X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=dither_effect.h;h=20fb025532d5fea4e92329c7733d06669354b39d;hp=943220aed55ad3dc524e4404b06ef2838f917831;hb=45955bca8c14dd8cac4fa922e45fb0f8be507d58;hpb=f1a81dca72da9aa5103527b8c9494381204e70c5

diff --git a/dither_effect.h b/dither_effect.h
index 943220a..20fb025 100644
--- a/dither_effect.h
+++ b/dither_effect.h
@@ -1,5 +1,5 @@
-#ifndef _DITHER_EFFECT_H
-#define _DITHER_EFFECT_H 1
+#ifndef _MOVIT_DITHER_EFFECT_H
+#define _MOVIT_DITHER_EFFECT_H 1
 
 // Implements simple rectangular-PDF dither.
 //
@@ -43,15 +43,30 @@
 // like many LCD monitors do, but it starts to get very hairy, again, for limited gains.)
 // The dither is also deterministic across runs.
 
+#include <GL/glew.h>
+#include <string>
+
 #include "effect.h"
 
+namespace movit {
+
 class DitherEffect : public Effect {
-public:
+private:
+	// Should not be instantiated by end users;
+	// call EffectChain::set_dither_bits() instead.
 	DitherEffect();
+	friend class EffectChain;
+
+public:
 	~DitherEffect();
 	virtual std::string effect_type_id() const { return "DitherEffect"; }
 	std::string output_fragment_shader();
 
+	// Note that if we did error diffusion, we'd actually want to diffuse the
+	// premultiplied error. However, we need to do dithering in the same
+	// space as quantization, whether that be pre- or postmultiply.
+	virtual AlphaHandling alpha_handling() const { return DONT_CARE_ALPHA_TYPE; }
+
 	void set_gl_state(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num);
 
 private:
@@ -62,7 +77,8 @@ private:
 	int texture_width, texture_height;
 
 	GLuint texnum;
-	bool need_texture_update;
 };
 
-#endif // !defined(_DITHER_EFFECT_H)
+}  // namespace movit
+
+#endif // !defined(_MOVIT_DITHER_EFFECT_H)