kc3-lang/angle/samples/simple_instancing/SimpleInstancing.cpp

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• Hash : 9d737966
  Author :
  Date : 2019-08-14T12:25:12
  

  Standardize copyright notices to project style
  
  For all "ANGLE Project" copyrights, standardize to the format specified
  by the style guide. Changes:
  - "Copyright (c)" and "Copyright(c)" changed to just "Copyright".
  - Removed the second half of date ranges ("Y1Y1-Y2Y2"->"Y1Y1").
  - Fixed a small number of files that had no copyright date using the
    initial commit year from the version control history.
  - Fixed one instance of copyright being "The ANGLE Project" rather than
    "The ANGLE Project Authors"
  
  These changes are applied both to the copyright of source file, and
  where applicable to copyright statements that are generated by
  templates.
  
  BUG=angleproject:3811
  
  Change-Id: I973dd65e4ef9deeba232d5be74c768256a0eb2e5
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1754397
  Commit-Queue: Jamie Madill <jmadill@chromium.org>
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  

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• samples/simple_instancing/SimpleInstancing.cpp

• //
  // Copyright 2014 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  
  //            Based on Simple_Texture2D.c from
  // Book:      OpenGL(R) ES 2.0 Programming Guide
  // Authors:   Aaftab Munshi, Dan Ginsburg, Dave Shreiner
  // ISBN-10:   0321502795
  // ISBN-13:   9780321502797
  // Publisher: Addison-Wesley Professional
  // URLs:      http://safari.informit.com/9780321563835
  //            http://www.opengles-book.com
  
  #include "SampleApplication.h"
  
  #include "common/vector_utils.h"
  #include "texture_utils.h"
  #include "util/shader_utils.h"
  
  #include <cstring>
  #include <iostream>
  #include <vector>
  
  using namespace angle;
  
  class SimpleInstancingSample : public SampleApplication
  {
    public:
      SimpleInstancingSample(int argc, char **argv)
          : SampleApplication("SimpleInstancing", argc, argv)
      {}
  
      bool initialize() override
      {
          // init instancing functions
          char *extensionString = (char *)glGetString(GL_EXTENSIONS);
          if (strstr(extensionString, "GL_ANGLE_instanced_arrays"))
          {
              mVertexAttribDivisorANGLE =
                  (PFNGLVERTEXATTRIBDIVISORANGLEPROC)eglGetProcAddress("glVertexAttribDivisorANGLE");
              mDrawArraysInstancedANGLE =
                  (PFNGLDRAWARRAYSINSTANCEDANGLEPROC)eglGetProcAddress("glDrawArraysInstancedANGLE");
              mDrawElementsInstancedANGLE = (PFNGLDRAWELEMENTSINSTANCEDANGLEPROC)eglGetProcAddress(
                  "glDrawElementsInstancedANGLE");
          }
  
          if (!mVertexAttribDivisorANGLE || !mDrawArraysInstancedANGLE ||
              !mDrawElementsInstancedANGLE)
          {
              std::cerr << "Unable to load GL_ANGLE_instanced_arrays entry points.";
              return false;
          }
  
          constexpr char kVS[] = R"(attribute vec3 a_position;
  attribute vec2 a_texCoord;
  attribute vec3 a_instancePos;
  varying vec2 v_texCoord;
  void main()
  {
      gl_Position = vec4(a_position.xyz + a_instancePos.xyz, 1.0);
      v_texCoord = a_texCoord;
  })";
  
          constexpr char kFS[] = R"(precision mediump float;
  varying vec2 v_texCoord;
  uniform sampler2D s_texture;
  void main()
  {
      gl_FragColor = texture2D(s_texture, v_texCoord);
  })";
  
          mProgram = CompileProgram(kVS, kFS);
          if (!mProgram)
          {
              return false;
          }
  
          // Get the attribute locations
          mPositionLoc    = glGetAttribLocation(mProgram, "a_position");
          mTexCoordLoc    = glGetAttribLocation(mProgram, "a_texCoord");
          mInstancePosLoc = glGetAttribLocation(mProgram, "a_instancePos");
  
          // Get the sampler location
          mSamplerLoc = glGetUniformLocation(mProgram, "s_texture");
  
          // Load the texture
          mTextureID = CreateSimpleTexture2D();
  
          // Initialize the vertex and index vectors
          const GLfloat quadRadius = 0.01f;
  
          mVertices.push_back(Vector3(-quadRadius, quadRadius, 0.0f));
          mVertices.push_back(Vector3(-quadRadius, -quadRadius, 0.0f));
          mVertices.push_back(Vector3(quadRadius, -quadRadius, 0.0f));
          mVertices.push_back(Vector3(quadRadius, quadRadius, 0.0f));
  
          mTexcoords.push_back(Vector2(0.0f, 0.0f));
          mTexcoords.push_back(Vector2(0.0f, 1.0f));
          mTexcoords.push_back(Vector2(1.0f, 1.0f));
          mTexcoords.push_back(Vector2(1.0f, 0.0f));
  
          mIndices.push_back(0);
          mIndices.push_back(1);
          mIndices.push_back(2);
          mIndices.push_back(0);
          mIndices.push_back(2);
          mIndices.push_back(3);
  
          // Tile thousands of quad instances
          for (float y = -1.0f + quadRadius; y < 1.0f - quadRadius; y += quadRadius * 3)
          {
              for (float x = -1.0f + quadRadius; x < 1.0f - quadRadius; x += quadRadius * 3)
              {
                  mInstances.push_back(Vector3(x, y, 0.0f));
              }
          }
  
          glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
  
          return true;
      }
  
      void destroy() override
      {
          glDeleteProgram(mProgram);
          glDeleteTextures(1, &mTextureID);
      }
  
      void draw() override
      {
          // Set the viewport
          glViewport(0, 0, getWindow()->getWidth(), getWindow()->getHeight());
  
          // Clear the color buffer
          glClear(GL_COLOR_BUFFER_BIT);
  
          // Use the program object
          glUseProgram(mProgram);
  
          // Load the vertex position
          glVertexAttribPointer(mPositionLoc, 3, GL_FLOAT, GL_FALSE, 0, mVertices.data());
          glEnableVertexAttribArray(mPositionLoc);
  
          // Load the texture coordinate
          glVertexAttribPointer(mTexCoordLoc, 2, GL_FLOAT, GL_FALSE, 0, mTexcoords.data());
          glEnableVertexAttribArray(mTexCoordLoc);
  
          // Load the instance position
          glVertexAttribPointer(mInstancePosLoc, 3, GL_FLOAT, GL_FALSE, 0, mInstances.data());
          glEnableVertexAttribArray(mInstancePosLoc);
  
          // Enable instancing
          mVertexAttribDivisorANGLE(mInstancePosLoc, 1);
  
          // Bind the texture
          glActiveTexture(GL_TEXTURE0);
          glBindTexture(GL_TEXTURE_2D, mTextureID);
  
          // Set the sampler texture unit to 0
          glUniform1i(mSamplerLoc, 0);
  
          // Do the instanced draw
          mDrawElementsInstancedANGLE(GL_TRIANGLES, static_cast<GLsizei>(mIndices.size()),
                                      GL_UNSIGNED_SHORT, mIndices.data(),
                                      static_cast<GLsizei>(mInstances.size()));
      }
  
    private:
      // Handle to a program object
      GLuint mProgram;
  
      // Attribute locations
      GLint mPositionLoc;
      GLint mTexCoordLoc;
  
      // Sampler location
      GLint mSamplerLoc;
  
      // Texture handle
      GLuint mTextureID;
  
      // Instance VBO
      GLint mInstancePosLoc;
  
      // Loaded entry points
      PFNGLVERTEXATTRIBDIVISORANGLEPROC mVertexAttribDivisorANGLE;
      PFNGLDRAWARRAYSINSTANCEDANGLEPROC mDrawArraysInstancedANGLE;
      PFNGLDRAWELEMENTSINSTANCEDANGLEPROC mDrawElementsInstancedANGLE;
  
      // Vertex data
      std::vector<Vector3> mVertices;
      std::vector<Vector2> mTexcoords;
      std::vector<Vector3> mInstances;
      std::vector<GLushort> mIndices;
  };
  
  int main(int argc, char **argv)
  {
      SimpleInstancingSample app(argc, argv);
      return app.run();
  }
  

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