Support multiple Y'CbCr outputs.

[movit] / effect_chain.h

diff --git a/effect_chain.h b/effect_chain.h
index 48ed15291bbcbf92014ddd24ec1cb0b0a0554d44..ffa938947a6de8311ca8f17681b70ac4e9f4ca24 100644 (file)
--- a/effect_chain.h
+++ b/effect_chain.h
@@ -259,15 +259,21 @@ public:
        }
        Effect *add_effect(Effect *effect, const std::vector<Effect *> &inputs);
 
-       // Adds an RGBA output. Note that you can have at most one RGBA output and one
-       // Y'CbCr output (see below for details).
+       // Adds an RGBA output. Note that you can have at most one RGBA output and two
+       // Y'CbCr outputs (see below for details).
        void add_output(const ImageFormat &format, OutputAlphaFormat alpha_format);
 
-       // Adds an YCbCr output. Note that you can only have one Y'CbCr output.
-       // Currently, only 4:4:4 output is supported, so chroma_subsampling_x
-       // and chroma_subsampling_y must both be 1.
+       // Adds an YCbCr output. Note that you can only have at most two Y'CbCr
+       // outputs, and they must have the same <ycbcr_format>.
+       // (This limitation may be lifted in the future, to allow e.g. simultaneous
+       // 8- and 10-bit output. Currently, multiple Y'CbCr outputs are only
+       // useful in some very limited circumstances, like if one texture goes
+       // to some place you cannot easily read from later.)
        //
-       // If you have both RGBA and Y'CbCr output, the RGBA output will come
+       // Only 4:4:4 output is supported due to fragment shader limitations,
+       // so chroma_subsampling_x and chroma_subsampling_y must both be 1.
+       //
+       // If you have both RGBA and Y'CbCr output(s), 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,
@@ -485,9 +491,10 @@ private:
        ImageFormat output_format;
        OutputAlphaFormat output_alpha_format;
 
-       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.
+       bool output_color_rgba;
+       int num_output_color_ycbcr;                      // Max 2.
+       YCbCrFormat output_ycbcr_format;                 // If num_output_color_ycbcr is > 0.
+       YCbCrOutputSplitting output_ycbcr_splitting[2];  // If num_output_color_ycbcr is > N.
 
        std::vector<Node *> nodes;
        std::map<Effect *, Node *> node_map;