text: /******************************************************************************
   * The MIT License (MIT)
   *
   * Copyright (c) 2015-2019 Baldur Karlsson
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   ******************************************************************************/
  
  #include "gl_test.h"
  
  RD_TEST(GL_Per_Type_Tex_Units, OpenGLGraphicsTest)
  {
    static constexpr const char *Description =
        "GL lets each type (2D, 3D, Cube) have a different binding to the same texture unit. This "
        "test uses that in various ways that might cause problems if tracking doesn't accurately "
        "account for that.";
  
    std::string common = R"EOSHADER(
  
  #version 420 core
  
  #define v2f v2f_block \
  {                     \
  	vec4 pos;           \
  	vec4 col;           \
  	vec4 uv;            \
  }
  
  )EOSHADER";
  
    std::string vertex = R"EOSHADER(
  
  layout(location = 0) in vec3 Position;
  layout(location = 1) in vec4 Color;
  layout(location = 2) in vec2 UV;
  
  out v2f vertOut;
  
  void main()
  {
  	vertOut.pos = vec4(Position.xyz, 1);
  	gl_Position = vertOut.pos;
  	vertOut.col = Color;
  	vertOut.uv = vec4(UV.xy, 0, 1);
  }
  
  )EOSHADER";
  
    std::string pixel = R"EOSHADER(
  
  in v2f vertIn;
  
  layout(location = 0, index = 0) out vec4 Color;
  
  layout(binding = 2) uniform sampler2D tex2;
  layout(binding = 3) uniform sampler3D tex3;
  
  void main()
  {
  	Color = texture(tex2, vertIn.uv.xy)*vec4(1.0f, 0.1f, 0.1f, 0.1f) +
            texture(tex3, vertIn.uv.xyz)*vec4(0.1f, 1.0f, 0.1f, 0.1f);
  }
  
  )EOSHADER";
  
    int main()
    {
      // initialise, create window, create context, etc
      if(!Init())
        return 3;
  
      GLuint vao = MakeVAO();
      glBindVertexArray(vao);
  
      GLuint vb = MakeBuffer();
      glBindBuffer(GL_ARRAY_BUFFER, vb);
      glBufferStorage(GL_ARRAY_BUFFER, sizeof(DefaultTri), DefaultTri, 0);
  
      glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(DefaultA2V), (void *)(0));
      glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, sizeof(DefaultA2V), (void *)(sizeof(Vec3f)));
      glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(DefaultA2V),
                            (void *)(sizeof(Vec3f) + sizeof(Vec4f)));
  
      glEnableVertexAttribArray(0);
      glEnableVertexAttribArray(1);
      glEnableVertexAttribArray(2);
  
      GLuint tex2d = MakeTexture();
      GLuint tex3d = MakeTexture();
  
      uint32_t green[4 * 4 * 4], red[8 * 8];
      for(int i = 0; i < 4 * 4 * 4; i++)
        green[i] = 0xff00ff00;
      for(int i = 0; i < 8 * 8; i++)
        red[i] = 0xff0000ff;
  
      // be explicit, all this happens on slot 0
      glActiveTexture(GL_TEXTURE0);
  
      // bind tex3d to the 3D target, then clear the 3D target
      glBindTexture(GL_TEXTURE_3D, tex3d);
      glBindTexture(GL_TEXTURE_2D, 0);
  
      // allocate storage and upload on 3D - even though 2D was the last bound target
      glTexStorage3D(GL_TEXTURE_3D, 1, GL_RGBA8, 4, 4, 4);
      glTexSubImage3D(GL_TEXTURE_3D, 0, 0, 0, 0, 4, 4, 4, GL_RGBA, GL_UNSIGNED_BYTE, green);
  
      // now do the same in reverse
      glBindTexture(GL_TEXTURE_2D, tex2d);
      glBindTexture(GL_TEXTURE_3D, 0);
  
      glTexStorage2D(GL_TEXTURE_2D, 1, GL_RGBA8, 8, 8);
      glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 8, 8, GL_RGBA, GL_UNSIGNED_BYTE, red);
  
      // unbind both
      glBindTexture(GL_TEXTURE_2D, 0);
      glBindTexture(GL_TEXTURE_3D, 0);
  
      glObjectLabel(GL_TEXTURE, tex2d, -1, "Red 2D");
      glObjectLabel(GL_TEXTURE, tex3d, -1, "Green 3D");
  
      GLuint program = MakeProgram(common + vertex, common + pixel);
  
      while(Running())
      {
        float col[] = {0.4f, 0.5f, 0.6f, 1.0f};
        glClearBufferfv(GL_COLOR, 0, col);
  
        glBindVertexArray(vao);
  
        glUseProgram(program);
  
        // bind both textures to both slots, only the 'right' one will be used by GL. To be extra
        // clear, bind the intended texture first, then 'overwrite' (which doesn't overwrite) with the
        // wrong one.
        glActiveTexture(GL_TEXTURE2);
        glBindTexture(GL_TEXTURE_2D, tex2d);
        glBindTexture(GL_TEXTURE_3D, tex3d);
  
        glActiveTexture(GL_TEXTURE3);
        glBindTexture(GL_TEXTURE_3D, tex3d);
        glBindTexture(GL_TEXTURE_2D, tex2d);
  
        glViewport(0, 0, GLsizei(screenWidth), GLsizei(screenHeight));
  
        glDrawArrays(GL_TRIANGLES, 0, 3);
  
        Present();
      }
  
      return 0;
    }
  };
  
  REGISTER_TEST();
  