kc3-lang/angle/samples/gles1/DrawTexture.cpp

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• Hash : 0df813c3
  Author :
  Date : 2018-07-12T12:52:06
  

  GLES1: GL_OES_draw_texture
  
  BUG=angleproject:2306
  
  This implements GL_OES_draw_texture using a few bits of new state
  in the renderer and adding a code path for it in the shader, using
  gl_VertexID to draw the quad backing the texture draw. This allows us
  to avoid allocating a separate vertex array for the texture draw and
  reuses the current shader as much as possible, plugging in to the
  existing multitexturing pipeline.
  
  - Add unit test and sample
  - No new test expectations, but advertising GL_OES_draw_texture makes
  the DrawTex GLES1 conformance test non-trivial and actually test
  glDrawTex*.
  
  Change-Id: I1485098249fe44d46a01cab4bb7b2c39d0492923
  Reviewed-on: https://chromium-review.googlesource.com/1135930
  Reviewed-by: Corentin Wallez <cwallez@chromium.org>
  Commit-Queue: Lingfeng Yang <lfy@google.com>
  

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• samples/gles1/DrawTexture.cpp

• //
  // Copyright 2018 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 "shader_utils.h"
  #include "texture_utils.h"
  #include "util/system_utils.h"
  
  #include <GLES/gl.h>
  #include <GLES/glext.h>
  
  class GLES1DrawTextureSample : public SampleApplication
  {
    public:
      GLES1DrawTextureSample(int argc, char **argv)
          : SampleApplication("GLES1DrawTexture", argc, argv, 1, 0, 1280, 800)
      {
      }
  
      bool initialize() override
      {
          // Load the texture
          mTexture = CreateSimpleTexture2D();
  
          glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
          glActiveTexture(GL_TEXTURE0);
          glEnable(GL_TEXTURE_2D);
  
          glActiveTexture(GL_TEXTURE0);
          glEnable(GL_TEXTURE_2D);
          glBindTexture(GL_TEXTURE_2D, mTexture);
  
          GLint crop[4] = {0, 0, 2, 2};
          glTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_CROP_RECT_OES, crop);
          glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
  
          glViewport(0, 0, getWindow()->getWidth(), getWindow()->getHeight());
  
          return true;
      }
  
      void destroy() override { glDeleteTextures(1, &mTexture); }
  
      void draw() override
      {
          glClear(GL_COLOR_BUFFER_BIT);
  
          GLint windowWidth  = getWindow()->getWidth();
          GLint windowHeight = getWindow()->getHeight();
  
          glDrawTexiOES(mX, mY, 0, mWidth, mHeight);
          glDrawTexiOES(windowWidth - mX, mY, 0, mWidth, mHeight);
          glDrawTexiOES(mX, windowHeight - mY, 0, mWidth, mHeight);
          glDrawTexiOES(windowWidth - mX, windowHeight - mY, 0, mWidth, mHeight);
  
          mX += mReverseX ? -1 : 1;
          mY += mReverseY ? -1 : 1;
  
          if (mX + mWidth >= windowWidth)
              mReverseX = true;
          if (mX < 0)
              mReverseX = false;
  
          if (mY + mHeight >= windowHeight)
              mReverseY = true;
          if (mY < 0)
              mReverseY = false;
  
          ++mWidth;
          ++mHeight;
          if (mWidth >= windowWidth)
              mWidth = 0;
          if (mHeight >= windowHeight)
              mHeight = 0;
  
          angle::Sleep(16);
      }
  
    private:
      // Texture handle
      GLuint mTexture = 0;
  
      // Draw texture coordinates and dimensions to loop through
      GLint mX      = 0;
      GLint mY      = 0;
      GLint mWidth  = 0;
      GLint mHeight = 0;
  
      bool mReverseX = false;
      bool mReverseY = false;
  };
  
  int main(int argc, char **argv)
  {
      GLES1DrawTextureSample app(argc, argv);
      return app.run();
  }
  

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