X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=effect.h;h=56c34d917c5c46084e89904ed76d938cc7782269;hb=1ec439c7fb975c09029adaa9090e7f35ce6484b8;hp=16b6cbb92149f7de70cf24d92d01a1182c8c343a;hpb=8ea03db1932e4a76f457e0ecdfe31a4c8be0e0eb;p=movit

diff --git a/effect.h b/effect.h
index 16b6cbb..56c34d9 100644
--- a/effect.h
+++ b/effect.h
@@ -25,6 +25,7 @@ class Node;
 
 // Can alias on a float[2].
 struct Point2D {
+	Point2D() {}
 	Point2D(float x, float y)
 		: x(x), y(y) {}
 
@@ -33,6 +34,7 @@ struct Point2D {
 
 // Can alias on a float[3].
 struct RGBTriplet {
+	RGBTriplet() {}
 	RGBTriplet(float r, float g, float b)
 		: r(r), g(g), b(b) {}
 
@@ -41,6 +43,7 @@ struct RGBTriplet {
 
 // Can alias on a float[4].
 struct RGBATuple {
+	RGBATuple() {}
 	RGBATuple(float r, float g, float b, float a)
 		: r(r), g(g), b(b), a(a) {}
 
@@ -161,12 +164,47 @@ public:
 	// needs mipmaps, you will also get them).
 	virtual bool needs_mipmaps() const { return false; }
 
+	// Whether there is a direct correspondence between input and output
+	// texels. Specifically, the effect must not:
+	//
+	//   1. Try to sample in the border (ie., outside the 0.0 to 1.0 area).
+	//   2. Try to sample between texels.
+	//   3. Sample with an x- or y-derivative different from -1 or 1.
+	//      (This also means needs_mipmaps() and one_to_one_sampling()
+	//      together would make no sense.)
+	//
+	// The most common case for this would be an effect that has an exact
+	// 1:1-correspondence between input and output texels, e.g. SaturationEffect.
+	// However, more creative things, like mirroring/flipping or padding,
+	// would also be allowed.
+	//
+	// The primary gain from setting this is that you can sample directly
+	// from an effect that changes output size (see changes_output_size() below),
+	// without going through a bounce texture. It won't work for effects that
+	// set sets_virtual_output_size(), though.
+	//
+	// Does not make a lot of sense together with needs_texture_bounce().
+	virtual bool one_to_one_sampling() const { return false; }
+
 	// Whether this effect wants to output to a different size than
-	// its input(s) (see inform_input_size(), below). If you set this to
-	// true, the output will be bounced to a texture (similarly to if the
-	// next effect set needs_texture_bounce()).
+	// its input(s) (see inform_input_size(), below). See also
+	// sets_virtual_output_size() below.
 	virtual bool changes_output_size() const { return false; }
 
+	// Whether your get_output_size() function (see below) intends to ever set
+	// virtual_width different from width, or similar for height.
+	// It does not make sense to set this to true if changes_output_size() is false.
+	virtual bool sets_virtual_output_size() const { return changes_output_size(); }
+
+	// Whether this effect is effectively sampling from a a single texture.
+	// If so, it will override needs_texture_bounce(); however, there are also
+	// two demands it needs to fulfill:
+	//
+	//  1. It needs to be an Input, ie. num_inputs() == 0.
+	//  2. It needs to allocate exactly one sampler in set_gl_state(),
+	//     and allow dependent effects to change that sampler state.
+	virtual bool is_single_texture() const { return false; }
+
 	// If changes_output_size() is true, you must implement this to tell
 	// the framework what output size you want. Also, you can set a
 	// virtual width/height, which is the size the next effect (if any)