kc3-lang/angle/samples/post_sub_buffer

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• Author : Jamie Madill
  Date : 2020-06-11 13:31:01
  Hash : 37e6ede6
  Message : Minor cleanup to PostSubBuffer sample. We shouldn't need to query function pointers now that we're using a custom loader. Bug: angleproject:4729 Change-Id: I50f50545a2f29e16ab675afe0155700332c8f670 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2241618 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>

• PostSubBuffer.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_VertexShader.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 "texture_utils.h"
  #include "util/Matrix.h"
  #include "util/geometry_utils.h"
  #include "util/shader_utils.h"
  
  #include <cmath>
  #include <iostream>
  
  class PostSubBufferSample : public SampleApplication
  {
    public:
      PostSubBufferSample(int argc, char **argv) : SampleApplication("PostSubBuffer", argc, argv) {}
  
      bool initialize() override
      {
          constexpr char kVS[] = R"(uniform mat4 u_mvpMatrix;
  attribute vec4 a_position;
  attribute vec2 a_texcoord;
  varying vec2 v_texcoord;
  void main()
  {
      gl_Position = u_mvpMatrix * a_position;
      v_texcoord = a_texcoord;
  })";
  
          constexpr char kFS[] = R"(precision mediump float;
  varying vec2 v_texcoord;
  void main()
  {
      gl_FragColor = vec4(v_texcoord.x, v_texcoord.y, 1.0, 1.0);
  })";
  
          mProgram = CompileProgram(kVS, kFS);
          if (!mProgram)
          {
              return false;
          }
  
          // Get the attribute locations
          mPositionLoc = glGetAttribLocation(mProgram, "a_position");
          mTexcoordLoc = glGetAttribLocation(mProgram, "a_texcoord");
  
          // Get the uniform locations
          mMVPMatrixLoc = glGetUniformLocation(mProgram, "u_mvpMatrix");
  
          // Generate the geometry data
          GenerateCubeGeometry(0.5f, &mCube);
  
          // Set an initial rotation
          mRotation = 45.0f;
  
          // Clear the whole window surface to blue.
          glClearColor(0.0f, 0.0f, 1.0f, 0.0f);
          glClear(GL_COLOR_BUFFER_BIT);
          SampleApplication::swap();
  
          glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
          glCullFace(GL_BACK);
          glEnable(GL_CULL_FACE);
  
          return true;
      }
  
      void destroy() override { glDeleteProgram(mProgram); }
  
      void step(float dt, double totalTime) override
      {
          mRotation = fmod(mRotation + (dt * 40.0f), 360.0f);
  
          Matrix4 perspectiveMatrix = Matrix4::perspective(
              60.0f, float(getWindow()->getWidth()) / getWindow()->getHeight(), 1.0f, 20.0f);
  
          Matrix4 modelMatrix = Matrix4::translate(angle::Vector3(0.0f, 0.0f, -2.0f)) *
                                Matrix4::rotate(mRotation, angle::Vector3(1.0f, 0.0f, 1.0f));
  
          Matrix4 viewMatrix = Matrix4::identity();
  
          Matrix4 mvpMatrix = perspectiveMatrix * viewMatrix * modelMatrix;
  
          // Load the matrices
          glUniformMatrix4fv(mMVPMatrixLoc, 1, GL_FALSE, mvpMatrix.data);
      }
  
      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, mCube.positions.data());
          glEnableVertexAttribArray(mPositionLoc);
  
          // Load the texcoord data
          glVertexAttribPointer(mTexcoordLoc, 2, GL_FLOAT, GL_FALSE, 0, mCube.texcoords.data());
          glEnableVertexAttribArray(mTexcoordLoc);
  
          // Draw the cube
          glDrawElements(GL_TRIANGLES, static_cast<GLsizei>(mCube.indices.size()), GL_UNSIGNED_SHORT,
                         mCube.indices.data());
      }
  
      void swap() override
      {
          // Instead of letting the application call eglSwapBuffers, call eglPostSubBufferNV here
          // instead
          EGLint windowWidth  = static_cast<EGLint>(getWindow()->getWidth());
          EGLint windowHeight = static_cast<EGLint>(getWindow()->getHeight());
          EGLDisplay display  = getDisplay();
          EGLSurface surface  = getSurface();
          eglPostSubBufferNV(display, surface, 60, 60, windowWidth - 120, windowHeight - 120);
      }
  
    private:
      // Handle to a program object
      GLuint mProgram;
  
      // Attribute locations
      GLint mPositionLoc;
      GLint mTexcoordLoc;
  
      // Uniform locations
      GLuint mMVPMatrixLoc;
  
      // Current rotation
      float mRotation;
  
      // Geometry data
      CubeGeometry mCube;
  };
  
  int main(int argc, char **argv)
  {
      PostSubBufferSample app(argc, argv);
      return app.run();
  }