-#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 <epoxy/gl.h>
+#include <assert.h>
+#include <stddef.h>
#include <map>
#include <string>
-#include <vector>
-#include <GL/gl.h>
+#include "defs.h"
+
+namespace movit {
+
+class EffectChain;
+class Node;
// Can alias on a float[2].
struct Point2D {
float r, g, b;
};
-// Convenience functions that deal with prepending the prefix.
-GLint get_uniform_location(GLuint glsl_program_num, const std::string &prefix, const std::string &key);
-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_float_array(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values, size_t num_values);
-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);
-void set_uniform_vec4_array(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values, size_t num_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:
+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; }
- virtual bool needs_many_samples() const { return false; }
+
+ // 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 void add_self_to_effect_chain(std::vector<Effect *> *chain) {
- chain->push_back(this);
+
+ // 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.
+ //
+ // <sampler_num> is the first free texture sampler. If you want to use
+ // textures, you can bind a texture to GL_TEXTURE0 + <sampler_num>,
+ // 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.
- virtual bool set_int(const std::string&, int value);
- virtual bool set_float(const std::string &key, float value);
- virtual bool set_vec2(const std::string &key, const float *values);
- virtual 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<std::string, int *> params_int;
std::map<std::string, float *> params_float;
std::map<std::string, float *> params_vec2;
std::map<std::string, float *> params_vec3;
- std::map<std::string, Texture1D> params_tex_1d;
+ std::map<std::string, float *> params_vec4;
};
-#endif // !defined(_EFFECT_H)
+} // namespace movit
+
+#endif // !defined(_MOVIT_EFFECT_H)
projects / movit / blobdiff