Merged in recent changes to command buffer code.

gpu/command_buffer/client/gles2_demo_cc.cc

Index: gpu/command_buffer/client/gles2_demo_cc.cc
===================================================================
--- gpu/command_buffer/client/gles2_demo_cc.cc	(revision 33021)
+++ gpu/command_buffer/client/gles2_demo_cc.cc	(working copy)
@@ -8,14 +8,187 @@
 #include <GLES2/gl2.h>
 #include "gpu/command_buffer/client/gles2_demo_cc.h"
 
+namespace {
+
+int g_width = 512;
+int g_height = 512;
+GLuint g_texture = 0;
+int g_textureLoc = -1;
+GLuint g_programObject = 0;
+GLuint g_vbo = 0;
+GLsizei g_texCoordOffset = 0;
+
+void CheckGLError() {
+  GLenum error = glGetError();
+  if (error != GL_NO_ERROR) {
+    DLOG(ERROR) << "GL Error: " << error;
+  }
+}
+
+GLuint LoadShader(GLenum type, const char* shaderSrc) {
+  GLuint shader = glCreateShader(type);
+  if (shader == 0) {
+    return 0;
+  }
+  // Load the shader source
+  glShaderSource(shader, 1, &shaderSrc, NULL);
+  // Compile the shader
+  glCompileShader(shader);
+  // Check the compile status
+  GLint value;
+  glGetShaderiv(shader, GL_COMPILE_STATUS, &value);
+  if (value == 0) {
+    char buffer[1024];
+    GLsizei length;
+    glGetShaderInfoLog(shader, sizeof(buffer), &length, buffer);
+    std::string log(buffer, length);
+    DLOG(ERROR) << "Error compiling shader:" << log;
+    glDeleteShader(shader);
+    return 0;
+  }
+  return shader;
+}
+
+void InitShaders() {
+  static const char* vShaderStr =
+    "attribute vec3 g_Position;\n"
+    "attribute vec2 g_TexCoord0;\n"
+    "varying vec2 texCoord;\n"
+    "void main()\n"
+    "{\n"
+    "   gl_Position = vec4(g_Position.x, g_Position.y, g_Position.z, 1.0);\n"
+    "   texCoord = g_TexCoord0;\n"
+    "}\n";
+  static const char* fShaderStr =
+    "uniform sampler2D tex;\n"
+    "varying vec2 texCoord;\n"
+    "void main()\n"
+    "{\n"
+    "  gl_FragColor = texture2D(tex, texCoord);\n"
+    "}\n";
+
+  GLuint vertexShader = LoadShader(GL_VERTEX_SHADER, vShaderStr);
+  GLuint fragmentShader = LoadShader(GL_FRAGMENT_SHADER, fShaderStr);
+  // Create the program object
+  GLuint programObject = glCreateProgram();
+  if (programObject == 0) {
+    DLOG(ERROR) << "Creating program failed";
+    return;
+  }
+  glAttachShader(programObject, vertexShader);
+  glAttachShader(programObject, fragmentShader);
+  // Bind g_Position to attribute 0
+  // Bind g_TexCoord0 to attribute 1
+  glBindAttribLocation(programObject, 0, "g_Position");
+  glBindAttribLocation(programObject, 1, "g_TexCoord0");
+  // Link the program
+  glLinkProgram(programObject);
+  // Check the link status
+  GLint linked;
+  glGetProgramiv(programObject, GL_LINK_STATUS, &linked);
+  if (linked == 0) {
+    char buffer[1024];
+    GLsizei length;
+    glGetProgramInfoLog(programObject, sizeof(buffer), &length, buffer);
+    std::string log(buffer, length);
+    DLOG(ERROR) << "Error linking program:" << log;
+    glDeleteProgram(programObject);
+    return;
+  }
+  g_programObject = programObject;
+  g_textureLoc = glGetUniformLocation(g_programObject, "tex");
+  glGenBuffers(1, &g_vbo);
+  glBindBuffer(GL_ARRAY_BUFFER, g_vbo);
+  static float vertices[] = {
+      0.25,  0.75, 0.0,
+     -0.75,  0.75, 0.0,
+     -0.75, -0.25, 0.0,
+      0.25,  0.75, 0.0,
+     -0.75, -0.25, 0.0,
+      0.25, -0.25, 0.0,
+  };
+  static float texCoords[] = {
+    1.0, 1.0,
+    0.0, 1.0,
+    0.0, 0.0,
+    1.0, 1.0,
+    0.0, 0.0,
+    1.0, 0.0,
+  };
+  g_texCoordOffset = sizeof(vertices);
+  glBufferData(GL_ARRAY_BUFFER,
+               sizeof(vertices) + sizeof(texCoords),
+               NULL,
+               GL_STATIC_DRAW);
+  glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertices), vertices);
+  glBufferSubData(GL_ARRAY_BUFFER, g_texCoordOffset,
+                  sizeof(texCoords), texCoords);
+  CheckGLError();
+}
+
+void Draw() {
+  // Note: the viewport is automatically set up to cover the entire Canvas.
+  // Clear the color buffer
+  glClear(GL_COLOR_BUFFER_BIT);
+  CheckGLError();
+  // Use the program object
+  glUseProgram(g_programObject);
+  CheckGLError();
+  // Load the vertex data
+  glBindBuffer(GL_ARRAY_BUFFER, g_vbo);
+  glEnableVertexAttribArray(0);
+  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
+  glEnableVertexAttribArray(1);
+  glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0,
+                        reinterpret_cast<const void*>(g_texCoordOffset));
+  CheckGLError();
+  // Bind the texture to texture unit 0
+  glBindTexture(GL_TEXTURE_2D, g_texture);
+  CheckGLError();
+  // Point the uniform sampler to texture unit 0
+  glUniform1i(g_textureLoc, 0);
+  CheckGLError();
+  glDrawArrays(GL_TRIANGLES, 0, 6);
+  CheckGLError();
+  glFlush();
+}
+
+GLuint CreateCheckerboardTexture() {
+  static unsigned char pixels[] = {
+    255, 255, 255,
+    0,   0,   0,
+    0,   0,   0,
+    255, 255, 255,
+  };
+  GLuint texture;
+  glGenTextures(1, &texture);
+  glBindTexture(GL_TEXTURE_2D, texture);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+  glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 2, 2, 0, GL_RGB, GL_UNSIGNED_BYTE,
+               pixels);
+  return texture;
+}
+
+void Init() {
+  glClearColor(0.f, 0.f, .7f, 1.f);
+  g_texture = CreateCheckerboardTexture();
+  InitShaders();
+}
+
+}  // anonymous namespace.
+
 void GLFromCPPTestFunction() {
-  static bool foo = true;
-  foo = !foo;
-  glClearColor(
-      foo ? 1.0f : 0.0f,
-      foo ? 0.0f : 1.0f,
-      1.0f,
-      1.0f);
+  static bool initialized = false;
+  if (!initialized) {
+    initialized = true;
+    Init();
+  }
+  Draw();
 }
 
 
+