text: /**************************************************************************
   *
   * Copyright 2008 VMware, Inc.
   * All Rights Reserved.
   *
   **************************************************************************/
  
  
  /**
   * Implementation of glDrawTex() for GL_OES_draw_tex
   */
  
  
  
  
  #include "main/image.h"
  #include "main/macros.h"
  #include "main/teximage.h"
  #include "main/framebuffer.h"
  #include "program/program.h"
  #include "program/prog_print.h"
  
  #include "st_context.h"
  #include "st_atom.h"
  #include "st_cb_bitmap.h"
  #include "st_cb_drawtex.h"
  #include "st_nir.h"
  #include "st_util.h"
  
  #include "pipe/p_context.h"
  #include "pipe/p_defines.h"
  #include "util/u_inlines.h"
  #include "pipe/p_shader_tokens.h"
  #include "util/u_draw_quad.h"
  #include "util/u_simple_shaders.h"
  #include "util/u_upload_mgr.h"
  
  #include "cso_cache/cso_context.h"
  
  
  struct cached_shader
  {
     void *handle;
  
     uint num_attribs;
     uint semantic_names[2 + MAX_TEXTURE_UNITS];
     uint semantic_indexes[2 + MAX_TEXTURE_UNITS];
  };
  
  #define MAX_SHADERS (2 * MAX_TEXTURE_UNITS)
  
  /**
   * Simple linear list cache.
   * Most of the time there'll only be one cached shader.
   * XXX This should be per-st_context state.
   */
  static struct cached_shader CachedShaders[MAX_SHADERS];
  static GLuint NumCachedShaders = 0;
  
  static gl_vert_attrib
  semantic_to_vert_attrib(unsigned semantic)
  {
     switch (semantic) {
     case TGSI_SEMANTIC_POSITION:
        return VERT_ATTRIB_POS;
     case TGSI_SEMANTIC_COLOR:
        return VERT_ATTRIB_COLOR0;
     case TGSI_SEMANTIC_GENERIC:
     case TGSI_SEMANTIC_TEXCOORD:
        return VERT_ATTRIB_GENERIC0;
     default:
        unreachable("unhandled semantic");
     }
  }
  
  static gl_varying_slot
  semantic_to_varying_slot(unsigned semantic)
  {
     switch (semantic) {
     case TGSI_SEMANTIC_POSITION:
        return VARYING_SLOT_POS;
     case TGSI_SEMANTIC_COLOR:
        return VARYING_SLOT_COL0;
     case TGSI_SEMANTIC_GENERIC:
     case TGSI_SEMANTIC_TEXCOORD:
        return VARYING_SLOT_TEX0;
     default:
        unreachable("unhandled semantic");
     }
  }
  
  static void *
  lookup_shader(struct st_context *st,
                uint num_attribs,
                const enum tgsi_semantic *semantic_names,
                const uint *semantic_indexes)
  {
     struct pipe_context *pipe = st->pipe;
     struct pipe_screen *screen = st->screen;
     GLuint i, j;
  
     /* look for existing shader with same attributes */
     for (i = 0; i < NumCachedShaders; i++) {
        if (CachedShaders[i].num_attribs == num_attribs) {
           GLboolean match = GL_TRUE;
           for (j = 0; j < num_attribs; j++) {
              if (semantic_names[j] != CachedShaders[i].semantic_names[j] ||
                  semantic_indexes[j] != CachedShaders[i].semantic_indexes[j]) {
                 match = GL_FALSE;
                 break;
              }
           }
           if (match)
              return CachedShaders[i].handle;
        }
     }
  
     /* not found - create new one now */
     if (NumCachedShaders >= MAX_SHADERS) {
        return NULL;
     }
  
     CachedShaders[i].num_attribs = num_attribs;
     for (j = 0; j < num_attribs; j++) {
        CachedShaders[i].semantic_names[j] = semantic_names[j];
        CachedShaders[i].semantic_indexes[j] = semantic_indexes[j];
     }
  
     enum pipe_shader_ir preferred_ir =
        screen->get_shader_param(screen, PIPE_SHADER_VERTEX,
                                 PIPE_SHADER_CAP_PREFERRED_IR);
  
     if (preferred_ir == PIPE_SHADER_IR_NIR) {
        unsigned inputs[2 + MAX_TEXTURE_UNITS];
        unsigned outputs[2 + MAX_TEXTURE_UNITS];
  
        for (int j = 0; j < num_attribs; j++) {
           inputs[j] = semantic_to_vert_attrib(semantic_names[j]);
           outputs[j] = semantic_to_varying_slot(semantic_names[j]);
        }
  
        CachedShaders[i].handle =
           st_nir_make_passthrough_shader(st, "st/drawtex VS",
                                          MESA_SHADER_VERTEX,
                                          num_attribs, inputs,
                                          outputs, NULL, 0);
     } else {
        CachedShaders[i].handle =
           util_make_vertex_passthrough_shader(pipe,
                                               num_attribs,
                                               semantic_names,
                                               semantic_indexes, FALSE);
     }
  
     NumCachedShaders++;
  
     return CachedShaders[i].handle;
  }
  
  
  void
  st_DrawTex(struct gl_context *ctx, GLfloat x, GLfloat y, GLfloat z,
             GLfloat width, GLfloat height)
  {
     struct st_context *st = ctx->st;
     struct pipe_context *pipe = st->pipe;
     struct cso_context *cso = st->cso_context;
     struct pipe_resource *vbuffer = NULL;
     GLuint i, numTexCoords, numAttribs;
     GLboolean emitColor;
     enum tgsi_semantic semantic_names[2 + MAX_TEXTURE_UNITS];
     uint semantic_indexes[2 + MAX_TEXTURE_UNITS];
     struct cso_velems_state velems;
     unsigned offset;
  
     st_flush_bitmap_cache(st);
     st_invalidate_readpix_cache(st);
  
     st_validate_state(st, ST_PIPELINE_META);
  
     /* determine if we need vertex color */
     if (ctx->FragmentProgram._Current->info.inputs_read & VARYING_BIT_COL0)
        emitColor = GL_TRUE;
     else
        emitColor = GL_FALSE;
  
     /* determine how many enabled sets of texcoords */
     numTexCoords = 0;
     for (i = 0; i < ctx->Const.MaxTextureUnits; i++) {
        if (ctx->Texture.Unit[i]._Current &&
            ctx->Texture.Unit[i]._Current->Target == GL_TEXTURE_2D) {
           numTexCoords++;
        }
     }
  
     /* total number of attributes per vertex */
     numAttribs = 1 + emitColor + numTexCoords;
  
     /* load vertex buffer */
     {
  #define SET_ATTRIB(VERT, ATTR, X, Y, Z, W)                              \
        do {                                                              \
           GLuint k = (((VERT) * numAttribs + (ATTR)) * 4);               \
           assert(k < 4 * 4 * numAttribs);                                \
           vbuf[k + 0] = X;                                               \
           vbuf[k + 1] = Y;                                               \
           vbuf[k + 2] = Z;                                               \
           vbuf[k + 3] = W;                                               \
        } while (0)
  
        const GLfloat x0 = x, y0 = y, x1 = x + width, y1 = y + height;
        GLfloat *vbuf = NULL;
        GLuint tex_attr;
  
        u_upload_alloc(pipe->stream_uploader, 0,
                       numAttribs * 4 * 4 * sizeof(GLfloat), 4,
                       &offset, &vbuffer, (void **) &vbuf);
        if (!vbuffer) {
           return;
        }
  
        z = SATURATE(z);
  
        /* positions (in clip coords) */
        {
           const struct gl_framebuffer *fb = ctx->DrawBuffer;
           const GLfloat fb_width = (GLfloat)_mesa_geometric_width(fb);
           const GLfloat fb_height = (GLfloat)_mesa_geometric_height(fb);
  
           const GLfloat clip_x0 = (GLfloat)(x0 / fb_width * 2.0 - 1.0);
           const GLfloat clip_y0 = (GLfloat)(y0 / fb_height * 2.0 - 1.0);
           const GLfloat clip_x1 = (GLfloat)(x1 / fb_width * 2.0 - 1.0);
           const GLfloat clip_y1 = (GLfloat)(y1 / fb_height * 2.0 - 1.0);
  
           SET_ATTRIB(0, 0, clip_x0, clip_y0, z, 1.0f);   /* lower left */
           SET_ATTRIB(1, 0, clip_x1, clip_y0, z, 1.0f);   /* lower right */
           SET_ATTRIB(2, 0, clip_x1, clip_y1, z, 1.0f);   /* upper right */
           SET_ATTRIB(3, 0, clip_x0, clip_y1, z, 1.0f);   /* upper left */
  
           semantic_names[0] = TGSI_SEMANTIC_POSITION;
           semantic_indexes[0] = 0;
        }
  
        /* colors */
        if (emitColor) {
           const GLfloat *c = ctx->Current.Attrib[VERT_ATTRIB_COLOR0];
           SET_ATTRIB(0, 1, c[0], c[1], c[2], c[3]);
           SET_ATTRIB(1, 1, c[0], c[1], c[2], c[3]);
           SET_ATTRIB(2, 1, c[0], c[1], c[2], c[3]);
           SET_ATTRIB(3, 1, c[0], c[1], c[2], c[3]);
           semantic_names[1] = TGSI_SEMANTIC_COLOR;
           semantic_indexes[1] = 0;
           tex_attr = 2;
        }
        else {
           tex_attr = 1;
        }
  
        /* texcoords */
        for (i = 0; i < ctx->Const.MaxTextureUnits; i++) {
           if (ctx->Texture.Unit[i]._Current &&
               ctx->Texture.Unit[i]._Current->Target == GL_TEXTURE_2D) {
              struct gl_texture_object *obj = ctx->Texture.Unit[i]._Current;
              const struct gl_texture_image *img = _mesa_base_tex_image(obj);
              const GLfloat wt = (GLfloat) img->Width;
              const GLfloat ht = (GLfloat) img->Height;
              const GLfloat s0 = obj->CropRect[0] / wt;
              const GLfloat t0 = obj->CropRect[1] / ht;
              const GLfloat s1 = (obj->CropRect[0] + obj->CropRect[2]) / wt;
              const GLfloat t1 = (obj->CropRect[1] + obj->CropRect[3]) / ht;
  
              /*printf("crop texcoords: %g, %g .. %g, %g\n", s0, t0, s1, t1);*/
              SET_ATTRIB(0, tex_attr, s0, t0, 0.0f, 1.0f);  /* lower left */
              SET_ATTRIB(1, tex_attr, s1, t0, 0.0f, 1.0f);  /* lower right */
              SET_ATTRIB(2, tex_attr, s1, t1, 0.0f, 1.0f);  /* upper right */
              SET_ATTRIB(3, tex_attr, s0, t1, 0.0f, 1.0f);  /* upper left */
  
              semantic_names[tex_attr] = st->needs_texcoord_semantic ?
                 TGSI_SEMANTIC_TEXCOORD : TGSI_SEMANTIC_GENERIC;
              /* XXX: should this use semantic index i instead of 0 ? */
              semantic_indexes[tex_attr] = 0;
  
              tex_attr++;
           }
        }
  
        u_upload_unmap(pipe->stream_uploader);
  
  #undef SET_ATTRIB
     }
  
     cso_save_state(cso, (CSO_BIT_VIEWPORT |
                          CSO_BIT_STREAM_OUTPUTS |
                          CSO_BIT_VERTEX_SHADER |
                          CSO_BIT_TESSCTRL_SHADER |
                          CSO_BIT_TESSEVAL_SHADER |
                          CSO_BIT_GEOMETRY_SHADER |
                          CSO_BIT_VERTEX_ELEMENTS));
  
     {
        void *vs = lookup_shader(st, numAttribs,
                                 semantic_names, semantic_indexes);
        cso_set_vertex_shader_handle(cso, vs);
     }
     cso_set_tessctrl_shader_handle(cso, NULL);
     cso_set_tesseval_shader_handle(cso, NULL);
     cso_set_geometry_shader_handle(cso, NULL);
  
     for (i = 0; i < numAttribs; i++) {
        velems.velems[i].src_offset = i * 4 * sizeof(float);
        velems.velems[i].instance_divisor = 0;
        velems.velems[i].vertex_buffer_index = 0;
        velems.velems[i].src_format = PIPE_FORMAT_R32G32B32A32_FLOAT;
        velems.velems[i].dual_slot = false;
     }
     velems.count = numAttribs;
  
     cso_set_vertex_elements(cso, &velems);
     cso_set_stream_outputs(cso, 0, NULL, NULL);
  
     /* viewport state: viewport matching window dims */
     {
        const struct gl_framebuffer *fb = ctx->DrawBuffer;
        const GLboolean invert = (_mesa_fb_orientation(fb) == Y_0_TOP);
        const GLfloat width = (GLfloat)_mesa_geometric_width(fb);
        const GLfloat height = (GLfloat)_mesa_geometric_height(fb);
        struct pipe_viewport_state vp;
        vp.scale[0] =  0.5f * width;
        vp.scale[1] = height * (invert ? -0.5f : 0.5f);
        vp.scale[2] = 1.0f;
        vp.translate[0] = 0.5f * width;
        vp.translate[1] = 0.5f * height;
        vp.translate[2] = 0.0f;
        vp.swizzle_x = PIPE_VIEWPORT_SWIZZLE_POSITIVE_X;
        vp.swizzle_y = PIPE_VIEWPORT_SWIZZLE_POSITIVE_Y;
        vp.swizzle_z = PIPE_VIEWPORT_SWIZZLE_POSITIVE_Z;
        vp.swizzle_w = PIPE_VIEWPORT_SWIZZLE_POSITIVE_W;
        cso_set_viewport(cso, &vp);
     }
  
     util_draw_vertex_buffer(pipe, cso, vbuffer, 0,
                             offset,  /* offset */
                             PIPE_PRIM_TRIANGLE_FAN,
                             4,  /* verts */
                             numAttribs); /* attribs/vert */
     st->last_num_vbuffers = MAX2(st->last_num_vbuffers, 1);
  
     pipe_resource_reference(&vbuffer, NULL);
  
     /* restore state */
     cso_restore_state(cso, 0);
     ctx->Array.NewVertexElements = true;
     st->dirty |= ST_NEW_VERTEX_ARRAYS;
  }
  
  /**
   * Free any cached shaders
   */
  void
  st_destroy_drawtex(struct st_context *st)
  {
     GLuint i;
     for (i = 0; i < NumCachedShaders; i++) {
        st->pipe->delete_vs_state(st->pipe, CachedShaders[i].handle);
     }
     NumCachedShaders = 0;
  }
  