X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=effect.h;h=9d95705f6a66ce344a54bd18eb83154018d85c35;hp=af2f516593c4bea25404a10ec1c76049006713da;hb=56ff92c5828a143595eeb7a1906418cc30668f9d;hpb=2ced784c6599cb0b21427481ee17f4c8f6afdada diff --git a/effect.h b/effect.h index af2f516..9d95705 100644 --- a/effect.h +++ b/effect.h @@ -1,10 +1,27 @@ -#ifndef _EFFECT_H -#define _EFFECT_H 1 +#ifndef _MOVIT_EFFECT_H +#define _MOVIT_EFFECT_H 1 +// Effect is the base class for every effect. It basically represents a single +// GLSL function, with an optional set of user-settable parameters. +// +// A note on naming: Since all effects run in the same GLSL namespace, +// you can't use any name you want for global variables (e.g. uniforms). +// The framework assigns a prefix to you which will be unique for each +// effect instance; use the macro PREFIX() around your identifiers to +// automatically prepend that prefix. + +#include +#include +#include #include #include -#include +#include "defs.h" + +namespace movit { + +class EffectChain; +class Node; // Can alias on a float[2]. struct Point2D { @@ -22,52 +39,249 @@ struct RGBTriplet { float r, g, b; }; -// Convenience functions that deal with prepending the prefix. -void set_uniform_int(GLuint glsl_program_num, const std::string &prefix, const std::string &key, int value); -void set_uniform_float(GLuint glsl_program_num, const std::string &prefix, const std::string &key, float value); -void set_uniform_vec2(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values); -void set_uniform_vec3(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values); +// Can alias on a float[4]. +struct RGBATuple { + RGBATuple(float r, float g, float b, float a) + : r(r), g(g), b(b), a(a) {} + + float r, g, b, a; +}; class Effect { -public: - virtual bool needs_linear_light() { return true; } - virtual bool needs_srgb_primaries() { return true; } - virtual bool needs_many_samples() { return false; } - virtual bool needs_mipmaps() { return false; } +public: + virtual ~Effect() {} + + // An identifier for this type of effect, mostly used for debug output + // (but some special names, like "ColorspaceConversionEffect", holds special + // meaning). Same as the class name is fine. + virtual std::string effect_type_id() const = 0; + + // Whether this effects expects its input (and output) to be in + // linear gamma, ie. without an applied gamma curve. Most effects + // will want this, although the ones that never actually look at + // the pixels, e.g. mirror, won't need to care, and can set this + // to false. If so, the input gamma will be undefined. + // + // Also see the note on needs_texture_bounce(), below. + virtual bool needs_linear_light() const { return true; } + + // Whether this effect expects its input to be in the sRGB + // color space, ie. use the sRGB/Rec. 709 RGB primaries. + // (If not, it would typically come in as some slightly different + // set of RGB primaries; you would currently not get YCbCr + // or something similar). + // + // Again, most effects will want this, but you can set it to false + // if you process each channel independently, equally _and_ + // in a linear fashion. + virtual bool needs_srgb_primaries() const { return true; } + + // How this effect handles alpha, ie. what it outputs in its + // alpha channel. The choices are basically blank (alpha is always 1.0), + // premultiplied and postmultiplied. + // + // Premultiplied alpha is when the alpha value has been be multiplied + // into the three color components, so e.g. 100% red at 50% alpha + // would be (0.5, 0.0, 0.0, 0.5) instead of (1.0, 0.0, 0.0, 0.5) + // as it is stored in most image formats (postmultiplied alpha). + // The multiplication is taken to have happened in linear light. + // This is the most natural format for processing, and the default in + // most of Movit (just like linear light is). + // + // If you set INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA or + // INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK, all of your inputs + // (if any) are guaranteed to also be in premultiplied alpha. + // Otherwise, you can get postmultiplied or premultiplied alpha; + // you won't know. If you have multiple inputs, you will get the same + // (pre- or postmultiplied) for all inputs, although most likely, + // you will want to combine them in a premultiplied fashion anyway + // in that case. + enum AlphaHandling { + // Always outputs blank alpha (ie. alpha=1.0). Only appropriate + // for inputs that do not output an alpha channel. + // Blank alpha is special in that it can be treated as both + // pre- and postmultiplied. + OUTPUT_BLANK_ALPHA, + + // Always outputs postmultiplied alpha. Only appropriate for inputs. + OUTPUT_POSTMULTIPLIED_ALPHA, + + // Always outputs premultiplied alpha. As noted above, + // you will then also get all inputs in premultiplied alpha. + // If you set this, you should also set needs_linear_light(). + INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA, + + // Like INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA, but also guarantees + // that if you get blank alpha in, you also keep blank alpha out. + // This is a somewhat weaker guarantee than DONT_CARE_ALPHA_TYPE, + // but is still useful in many situations, and appropriate when + // e.g. you don't touch alpha at all. + // + // Does not make sense for inputs. + INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK, + + // Keeps the type of alpha (premultiplied, postmultiplied, blank) + // unchanged from input to output. Usually appropriate if you + // process all color channels in a linear fashion, do not change + // alpha, and do not produce any new pixels thare have alpha != 1.0. + // + // Does not make sense for inputs. + DONT_CARE_ALPHA_TYPE, + }; + virtual AlphaHandling alpha_handling() const { return INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA; } + + // Whether this effect expects its input to come directly from + // a texture. If this is true, the framework will not chain the + // input from other effects, but will store the results of the + // chain to a temporary (RGBA fp16) texture and let this effect + // sample directly from that. + // + // There are two good reasons why you might want to set this: + // + // 1. You are sampling more than once from the input, + // in which case computing all the previous steps might + // be more expensive than going to a memory intermediate. + // 2. You rely on previous effects, possibly including gamma + // expansion, to happen pre-filtering instead of post-filtering. + // (This is only relevant if you actually need the filtering; if + // you sample 1:1 between pixels and texels, it makes no difference.) + // + // Note that in some cases, you might get post-filtered gamma expansion + // even when setting this option. More specifically, if you are the + // first effect in the chain, and the GPU is doing sRGB gamma + // expansion, it is undefined (from OpenGL's side) whether expansion + // happens pre- or post-filtering. For most uses, however, + // either will be fine. + virtual bool needs_texture_bounce() const { return false; } + + // Whether this effect expects mipmaps or not. If you set this to + // true, you will be sampling with bilinear filtering; if not, + // you could be sampling with simple linear filtering and no mipmaps + // (although there is no guarantee; if a different effect in the chain + // needs mipmaps, you will also get them). + virtual bool needs_mipmaps() const { return false; } - virtual std::string output_convenience_uniforms(); + // 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()). + virtual bool changes_output_size() const { return false; } + + // 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) + // will _think_ your data is in. This is primarily useful if you are + // relying on getting OpenGL's bilinear resizing for free; otherwise, + // your virtual_width/virtual_height should be the same as width/height. + // + // Note that it is explicitly allowed to change width and height + // from frame to frame; EffectChain will reallocate textures as needed. + virtual void get_output_size(unsigned *width, unsigned *height, + unsigned *virtual_width, unsigned *virtual_height) const { + assert(false); + } + + // Tells the effect the resolution of each of its input. + // This will be called every frame, and always before get_output_size(), + // so you can change your output size based on the input if so desired. + // + // Note that in some cases, an input might not have a single well-defined + // resolution (for instance if you fade between two inputs with + // different resolutions). In this case, you will get width=0 and height=0 + // for that input. If you cannot handle that, you will need to set + // needs_texture_bounce() to true, which will force a render to a single + // given resolution before you get the input. + virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height) {} + + // How many inputs this effect will take (a fixed number). + // If you have only one input, it will be called INPUT() in GLSL; + // if you have several, they will be INPUT1(), INPUT2(), and so on. + virtual unsigned num_inputs() const { return 1; } + + // Inform the effect that it has been just added to the EffectChain. + // The primary use for this is to store the ResourcePool uesd by + // the chain; for modifications to it, rewrite_graph() below + // is probably a better fit. + virtual void inform_added(EffectChain *chain) {} + + // Let the effect rewrite the effect chain as it sees fit. + // Most effects won't need to do this, but this is very useful + // if you have an effect that consists of multiple sub-effects + // (for instance, two passes). The effect is given to its own + // pointer, and it can add new ones (by using add_node() + // and connect_node()) as it sees fit. This is called at + // EffectChain::finalize() time, when the entire graph is known, + // in the order that the effects were originally added. + // + // Note that if the effect wants to take itself entirely out + // of the chain, it must set “disabled” to true and then disconnect + // itself from all other effects. + virtual void rewrite_graph(EffectChain *graph, Node *self) {} + + // Outputs one GLSL uniform declaration for each registered parameter + // (see below), with the right prefix prepended to each uniform name. + // If you do not want this behavior, you can override this function. + virtual std::string output_convenience_uniforms() const; + + // Returns the GLSL fragment shader string for this effect. virtual std::string output_fragment_shader() = 0; - virtual void set_uniforms(GLuint glsl_program_num, const std::string& prefix, unsigned *sampler_num); + // Set all OpenGL state that this effect needs before rendering. + // The default implementation sets one uniform per registered parameter, + // but no other state. + // + // is the first free texture sampler. If you want to use + // textures, you can bind a texture to GL_TEXTURE0 + , + // and then increment the number (so that the next effect in the chain + // will use a different sampler). + virtual void set_gl_state(GLuint glsl_program_num, const std::string& prefix, unsigned *sampler_num); - // Neither of these take ownership. - bool set_int(const std::string&, int value); - bool set_float(const std::string &key, float value); - bool set_vec2(const std::string &key, const float *values); - bool set_vec3(const std::string &key, const float *values); + // If you set any special OpenGL state in set_gl_state(), you can clear it + // after rendering here. The default implementation does nothing. + virtual void clear_gl_state(); + + // Set a parameter; intended to be called from user code. + // Neither of these take ownership of the pointer. + virtual bool set_int(const std::string&, int value) MUST_CHECK_RESULT; + virtual bool set_float(const std::string &key, float value) MUST_CHECK_RESULT; + virtual bool set_vec2(const std::string &key, const float *values) MUST_CHECK_RESULT; + virtual bool set_vec3(const std::string &key, const float *values) MUST_CHECK_RESULT; + virtual bool set_vec4(const std::string &key, const float *values) MUST_CHECK_RESULT; protected: - // Neither of these take ownership. + // Register a parameter. Whenever set_*() is called with the same key, + // it will update the value in the given pointer (typically a pointer + // to some private member variable in your effect). + // + // Neither of these take ownership of the pointer. + + // int is special since GLSL pre-1.30 doesn't have integer uniforms. + // Thus, ints that you register will _not_ be converted to GLSL uniforms. void register_int(const std::string &key, int *value); + + // These correspond directly to float/vec2/vec3/vec4 in GLSL. void register_float(const std::string &key, float *value); void register_vec2(const std::string &key, float *values); void register_vec3(const std::string &key, float *values); - void register_1d_texture(const std::string &key, float *values, size_t size); - void invalidate_1d_texture(const std::string &key); - -private: - struct Texture1D { - float *values; - size_t size; - bool needs_update; - GLuint texture_num; - }; + void register_vec4(const std::string &key, float *values); +private: std::map params_int; std::map params_float; std::map params_vec2; std::map params_vec3; - std::map params_tex_1d; + std::map params_vec4; }; -#endif // !defined(_EFFECT_H) +} // namespace movit + +#endif // !defined(_MOVIT_EFFECT_H)