Make Movit work in premultiplied alpha.

[movit] / alpha_multiplication_effect.h

diff --git a/alpha_multiplication_effect.h b/alpha_multiplication_effect.h
new file mode 100644 (file)
index 0000000..c64f2dc
--- /dev/null
+++ b/alpha_multiplication_effect.h
@@ -0,0 +1,15 @@
+#ifndef _ALPHA_MULTIPLICATION_EFFECT_H
+#define _ALPHA_MULTIPLICATION_EFFECT_H 1
+
+// Convert postmultiplied alpha to premultiplied alpha, simply by multiplying.
+
+#include "effect.h"
+
+class AlphaMultiplicationEffect : public Effect {
+public:
+       AlphaMultiplicationEffect() {}
+       virtual std::string effect_type_id() const { return "AlphaMultiplicationEffect"; }
+       std::string output_fragment_shader();
+};
+
+#endif // !defined(_ALPHA_MULTIPLICATION_EFFECT_H)