buffer_bindings_gles.h

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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#ifndef FLUTTER_IMPELLER_RENDERER_BACKEND_GLES_BUFFER_BINDINGS_GLES_H_
#define FLUTTER_IMPELLER_RENDERER_BACKEND_GLES_BUFFER_BINDINGS_GLES_H_
 
#include <unordered_map>
#include <vector>
 
#include "impeller/core/shader_types.h"
#include "impeller/renderer/backend/gles/gles.h"
#include "impeller/renderer/backend/gles/proc_table_gles.h"
#include "impeller/renderer/command.h"
 
namespace impeller {
 
//------------------------------------------------------------------------------
/// @brief      Sets up stage bindings for single draw call in the OpenGLES
///             backend.
///
class BufferBindingsGLES {
 public:
  BufferBindingsGLES();
 
  ~BufferBindingsGLES();
 
  bool RegisterVertexStageInput(
      const ProcTableGLES& gl,
      const std::vector<ShaderStageIOSlot>& inputs,
      const std::vector<ShaderStageBufferLayout>& layouts);
 
  bool ReadUniformsBindings(const ProcTableGLES& gl, GLuint program);
 
  bool BindVertexAttributes(const ProcTableGLES& gl,
                            size_t vertex_offset) const;
 
  bool BindUniformData(const ProcTableGLES& gl,
                       Allocator& transients_allocator,
                       const Bindings& vertex_bindings,
                       const Bindings& fragment_bindings);
 
  bool UnbindVertexAttributes(const ProcTableGLES& gl) const;
 
 private:
  //----------------------------------------------------------------------------
  /// @brief      The arguments to glVertexAttribPointer.
  ///
  struct VertexAttribPointer {
    GLuint index = 0u;
    GLint size = 4;
    GLenum type = GL_FLOAT;
    GLenum normalized = GL_FALSE;
    GLsizei stride = 0u;
    GLsizei offset = 0u;
  };
  std::vector<VertexAttribPointer> vertex_attrib_arrays_;
 
  std::unordered_map<std::string, GLint> uniform_locations_;
 
  using BindingMap = std::unordered_map<std::string, std::vector<GLint>>;
  BindingMap binding_map_ = {};
 
  const std::vector<GLint>& ComputeUniformLocations(
      const ShaderMetadata* metadata);
 
  GLint ComputeTextureLocation(const ShaderMetadata* metadata);
 
  bool BindUniformBuffer(const ProcTableGLES& gl,
                         Allocator& transients_allocator,
                         const BufferResource& buffer);
 
  std::optional<size_t> BindTextures(const ProcTableGLES& gl,
                                     const Bindings& bindings,
                                     ShaderStage stage,
                                     size_t unit_start_index = 0);
 
  BufferBindingsGLES(const BufferBindingsGLES&) = delete;
 
  BufferBindingsGLES& operator=(const BufferBindingsGLES&) = delete;
};
 
}  // namespace impeller
 
#endif  // FLUTTER_IMPELLER_RENDERER_BACKEND_GLES_BUFFER_BINDINGS_GLES_H_