Adding the iOS app and integration example with GlRenderer.

remoting/client/ios/display/gl_demo_screen.mm

Index: remoting/client/ios/display/gl_demo_screen.mm
diff --git a/remoting/client/ios/display/gl_demo_screen.mm b/remoting/client/ios/display/gl_demo_screen.mm
new file mode 100644
index 0000000000000000000000000000000000000000..f1def2202fabf6848f216972e6e0871bf7521c8d
--- /dev/null
+++ b/remoting/client/ios/display/gl_demo_screen.mm
@@ -0,0 +1,111 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.

[Yuwei, 2017/01/23 21:56:16]

Why is this implemented in a .mm file? Does it use anything from core
foundation?

[joedow, 2017/01/25 23:16:28]

There is Chromium guidance that says to use the mm extension for objective c.

[Yuwei, 2017/01/26 20:18:25]

What I meant is this file looks the same as a normal cc file. It seems weird to
me to give it mm extension just because it's part of an objective-c target.
Anyway if this is what the style guide says then I'm good with that.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "remoting/client/ios/display/gl_demo_screen.h"
+
+#import <Foundation/Foundation.h>
+
+#include "base/logging.h"
+#include "base/memory/ptr_util.h"

[joedow, 2017/01/25 23:16:28]

Remove ptr_util.h?  I don't see it used here.

[nicholss, 2017/01/26 18:00:16]

Done.

+#include "remoting/client/display/canvas.h"
+#include "remoting/client/display/gl_math.h"
+
+namespace remoting {
+
+const GLfloat square[] = {-1.0, -1.0, 1.0, -1.0, -1.0, 1.0, 1.0, 1.0};
+
+const GLchar* fragmentShaderSource =
+    "precision mediump float;"
+    "void main() {"
+    "  gl_FragColor = vec4(1.0, 1.0, 0.0, 1.0);"
+    "} ";
+
+const GLchar* vertexShaderSource =
+    "precision mediump float;"
+    "attribute vec4 a_position;"
+    "void main() {"
+    "  gl_Position = a_position;"
+    "}";
+
+const GLchar* a_position = "a_position";

[joedow, 2017/01/25 23:16:28]

Encapsulating constants in an anonymous namespace would be good here (avoid
polluting the remoting namespace).

[nicholss, 2017/01/26 18:00:16]

Done.

+
+GlDemoScreen::GlDemoScreen() : weak_factory_(this)  {}
+
+GlDemoScreen::~GlDemoScreen() {}
+
+void GlDemoScreen::SetCanvas(base::WeakPtr<Canvas> canvas) {
+  canvas_ = canvas;
+
+  // Create and compile vertex shader

[joedow, 2017/01/25 23:16:28]

All comments should end in a period (chromium style guide).

[nicholss, 2017/01/26 18:00:16]

Done. And added a short description for the class.

+  GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
+  glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
+  glCompileShader(vertexShader);
+
+  // Create and compile fragment shader
+  GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+  glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
+  glCompileShader(fragmentShader);
+
+  // Create and link program
+  program_ = glCreateProgram();
+  glAttachShader(program_, vertexShader);
+  glAttachShader(program_, fragmentShader);
+  glLinkProgram(program_);
+}
+
+int GlDemoScreen::GetZIndex() {
+  return Drawable::DESKTOP;
+}
+
+bool GlDemoScreen::Draw() {
+  if (!canvas_) {
+    return false;
+  }
+
+  int width = 640;
+  int height = 1024;

[joedow, 2017/01/25 23:16:28]

you could make width and height const or a constexpr at the top of the file

[nicholss, 2017/01/26 18:00:16]

well... I am not so sure about this. These values might need to be dynamic in
the future based on the requested desktop size... because this is a demo app
(really for me to test integration with GL) I think I will leave this here and
as I work on the gestures this will become dynamic. 

Added a TODO to work on that when gestures get worked on.

+  square_size_++;
+  if (square_size_ > 300) {
+    square_size_ = 1;
+  }
+
+  // Set the viewport
+  glViewport(0, 0, width, height);
+
+  // Clear
+  glClearColor(0, 1, 0, 1);
+  glClear(GL_COLOR_BUFFER_BIT);
+
+  // Use program
+  glUseProgram(program_);
+
+  int skip = 0;
+  for (int i = 0; i < width; i += square_size_) {
+    if (skip == square_size_) {
+      skip = 0;
+    } else {
+      skip = square_size_;
+    }
+    for (int j = skip; j < height; j += square_size_ * 2) {
+      glViewport(i, j, square_size_, square_size_);
+
+      // Send geometry to vertex shader
+      GLuint aPosition = glGetAttribLocation(program_, a_position);
+
+      glVertexAttribPointer(aPosition, 2, GL_FLOAT, GL_FALSE, 0, square);
+      glEnableVertexAttribArray(aPosition);
+
+      // Draw
+      glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+    }
+  }
+  return true;
+}
+
+base::WeakPtr<Drawable> GlDemoScreen::GetWeakPtr() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  return weak_factory_.GetWeakPtr();
+}
+
+}  // namespace remoting