X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=multiply_effect.h;fp=multiply_effect.h;h=8de261aebaff82465b6e9c3671abb76b30b1db45;hb=e33b485dcb7bdbe056f6511945d5eb118c085d65;hp=0000000000000000000000000000000000000000;hpb=5c97329dd35909847e2120b0b368b2723ffe5a44;p=movit

diff --git a/multiply_effect.h b/multiply_effect.h
new file mode 100644
index 0000000..8de261a
--- /dev/null
+++ b/multiply_effect.h
@@ -0,0 +1,24 @@
+#ifndef _MOVIT_MULTIPLY_EFFECT_H
+#define _MOVIT_MULTIPLY_EFFECT_H 1
+
+// An effect that multiplies every pixel by a constant (separate for each of
+// R, G, B, A). A common use would be to reduce the alpha of an overlay before
+// sending it through OverlayEffect, e.g. with R=G=B=A=0.3 to get 30% alpha
+// (remember, alpha is premultiplied).
+
+#include <GL/glew.h>
+#include <string>
+
+#include "effect.h"
+
+class MultiplyEffect : public Effect {
+public:
+	MultiplyEffect();
+	virtual std::string effect_type_id() const { return "MultiplyEffect"; }
+	std::string output_fragment_shader();
+
+private:
+	RGBATuple factor;
+};
+
+#endif // !defined(_MOVIT_MULTIPLY_EFFECT_H)