+ // 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 at most two Y'CbCr
+ // outputs, and they must have the same <ycbcr_format> and <type>.
+ // (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.)
+ //
+ // Only 4:4:4 output is supported due to fragment shader limitations,
+ // so chroma_subsampling_x and chroma_subsampling_y must both be 1.
+ // <type> should match the data type of the FBO you are rendering to,
+ // so that if you use 16-bit output (GL_UNSIGNED_SHORT), you will get
+ // 8-, 10- or 12-bit output correctly as determined by <ycbcr_format.num_levels>.
+ // Using e.g. ycbcr_format.num_levels == 1024 with GL_UNSIGNED_BYTE is
+ // nonsensical and invokes undefined behavior.
+ //
+ // 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,
+ const YCbCrFormat &ycbcr_format,
+ YCbCrOutputSplitting output_splitting = YCBCR_OUTPUT_INTERLEAVED,
+ GLenum output_type = GL_UNSIGNED_BYTE);
+
+ // Change Y'CbCr output format. (This can be done also after finalize()).
+ // Note that you are not allowed to change subsampling parameters;
+ // however, you can change the color space parameters, ie.,
+ // luma_coefficients, full_range and num_levels.
+ void change_ycbcr_output_format(const YCbCrFormat &ycbcr_format);
+
+ // Set number of output bits, to scale the dither.
+ // 8 is the right value for most outputs.
+ //
+ // Special note for 10- and 12-bit Y'CbCr packed into GL_UNSIGNED_SHORT:
+ // This is relative to the actual output, not the logical one, so you should
+ // specify 16 here, not 10 or 12.
+ //
+ // The default, 0, is a special value that means no dither.
+ void set_dither_bits(unsigned num_bits)
+ {
+ 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;
+ }
+
+ // Set intermediate format for framebuffers used when we need to bounce
+ // to a temporary texture. The default, GL_RGBA16F, is good for most uses;
+ // it is precise, has good range, and is relatively efficient. However,
+ // if you need even more speed and your chain can do with some loss of
+ // accuracy, you can change the format here (before calling finalize).
+ // Calculations between bounce buffers are still in 32-bit floating-point
+ // no matter what you specify.