Implement a compute shdaer version of DeinterlaceEffect.

[movit] / deinterlace_effect.h

diff --git a/deinterlace_effect.h b/deinterlace_effect.h
index 793532242aa8d56321d791da02ab06e53bca37f5..5841f86767a512ef904766b841a46321c1616894 100644 (file)
--- a/deinterlace_effect.h
+++ b/deinterlace_effect.h
@@ -52,18 +52,26 @@
 // parity, so all the others are implicit).
 
 #include <epoxy/gl.h>
+#include <memory>
 #include <string>
 
 #include "effect.h"
 
 namespace movit {
 
+class DeinterlaceComputeEffect;
+
 class DeinterlaceEffect : public Effect {
 public:
        DeinterlaceEffect();
        virtual std::string effect_type_id() const { return "DeinterlaceEffect"; }
        std::string output_fragment_shader();
 
+       // Replaces itself with DeinterlaceComputeEffect if compute shaders are supported.
+       // Otherwise, does nothing.
+       void rewrite_graph(EffectChain *graph, Node *self);
+       bool set_int(const std::string &key, int value);
+
        void set_gl_state(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num);
 
        // First = before previous, second = previous, third = current,
@@ -85,6 +93,11 @@ public:
        enum FieldPosition { TOP = 0, BOTTOM = 1 };
 
 private:
+       // If compute shaders are supported, contains the actual effect.
+       // If not, nullptr.
+       std::unique_ptr<DeinterlaceComputeEffect> compute_effect_owner;
+       DeinterlaceComputeEffect *compute_effect = nullptr;
+
        unsigned widths[5], heights[5];
 
        // See file-level comment for explanation of this option.
@@ -114,6 +127,50 @@ private:
        float other_offset[3];
 };
 
+// A compute shader implementation of DeinterlaceEffect. It saves a bunch of loads
+// since it can share them between neighboring pixels (and also does not need
+// texture bounce), so it has the potential to be faster, although exactly how
+// much depends on your chain and other factors. DeinterlaceEffect will
+// automatically become a proxy to DeinterlaceComputeEffect if your system
+// supports compute shaders.
+class DeinterlaceComputeEffect : public Effect {
+public:
+       DeinterlaceComputeEffect();
+       virtual std::string effect_type_id() const { return "DeinterlaceComputeEffect"; }
+       std::string output_fragment_shader();
+
+       void set_gl_state(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num);
+
+       virtual unsigned num_inputs() const { return 5; }
+       virtual bool changes_output_size() const { return true; }
+       virtual bool is_compute_shader() const { return true; }
+       virtual void get_compute_dimensions(unsigned output_width, unsigned output_height,
+                                           unsigned *x, unsigned *y, unsigned *z) const;
+
+       virtual AlphaHandling alpha_handling() const { return INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK; }
+
+       virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height);
+       virtual void get_output_size(unsigned *width, unsigned *height,
+                                    unsigned *virtual_width, unsigned *virtual_height) const;
+
+       enum FieldPosition { TOP = 0, BOTTOM = 1 };
+
+private:
+       unsigned widths[5], heights[5];
+
+       // See file-level comment for explanation of this option.
+       bool enable_spatial_interlacing_check;
+
+       // Which field the current input (the middle one) is.
+       FieldPosition current_field_position;
+
+       // Offset for one pixel in the horizontal and verticla direction (1/width, 1/height).
+       float inv_width, inv_height;
+
+       // For evaluating the low-pass filter (in the current field). Four taps.
+       float current_field_vertical_offset;
+};
+
 }  // namespace movit
 
 #endif // !defined(_MOVIT_DEINTERLACE_EFFECT_H)