Make Movit work in premultiplied alpha.

[movit] / alpha_division_effect.h

diff --git a/alpha_division_effect.h b/alpha_division_effect.h
new file mode 100644 (file)
index 0000000..e700112
--- /dev/null
+++ b/alpha_division_effect.h
@@ -0,0 +1,15 @@
+#ifndef _ALPHA_DIVISION_EFFECT_H
+#define _ALPHA_DIVISION_EFFECT_H 1
+
+// Convert premultiplied alpha to postmultiplied alpha, simply by multiplying.
+
+#include "effect.h"
+
+class AlphaDivisionEffect : public Effect {
+public:
+       AlphaDivisionEffect() {}
+       virtual std::string effect_type_id() const { return "AlphaDivisionEffect"; }
+       std::string output_fragment_shader();
+};
+
+#endif // !defined(_ALPHA_DIVISION_EFFECT_H)