Revert of Splitting of layers for correct intersections

cc/output/geometry_binding.cc

 // Copyright 2011 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 "cc/output/geometry_binding.h"
 
 #include "cc/output/gl_renderer.h"  // For the GLC() macro.
 #include "gpu/command_buffer/client/gles2_interface.h"
 #include "ui/gfx/geometry/rect_f.h"
 
 namespace cc {
 
-void SetupGLContext(gpu::gles2::GLES2Interface* gl,
-                    GLuint quad_elements_vbo,
-                    GLuint quad_vertices_vbo) {
-  GLC(gl, gl->BindBuffer(GL_ELEMENT_ARRAY_BUFFER, quad_elements_vbo));
+GeometryBinding::GeometryBinding(gpu::gles2::GLES2Interface* gl,
+                                 const gfx::RectF& quad_vertex_rect)
+    : gl_(gl), quad_vertices_vbo_(0), quad_elements_vbo_(0) {
+  struct Vertex {
+    float a_position[3];
+    float a_texCoord[2];
+    // Index of the vertex, divide by 4 to have the matrix for this quad.
+    float a_index;
+  };
+  struct Quad {
+    Vertex v0, v1, v2, v3;
+  };
+  struct QuadIndex {
+    uint16 data[6];
+  };
 
-  GLC(gl, gl->BindBuffer(GL_ARRAY_BUFFER, quad_vertices_vbo));
+  static_assert(sizeof(Quad) == 24 * sizeof(float),
+                "struct Quad should be densely packed");
+  static_assert(sizeof(QuadIndex) == 6 * sizeof(uint16_t),
+                "struct QuadIndex should be densely packed");
+
+  Quad quad_list[8];
+  QuadIndex quad_index_list[8];
+  for (int i = 0; i < 8; i++) {
+    Vertex v0 = {{quad_vertex_rect.x(), quad_vertex_rect.bottom(), 0.0f, },
+                 {0.0f, 1.0f, }, i * 4.0f + 0.0f};
+    Vertex v1 = {{quad_vertex_rect.x(), quad_vertex_rect.y(), 0.0f, },
+                 {0.0f, 0.0f, }, i * 4.0f + 1.0f};
+    Vertex v2 = {{quad_vertex_rect.right(), quad_vertex_rect.y(), 0.0f, },
+                 {1.0f, .0f, }, i * 4.0f + 2.0f};
+    Vertex v3 = {{quad_vertex_rect.right(), quad_vertex_rect.bottom(), 0.0f, },
+                 {1.0f, 1.0f, }, i * 4.0f + 3.0f};
+    Quad x = {v0, v1, v2, v3};
+    quad_list[i] = x;
+    QuadIndex y = {
+        {static_cast<uint16>(0 + 4 * i), static_cast<uint16>(1 + 4 * i),
+         static_cast<uint16>(2 + 4 * i), static_cast<uint16>(3 + 4 * i),
+         static_cast<uint16>(0 + 4 * i), static_cast<uint16>(2 + 4 * i)}};
+    quad_index_list[i] = y;
+  }
+
+  gl_->GenBuffers(1, &quad_vertices_vbo_);
+  gl_->GenBuffers(1, &quad_elements_vbo_);
+  GLC(gl_, gl_->BindBuffer(GL_ARRAY_BUFFER, quad_vertices_vbo_));
+  GLC(gl_,
+      gl_->BufferData(
+          GL_ARRAY_BUFFER, sizeof(quad_list), quad_list, GL_STATIC_DRAW));
+  GLC(gl_, gl_->BindBuffer(GL_ELEMENT_ARRAY_BUFFER, quad_elements_vbo_));
+  GLC(gl_,
+      gl_->BufferData(GL_ELEMENT_ARRAY_BUFFER,
+                      sizeof(quad_index_list),
+                      quad_index_list,
+                      GL_STATIC_DRAW));
+}
+
+GeometryBinding::~GeometryBinding() {
+  gl_->DeleteBuffers(1, &quad_vertices_vbo_);
+  gl_->DeleteBuffers(1, &quad_elements_vbo_);
+}
+
+void GeometryBinding::PrepareForDraw() {
+  GLC(gl_, gl_->BindBuffer(GL_ELEMENT_ARRAY_BUFFER, quad_elements_vbo_));
+
+  GLC(gl_, gl_->BindBuffer(GL_ARRAY_BUFFER, quad_vertices_vbo_));
   // OpenGL defines the last parameter to VertexAttribPointer as type
   // "const GLvoid*" even though it is actually an offset into the buffer
   // object's data store and not a pointer to the client's address space.
   const void* offsets[3] = {
       0,
       reinterpret_cast<const void*>(3 * sizeof(float)),
       reinterpret_cast<const void*>(5 * sizeof(float)),
   };
 
-  GLC(gl,
-      gl->VertexAttribPointer(GeometryBinding::PositionAttribLocation(), 3,
-                              GL_FLOAT, false, 6 * sizeof(float), offsets[0]));
-  GLC(gl,
-      gl->VertexAttribPointer(GeometryBinding::TexCoordAttribLocation(), 2,
-                              GL_FLOAT, false, 6 * sizeof(float), offsets[1]));
-  GLC(gl,
-      gl->VertexAttribPointer(GeometryBinding::TriangleIndexAttribLocation(), 1,
-                              GL_FLOAT, false, 6 * sizeof(float), offsets[2]));
-  GLC(gl,
-      gl->EnableVertexAttribArray(GeometryBinding::PositionAttribLocation()));
-  GLC(gl,
-      gl->EnableVertexAttribArray(GeometryBinding::TexCoordAttribLocation()));
-  GLC(gl, gl->EnableVertexAttribArray(
-              GeometryBinding::TriangleIndexAttribLocation()));
+  GLC(gl_, gl_->VertexAttribPointer(PositionAttribLocation(), 3, GL_FLOAT,
+                                    false, 6 * sizeof(float), offsets[0]));
+  GLC(gl_, gl_->VertexAttribPointer(TexCoordAttribLocation(), 2, GL_FLOAT,
+                                    false, 6 * sizeof(float), offsets[1]));
+  GLC(gl_, gl_->VertexAttribPointer(TriangleIndexAttribLocation(), 1, GL_FLOAT,
+                                    false, 6 * sizeof(float), offsets[2]));
+  GLC(gl_, gl_->EnableVertexAttribArray(PositionAttribLocation()));
+  GLC(gl_, gl_->EnableVertexAttribArray(TexCoordAttribLocation()));
+  GLC(gl_, gl_->EnableVertexAttribArray(TriangleIndexAttribLocation()));
 }
 
 }  // namespace cc