X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=mix_effect.h;h=fda06a6f9426426e9794637348c19f907a5894d5;hp=7342b90500538b10c08fb27840a3744a1a304cb7;hb=ac4fc36aa70ffefb6b9632dc0abea5cbbce5387b;hpb=ef7665d0d3854b3464800d8d7fef9a90f14d9a9f

diff --git a/mix_effect.h b/mix_effect.h
index 7342b90..fda06a6 100644
--- a/mix_effect.h
+++ b/mix_effect.h
@@ -1,20 +1,28 @@
-#ifndef _MIX_EFFECT_H
-#define _MIX_EFFECT_H 1
+#ifndef _MOVIT_MIX_EFFECT_H
+#define _MOVIT_MIX_EFFECT_H 1
 
-// Combine two images: a*x + b*y. (If you set a within [0,1] and b=1-a, you will get a fade.)
+// Combine two images: a*x + b*y. If you set a within [0,1] and b=1-a,
+// you will get a fade; if not, you may get surprising results (consider alpha).
+
+#include <string>
 
 #include "effect.h"
 
 class MixEffect : public Effect {
 public:
 	MixEffect();
+	virtual std::string effect_type_id() const { return "MixEffect"; }
 	std::string output_fragment_shader();
 
 	virtual bool needs_srgb_primaries() const { return false; }
 	virtual unsigned num_inputs() const { return 2; }
 
+	// TODO: In the common case where a+b=1, it would be useful to be able to set
+	// alpha_handling() to INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK. However, right now
+	// we have no way of knowing that at instantiation time.
+
 private:
 	float strength_first, strength_second;
 };
 
-#endif // !defined(_MIX_EFFECT_H)
+#endif // !defined(_MOVIT_MIX_EFFECT_H)