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 {
 
-GeometryBinding::GeometryBinding(gpu::gles2::GLES2Interface* gl,
-                                 const gfx::RectF& quad_vertex_rect)
-    : gl_(gl), quad_vertices_vbo_(0), quad_elements_vbo_(0) {
-  struct Vertex {
+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];
-  };
+};
+
+struct Quad {
+  Vertex v0, v1, v2, v3;
+};
+
+struct QuadIndex {
+  uint16 data[6];
+};
+
+StaticGeometryBinding::StaticGeometryBinding(gpu::gles2::GLES2Interface* gl,
+                                             const gfx::RectF& quad_vertex_rect)
+    : gl_(gl), quad_vertices_vbo_(0), quad_elements_vbo_(0) {
+  Quad quads[8];
+  QuadIndex quad_indices[8];
 
   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};
+  for (size_t 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, 0.0f},
+                 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;
+    quads[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;
+    quad_indices[i] = y;
   }
 
-  gl_->GenBuffers(1, &quad_vertices_vbo_);
-  gl_->GenBuffers(1, &quad_elements_vbo_);
+  GLC(gl_, gl_->GenBuffers(1, &quad_vertices_vbo_));
+  GLC(gl_, 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_->BufferData(GL_ARRAY_BUFFER, sizeof(Quad) * 8, quads,
+                           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));
+  GLC(gl_, gl_->BufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(QuadIndex) * 8,
+                           &quad_indices, GL_STATIC_DRAW));
 }
 
-GeometryBinding::~GeometryBinding() {
-  gl_->DeleteBuffers(1, &quad_vertices_vbo_);
-  gl_->DeleteBuffers(1, &quad_elements_vbo_);
-}
+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));
 
-void GeometryBinding::PrepareForDraw() {
-  GLC(gl_, gl_->BindBuffer(GL_ELEMENT_ARRAY_BUFFER, quad_elements_vbo_));
-
-  GLC(gl_, gl_->BindBuffer(GL_ARRAY_BUFFER, quad_vertices_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(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()));
+  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()));
+}
+
+StaticGeometryBinding::~StaticGeometryBinding() {
+  gl_->DeleteBuffers(1, &quad_vertices_vbo_);
+  gl_->DeleteBuffers(1, &quad_elements_vbo_);
+}
+
+void StaticGeometryBinding::PrepareForDraw() {
+  SetupGLContext(gl_, quad_elements_vbo_, quad_vertices_vbo_);
+}
+
+DynamicGeometryBinding::DynamicGeometryBinding(gpu::gles2::GLES2Interface* gl)
+    : gl_(gl), quad_vertices_vbo_(0), quad_elements_vbo_(0) {
+  Quad quads[8];
+  QuadIndex quad_indices[8];
+
+  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");
+
+  GLC(gl_, gl_->GenBuffers(1, &quad_vertices_vbo_));
+  GLC(gl_, 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) * 1, quads,
+                           GL_DYNAMIC_DRAW));
+
+  GLC(gl_, gl_->BindBuffer(GL_ELEMENT_ARRAY_BUFFER, quad_elements_vbo_));
+  GLC(gl_, gl_->BufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(QuadIndex) * 1,
+                           &quad_indices, GL_DYNAMIC_DRAW));
+}
+
+void DynamicGeometryBinding::InitializeCustomQuad(const gfx::QuadF& quad) {
+  float uv[] = {0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f};
+  InitializeCustomQuadWithUVs(quad, uv);
+}
+
+void DynamicGeometryBinding::InitializeCustomQuadWithUVs(const gfx::QuadF& quad,
+                                                         const float uv[8]) {
+  Vertex v0 = {{quad.p1().x(), quad.p1().y(), 0.0f}, {uv[0], uv[1]}, 0.0f};
+  Vertex v1 = {{quad.p2().x(), quad.p2().y(), 0.0f}, {uv[2], uv[3]}, 1.0f};
+  Vertex v2 = {{quad.p3().x(), quad.p3().y(), 0.0f}, {uv[4], uv[5]}, 2.0f};
+  Vertex v3 = {{quad.p4().x(), quad.p4().y(), 0.0f}, {uv[6], uv[7]}, 3.0f};
+
+  Quad local_quad = {v0, v1, v2, v3};
+  QuadIndex quad_index = {{static_cast<uint16>(0),
+                           static_cast<uint16>(1),
+                           static_cast<uint16>(2),
+                           static_cast<uint16>(3),
+                           static_cast<uint16>(0),
+                           static_cast<uint16>(2)}};
+
+  GLC(gl_, gl_->BufferSubData(GL_ARRAY_BUFFER, 0, sizeof(Quad), &local_quad));
+  GLC(gl_, gl_->BufferSubData(GL_ELEMENT_ARRAY_BUFFER, 0, sizeof(QuadIndex),
+                              &quad_index));
+}
+
+void DynamicGeometryBinding::PrepareForDraw() {
+  SetupGLContext(gl_, quad_elements_vbo_, quad_vertices_vbo_);
 }
 
 }  // namespace cc