[Remoting] OpenGL Rendering Layer

remoting/client/opengl/gl_canvas.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "remoting/client/opengl/gl_canvas.h"

[Sergey Ulanov, 2016/06/27 23:15:29]

please add empty line after this one

[Yuwei, 2016/06/28 22:51:11]

Done.

+#include "base/logging.h"
+#include "remoting/client/opengl/gl_helpers.h"
+#include "remoting/client/opengl/shaders.h"
+
+namespace {
+
+const int kVertexSize = 2;
+const int kVertexCount = 4;
+
+const float k3x3ZeroMatrix[] = {0, 0, 0, 0, 0, 0, 0, 0, 0};
+
+}  // namespace
+
+namespace remoting {
+
+GlCanvas::GlCanvas() {
+  vertex_shader_ = CompileShader(GL_VERTEX_SHADER, kTexCoordToViewVert);
+  fragment_shader_ = CompileShader(GL_FRAGMENT_SHADER, kDrawTexFrag);
+  program_ = CreateProgram(vertex_shader_, fragment_shader_);
+  glUseProgram(program_);
+
+  transform_loc_ = glGetUniformLocation(program_, "u_transform");
+  texture_loc_ = glGetUniformLocation(program_, "u_texture");
+  position_loc_ = glGetAttribLocation(program_, "a_position");
+  tex_cord_loc_ = glGetAttribLocation(program_, "a_texCoord");
+  glEnableVertexAttribArray(position_loc_);
+  glEnableVertexAttribArray(tex_cord_loc_);
+  glEnable(GL_BLEND);
+  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
+  SetNormalizedTransformation(k3x3ZeroMatrix);
+}
+
+GlCanvas::~GlCanvas() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  glDeleteProgram(program_);
+  glDeleteShader(vertex_shader_);
+  glDeleteShader(fragment_shader_);
+}
+
+void GlCanvas::SetNormalizedTransformation(const float* matrix) {

[Sergey Ulanov, 2016/06/27 23:15:29]

This is called only from the constructor. Do you need it as a public method?

[Yuwei, 2016/06/28 01:31:20]

Sorry that current CL doesn't show enough use case of this class...

Actually this function will be used by GlRenderer (not in this CL) to change the
pan and zoom configuration of the canvas.

+  DCHECK(thread_checker_.CalledOnValidThread());
+  glUniformMatrix3fv(transform_loc_, 1, GL_TRUE, matrix);
+}
+
+void GlCanvas::DrawTexture(int texture_id,
+                           GLuint texture_handle,
+                           GLuint vertex_buffer) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  glActiveTexture(GL_TEXTURE0 + texture_id);
+  glBindTexture(GL_TEXTURE_2D, texture_handle);
+  glUniform1i(texture_loc_, texture_id);
+  glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer);
+
+  glVertexAttribPointer(position_loc_, kVertexSize, GL_FLOAT, GL_FALSE, 0, 0);
+  glVertexAttribPointer(tex_cord_loc_, kVertexSize, GL_FLOAT, GL_FALSE, 0,
+                        static_cast<float*>(0) + kVertexSize * kVertexCount);
+
+  glDrawArrays(GL_TRIANGLE_STRIP, 0, kVertexCount);
+  glBindBuffer(GL_ARRAY_BUFFER, 0);
+  glBindTexture(GL_TEXTURE_2D, 0);
+}
+
+}  // namespace remoting