Optimize VAO/VBO usage for minimal state changes.

[movit] / dither_effect.h

diff --git a/dither_effect.h b/dither_effect.h
index 943220aed55ad3dc524e4404b06ef2838f917831..921a1ef5e1130ca6184e401fe06e8b267b4c67e2 100644 (file)
--- 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 +43,31 @@
 // like many LCD monitors do, but it starts to get very hairy, again, for limited gains.)
 // The dither is also deterministic across runs.
 
+#include <epoxy/gl.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; }
+       virtual bool one_to_one_sampling() const { return true; }
+
        void set_gl_state(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num);
 
 private:
@@ -62,7 +78,11 @@ private:
        int texture_width, texture_height;
 
        GLuint texnum;
-       bool need_texture_update;
+       float uniform_round_fac, uniform_inv_round_fac;
+       float uniform_tc_scale[2];
+       GLint uniform_dither_tex;
 };
 
-#endif // !defined(_DITHER_EFFECT_H)
+}  // namespace movit
+
+#endif // !defined(_MOVIT_DITHER_EFFECT_H)