180.), tmp_pMatrix)
    | {_3D} ->
      do mat4.perspective(45., float_of_int(eng.canvas.width) / float_of_int(eng.canvas.height), 0.1, 100.0, tmp_pMatrix);
      c = mat4.create() ;
      do mat4.lookAt(vec3.from_public(eye), vec3.from_public((0.0, 0.0, 0.0)), vec3.from_public(up), c);
      do mat4.multiply(tmp_pMatrix, c, tmp_pMatrix);
      tmp_pMatrix
    end ;
  mvMatrix =
    tmp_mvMatrix = mat4.create();
    do mat4.identity(tmp_mvMatrix);
    Stack.push(Stack.create(), tmp_mvMatrix);
  do setMatrixUniforms(gl, shaderProgram, pMatrix, Stack.peek(mvMatrix));
  draw_rep(r, g, b, rep) =
    do Webgl.uniform3f(gl, shaderProgram.ambientColorUniform, r, g, b);
    do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), rep.positions);
    do Webgl.vertexAttribPointer(gl, shaderProgram.vertexPositionAttribute, rep.itemSize, Webgl.FLOAT(gl), false, 0, 0);
    do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), rep.normals);
    do Webgl.vertexAttribPointer(gl, shaderProgram.vertexNormalAttribute, rep.itemSize, Webgl.FLOAT(gl), false, 0, 0);
    do Webgl.drawArrays(gl, Webgl.LINES(gl), 0, rep.numItems);
    void ;

  _ =
    match mode with
    | {normal} ->
      do Webgl.uniform1i(gl, shaderProgram.useLightingUniform, 0); // 0 = false
      do draw_rep(1.0, 0.0, 0.0, repcoords.x);
      do draw_rep(0.0, 1.0, 0.0, repcoords.y);
      do draw_rep(0.0, 0.0, 1.0, repcoords.z);
      do match who with
        | {_3D} ->
          do Webgl.uniform1i(gl, shaderProgram.useLightingUniform, 1); // 1 = true
          Webgl.uniform3f(gl, shaderProgram.lightingDirectionUniform, 0.85, 0.8, 0.75)
        | _ -> void end;
      List.iter((object -> display(eng, pMatrix, mvMatrix, object, false)), scene)
    | {pick} ->
      do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.some(eng.framePickBuffer));
      do Webgl.clear(gl, Webgl.GLbitfield_OR(Webgl.COLOR_BUFFER_BIT(gl), Webgl.DEPTH_BUFFER_BIT(gl)));
      do Webgl.uniform1i(gl, shaderProgram.useLightingUniform, 0); // 0 = false;
      do List.iter((object -> display(eng, pMatrix, mvMatrix, object, true)), scene);
      void
    end ;

  (pMatrix, mvMatrix)
;

@private drawScene_and_register(org_eng, get_scene : (->Scene.Client.scene), get_mode) =
  viewbox = setup_boxes(org_eng) ;
  rec aux(eng:engine) =
    gl = eng.context;
    (eng, scene) =
      f(is_selected, p) =
        match List.find((z_in_mem -> z_in_mem.id == p.id), eng.scene) with
        | { some=in_mem } -> { in_mem with position=p.cube; ~is_selected; color=p.color }
        | { none } -> Cube.create(gl, p, is_selected)
        end;
      scene : engine.scene =
        tmp = get_scene();
        others_scene = List.map(f(false, _), tmp.others.objs);
        selection_scene = Option.switch((the -> [ f(true, the) ]), List.empty, tmp.selection);
        List.append(selection_scene, others_scene);
      ({ eng with ~scene }, scene);
    do match get_mode() with
    | {pick=pos; ~cont} ->
      match which_box(viewbox, pos) with
        | {out} -> void
        | {_YX} as who | {_YZ} as who | {_ZX} as who | {_3D} as who ->
          //do Log.debug("Picking", "in box: '{who}' \t {viewbox}");
          this_viewbox = fetch_box(viewbox, who);
          (pMatrix, s) = drawScene_for_a_viewport(eng, who, this_viewbox, (0.0, 0.0, 15.0), (0.0, 1.0, 0.0), scene, {pick});
          mvMatrix = Stack.peek(s) ;
          do mat4.multiply(pMatrix, mvMatrix, mvMatrix);
          do mat4.inverse(mvMatrix, mvMatrix);
          g(pos) =
            x = (float_of_int(pos.x_px - this_viewbox.x) / float_of_int(this_viewbox.w)) * 2.0 - 1.0;
            y = (float_of_int(pos.y_px - this_viewbox.y) / float_of_int(this_viewbox.h)) * 2.0 - 1.0;
            vstart = vec4.from_public((x, y, 1.0, 1.0));
            vtmp = vec4.from_public((9.9, 9.9, 9.9, 9.9));
            do mat4.multiplyVec4(mvMatrix, vstart, vtmp);
            vpreres = vec4.to_public(vtmp);
            vres = (vpreres.f1 / vpreres.f4, vpreres.f2 / vpreres.f4, vpreres.f3 / vpreres.f4);
            do Log.debug("Converting coord", "vstart={ vec4.str(vstart) }, \t vres={ vres }");
            vres;
          pos_result = g(pos);
          possible_target =
            pickedColor =
              data = Webgl.Uint8Array.from_int_list(List.init((_->123), 4));
              do Webgl.readPixels(gl, pos.x_px, pos.y_px, 1, 1, Webgl.RGBA(gl), Webgl.UNSIGNED_BYTE(gl), Webgl.Uint8Array.to_ArrayBuffer(data));
              match Webgl.Uint8Array.to_int_list(data) with
              | [r, g, b, _] -> (r, g, b)
              | _ -> error("Picking failure")
              end ;
            do Log.debug("Picking", "Color is: { pickedColor }");
            f =
              (r, g, b) = pickedColor;
              (z -> (z.picking_color == (float_of_int(r) / 255., float_of_int(g) / 255., float_of_int(b) / 255.))) ;
            Option.map((u -> u.id), List.find(f, eng.scene));
          do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.none);
          cont({ mousedown; pos=this_viewbox.clear_near_far(pos_result); ~possible_target; coord_fixer=Option.none })
          end
    | {normal} ->
      do Webgl.clear(gl, Webgl.GLbitfield_OR(Webgl.COLOR_BUFFER_BIT(gl), Webgl.DEPTH_BUFFER_BIT(gl)));
      _ = drawScene_for_a_viewport(eng, {_YX}, viewbox._YX, (0.0, 0.0, 15.0), (0.0, 1.0, 0.0), scene, {normal});
      _ = drawScene_for_a_viewport(eng, {_YZ}, viewbox._YZ, (-15.0, 0.0, 0.0), (0.0, 1.0, 0.0), scene, {normal});
      _ = drawScene_for_a_viewport(eng, {_ZX}, viewbox._ZX, (0.0, -15.0, 0.0), (0.0, 0.0, 1.0), scene, {normal});
      _ = drawScene_for_a_viewport(eng, {_3D}, viewbox._3D, (10.0, 5.0, 15.0), (0.0, 1.0, 0.0), scene, {normal});
      void
    end ;
    do RequestAnimationFrame.request((_ -> aux(eng)), eng.selector);
    void
    ;
  aux(org_eng)
;

initGL(canvas_sel, width, height, get_scene, mouse_listener) : outcome =
  match WebGLUtils.setupWebGL_with_custom_failure(Dom.of_selection(canvas_sel)) with
  | { ok=context } ->
    mode = Mutable.make({normal});
    is_picking(m) = match m with | { pick=_; cont=_ } -> true | _ -> false end;
    _ =
      recompute_pos(rel_mouse_position_on_page) =
        m_pos = // we transform the pos to be relative to the upper leftcorner of the canvas
          c_pos = Dom.get_offset(canvas_sel);
          rel = rel_mouse_position_on_page;
          { x_px=max(rel.x_px - c_pos.x_px, 0); y_px=max(rel.y_px - c_pos.y_px, 0) };
        // now with gl the origin will be at the lower left corner
        gl_pos = { x_px=min(max(m_pos.x_px,0), width-1); y_px=min(max(height - 1 - m_pos.y_px, 0), height-1) };
        do Log.debug("P", "[({m_pos.x_px},{m_pos.y_px})] {gl_pos.x_px}, {gl_pos.y_px}");
        gl_pos;
      handler_mousedown(e) =
        gl_pos = recompute_pos(e.mouse_position_on_page);
        cont(e) =
          do mode.set({normal});
          mouse_listener(e);
        if not(is_picking(mode.get())) then mode.set({pick=gl_pos; ~cont}) else void;
      _ = Dom.bind(canvas_sel, { mousedown }, handler_mousedown);
      void;
    gl = context;
    eng : engine =
      start = @openrecord({ context=gl; canvas={ selector=canvas_sel; ~width; ~height }; scene=List.empty; selector=canvas_sel });
      start = { start with shaderProgram=initShaders(gl) };
      start = { start with framePickBuffer=initPickBuffer(start) } ;
      { start with static_buffers.repcoords=
        { x=initLineXBuffers(gl, {x}); y=initLineXBuffers(gl, {y}); z=initLineXBuffers(gl, {z}) } };
    //Clear screen and make everything light gray // disabled to show png grid
    //do Webgl.clearColor(gl, 0.875, 0.875, 0.875, 1.0);
    //we should do depth testing so that things drawn behind other
    //things should be hidden by the things in front of them).
    do Webgl.clearDepth(gl, 1.0);
    do Webgl.enable(gl, Webgl.DEPTH_TEST(gl));
    do Webgl.depthFunc(gl, Webgl.LEQUAL(gl));
    do drawScene_and_register(eng, get_scene, mode.get);
    { success }
  | { ~ko } -> { failure=ko }
  end ;

@private type my_custom_shaderProgram = {
  program: Webgl.WebGLProgram;
  vertexPositionAttribute: Webgl.GLint;
  vertexNormalAttribute: Webgl.GLint;
  pMatrixUniform: Webgl.WebGLUniformLocation;
  mvMatrixUniform: Webgl.WebGLUniformLocation;
  nMatrixUniform: Webgl.WebGLUniformLocation;
  ambientColorUniform: Webgl.WebGLUniformLocation;
  lightingDirectionUniform: Webgl.WebGLUniformLocation;
  useLightingUniform: Webgl.WebGLUniformLocation
};

@private type static_buffer = {
  positions: Webgl.WebGLBuffer;
  itemSize: int; numItems: int;
  normals: Webgl.WebGLBuffer
};

@private type engine.scene = list(object);

@private type engine = {
  context: Webgl.Context.private;
  canvas: { selector:dom; width: int; height: int };
  shaderProgram: my_custom_shaderProgram
  static_buffers: { repcoords: { x:static_buffer; y:static_buffer; z:static_buffer } };
  framePickBuffer: Webgl.WebGLFramebuffer;
  scene: engine.scene
  selector: dom
} ;

@client initPickBuffer(eng) =
  gl = eng.context;
  framePickBuffer = Webgl.createFramebuffer(gl);
  renderPickBuffer = Webgl.createRenderbuffer(gl);
  pickTexture = Webgl.createTexture(gl);
  do Webgl.bindTexture(gl, Webgl.TEXTURE_2D(gl), Option.some(pickTexture));
  tex = Webgl.Uint8Array.from_int_list([0, 0, 0]);
  do Webgl.texImage2D(gl, Webgl.TEXTURE_2D(gl), 0, Webgl.RGB(gl), eng.canvas.width, eng.canvas.height, 0, Webgl.RGB(gl), Webgl.UNSIGNED_BYTE(gl), Webgl.Uint8Array.to_ArrayBuffer(tex));
  do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.some(framePickBuffer));
  do Webgl.bindRenderbuffer(gl, Webgl.RENDERBUFFER(gl), Option.some(renderPickBuffer));
  do Webgl.renderbufferStorage(gl, Webgl.RENDERBUFFER(gl), Webgl.DEPTH_COMPONENT16(gl), eng.canvas.width, eng.canvas.height);
  do Webgl.bindRenderbuffer(gl, Webgl.RENDERBUFFER(gl), Option.none);

  do Webgl.framebufferTexture2D(gl, Webgl.FRAMEBUFFER(gl), Webgl.COLOR_ATTACHMENT0(gl), Webgl.TEXTURE_2D(gl), pickTexture, 0);
  do Webgl.framebufferRenderbuffer(gl, Webgl.FRAMEBUFFER(gl), Webgl.DEPTH_ATTACHMENT(gl), Webgl.RENDERBUFFER(gl), renderPickBuffer);
  do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.none);
  do Webgl.bindTexture(gl, Webgl.TEXTURE_2D(gl), Option.none);
  framePickBuffer
;

initShaders(gl) =
  f(e, str) =
    shader = Webgl.createShader(gl, e);
    do Webgl.shaderSource(gl, shader, str);
    do Webgl.compileShader(gl, shader);
    shader;
  fragmentShader = f(Webgl.FRAGMENT_SHADER(gl), CustomShaders.shader_fs);
  vertexShader = f(Webgl.VERTEX_SHADER(gl), CustomShaders.shader_vs);
  // TODO getShaderParameter
  shaderProgram = Webgl.createProgram(gl);
  do Webgl.attachShader(gl, shaderProgram, vertexShader);
  do Webgl.attachShader(gl, shaderProgram, fragmentShader);
  do Webgl.linkProgram(gl, shaderProgram);
  // TODO : getProgramParameter(shaderProgram, gl.LINK_STATUS)) {
  do Webgl.useProgram(gl, shaderProgram);
  shaderProgram =
    vertexPositionAttribute = Webgl.getAttribLocation(gl, shaderProgram, "aVertexPosition");
    vertexNormalAttribute = Webgl.getAttribLocation(gl, shaderProgram, "aVertexNormal");
    do Webgl.enableVertexAttribArray(gl, vertexPositionAttribute);
    do Webgl.enableVertexAttribArray(gl, vertexNormalAttribute);
    { program = shaderProgram;
      ~vertexPositionAttribute;
      ~vertexNormalAttribute;
      pMatrixUniform = Webgl.getUniformLocation(gl, shaderProgram, "uPMatrix");
      mvMatrixUniform = Webgl.getUniformLocation(gl, shaderProgram, "uMVMatrix");
      nMatrixUniform = Webgl.getUniformLocation(gl, shaderProgram, "uNMatrix");
      ambientColorUniform = Webgl.getUniformLocation(gl, shaderProgram, "uAmbientColor");
      lightingDirectionUniform = Webgl.getUniformLocation(gl, shaderProgram, "uLightingDirection");
      useLightingUniform = Webgl.getUniformLocation(gl, shaderProgram, "uUseLighting");
    };
  shaderProgram
;

initLineXBuffers(gl, orient) =
  (vertices, vertexNormals) = match orient with
    | {x} -> ([ 0.0, 0.0, 0.0, 5.0, 0.0, 0.0 ], [ 2.5, 0.0, 0.0,        2.5, -1.0, 0.0 ])
    | {y} -> ([ 0.0, 0.0, 0.0, 0.0, 5.0, 0.0 ], [ 0.0, 2.5, 0.0,        -1.0, 2.5, 0.0 ])
    | {z} -> ([ 0.0, 0.0, 0.0, 0.0, 0.0, 5.0 ], [ 0.0, 0.0, 2.5,        0.0, -1.0, 2.5 ])
    end ;
  vertexPositionBuffer = Webgl.createBuffer(gl);
  do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), vertexPositionBuffer);
  do Webgl.bufferData(gl, Webgl.ARRAY_BUFFER(gl),
    Webgl.Float32Array.to_ArrayBuffer(Webgl.Float32Array.from_float_list(vertices)),
    Webgl.STATIC_DRAW(gl));
  vertexNormalBuffer = Webgl.createBuffer(gl);
  do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), vertexNormalBuffer);
  do Webgl.bufferData(gl, Webgl.ARRAY_BUFFER(gl),
    Webgl.Float32Array.to_ArrayBuffer(Webgl.Float32Array.from_float_list(vertexNormals)),
    Webgl.STATIC_DRAW(gl));
  { positions=vertexPositionBuffer; itemSize=3; numItems=2; normals=vertexNormalBuffer }
;

setMatrixUniforms(gl, shaderProgram, pMatrix, mvMatrix) =
  a =
    b = mat4.to_list(pMatrix);
    c = Webgl.Float32Array.from_float_list(b);
    c;
  e =
    f = mat4.to_list(mvMatrix);
    g = Webgl.Float32Array.from_float_list(f);
    g;
  do Webgl.uniformMatrix4fv(gl, shaderProgram.pMatrixUniform, false, a);
  do Webgl.uniformMatrix4fv(gl, shaderProgram.mvMatrixUniform, false, e);
  normalMatrix = mat3.create();
  do mat4.toInverseMat3(mvMatrix, normalMatrix);
  do mat3.transpose(normalMatrix, normalMatrix);
  do Webgl.uniformMatrix3fv(gl, shaderProgram.nMatrixUniform, false, Webgl.Float32Array.from_float_list(mat3.to_list(normalMatrix)));
  void
;

setup_boxes(eng) =
  cnf_x(pos) = { pos with f1=0.0 }; cnf_y(pos) = { pos with f2=0.0 }; cnf_z(pos) = { pos with f3=0.0 };
  g(x:int, y:int, w:int, h:int, clear_near_far) =
    inbox(pos) = (pos.x_px >= x) && (pos.y_px >= y) && (pos.x_px < (w + x)) && (pos.y_px < (h + y));
    { ~x; ~y; ~w; ~h; ~inbox; ~clear_near_far } ;
  compute_left_right(x) = if ((mod(x, 2)) == 0) then
      a = (x / 2);
      ((a, a), 0)
    else
      b = (x / 2);
      ((b, b+1), 0);
  ((w_l, w_r), e_w) = compute_left_right(eng.canvas.width);
  ((h_u, h_d), e_h) = compute_left_right(eng.canvas.height);
  { _YX=g(0, h_d+e_h, w_l, h_u, cnf_z); _YZ=g(w_l+e_w, h_d+e_h, w_r, h_u, cnf_x);
    _ZX=g(0, 0, w_l, h_d, cnf_y);       _3D=g(w_l+e_w, 0, w_r, h_d, cnf_y) }
;

which_box(b, pos) =
  if b._YX.inbox(pos) then {_YX}
  else if b._YZ.inbox(pos) then {_YZ}
  else if b._ZX.inbox(pos) then {_ZX}
  else if b._3D.inbox(pos) then {_3D}
  else {out}
;

fetch_box(b, who) = match who with
  | {_YX} -> b._YX
  | {_YZ} -> b._YZ
  | {_ZX} -> b._ZX
  | {_3D} -> b._3D
  end ;

drawScene_for_a_viewport(eng, who, viewport, eye, up, scene, mode) =
  gl = eng.context; shaderProgram = eng.shaderProgram; repcoords = eng.static_buffers.repcoords;
  do Webgl.viewport(gl, viewport.x, viewport.y, viewport.w, viewport.h);
  pMatrix =
    tmp_pMatrix = mat4.create();
    tmp_x = Float.of_int(viewport.w / 40)
    tmp_y = Float.of_int(viewport.h / 40)
    match who with
    | {_YX} ->
      do mat4.ortho(-tmp_x, tmp_x, -tmp_y, tmp_y, -10., 10., tmp_pMatrix);
      tmp_pMatrix
    | {_YZ} ->
      do mat4.ortho(-tmp_x, tmp_x, -tmp_y, tmp_y, -10., 10., tmp_pMatrix);
      mat4.rotateY(tmp_pMatrix, (90. * Math.PI / 180.), tmp_pMatrix)
    | {_ZX} ->
      do mat4.ortho(-tmp_x, tmp_x, -tmp_y, tmp_y, -10., 10., tmp_pMatrix);
      mat4.rotateX(tmp_pMatrix, (90. * Math.PI / 180.), tmp_pMatrix)
    | {_3D} ->
      do mat4.perspective(45., float_of_int(eng.canvas.width) / float_of_int(eng.canvas.height), 0.1, 100.0, tmp_pMatrix);
      c = mat4.create() ;
      do mat4.lookAt(vec3.from_public(eye), vec3.from_public((0.0, 0.0, 0.0)), vec3.from_public(up), c);
      do mat4.multiply(tmp_pMatrix, c, tmp_pMatrix);
      tmp_pMatrix
    end ;
  mvMatrix =
    tmp_mvMatrix = mat4.create();
    do mat4.identity(tmp_mvMatrix);
    Stack.push(Stack.create(), tmp_mvMatrix);
  do setMatrixUniforms(gl, shaderProgram, pMatrix, Stack.peek(mvMatrix));
  draw_rep(r, g, b, rep) =
    do Webgl.uniform3f(gl, shaderProgram.ambientColorUniform, r, g, b);
    do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), rep.positions);
    do Webgl.vertexAttribPointer(gl, shaderProgram.vertexPositionAttribute, rep.itemSize, Webgl.FLOAT(gl), false, 0, 0);
    do Webgl.bindBuffer(gl, Webgl.ARRAY_BUFFER(gl), rep.normals);
    do Webgl.vertexAttribPointer(gl, shaderProgram.vertexNormalAttribute, rep.itemSize, Webgl.FLOAT(gl), false, 0, 0);
    do Webgl.drawArrays(gl, Webgl.LINES(gl), 0, rep.numItems);
    void ;

  _ =
    match mode with
    | {normal} ->
      do Webgl.uniform1i(gl, shaderProgram.useLightingUniform, 0); // 0 = false
      do draw_rep(1.0, 0.0, 0.0, repcoords.x);
      do draw_rep(0.0, 1.0, 0.0, repcoords.y);
      do draw_rep(0.0, 0.0, 1.0, repcoords.z);
      do match who with
        | {_3D} ->
          do Webgl.uniform1i(gl, shaderProgram.useLightingUniform, 1); // 1 = true
          Webgl.uniform3f(gl, shaderProgram.lightingDirectionUniform, 0.85, 0.8, 0.75)
        | _ -> void end;
      List.iter((object -> display(eng, pMatrix, mvMatrix, object, false)), scene)
    | {pick} ->
      do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.some(eng.framePickBuffer));
      do Webgl.clear(gl, Webgl.GLbitfield_OR(Webgl.COLOR_BUFFER_BIT(gl), Webgl.DEPTH_BUFFER_BIT(gl)));
      do Webgl.uniform1i(gl, shaderProgram.useLightingUniform, 0); // 0 = false;
      do List.iter((object -> display(eng, pMatrix, mvMatrix, object, true)), scene);
      void
    end ;

  (pMatrix, mvMatrix)
;

@private drawScene_and_register(org_eng, get_scene : (->Scene.Client.scene), get_mode) =
  viewbox = setup_boxes(org_eng) ;
  rec aux(eng:engine) =
    gl = eng.context;
    (eng, scene) =
      f(is_selected, p) =
        match List.find((z_in_mem -> z_in_mem.id == p.id), eng.scene) with
        | { some=in_mem } -> { in_mem with position=p.cube; ~is_selected; color=p.color }
        | { none } -> Cube.create(gl, p, is_selected)
        end;
      scene : engine.scene =
        tmp = get_scene();
        others_scene = List.map(f(false, _), tmp.others.objs);
        selection_scene = Option.switch((the -> [ f(true, the) ]), List.empty, tmp.selection);
        List.append(selection_scene, others_scene);
      ({ eng with ~scene }, scene);
    do match get_mode() with
    | {pick=pos; ~cont} ->
      match which_box(viewbox, pos) with
        | {out} -> void
        | {_YX} as who | {_YZ} as who | {_ZX} as who | {_3D} as who ->
          //do Log.debug("Picking", "in box: '{who}' \t {viewbox}");
          this_viewbox = fetch_box(viewbox, who);
          (pMatrix, s) = drawScene_for_a_viewport(eng, who, this_viewbox, (0.0, 0.0, 15.0), (0.0, 1.0, 0.0), scene, {pick});
          x = (float_of_int(pos.x_px - this_viewbox.x) / float_of_int(this_viewbox.w)) * 2.0 - 1.0;
          y = (float_of_int(pos.y_px - this_viewbox.y) / float_of_int(this_viewbox.h)) * 2.0 - 1.0;
          mvMatrix = Stack.peek(s) ;
          do mat4.multiply(pMatrix, mvMatrix, mvMatrix);
          do mat4.inverse(mvMatrix, mvMatrix);
          g(x, y) =
            vstart = vec4.from_public((x, y, 1.0, 1.0));
            vtmp = vec4.from_public((9.9, 9.9, 9.9, 9.9));
            do mat4.multiplyVec4(mvMatrix, vstart, vtmp);
            vpreres = vec4.to_public(vtmp);
            vres = (vpreres.f1 / vpreres.f4, vpreres.f2 / vpreres.f4, vpreres.f3 / vpreres.f4);
            do Log.debug("Converting coord", "vstart={ vec4.str(vstart) }, \t vres={ vres }");
            vres;
          v2 = g(x, y);
          possible_target =
            pickedColor =
              data = Webgl.Uint8Array.from_int_list(List.init((_->123), 4));
              do Webgl.readPixels(gl, pos.x_px, pos.y_px, 1, 1, Webgl.RGBA(gl), Webgl.UNSIGNED_BYTE(gl), Webgl.Uint8Array.to_ArrayBuffer(data));
              match Webgl.Uint8Array.to_int_list(data) with
              | [r, g, b, _] -> (r, g, b)
              | _ -> error("Picking failure")
              end ;
            do Log.debug("Picking", "Color is: { pickedColor }");
            f =
              (r, g, b) = pickedColor;
              (z -> (z.picking_color == (float_of_int(r) / 255., float_of_int(g) / 255., float_of_int(b) / 255.))) ;
            Option.map((u -> u.id), List.find(f, eng.scene));
          do Webgl.bindFramebuffer(gl, Webgl.FRAMEBUFFER(gl), Option.none);
          cont({ mousedown; pos=this_viewbox.clear_near_far(v2); ~possible_target; coord_fixer=Option.none })
          end
    | {normal} ->
      do Webgl.clear(gl, Webgl.GLbitfield_OR(Webgl.COLOR_BUFFER_BIT(gl), Webgl.DEPTH_BUFFER_BIT(gl)));
      _ = drawScene_for_a_viewport(eng, {_YX}, viewbox._YX, (0.0, 0.0, 15.0), (0.0, 1.0, 0.0), scene, {normal});
      _ = drawScene_for_a_viewport(eng, {_YZ}, viewbox._YZ, (-15.0, 0.0, 0.0), (0.0, 1.0, 0.0), scene, {normal});
      _ = drawScene_for_a_viewport(eng, {_ZX}, viewbox._ZX, (0.0, -15.0, 0.0), (0.0, 0.0, 1.0), scene, {normal});
      _ = drawScene_for_a_viewport(eng, {_3D}, viewbox._3D, (10.0, 5.0, 15.0), (0.0, 1.0, 0.0), scene, {normal});
      void
    end ;
    do RequestAnimationFrame.request((_ -> aux(eng)), eng.selector);
    void
    ;
  aux(org_eng)
;

initGL(canvas_sel, width, height, get_scene, mouse_listener) : outcome =
  match WebGLUtils.setupWebGL_with_custom_failure(Dom.of_selection(canvas_sel)) with
  | { ok=context } ->
    mode = Mutable.make({normal});
    is_picking(m) = match m with | { pick=_; cont=_ } -> true | _ -> false end;
    _ =
      recompute_pos(rel_mouse_position_on_page) =
        m_pos = // we transform the pos to be relative to the upper leftcorner of the canvas
          c_pos = Dom.get_offset(canvas_sel);
          rel = rel_mouse_position_on_page;
          { x_px=max(rel.x_px - c_pos.x_px, 0); y_px=max(rel.y_px - c_pos.y_px, 0) };
        // now with gl the origin will be at the lower left corner
        gl_pos = { x_px=min(max(m_pos.x_px,0), width-1); y_px=min(max(height - 1 - m_pos.y_px, 0), height-1) };
        do Log.debug("P", "[({m_pos.x_px},{m_pos.y_px})] {gl_pos.x_px}, {gl_pos.y_px}");
        gl_pos;
      handler_mousedown(e) =
        gl_pos = recompute_pos(e.mouse_position_on_page);
        cont(e) =
          do mode.set({normal});
          mouse_listener(e);
        if not(is_picking(mode.get())) then mode.set({pick=gl_pos; ~cont}) else void;
      _ = Dom.bind(canvas_sel, { mousedown }, handler_mousedown);
      void;
    gl = context;
    eng : engine =
      start = @openrecord({ context=gl; canvas={ selector=canvas_sel; ~width; ~height }; scene=List.empty; selector=canvas_sel });
      start = { start with shaderProgram=initShaders(gl) };
      start = { start with framePickBuffer=initPickBuffer(start) } ;
      { start with static_buffers.repcoords=
        { x=initLineXBuffers(gl, {x}); y=initLineXBuffers(gl, {y}); z=initLineXBuffers(gl, {z}) } };
    //Clear screen and make everything light gray // disabled to show png grid
    //do Webgl.clearColor(gl, 0.875, 0.875, 0.875, 1.0);
    //we should do depth testing so that things drawn behind other
    //things should be hidden by the things in front of them).
    do Webgl.clearDepth(gl, 1.0);
    do Webgl.enable(gl, Webgl.DEPTH_TEST(gl));
    do Webgl.depthFunc(gl, Webgl.LEQUAL(gl));
    do drawScene_and_register(eng, get_scene, mode.get);
    { success }
  | { ~ko } -> { failure=ko }
  end ;


fixed a warning wrt Opa v0.9.2

fixed a warning wrt Opa v0.9.2

type Modeler.Shared.modeler = {
  scene: Scene.scene;
  address: string;
  clients: list(channel(Central.Modelers.sync.message))
} ;

@server SHF : Fresh.next(int) = Fresh.server((i -> i : int));

@server `Modeler.Shared` = {{

  empty(server_id, address) : Modeler.Shared.modeler =
    { scene=Scene.empty(SHF, server_id); ~address; clients=List.empty };

  add_client(modsha, client) : Modeler.Shared.modeler =
    do Session.send(client, { load=modsha.scene });
    { modsha with clients=List.cons(client, modsha.clients) };

  apply_patch(modsha, patch) : Modeler.Shared.modeler =
    do Log.info("Modeler.Shared", "a patch as been apply for address '{modsha.address}'");
    do
      f(c) = Session.send(c, { write_patch; ~patch});
      List.iter(f, modsha.clients);
    { modsha with scene=Scene.apply_patch(modsha.scene, patch) };

}}

type Central.Modelers.state = { my_id: int; files: stringmap(Modeler.Shared.modeler) };
type Central.Modelers.message =
  { register; scene_url: string; sync_channel: channel(Central.Modelers.sync.message); client_id: int }
/ { apply_patch; patch: Scene.patch; address: string }
/ { with_address_list : list(string) -> void }
;

type Central.Modelers.sync.message =
  { load: Scene.scene }
/ { write_patch; patch: Scene.patch };

@server `Central.Modelers` = {{
  empty() : Central.Modelers.state = { my_id=SHF(); files=StringMap.empty };

  find_file(state, address) = StringMap.get(address, state.files);

  get_file(state, address) : Modeler.Shared.modeler = match find_file(state, address) with
    | {some=hit} -> hit
    | {none} ->
      scene = Scene.empty(SHF, state.my_id);
      scene = Scene.add_object(scene, Scene.cube(scene, (0.0, 0.0, -3.0)));
      scene = Scene.add_object(scene, Scene.cube(scene, (3.0, 0.0, 0.0)));
      scene = Scene.add_object(scene, Scene.cube(scene, (6.0, 0.0, 0.0)));
      { `Modeler.Shared`.empty(state.my_id, address) with ~scene }
    end;

  update_file(state, address, f) : Central.Modelers.state =
    modsha = get_file(state, address);
    { state with files=StringMap.add(address, f(modsha), state.files) };

  apply_patch(state, address, patch) : Central.Modelers.state =
    f(modsha) = `Modeler.Shared`.apply_patch(modsha, patch);
    update_file(state, address, f);

  get_address_list(state) =
    StringMap.To.key_list(state.files)
}}

@server central_modelers : channel(Central.Modelers.message) =
  on_message(state : Central.Modelers.state, message) = match message with
    | { register; ~scene_url; ~sync_channel; client_id=_ } ->
      do Log.info("CM", "register for url '{scene_url}'");
      state =
        up(modsha) = `Modeler.Shared`.add_client(modsha, sync_channel);
        `Central.Modelers`.update_file(state, scene_url, up);
      { set=state }
    | { apply_patch; ~patch; ~address } ->
      state = `Central.Modelers`.apply_patch(state, address, patch);
      { set=state }
    | { ~with_address_list } ->
      l = List.sort_by((_ -> Random.int(Limits.max_int)), `Central.Modelers`.get_address_list(state));
      _ = with_address_list(l)
      { unchanged }
    end;
  Session.make_dynamic(`Central.Modelers`.empty(), on_message);

type Modeler.Shared.modeler = {
  scene: Scene.scene;
  address: string;
  clients: list(channel(Central.Modelers.sync.message))
} ;

@server SHF : Fresh.next(int) = Fresh.server((i -> i : int));

@server `Modeler.Shared` = {{

  empty(server_id, address) : Modeler.Shared.modeler =
    { scene=Scene.empty(SHF, server_id); ~address; clients=List.empty };

  add_client(modsha, client) : Modeler.Shared.modeler =
    do Session.send(client, { load=modsha.scene });
    { modsha with clients=List.cons(client, modsha.clients) };

  apply_patch(modsha, patch) : Modeler.Shared.modeler =
    do Log.info("Modeler.Shared", "a patch as been apply for address '{modsha.address}'");
    do
      f(c) = Session.send(c, { write_patch; ~patch});
      List.iter(f, modsha.clients);
    { modsha with scene=Scene.apply_patch(modsha.scene, patch) };

}}

type Central.Modelers.state = { my_id: int; files: stringmap(Modeler.Shared.modeler) };
type Central.Modelers.message =
  { register; scene_url: string; sync_channel: channel(Central.Modelers.sync.message); client_id: int }
/ { apply_patch; patch: Scene.patch; address: string }
/ { with_address_list : list(string) -> void }
;

type Central.Modelers.sync.message =
  { load: Scene.scene }
/ { write_patch; patch: Scene.patch };

@server `Central.Modelers` = {{
  empty() : Central.Modelers.state = { my_id=SHF(); files=StringMap.empty };

  find_file(state, address) = StringMap.get(address, state.files);

  get_file(state, address) : Modeler.Shared.modeler = match find_file(state, address) with
    | {some=hit} -> hit
    | {none} ->
      scene = Scene.empty(SHF, state.my_id);
      scene = Scene.add_object(scene, Scene.cube(scene, (0.0, 0.0, -3.0)));
      scene = Scene.add_object(scene, Scene.cube(scene, (3.0, 0.0, 0.0)));
      scene = Scene.add_object(scene, Scene.cube(scene, (6.0, 0.0, 0.0)));
      { `Modeler.Shared`.empty(state.my_id, address) with ~scene }
    end;

  update_file(state, address, f) : Central.Modelers.state =
    modsha = get_file(state, address);
    { state with files=StringMap.add(address, f(modsha), state.files) };

  apply_patch(state, address, patch) : Central.Modelers.state =
    f(modsha) = `Modeler.Shared`.apply_patch(modsha, patch);
    update_file(state, address, f);

  get_address_list(state) =
    StringMap.To.key_list(state.files)
}}

@server central_modelers : channel(Central.Modelers.message) =
  on_message(state : Central.Modelers.state, message) = match message with
    | { register; ~scene_url; ~sync_channel; client_id=_ } ->
      do Log.info("CM", "register for url '{scene_url}'");
      state =
        up(modsha) = `Modeler.Shared`.add_client(modsha, sync_channel);
        `Central.Modelers`.update_file(state, scene_url, up);
      { set=state }
    | { apply_patch; ~patch; ~address } ->
      state = `Central.Modelers`.apply_patch(state, address, patch);
      { set=state }
    | { ~with_address_list } ->
      l = List.sort_by((_ -> Random.int(max_int)), `Central.Modelers`.get_address_list(state));
      _ = with_address_list(l)
      { unchanged }
    end;
  Session.make_dynamic(`Central.Modelers`.empty(), on_message);


added date to messages

added date to messages

/*  A simple, one-room, scalable real-time web chat

    Copyright (C) 2010-2011  MLstate

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as
    published by the Free Software Foundation, either version 3 of the
    License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * A simple, one-room, scalable real-time web chat.
 *
 * @author David Rajchenbach-Teller, David@opalang.org
 */

import stdlib.date

/**
 * {1 Network infrastructure}
 */

/**
 * The type of messages sent by a client to the chatroom
 */
type message = {author: string /**The name of the author (arbitrary string)*/
               ; text: string  /**Content entered by the user*/
               ; date: Date.date
               }

/**
 * The chatroom.
 */
room = Network.cloud("room"): Network.network(message)

/**
 * {1 User interface}
 */

/**
 * Update the user interface in reaction to reception of a message.
 *
 * This function is meant to be registered with [room] as a callback.
 * Its sole role is to display the new message in [#conversation].
 *
 * @param x The message received from the chatroom
 */
user_update(x: message) =
  line =

            {Date.to_string_time_only(x.date)}
            {x.author}:
            {x.text}

  do Dom.transform([#conversation +<- line ])
  Dom.scroll_to_bottom(#conversation)

/**
 * Broadcast text to the [room].
 *
 * Read the contents of [#entry], clear these contents and send the message to [room].
 *
 * @param author The name of the author. Will be included in the message broadcasted.
 */
broadcast(author) =
   do Network.broadcast({~author text=Dom.get_value(#entry) date=Date.now()}, room)
   Dom.clear_value(#entry)

/**
 * Build the user interface for a client.
 *
 * Pick a random author name which will be used throughout the chat.
 *
 * @return The user interface, ready to be sent by the server to the client on connection.
 */
start() =
   author = Random.string(8)

 Network.add_callback(user_update, room)}>

   <input id=#entry  onnewline={_ -> broadcast(author)}/>

 broadcast(author)}>Send!

/**
 * {1 Application}
 */

/**
 * Main entry point.
 *
 * Construct an application called "Chat" (users will see the name in the title bar),
 * embedding statically the contents of directory "resources", using the global stylesheet
 * "resources/css.css" and the user interface defined in [start].
 */
server = Server.one_page_bundle("Chat",
       [@static_resource_directory("resources")],
       ["resources/css.css"], start)

/*  A simple, one-room, scalable real-time web chat

    Copyright (C) 2010-2011  MLstate

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as
    published by the Free Software Foundation, either version 3 of the
    License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * A simple, one-room, scalable real-time web chat.
 *
 * @author David Rajchenbach-Teller, David@opalang.org
 */

/**
 * {1 Network infrastructure}
 */

/**
 * The type of messages sent by a client to the chatroom
 */
type message = {author: string /**The name of the author (arbitrary string)*/
               ; text: string  /**Content entered by the user*/}

/**
 * The chatroom.
 */
room = Network.cloud("room"): Network.network(message)

/**
 * {1 User interface}
 */

/**
 * Update the user interface in reaction to reception of a message.
 *
 * This function is meant to be registered with [room] as a callback.
 * Its sole role is to display the new message in [#conversation].
 *
 * @param x The message received from the chatroom
 */
user_update(x: message) =
  line =

{x.author}:

{x.text}

  do Dom.transform([#conversation +<- line ])
  Dom.scroll_to_bottom(#conversation)

/**
 * Broadcast text to the [room].
 *
 * Read the contents of [#entry], clear these contents and send the message to [room].
 *
 * @param author The name of the author. Will be included in the message broadcasted.
 */
broadcast(author) =
   do Network.broadcast({~author text=Dom.get_value(#entry)}, room)
   Dom.clear_value(#entry)

/**
 * Build the user interface for a client.
 *
 * Pick a random author name which will be used throughout the chat.
 *
 * @return The user interface, ready to be sent by the server to the client on connection.
 */
start() =
   author = Random.string(8)

 Network.add_callback(user_update, room)}>

   <input id=#entry  onnewline={_ -> broadcast(author)}/>

 broadcast(author)}>Send!

/**
 * {1 Application}
 */

/**
 * Main entry point.
 *
 * Construct an application called "Chat" (users will see the name in the title bar),
 * embedding statically the contents of directory "resources", using the global stylesheet
 * "resources/css.css" and the user interface defined in [start].
 */
server = Server.one_page_bundle("Chat",
       [@static_resource_directory("resources")],
       ["resources/css.css"], start)