Add a simple luma wipe transition.

[movit] / luma_mix_effect.h

diff --git a/luma_mix_effect.h b/luma_mix_effect.h
new file mode 100644 (file)
index 0000000..8bd3c50
--- /dev/null
+++ b/luma_mix_effect.h
@@ -0,0 +1,35 @@
+#ifndef _MOVIT_LUMA_MIX_EFFECT_H
+#define _MOVIT_LUMA_MIX_EFFECT_H 1
+
+// Fade between two images based on a third monochrome one; lighter pixels
+// will be faded before darker pixels. This allows a wide range of different
+// video wipes implemented using a single effect.
+//
+// Note that despite the name, the third input's _red_ channel is what's used
+// for transitions; there is no luma calculation done. If you need that,
+// put a SaturationEffect in front to desaturate (which calculates luma).
+
+#include <string>
+
+#include "effect.h"
+
+namespace movit {
+
+class LumaMixEffect : public Effect {
+public:
+       LumaMixEffect();
+       virtual std::string effect_type_id() const { return "LumaMixEffect"; }
+       std::string output_fragment_shader();
+       virtual void set_gl_state(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num);
+
+       virtual bool needs_srgb_primaries() const { return false; }
+       virtual unsigned num_inputs() const { return 3; }
+       virtual AlphaHandling alpha_handling() const { return INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK; }
+
+private:
+       float transition_width, progress;
+};
+
+}  // namespace movit
+
+#endif // !defined(_MOVIT_MIX_EFFECT_H)