src/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 "third_party/khronos/GLES2/gl2.h"
  10 #include "ui/gfx/rect_f.h"
  11
  12 namespace cc {
  13
  14 GeometryBinding::GeometryBinding(gpu::gles2::GLES2Interface* gl,
  15                                  const gfx::RectF& quad_vertex_rect)
  16     : gl_(gl), quad_vertices_vbo_(0), quad_elements_vbo_(0) {
  17   struct Vertex {
  18     float a_position[3];
  19     float a_texCoord[2];
  20     // Index of the vertex, divide by 4 to have the matrix for this quad.
  21     float a_index;
  22   };
  23   struct Quad {
  24     Vertex v0, v1, v2, v3;
  25   };
  26   struct QuadIndex {
  27     uint16 data[6];
  28   };
  29
  30   COMPILE_ASSERT(sizeof(Quad) == 24 * sizeof(float),  // NOLINT(runtime/sizeof)
  31                  struct_is_densely_packed);
  32   COMPILE_ASSERT(
  33       sizeof(QuadIndex) == 6 * sizeof(uint16_t),  // NOLINT(runtime/sizeof)
  34       struct_is_densely_packed);
  35
  36   Quad quad_list[8];
  37   QuadIndex quad_index_list[8];
  38   for (int i = 0; i < 8; i++) {
  39     Vertex v0 = {{quad_vertex_rect.x(), quad_vertex_rect.bottom(), 0.0f, },
  40                  {0.0f, 1.0f, }, i * 4.0f + 0.0f};
  41     Vertex v1 = {{quad_vertex_rect.x(), quad_vertex_rect.y(), 0.0f, },
  42                  {0.0f, 0.0f, }, i * 4.0f + 1.0f};
  43     Vertex v2 = {{quad_vertex_rect.right(), quad_vertex_rect.y(), 0.0f, },
  44                  {1.0f, .0f, }, i * 4.0f + 2.0f};
  45     Vertex v3 = {{quad_vertex_rect.right(), quad_vertex_rect.bottom(), 0.0f, },
  46                  {1.0f, 1.0f, }, i * 4.0f + 3.0f};
  47     Quad x = {v0, v1, v2, v3};
  48     quad_list[i] = x;
  49     QuadIndex y = {
  50         {static_cast<uint16>(0 + 4 * i), static_cast<uint16>(1 + 4 * i),
  51          static_cast<uint16>(2 + 4 * i), static_cast<uint16>(3 + 4 * i),
  52          static_cast<uint16>(0 + 4 * i), static_cast<uint16>(2 + 4 * i)}};
  53     quad_index_list[i] = y;
  54   }
  55
  56   gl_->GenBuffers(1, &quad_vertices_vbo_);
  57   gl_->GenBuffers(1, &quad_elements_vbo_);
  58   GLC(gl_, gl_->BindBuffer(GL_ARRAY_BUFFER, quad_vertices_vbo_));
  59   GLC(gl_,
  60       gl_->BufferData(
  61           GL_ARRAY_BUFFER, sizeof(quad_list), quad_list, GL_STATIC_DRAW));
  62   GLC(gl_, gl_->BindBuffer(GL_ELEMENT_ARRAY_BUFFER, quad_elements_vbo_));
  63   GLC(gl_,
  64       gl_->BufferData(GL_ELEMENT_ARRAY_BUFFER,
  65                       sizeof(quad_index_list),
  66                       quad_index_list,
  67                       GL_STATIC_DRAW));
  68 }
  69
  70 GeometryBinding::~GeometryBinding() {
  71   gl_->DeleteBuffers(1, &quad_vertices_vbo_);
  72   gl_->DeleteBuffers(1, &quad_elements_vbo_);
  73 }
  74
  75 void GeometryBinding::PrepareForDraw() {
  76   GLC(gl_, gl_->BindBuffer(GL_ELEMENT_ARRAY_BUFFER, quad_elements_vbo_));
  77
  78   GLC(gl_, gl_->BindBuffer(GL_ARRAY_BUFFER, quad_vertices_vbo_));
  79   // OpenGL defines the last parameter to VertexAttribPointer as type
  80   // "const GLvoid*" even though it is actually an offset into the buffer
  81   // object's data store and not a pointer to the client's address space.
  82   const void* offsets[3] = {
  83       0, reinterpret_cast<const void*>(
  84              3 * sizeof(float)),  // NOLINT(runtime/sizeof)
  85       reinterpret_cast<const void*>(5 *
  86                                     sizeof(float)),  // NOLINT(runtime/sizeof)
  87   };
  88
  89   GLC(gl_,
  90       gl_->VertexAttribPointer(PositionAttribLocation(),
  91                                3,
  92                                GL_FLOAT,
  93                                false,
  94                                6 * sizeof(float),  // NOLINT(runtime/sizeof)
  95                                offsets[0]));
  96   GLC(gl_,
  97       gl_->VertexAttribPointer(TexCoordAttribLocation(),
  98                                2,
  99                                GL_FLOAT,
 100                                false,
 101                                6 * sizeof(float),  // NOLINT(runtime/sizeof)
 102                                offsets[1]));
 103   GLC(gl_,
 104       gl_->VertexAttribPointer(TriangleIndexAttribLocation(),
 105                                1,
 106                                GL_FLOAT,
 107                                false,
 108                                6 * sizeof(float),  // NOLINT(runtime/sizeof)
 109                                offsets[2]));
 110   GLC(gl_, gl_->EnableVertexAttribArray(PositionAttribLocation()));
 111   GLC(gl_, gl_->EnableVertexAttribArray(TexCoordAttribLocation()));
 112   GLC(gl_, gl_->EnableVertexAttribArray(TriangleIndexAttribLocation()));
 113 }
 114
 115 }  // namespace cc