#include "effect.h"
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:
int width, height, num_bits;
int last_width, last_height, last_num_bits;
+ int texture_width, texture_height;
GLuint texnum;
bool need_texture_update;