X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=resample_effect.h;fp=resample_effect.h;h=fbe5fc506674197d0433c1c4eed4eedbf3ec9e73;hp=0000000000000000000000000000000000000000;hb=fb92a4e217a92ecf83b7812cc6933f6f3048b752;hpb=9e62fbe2ac764479c449472d8bda52ac4df0de91

diff --git a/resample_effect.h b/resample_effect.h
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+#ifndef _RESAMPLE_EFFECT_H
+#define _RESAMPLE_EFFECT_H 1
+
+// High-quality image resizing, either up or down.
+//
+// The default scaling offered by the GPU (and as used in ResizeEffect)
+// is bilinear (optionally mipmapped), which is not the highest-quality
+// choice, especially for upscaling. ResampleEffect offers the three-lobed
+// Lanczos kernel, which is among the most popular choices in image
+// processing. While it does have its weaknesses, in particular a certain
+// ringing/sharpening effect with artifacts that accumulate over several
+// consecutive resizings, it is generally regarded as the best tradeoff.
+//
+// Works in two passes; first horizontal, then vertical (ResampleEffect,
+// which is what the user is intended to use, instantiates two copies of
+// SingleResamplePassEffect behind the scenes).
+
+#include "effect.h"
+
+class SingleResamplePassEffect;
+
+class ResampleEffect : public Effect {
+public:
+	ResampleEffect();
+
+	virtual std::string effect_type_id() const { return "ResampleEffect"; }
+
+	// We want this for the same reason as ResizeEffect; we could end up scaling
+	// down quite a lot.
+	virtual bool needs_texture_bounce() const { return true; }
+	virtual bool needs_srgb_primaries() const { return false; }
+
+	virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height);
+
+	virtual std::string output_fragment_shader() {
+		assert(false);
+	}
+	virtual void set_gl_state(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num) {
+		assert(false);
+	}
+
+	virtual void rewrite_graph(EffectChain *graph, Node *self);
+	virtual bool set_float(const std::string &key, float value);
+	
+private:
+	void update_size();
+	
+	SingleResamplePassEffect *hpass, *vpass;
+	int input_width, input_height, output_width, output_height;
+};
+
+class SingleResamplePassEffect : public Effect {
+public:
+	// If parent is non-NULL, calls to inform_input_size will be forwarded,
+	// so that it can inform both passes about the right input and output
+	// resolutions.
+	SingleResamplePassEffect(ResampleEffect *parent);
+	~SingleResamplePassEffect();
+	virtual std::string effect_type_id() const { return "SingleResamplePassEffect"; }
+
+	std::string output_fragment_shader();
+
+	virtual bool needs_texture_bounce() const { return true; }
+	virtual bool needs_srgb_primaries() const { return false; }
+
+	virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height) {
+		if (parent != NULL) {
+			parent->inform_input_size(input_num, width, height);
+		}
+	}
+	virtual bool changes_output_size() const { return true; }
+
+	virtual void get_output_size(unsigned *width, unsigned *height) const {
+		*width = this->output_width;
+		*height = this->output_height;
+	}
+
+	void set_gl_state(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num);
+	
+	enum Direction { HORIZONTAL = 0, VERTICAL = 1 };
+
+private:
+	void update_texture(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num);
+
+	ResampleEffect *parent;
+	Direction direction;
+	GLuint texnum;
+	int input_width, input_height, output_width, output_height;
+	int last_input_width, last_input_height, last_output_width, last_output_height;
+	int src_samples;
+};
+
+#endif // !defined(_RESAMPLE_EFFECT_H)