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.
27 // Can alias on a float[2].
29 Point2D(float x, float y)
35 // Can alias on a float[3].
37 RGBTriplet(float r, float g, float b)
43 // Convenience functions that deal with prepending the prefix.
44 GLint get_uniform_location(GLuint glsl_program_num, const std::string &prefix, const std::string &key);
45 void set_uniform_int(GLuint glsl_program_num, const std::string &prefix, const std::string &key, int value);
46 void set_uniform_float(GLuint glsl_program_num, const std::string &prefix, const std::string &key, float value);
47 void set_uniform_vec2(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values);
48 void set_uniform_vec3(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values);
49 void set_uniform_vec4_array(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values, size_t num_values);
50 void set_uniform_mat3(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const Eigen::Matrix3d &matrix);
56 // An identifier for this type of effect, mostly used for debug output
57 // (but some special names, like "ColorspaceConversionEffect", holds special
58 // meaning). Same as the class name is fine.
59 virtual std::string effect_type_id() const = 0;
61 // Whether this effects expects its input (and output) to be in
62 // linear gamma, ie. without an applied gamma curve. Most effects
63 // will want this, although the ones that never actually look at
64 // the pixels, e.g. mirror, won't need to care, and can set this
65 // to false. If so, the input gamma will be undefined.
67 // Also see the note on needs_texture_bounce(), below.
68 virtual bool needs_linear_light() const { return true; }
70 // Whether this effect expects its input to be in the sRGB
71 // color space, ie. use the sRGB/Rec. 709 RGB primaries.
72 // (If not, it would typically come in as some slightly different
73 // set of RGB primaries; you would currently not get YCbCr
74 // or something similar).
76 // Again, most effects will want this, but you can set it to false
77 // if you process each channel independently, equally _and_
78 // in a linear fashion.
79 virtual bool needs_srgb_primaries() const { return true; }
81 // Whether this effect expects its input to come directly from
82 // a texture. If this is true, the framework will not chain the
83 // input from other effects, but will store the results of the
84 // chain to a temporary (RGBA fp16) texture and let this effect
85 // sample directly from that.
87 // There are two good reasons why you might want to set this:
89 // 1. You are sampling more than once from the input,
90 // in which case computing all the previous steps might
91 // be more expensive than going to a memory intermediate.
92 // 2. You rely on previous effects, possibly including gamma
93 // expansion, to happen pre-filtering instead of post-filtering.
94 // (This is only relevant if you actually need the filtering; if
95 // you sample 1:1 between pixels and texels, it makes no difference.)
97 // Note that in some cases, you might get post-filtered gamma expansion
98 // even when setting this option. More specifically, if you are the
99 // first effect in the chain, and the GPU is doing sRGB gamma
100 // expansion, it is undefined (from OpenGL's side) whether expansion
101 // happens pre- or post-filtering. For most uses, however,
102 // either will be fine.
103 virtual bool needs_texture_bounce() const { return false; }
105 // Whether this effect expects mipmaps or not. If you set this to
106 // true, you will be sampling with bilinear filtering; if not,
107 // you could be sampling with simple linear filtering and no mipmaps
108 // (although there is no guarantee; if a different effect in the chain
109 // needs mipmaps, you will also get them).
110 virtual bool needs_mipmaps() const { return false; }
112 // Whether this effect wants to output to a different size than
113 // its input(s) (see inform_input_size(), below). If you set this to
114 // true, the output will be bounced to a texture (similarly to if the
115 // next effect set needs_texture_bounce()).
116 virtual bool changes_output_size() const { return false; }
118 // If changes_output_size() is true, you must implement this to tell
119 // the framework what output size you want.
121 // Note that it is explicitly allowed to change width and height
122 // from frame to frame; EffectChain will reallocate textures as needed.
123 virtual void get_output_size(unsigned *width, unsigned *height) const {
127 // Tells the effect the resolution of each of its input.
128 // This will be called every frame, and always before get_output_size(),
129 // so you can change your output size based on the input if so desired.
131 // Note that in some cases, an input might not have a single well-defined
132 // resolution (for instance if you fade between two inputs with
133 // different resolutions). In this case, you will get width=0 and height=0
134 // for that input. If you cannot handle that, you will need to set
135 // needs_texture_bounce() to true, which will force a render to a single
136 // given resolution before you get the input.
137 virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height) {}
139 // How many inputs this effect will take (a fixed number).
140 // If you have only one input, it will be called INPUT() in GLSL;
141 // if you have several, they will be INPUT1(), INPUT2(), and so on.
142 virtual unsigned num_inputs() const { return 1; }
144 // Let the effect rewrite the effect chain as it sees fit.
145 // Most effects won't need to do this, but this is very useful
146 // if you have an effect that consists of multiple sub-effects
147 // (for instance, two passes). The effect is given to its own
148 // pointer, and it can add new ones (by using add_node()
149 // and connect_node()) as it sees fit. This is called at
150 // EffectChain::finalize() time, when the entire graph is known,
151 // in the order that the effects were originally added.
153 // Note that if the effect wants to take itself entirely out
154 // of the chain, it must set “disabled” to true and then disconnect
155 // itself from all other effects.
156 virtual void rewrite_graph(EffectChain *graph, Node *self) {}
158 // Outputs one GLSL uniform declaration for each registered parameter
159 // (see below), with the right prefix prepended to each uniform name.
160 // If you do not want this behavior, you can override this function.
161 virtual std::string output_convenience_uniforms() const;
163 // Returns the GLSL fragment shader string for this effect.
164 virtual std::string output_fragment_shader() = 0;
166 // Set all OpenGL state that this effect needs before rendering.
167 // The default implementation sets one uniform per registered parameter,
168 // but no other state.
170 // <sampler_num> is the first free texture sampler. If you want to use
171 // textures, you can bind a texture to GL_TEXTURE0 + <sampler_num>,
172 // and then increment the number (so that the next effect in the chain
173 // will use a different sampler).
174 virtual void set_gl_state(GLuint glsl_program_num, const std::string& prefix, unsigned *sampler_num);
176 // If you set any special OpenGL state in set_gl_state(), you can clear it
177 // after rendering here. The default implementation does nothing.
178 virtual void clear_gl_state();
180 // Set a parameter; intended to be called from user code.
181 // Neither of these take ownership of the pointer.
182 virtual bool set_int(const std::string&, int value);
183 virtual bool set_float(const std::string &key, float value);
184 virtual bool set_vec2(const std::string &key, const float *values);
185 virtual bool set_vec3(const std::string &key, const float *values);
188 // Register a parameter. Whenever set_*() is called with the same key,
189 // it will update the value in the given pointer (typically a pointer
190 // to some private member variable in your effect).
192 // Neither of these take ownership of the pointer.
194 // int is special since GLSL pre-1.30 doesn't have integer uniforms.
195 // Thus, ints that you register will _not_ be converted to GLSL uniforms.
196 void register_int(const std::string &key, int *value);
198 // These correspond directly to float/vec2/vec3 in GLSL.
199 void register_float(const std::string &key, float *value);
200 void register_vec2(const std::string &key, float *values);
201 void register_vec3(const std::string &key, float *values);
203 // This will register a 1D texture, which will be bound to a sampler
204 // when your GLSL code runs (so it corresponds 1:1 to a sampler2D uniform
207 // Note that if you change the contents of <values>, you will need to
208 // call invalidate_1d_texture() to have the picture re-uploaded on the
209 // next frame. This is in contrast to all the other parameters, which are
210 // set anew every frame.
211 void register_1d_texture(const std::string &key, float *values, size_t size);
212 void invalidate_1d_texture(const std::string &key);
222 std::map<std::string, int *> params_int;
223 std::map<std::string, float *> params_float;
224 std::map<std::string, float *> params_vec2;
225 std::map<std::string, float *> params_vec3;
226 std::map<std::string, Texture1D> params_tex_1d;
229 #endif // !defined(_EFFECT_H)