Change the color of the spinning cube on click.

Review URL: https://codereview.chromium.org/297113002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@272684 0039d316-1c4b-4281-b951-d872f2087c98

mojo/examples/sample_app/gles2_client_impl.cc

@@ -7,6 +7,7 @@
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
 #include <math.h>
+#include <stdlib.h>
 
 #include "mojo/public/c/gles2/gles2.h"
 #include "ui/events/event_constants.h"
@@ -19,6 +20,10 @@ float CalculateDragDistance(const gfx::PointF& start, const Point& end) {
   return hypot(start.x() - end.x(), start.y() - end.y());
 }
 
+float GetRandomColor() {
+  return static_cast<float>(rand()) / static_cast<float>(RAND_MAX);
+}
+
 }
 
 GLES2ClientImpl::GLES2ClientImpl(ScopedMessagePipeHandle pipe)
@@ -74,6 +79,8 @@ void GLES2ClientImpl::HandleInputEvent(const Event& event) {
           CalculateDragDistance(capture_point_, event.location()),
           delta);
 
+      cube_.set_color(GetRandomColor(), GetRandomColor(), GetRandomColor());
+
       capture_point_ = last_drag_point_ = gfx::PointF();
       RequestAnimationFrames();
     }

mojo/examples/sample_app/spinning_cube.cc

@@ -314,6 +314,7 @@ class SpinningCube::GLState {
   GLuint program_object_;
   GLint position_location_;
   GLint mvp_location_;
+  GLint color_location_;
   GLuint vbo_vertices_;
   GLuint vbo_indices_;
   int num_indices_;
@@ -329,6 +330,7 @@ void SpinningCube::GLState::OnGLContextLost() {
   program_object_ = 0;
   position_location_ = 0;
   mvp_location_ = 0;
+  color_location_ = 0;
   vbo_vertices_ = 0;
   vbo_indices_ = 0;
   num_indices_ = 0;
@@ -340,8 +342,10 @@ SpinningCube::SpinningCube()
       height_(0),
       state_(new GLState()),
       fling_multiplier_(1.0f),
-      direction_(1) {
+      direction_(1),
+      color_() {
   state_->angle_ = 45.0f;
+  set_color(0.0, 1.0, 0.0);
 }
 
 SpinningCube::~SpinningCube() {
@@ -369,9 +373,10 @@ void SpinningCube::Init(uint32_t width, uint32_t height) {
 
   const char fragment_shader_source[] =
       "precision mediump float;                            \n"
+      "uniform vec4 u_color;                               \n"
       "void main()                                         \n"
       "{                                                   \n"
-      "  gl_FragColor = vec4( 0.0, 1.0, 0.0, 1.0 );        \n"
+      "  gl_FragColor = u_color;                           \n"
       "}                                                   \n";
 
   state_->program_object_ = LoadProgram(
@@ -380,6 +385,8 @@ void SpinningCube::Init(uint32_t width, uint32_t height) {
       state_->program_object_, "a_position");
   state_->mvp_location_ = glGetUniformLocation(
       state_->program_object_, "u_mvpMatrix");
+  state_->color_location_ = glGetUniformLocation(
+      state_->program_object_, "u_color");
   state_->num_indices_ = GenerateCube(
       &state_->vbo_vertices_, &state_->vbo_indices_);
 
@@ -439,6 +446,7 @@ void SpinningCube::Draw() {
                         1,
                         GL_FALSE,
                         (GLfloat*) &state_->mvp_matrix_.m[0][0]);
+  glUniform4f(state_->color_location_, color_[0], color_[1], color_[2], 1.0);
   glDrawElements(GL_TRIANGLES,
                     state_->num_indices_,
                     GL_UNSIGNED_SHORT,

mojo/examples/sample_app/spinning_cube.h

@@ -19,6 +19,11 @@ class SpinningCube {
 
   void Init(uint32_t width, uint32_t height);
   void set_direction(int direction) { direction_ = direction; }
+  void set_color(float r, float g, float b) {
+    color_[0] = r;
+    color_[1] = g;
+    color_[2] = b;
+  }
   void SetFlingMultiplier(float drag_distance, float drag_time);
   void UpdateForTimeDelta(float delta_time);
   void UpdateForDragDistance(float distance);
@@ -37,6 +42,7 @@ class SpinningCube {
   scoped_ptr<GLState> state_;
   float fling_multiplier_;
   int direction_;
+  float color_[3];
 };
 
 }  // namespace examples