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 "gpu/command_buffer/client/gles2_interface.h"
   9 #include "ui/gfx/geometry/rect_f.h"
  10
  11 namespace cc {
  12
  13 GeometryBinding::GeometryBinding(gpu::gles2::GLES2Interface* gl,
  14                                  const gfx::RectF& quad_vertex_rect)
  15     : gl_(gl), quad_vertices_vbo_(0), quad_elements_vbo_(0) {
  16   struct Vertex {
  17     float a_position[3];
  18     float a_texCoord[2];
  19     // Index of the vertex, divide by 4 to have the matrix for this quad.
  20     float a_index;
  21   };
  22   struct Quad {
  23     Vertex v0, v1, v2, v3;
  24   };
  25   struct QuadIndex {
  26     uint16 data[6];
  27   };
  28
  29   COMPILE_ASSERT(sizeof(Quad) == 24 * sizeof(float),  // NOLINT(runtime/sizeof)
  30                  struct_is_densely_packed);
  31   COMPILE_ASSERT(
  32       sizeof(QuadIndex) == 6 * sizeof(uint16_t),  // NOLINT(runtime/sizeof)
  33       struct_is_densely_packed);
  34
  35   Quad quad_list[8];
  36   QuadIndex quad_index_list[8];
  37   for (int i = 0; i < 8; i++) {
  38     Vertex v0 = {{quad_vertex_rect.x(), quad_vertex_rect.bottom(), 0.0f, },
  39                  {0.0f, 1.0f, }, i * 4.0f + 0.0f};
  40     Vertex v1 = {{quad_vertex_rect.x(), quad_vertex_rect.y(), 0.0f, },
  41                  {0.0f, 0.0f, }, i * 4.0f + 1.0f};
  42     Vertex v2 = {{quad_vertex_rect.right(), quad_vertex_rect.y(), 0.0f, },
  43                  {1.0f, .0f, }, i * 4.0f + 2.0f};
  44     Vertex v3 = {{quad_vertex_rect.right(), quad_vertex_rect.bottom(), 0.0f, },
  45                  {1.0f, 1.0f, }, i * 4.0f + 3.0f};
  46     Quad x = {v0, v1, v2, v3};
  47     quad_list[i] = x;
  48     QuadIndex y = {
  49         {static_cast<uint16>(0 + 4 * i), static_cast<uint16>(1 + 4 * i),
  50          static_cast<uint16>(2 + 4 * i), static_cast<uint16>(3 + 4 * i),
  51          static_cast<uint16>(0 + 4 * i), static_cast<uint16>(2 + 4 * i)}};
  52     quad_index_list[i] = y;
  53   }
  54
  55   gl_->GenBuffers(1, &quad_vertices_vbo_);
  56   gl_->GenBuffers(1, &quad_elements_vbo_);
  57   GLC(gl_, gl_->BindBuffer(GL_ARRAY_BUFFER, quad_vertices_vbo_));
  58   GLC(gl_,
  59       gl_->BufferData(
  60           GL_ARRAY_BUFFER, sizeof(quad_list), quad_list, GL_STATIC_DRAW));
  61   GLC(gl_, gl_->BindBuffer(GL_ELEMENT_ARRAY_BUFFER, quad_elements_vbo_));
  62   GLC(gl_,
  63       gl_->BufferData(GL_ELEMENT_ARRAY_BUFFER,
  64                       sizeof(quad_index_list),
  65                       quad_index_list,
  66                       GL_STATIC_DRAW));
  67 }
  68
  69 GeometryBinding::~GeometryBinding() {
  70   gl_->DeleteBuffers(1, &quad_vertices_vbo_);
  71   gl_->DeleteBuffers(1, &quad_elements_vbo_);
  72 }
  73
  74 void GeometryBinding::PrepareForDraw() {
  75   GLC(gl_, gl_->BindBuffer(GL_ELEMENT_ARRAY_BUFFER, quad_elements_vbo_));
  76
  77   GLC(gl_, gl_->BindBuffer(GL_ARRAY_BUFFER, quad_vertices_vbo_));
  78   // OpenGL defines the last parameter to VertexAttribPointer as type
  79   // "const GLvoid*" even though it is actually an offset into the buffer
  80   // object's data store and not a pointer to the client's address space.
  81   const void* offsets[3] = {
  82       0, reinterpret_cast<const void*>(
  83              3 * sizeof(float)),  // NOLINT(runtime/sizeof)
  84       reinterpret_cast<const void*>(5 *
  85                                     sizeof(float)),  // NOLINT(runtime/sizeof)
  86   };
  87
  88   GLC(gl_,
  89       gl_->VertexAttribPointer(PositionAttribLocation(),
  90                                3,
  91                                GL_FLOAT,
  92                                false,
  93                                6 * sizeof(float),  // NOLINT(runtime/sizeof)
  94                                offsets[0]));
  95   GLC(gl_,
  96       gl_->VertexAttribPointer(TexCoordAttribLocation(),
  97                                2,
  98                                GL_FLOAT,
  99                                false,
 100                                6 * sizeof(float),  // NOLINT(runtime/sizeof)
 101                                offsets[1]));
 102   GLC(gl_,
 103       gl_->VertexAttribPointer(TriangleIndexAttribLocation(),
 104                                1,
 105                                GL_FLOAT,
 106                                false,
 107                                6 * sizeof(float),  // NOLINT(runtime/sizeof)
 108                                offsets[2]));
 109   GLC(gl_, gl_->EnableVertexAttribArray(PositionAttribLocation()));
 110   GLC(gl_, gl_->EnableVertexAttribArray(TexCoordAttribLocation()));
 111   GLC(gl_, gl_->EnableVertexAttribArray(TriangleIndexAttribLocation()));
 112 }
 113
 114 }  // namespace cc