cc/output/geometry_binding.cc

   1 // Copyright 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "cc/output/geometry_binding.h"
   6
   7 #include "cc/output/gl_renderer.h"  // For the GLC() macro.
   8 #include "third_party/WebKit/public/platform/WebGraphicsContext3D.h"
   9 #include "third_party/khronos/GLES2/gl2.h"
  10 #include "ui/gfx/rect_f.h"
  11
  12 namespace cc {
  13
  14 GeometryBinding::GeometryBinding(WebKit::WebGraphicsContext3D* context,
  15                                  const gfx::RectF& quad_vertex_rect)
  16     : context_(context),
  17       quad_vertices_vbo_(0),
  18       quad_elements_vbo_(0) {
  19   struct Vertex {
  20     float a_position[3];
  21     float a_texCoord[2];
  22     // Index of the vertex, divide by 4 to have the matrix for this quad.
  23     float a_index;
  24   };
  25   struct Quad {
  26     Vertex v0, v1, v2, v3;
  27   };
  28   struct QuadIndex {
  29     uint16 data[6];
  30   };
  31
  32   COMPILE_ASSERT(
  33       sizeof(Quad) == 24 * sizeof(float),  // NOLINT(runtime/sizeof)
  34       struct_is_densely_packed);
  35   COMPILE_ASSERT(
  36       sizeof(QuadIndex) == 6 * sizeof(uint16_t),  // NOLINT(runtime/sizeof)
  37       struct_is_densely_packed);
  38
  39   Quad quad_list[8];
  40   QuadIndex quad_index_list[8];
  41   for (int i = 0; i < 8; i++) {
  42     Vertex v0 = { { quad_vertex_rect.x(), quad_vertex_rect.bottom(), 0.0f, },
  43                   { 0.0f, 1.0f, },
  44                   i * 4.0f + 0.0f };
  45     Vertex v1 = { { quad_vertex_rect.x(), quad_vertex_rect.y(), 0.0f, },
  46                   { 0.0f, 0.0f, },
  47                   i * 4.0f + 1.0f };
  48     Vertex v2 = { { quad_vertex_rect.right(), quad_vertex_rect.y(), 0.0f, },
  49                   { 1.0f, .0f, },
  50                   i * 4.0f + 2.0f };
  51     Vertex v3 = { { quad_vertex_rect.right(),
  52                     quad_vertex_rect.bottom(),
  53                     0.0f, },
  54                   { 1.0f, 1.0f, },
  55                   i * 4.0f + 3.0f };
  56     Quad x = { v0, v1, v2, v3 };
  57     quad_list[i] = x;
  58     QuadIndex y = { { static_cast<uint16>(0 + 4 * i),
  59                       static_cast<uint16>(1 + 4 * i),
  60                       static_cast<uint16>(2 + 4 * i),
  61                       static_cast<uint16>(3 + 4 * i),
  62                       static_cast<uint16>(0 + 4 * i),
  63                       static_cast<uint16>(2 + 4 * i) } };
  64     quad_index_list[i] = y;
  65   }
  66
  67   GLC(context_, quad_vertices_vbo_ = context_->createBuffer());
  68   GLC(context_, quad_elements_vbo_ = context_->createBuffer());
  69   GLC(context_, context_->bindBuffer(GL_ARRAY_BUFFER, quad_vertices_vbo_));
  70   GLC(context_,
  71       context_->bufferData(
  72           GL_ARRAY_BUFFER, sizeof(quad_list), quad_list, GL_STATIC_DRAW));
  73   GLC(context_,
  74       context_->bindBuffer(GL_ELEMENT_ARRAY_BUFFER, quad_elements_vbo_));
  75   GLC(context_,
  76       context_->bufferData(GL_ELEMENT_ARRAY_BUFFER,
  77                            sizeof(quad_index_list),
  78                            quad_index_list,
  79                            GL_STATIC_DRAW));
  80 }
  81
  82 GeometryBinding::~GeometryBinding() {
  83   GLC(context_, context_->deleteBuffer(quad_vertices_vbo_));
  84   GLC(context_, context_->deleteBuffer(quad_elements_vbo_));
  85 }
  86
  87 void GeometryBinding::PrepareForDraw() {
  88   GLC(context_,
  89       context_->bindBuffer(GL_ELEMENT_ARRAY_BUFFER, quad_elements_vbo_));
  90
  91   GLC(context_, context_->bindBuffer(GL_ARRAY_BUFFER, quad_vertices_vbo_));
  92   GLC(context_,
  93       context_->vertexAttribPointer(
  94           PositionAttribLocation(),
  95           3,
  96           GL_FLOAT,
  97           false,
  98           6 * sizeof(float),  // NOLINT(runtime/sizeof)
  99           0));
 100   GLC(context_,
 101       context_->vertexAttribPointer(
 102           TexCoordAttribLocation(),
 103           2,
 104           GL_FLOAT,
 105           false,
 106           6 * sizeof(float),  // NOLINT(runtime/sizeof)
 107           3 * sizeof(float)));  // NOLINT(runtime/sizeof)
 108   GLC(context_,
 109       context_->vertexAttribPointer(
 110           TriangleIndexAttribLocation(),
 111           1,
 112           GL_FLOAT,
 113           false,
 114           6 * sizeof(float),  // NOLINT(runtime/sizeof)
 115           5 * sizeof(float)));  // NOLINT(runtime/sizeof)
 116   GLC(context_, context_->enableVertexAttribArray(PositionAttribLocation()));
 117   GLC(context_, context_->enableVertexAttribArray(TexCoordAttribLocation()));
 118   GLC(context_,
 119       context_->enableVertexAttribArray(TriangleIndexAttribLocation()));
 120 }
 121
 122 }  // namespace cc