kc3-lang/angle/samples/simple_vertex_shader/SimpleVertexShader.cpp

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• Hash : 17cee572
  Author :
  Date : 2018-06-18T08:28:50
  

  SampleApps: Refactor to use cli args the same way
  
  Bug: angleproject:2669
  Change-Id: Ica5b49e63e8af69595cdde3737b0aa1808d7d841
  Reviewed-on: https://chromium-review.googlesource.com/1104377
  Reviewed-by: Geoff Lang <geofflang@chromium.org>
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  Commit-Queue: Luc Ferron <lucferron@chromium.org>
  

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• samples/simple_vertex_shader/SimpleVertexShader.cpp

• //
  // Copyright (c) 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 "shader_utils.h"
  #include "texture_utils.h"
  #include "geometry_utils.h"
  #include "Matrix.h"
  
  #include <cmath>
  
  class SimpleVertexShaderSample : public SampleApplication
  {
    public:
      SimpleVertexShaderSample(int argc, char **argv)
          : SampleApplication("SimpleVertexShader", argc, argv)
      {
      }
  
      virtual bool initialize()
      {
          const std::string vs =
              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;
              })";
  
          const std::string fs =
              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(vs, fs);
          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;
  
          glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
          glCullFace(GL_BACK);
          glEnable(GL_CULL_FACE);
  
          return true;
      }
  
      virtual void destroy()
      {
          glDeleteProgram(mProgram);
      }
  
      virtual void step(float dt, double totalTime)
      {
          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);
      }
  
      virtual void draw()
      {
          // 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());
      }
  
    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)
  {
      SimpleVertexShaderSample app(argc, argv);
      return app.run();
  }
  

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