OUTPUT_ORIGIN_TOP_LEFT,
};
+// Transformation to apply (if any) to pixel data in temporary buffers.
+// See set_intermediate_format() below for more information.
+enum FramebufferTransformation {
+ // The default; just store the value. This is what you usually want.
+ NO_FRAMEBUFFER_TRANSFORMATION,
+
+ // If the values are in linear light, store sqrt(x) to the framebuffer
+ // instead of x itself, of course undoing it with x² on read. Useful as
+ // a rough approximation to the sRGB curve. (If the values are not in
+ // linear light, just store them as-is.)
+ SQUARE_ROOT_FRAMEBUFFER_TRANSFORMATION,
+};
+
// A node in the graph; basically an effect and some associated information.
class Node {
public:
std::vector<Node *> effects; // In order.
unsigned output_width, output_height, virtual_output_width, virtual_output_height;
+ // Whether this phase is compiled as a compute shader, ie., the last effect is
+ // marked as one.
+ bool is_compute_shader;
+
+ // If <is_compute_shader>, which image unit the output buffer is bound to.
+ // This is used as source for a Uniform<int> below.
+ int outbuf_image_unit;
+
+ // These are used in transforming from unnormalized to normalized coordinates
+ // in compute shaders.
+ Point2D inv_output_size, output_texcoord_adjust;
+
// Identifier used to create unique variables in GLSL.
// Unique per-phase to increase cacheability of compiled shaders.
std::map<Node *, std::string> effect_ids;
// Uniforms for this phase; combined from all the effects.
+ std::vector<Uniform<int> > uniforms_image2d;
std::vector<Uniform<int> > uniforms_sampler2d;
std::vector<Uniform<bool> > uniforms_bool;
std::vector<Uniform<int> > uniforms_int;
// will create its own that is not shared with anything else. Does not take
// ownership of the passed-in ResourcePool, but will naturally take ownership
// of its own internal one if created.
- EffectChain(float aspect_nom, float aspect_denom, ResourcePool *resource_pool = NULL, GLenum intermediate_format = GL_RGBA16F);
+ EffectChain(float aspect_nom, float aspect_denom, ResourcePool *resource_pool = NULL);
~EffectChain();
// User API:
}
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 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).
+ // 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, the RGBA output will come
+ // 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);
+ 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->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.
+ //
+ // Of special interest is GL_SRGB8_ALPHA8, which stores sRGB-encoded RGB
+ // and linear alpha; this is half the memory bandwidth of GL_RGBA16F,
+ // while retaining reasonable precision for typical image data. It will,
+ // however, cause some gamut clipping if your colorspace is far from sRGB,
+ // as it cannot represent values outside [0,1]. NOTE: If you construct
+ // a chain where you end up bouncing pixels in non-linear light
+ // (gamma different from GAMMA_LINEAR), this will be the wrong thing.
+ // However, it's hard to see how this could happen in a non-contrived
+ // chain; few effects ever need texture bounce or resizing without also
+ // combining multiple pixels, which really needs linear light and thus
+ // triggers a conversion before the bounce.
+ //
+ // If you don't need alpha (or can do with very little of it), GL_RGB10_A2
+ // is even better, as it has two more bits for each color component. There
+ // is no GL_SRGB10, unfortunately, so on its own, it is somewhat worse than
+ // GL_SRGB8, but you can set <transformation> to SQUARE_ROOT_FRAMEBUFFER_TRANSFORMATION,
+ // and sqrt(x) will be stored instead of x. This is a rough approximation to
+ // the sRGB curve, and reduces maximum error (in sRGB distance) by almost an
+ // order of magnitude, well below what you can get from 8-bit true sRGB.
+ // (Note that this strategy avoids the problem with bounced non-linear data
+ // above, since the square root is turned off in that case.) However, texture
+ // filtering will happen on the transformed values, so if you have heavy
+ // downscaling or the likes (e.g. mipmaps), you could get subtly bad results.
+ // You'll need to see which of the two that works the best for you in practice.
+ void set_intermediate_format(
+ GLenum intermediate_format,
+ FramebufferTransformation transformation = NO_FRAMEBUFFER_TRANSFORMATION)
+ {
+ this->intermediate_format = intermediate_format;
+ this->intermediate_transformation = transformation;
+ }
+
void finalize();
// Measure the GPU time used for each actual phase during rendering.
void reset_phase_timing();
void print_phase_timing();
- //void render(unsigned char *src, unsigned char *dst);
+ // Note: If you already know the width and height of the viewport,
+ // calling render_to_fbo() directly will be slightly more efficient,
+ // as it saves it from getting it from OpenGL.
void render_to_screen()
{
render_to_fbo(0, 0, 0);
// Execute one phase, ie. set up all inputs, effects and outputs, and render the quad.
void execute_phase(Phase *phase, bool last_phase,
- std::set<GLint> *bound__attribute_indices,
std::map<Phase *, GLuint> *output_textures,
std::set<Phase *> *generated_mipmaps);
void fix_output_gamma();
void add_ycbcr_conversion_if_needed();
void add_dither_if_needed();
+ void add_dummy_effect_if_needed();
float aspect_nom, aspect_denom;
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.
+ GLenum output_ycbcr_type; // 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;
Effect *dither_effect;
+ Node *ycbcr_conversion_effect_node;
std::vector<Input *> inputs; // Also contained in nodes.
std::vector<Phase *> phases;
GLenum intermediate_format;
+ FramebufferTransformation intermediate_transformation;
unsigned num_dither_bits;
OutputOrigin output_origin;
bool finalized;
projects / movit / blobdiff