Realtime Compositor: Implement static cache manager

This patch introduces the concept of a Cached Resource that can be
cached across compositor evaluations as well as used by multiple
operations in the same evaluation. Additionally, this patch implements a
new structure for the realtime compositor, the Static Cache Manager,
that manages all the cached resources and deletes them when they are no
longer needed.

This improves responsiveness while adjusting compositor node trees and
also conserves memory usage.

Differential Revision: https://developer.blender.org/D16357

Reviewed By: Clement Foucault

1 files changed, 53 insertions, 0 deletions

diff --git a/source/blender/compositor/realtime_compositor/cached_resources/COM_symmetric_separable_blur_weights.hh b/source/blender/compositor/realtime_compositor/cached_resources/COM_symmetric_separable_blur_weights.hh
new file mode 100644
index 00000000000..85e75e4535d
--- /dev/null
+++ b/source/blender/compositor/realtime_compositor/cached_resources/COM_symmetric_separable_blur_weights.hh
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#pragma once
+
+#include <cstdint>
+
+#include "BLI_math_vec_types.hh"
+
+#include "GPU_shader.h"
+#include "GPU_texture.h"
+
+#include "COM_cached_resource.hh"
+
+namespace blender::realtime_compositor {
+
+/* ------------------------------------------------------------------------------------------------
+ * Symmetric Separable Blur Weights Key.
+ */
+class SymmetricSeparableBlurWeightsKey {
+ public:
+  int type;
+  float radius;
+
+  SymmetricSeparableBlurWeightsKey(int type, float radius);
+
+  uint64_t hash() const;
+};
+
+bool operator==(const SymmetricSeparableBlurWeightsKey &a,
+                const SymmetricSeparableBlurWeightsKey &b);
+
+/* -------------------------------------------------------------------------------------------------
+ * Symmetric Separable Blur Weights.
+ *
+ * A cached resource that computes and caches a 1D GPU texture containing the weights of the
+ * separable filter of the given type and radius. The filter is assumed to be symmetric, because
+ * the filter functions are all even functions. Consequently, only the positive half of the filter
+ * is computed and the shader takes that into consideration. */
+class SymmetricSeparableBlurWeights : public CachedResource {
+ private:
+  GPUTexture *texture_ = nullptr;
+
+ public:
+  SymmetricSeparableBlurWeights(int type, float radius);
+
+  ~SymmetricSeparableBlurWeights();
+
+  void bind_as_texture(GPUShader *shader, const char *texture_name) const;
+
+  void unbind_as_texture() const;
+};
+
+}  // namespace blender::realtime_compositor