X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=effect_chain.h;h=9fb1d4ea6642a48ec38216a0c5a5b607b3f48015;hp=1be98916d9ccd6952580aef165488c55cecc7588;hb=865a82f44545fa48a67eda605a18315d6ea15cfd;hpb=ddbe6136a25fddc14c7b70c9d76857313b8f9957

diff --git a/effect_chain.h b/effect_chain.h
index 1be9891..9fb1d4e 100644
--- a/effect_chain.h
+++ b/effect_chain.h
@@ -55,6 +55,49 @@ enum OutputAlphaFormat {
 	OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED,
 };
 
+// RGBA output is nearly always packed; Y'CbCr, however, is often planar
+// due to chroma subsampling. This enum controls how add_ycbcr_output()
+// distributes the color channels between the fragment shader outputs.
+// Obviously, anything except YCBCR_OUTPUT_INTERLEAVED will be meaningless
+// unless you use render_to_fbo() and have an FBO with multiple render
+// targets attached (the other outputs will be discarded).
+enum YCbCrOutputSplitting {
+	// Only one output: Store Y'CbCr into the first three output channels,
+	// respectively, plus alpha. This is also called “chunked” or
+	// ”packed” mode.
+	YCBCR_OUTPUT_INTERLEAVED,
+
+	// Store Y' and alpha into the first output (in the red and alpha
+	// channels; effect to the others is undefined), and Cb and Cr into
+	// the first two channels of the second output. This is particularly
+	// useful if you want to end up in a format like NV12, where all the
+	// Y' samples come first and then Cb and Cr come interlevaed afterwards.
+	// You will still need to do the chroma subsampling yourself to actually
+	// get down to NV12, though.
+	YCBCR_OUTPUT_SPLIT_Y_AND_CBCR,
+
+	// Store Y' and alpha into the first output, Cb into the first channel
+	// of the second output and Cr into the first channel of the third output.
+	// (Effect on the other channels is undefined.) Essentially gives you
+	// 4:4:4 planar, or ”yuv444p”.
+	YCBCR_OUTPUT_PLANAR,
+};
+
+// Where (0,0) is taken to be in the output. If you want to render to an
+// OpenGL screen, you should keep the default of bottom-left, as that is
+// OpenGL's natural coordinate system. However, there are cases, such as if you
+// render to an FBO and read the pixels back into some other system, where
+// you'd want a top-left origin; if so, an additional flip step will be added
+// at the very end (but done in a vertex shader, so it will have zero extra
+// cost).
+//
+// Note that Movit's coordinate system in general consistently puts (0,0) in
+// the top left for _input_, no matter what you set as output origin.
+enum OutputOrigin {
+	OUTPUT_ORIGIN_BOTTOM_LEFT,
+	OUTPUT_ORIGIN_TOP_LEFT,
+};
+
 // A node in the graph; basically an effect and some associated information.
 class Node {
 public:
@@ -179,14 +222,20 @@ public:
 	}
 	Effect *add_effect(Effect *effect, const std::vector<Effect *> &inputs);
 
-	// Adds an RGB output. Note that you can only have one output.
+	// Adds an RGBA output. Note that you can have at most one RGBA output and one
+	// Y'CbCr output (see below for details).
 	void add_output(const ImageFormat &format, OutputAlphaFormat alpha_format);
 
 	// Adds an YCbCr output. Note that you can only have one output.
 	// Currently, only chunked packed output is supported, and only 4:4:4
 	// (so chroma_subsampling_x and chroma_subsampling_y must both be 1).
+	//
+	// If you have both RGBA and Y'CbCr output, the RGBA output will come
+	// in the last draw buffer. Also, <format> and <alpha_format> must be
+	// identical between the two.
 	void add_ycbcr_output(const ImageFormat &format, OutputAlphaFormat alpha_format,
-	                      const YCbCrFormat &ycbcr_format);
+	                      const YCbCrFormat &ycbcr_format,
+			      YCbCrOutputSplitting output_splitting = YCBCR_OUTPUT_INTERLEAVED);
 
 	// Set number of output bits, to scale the dither.
 	// 8 is the right value for most outputs.
@@ -196,6 +245,14 @@ public:
 		this->num_dither_bits = num_bits;
 	}
 
+	// Set where (0,0) is taken to be in the output. The default is
+	// OUTPUT_ORIGIN_BOTTOM_LEFT, which is usually what you want
+	// (see OutputOrigin above for more details).
+	void set_output_origin(OutputOrigin output_origin)
+	{
+		this->output_origin = output_origin;
+	}
+
 	void finalize();
 
 	// Measure the GPU time used for each actual phase during rendering.
@@ -336,9 +393,9 @@ private:
 	ImageFormat output_format;
 	OutputAlphaFormat output_alpha_format;
 
-	enum OutputColorType { OUTPUT_COLOR_RGB, OUTPUT_COLOR_YCBCR };
-	OutputColorType output_color_type;
-	YCbCrFormat output_ycbcr_format;  // If output_color_type == OUTPUT_COLOR_YCBCR.
+	bool output_color_rgba, output_color_ycbcr;
+	YCbCrFormat output_ycbcr_format;              // If output_color_ycbcr is true.
+	YCbCrOutputSplitting output_ycbcr_splitting;  // If output_color_ycbcr is true.
 
 	std::vector<Node *> nodes;
 	std::map<Effect *, Node *> node_map;
@@ -348,6 +405,7 @@ private:
 	std::vector<Phase *> phases;
 
 	unsigned num_dither_bits;
+	OutputOrigin output_origin;
 	bool finalized;
 
 	ResourcePool *resource_pool;