COM_symmetric_blur_weights.hh

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/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#pragma once
 
#include <cstdint>
#include <memory>
 
#include "BLI_map.hh"
#include "BLI_math_vector_types.hh"
 
#include "GPU_shader.hh"
#include "GPU_texture.hh"
 
#include "COM_cached_resource.hh"
 
namespace blender::realtime_compositor {
 
class Context;
 
/* ------------------------------------------------------------------------------------------------
 * Symmetric Blur Weights Key.
 */
class SymmetricBlurWeightsKey {
 public:
  int type;
  float2 radius;
 
  SymmetricBlurWeightsKey(int type, float2 radius);
 
  uint64_t hash() const;
};
 
bool operator==(const SymmetricBlurWeightsKey &a, const SymmetricBlurWeightsKey &b);
 
/* -------------------------------------------------------------------------------------------------
 * Symmetric Blur Weights.
 *
 * A cached resource that computes and caches a 2D GPU texture containing the weights of the filter
 * of the given type and radius. The filter is assumed to be symmetric, because the filter
 * functions are evaluated on the normalized distance to the center. Consequently, only the upper
 * right quadrant are computed and the shader takes that into consideration. */
class SymmetricBlurWeights : public CachedResource {
 private:
  GPUTexture *texture_ = nullptr;
 
 public:
  SymmetricBlurWeights(Context &context, int type, float2 radius);
 
  ~SymmetricBlurWeights();
 
  void bind_as_texture(GPUShader *shader, const char *texture_name) const;
 
  void unbind_as_texture() const;
};
 
/* ------------------------------------------------------------------------------------------------
 * Symmetric Blur Weights Container.
 */
class SymmetricBlurWeightsContainer : public CachedResourceContainer {
 private:
  Map<SymmetricBlurWeightsKey, std::unique_ptr<SymmetricBlurWeights>> map_;
 
 public:
  void reset() override;
 
  /* Check if there is an available SymmetricBlurWeights cached resource with the given parameters
   * in the container, if one exists, return it, otherwise, return a newly created one and add it
   * to the container. In both cases, tag the cached resource as needed to keep it cached for the
   * next evaluation. */
  SymmetricBlurWeights &get(Context &context, int type, float2 radius);
};
 
}  // namespace blender::realtime_compositor