4 // Effect is the base class for every effect. It basically represents a single
5 // GLSL function, with an optional set of user-settable parameters.
7 // A note on naming: Since all effects run in the same GLSL namespace,
8 // you can't use any name you want for global variables (e.g. uniforms).
9 // The framework assigns a prefix to you which will be unique for each
10 // effect instance; use the macro PREFIX() around your identifiers to
11 // automatically prepend that prefix.
24 // Can alias on a float[2].
26 Point2D(float x, float y)
32 // Can alias on a float[3].
34 RGBTriplet(float r, float g, float b)
40 // Convenience functions that deal with prepending the prefix.
41 GLint get_uniform_location(GLuint glsl_program_num, const std::string &prefix, const std::string &key);
42 void set_uniform_int(GLuint glsl_program_num, const std::string &prefix, const std::string &key, int value);
43 void set_uniform_float(GLuint glsl_program_num, const std::string &prefix, const std::string &key, float value);
44 void set_uniform_float_array(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values, size_t num_values);
45 void set_uniform_vec2(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values);
46 void set_uniform_vec3(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values);
47 void set_uniform_vec4_array(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values, size_t num_values);
51 // An identifier for this type of effect, mostly used for debug output
52 // (but some special names, like "ColorSpaceConversionEffect", holds special
53 // meaning). Same as the class name is fine.
54 virtual std::string effect_type_id() const = 0;
56 // Whether this effects expects its input (and output) to be in
57 // linear gamma, ie. without an applied gamma curve. Most effects
58 // will want this, although the ones that never actually look at
59 // the pixels, e.g. mirror, won't need to care, and can set this
60 // to false. If so, the input gamma will be undefined.
62 // Also see the note on needs_texture_bounce(), below.
63 virtual bool needs_linear_light() const { return true; }
65 // Whether this effect expects its input to be in the sRGB
66 // color space, ie. use the sRGB/Rec. 709 RGB primaries.
67 // (If not, it would typically come in as some slightly different
68 // set of RGB primaries; you would currently not get YCbCr
69 // or something similar).
71 // Again, most effects will want this, but you can set it to false
72 // if you process each channel independently, equally _and_
73 // in a linear fashion.
74 virtual bool needs_srgb_primaries() const { return true; }
76 // Whether this effect expects its input to come directly from
77 // a texture. If this is true, the framework will not chain the
78 // input from other effects, but will store the results of the
79 // chain to a temporary (RGBA fp16) texture and let this effect
80 // sample directly from that.
82 // There are two good reasons why you might want to set this:
84 // 1. You are sampling more than once from the input,
85 // in which case computing all the previous steps might
86 // be more expensive than going to a memory intermediate.
87 // 2. You rely on previous effects, possibly including gamma
88 // expansion, to happen pre-filtering instead of post-filtering.
89 // (This is only relevant if you actually need the filtering; if
90 // you sample on whole input pixels only, it makes no difference.)
92 // Note that in some cases, you might get post-filtered gamma expansion
93 // even when setting this option. More specifically, if you are the
94 // first effect in the chain, and the GPU is doing sRGB gamma
95 // expansion, it is undefined (from OpenGL's side) whether expansion
96 // happens pre- or post-filtering. For most uses, however,
97 // either will be fine.
98 virtual bool needs_texture_bounce() const { return false; }
100 // Whether this effect expects mipmaps or not. If you set this to
101 // true, you will be sampling with bilinear filtering; if not,
102 // you could be sampling with simple linear filtering and no mipmaps
103 // (although there is no guarantee; if a different effect in the chain
104 // needs mipmaps, you will also get them).
105 virtual bool needs_mipmaps() const { return false; }
107 // Whether this effect wants to output to a different size than
108 // its input(s). If you set this to true, the output will be
109 // bounced to a texture (similarly to if the next effect set
110 // needs_texture_bounce()).
111 virtual bool changes_output_size() const { return false; }
113 // If changes_output_size() is true, you must implement this to tell
114 // the framework what output size you want.
116 // Note that it is explicitly allowed to change width and height
117 // from frame to frame; EffectChain will reallocate textures as needed.
118 virtual void get_output_size(unsigned *width, unsigned *height) const {
122 // How many inputs this effect will take (a fixed number).
123 // If you have only one input, it will be called INPUT() in GLSL;
124 // if you have several, they will be INPUT1(), INPUT2(), and so on.
125 virtual unsigned num_inputs() const { return 1; }
127 // Let the effect rewrite the effect chain as it sees fit.
128 // Most effects won't need to do this, but this is very useful
129 // if you have an effect that consists of multiple sub-effects
130 // (for instance, two passes). The effect is given to its own
131 // pointer, and it can add new ones (by using add_node()
132 // and connect_node()) as it sees fit. This is called at
133 // EffectChain::finalize() time, when the entire graph is known,
134 // in the order that the effects were originally added.
136 // Note that if the effect wants to take itself entirely out
137 // of the chain, it must set “disabled” to true and then disconnect
138 // itself from all other effects.
139 virtual void rewrite_graph(EffectChain *graph, Node *self) {}
141 // Outputs one GLSL uniform declaration for each registered parameter
142 // (see below), with the right prefix prepended to each uniform name.
143 // If you do not want this behavior, you can override this function.
144 virtual std::string output_convenience_uniforms() const;
146 // Returns the GLSL fragment shader string for this effect.
147 virtual std::string output_fragment_shader() = 0;
149 // Set all OpenGL state that this effect needs before rendering.
150 // The default implementation sets one uniform per registered parameter,
151 // but no other state.
153 // <sampler_num> is the first free texture sampler. If you want to use
154 // textures, you can bind a texture to GL_TEXTURE0 + <sampler_num>,
155 // and then increment the number (so that the next effect in the chain
156 // will use a different sampler).
157 virtual void set_gl_state(GLuint glsl_program_num, const std::string& prefix, unsigned *sampler_num);
159 // If you set any special OpenGL state in set_gl_state(), you can clear it
160 // after rendering here. The default implementation does nothing.
161 virtual void clear_gl_state();
163 // Set a parameter; intended to be called from user code.
164 // Neither of these take ownership of the pointer.
165 virtual bool set_int(const std::string&, int value);
166 virtual bool set_float(const std::string &key, float value);
167 virtual bool set_vec2(const std::string &key, const float *values);
168 virtual bool set_vec3(const std::string &key, const float *values);
171 // Register a parameter. Whenever set_*() is called with the same key,
172 // it will update the value in the given pointer (typically a pointer
173 // to some private member variable in your effect).
175 // Neither of these take ownership of the pointer.
177 // int is special since GLSL pre-1.30 doesn't have integer uniforms.
178 // Thus, ints that you register will _not_ be converted to GLSL uniforms.
179 void register_int(const std::string &key, int *value);
181 // These correspond directly to float/vec2/vec3 in GLSL.
182 void register_float(const std::string &key, float *value);
183 void register_vec2(const std::string &key, float *values);
184 void register_vec3(const std::string &key, float *values);
186 // This will register a 1D texture, which will be bound to a sampler
187 // when your GLSL code runs (so it corresponds 1:1 to a sampler2D uniform
190 // Note that if you change the contents of <values>, you will need to
191 // call invalidate_1d_texture() to have the picture re-uploaded on the
192 // next frame. This is in contrast to all the other parameters, which are
193 // set anew every frame.
194 void register_1d_texture(const std::string &key, float *values, size_t size);
195 void invalidate_1d_texture(const std::string &key);
205 std::map<std::string, int *> params_int;
206 std::map<std::string, float *> params_float;
207 std::map<std::string, float *> params_vec2;
208 std::map<std::string, float *> params_vec3;
209 std::map<std::string, Texture1D> params_tex_1d;
212 #endif // !defined(_EFFECT_H)