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.
23 // Can alias on a float[2].
25 Point2D(float x, float y)
31 // Can alias on a float[3].
33 RGBTriplet(float r, float g, float b)
39 // Convenience functions that deal with prepending the prefix.
40 GLint get_uniform_location(GLuint glsl_program_num, const std::string &prefix, const std::string &key);
41 void set_uniform_int(GLuint glsl_program_num, const std::string &prefix, const std::string &key, int value);
42 void set_uniform_float(GLuint glsl_program_num, const std::string &prefix, const std::string &key, float value);
43 void set_uniform_float_array(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values, size_t num_values);
44 void set_uniform_vec2(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values);
45 void set_uniform_vec3(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values);
46 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 // Whether this effects expects its input (and output) to be in
51 // linear gamma, ie. without an applied gamma curve. Most effects
52 // will want this, although the ones that never actually look at
53 // the pixels, e.g. mirror, won't need to care, and can set this
54 // to false. If so, the input gamma will be undefined.
56 // Also see the note on needs_texture_bounce(), below.
57 virtual bool needs_linear_light() const { return true; }
59 // Whether this effect expects its input to be in the sRGB
60 // color space, ie. use the sRGB/Rec. 709 RGB primaries.
61 // (If not, it would typically come in as some slightly different
62 // set of RGB primaries; you would currently not get YCbCr
63 // or something similar).
65 // Again, most effects will want this, but you can set it to false
66 // if you process each channel independently, equally _and_
67 // in a linear fashion.
68 virtual bool needs_srgb_primaries() const { return true; }
70 // Whether this effect expects its input to come directly from
71 // a texture. If this is true, the framework will not chain the
72 // input from other effects, but will store the results of the
73 // chain to a temporary (RGBA fp16) texture and let this effect
74 // sample directly from that.
76 // There are two good reasons why you might want to set this:
78 // 1. You are sampling more than once from the input,
79 // in which case computing all the previous steps might
80 // be more expensive than going to a memory intermediate.
81 // 2. You rely on previous effects, possibly including gamma
82 // expansion, to happen pre-filtering instead of post-filtering.
83 // (This is only relevant if you actually need the filtering; if
84 // you sample on whole input pixels only, it makes no difference.)
86 // Note that in some cases, you might get post-filtered gamma expansion
87 // even when setting this option. More specifically, if you are the
88 // first effect in the chain, and the GPU is doing sRGB gamma
89 // expansion, it is undefined (from OpenGL's side) whether expansion
90 // happens pre- or post-filtering. For most uses, however,
91 // either will be fine.
92 virtual bool needs_texture_bounce() const { return false; }
94 // Whether this effect expects mipmaps or not. If you set this to
95 // true, you will be sampling with bilinear filtering; if not,
96 // you could be sampling with simple linear filtering and no mipmaps
97 // (although there is no guarantee; if a different effect in the chain
98 // needs mipmaps, you will also get them).
99 virtual bool needs_mipmaps() const { return false; }
101 // Whether this effect wants to output to a different size than
102 // its input(s). If you set this to true, the output will be
103 // bounced to a texture (similarly to if the next effect set
104 // needs_texture_bounce()).
105 virtual bool changes_output_size() const { return false; }
107 // If changes_output_size() is true, you must implement this to tell
108 // the framework what output size you want.
110 // Note that it is explicitly allowed to change width and height
111 // from frame to frame; EffectChain will reallocate textures as needed.
112 virtual void get_output_size(unsigned *width, unsigned *height) const {
116 // How many inputs this effect will take (a fixed number).
117 // If you have only one input, it will be called INPUT() in GLSL;
118 // if you have several, they will be INPUT1(), INPUT2(), and so on.
119 virtual unsigned num_inputs() const { return 1; }
121 // Requests that this effect adds itself to the given effect chain.
122 // For most effects, the default will be fine, but for effects that
123 // consist of multiple passes, it is often useful to replace this
124 // with something that adds completely different things to the chain.
125 virtual void add_self_to_effect_chain(EffectChain *graph, const std::vector<Effect *> &inputs);
127 // Outputs one GLSL uniform declaration for each registered parameter
128 // (see below), with the right prefix prepended to each uniform name.
129 // If you do not want this behavior, you can override this function.
130 virtual std::string output_convenience_uniforms() const;
132 // Returns the GLSL fragment shader string for this effect.
133 virtual std::string output_fragment_shader() = 0;
135 // Set all OpenGL state that this effect needs before rendering.
136 // The default implementation sets one uniform per registered parameter,
137 // but no other state.
139 // <sampler_num> is the first free texture sampler. If you want to use
140 // textures, you can bind a texture to GL_TEXTURE0 + <sampler_num>,
141 // and then increment the number (so that the next effect in the chain
142 // will use a different sampler).
143 virtual void set_gl_state(GLuint glsl_program_num, const std::string& prefix, unsigned *sampler_num);
145 // If you set any special OpenGL state in set_gl_state(), you can clear it
146 // after rendering here. The default implementation does nothing.
147 virtual void clear_gl_state();
149 // Set a parameter; intended to be called from user code.
150 // Neither of these take ownership of the pointer.
151 virtual bool set_int(const std::string&, int value);
152 virtual bool set_float(const std::string &key, float value);
153 virtual bool set_vec2(const std::string &key, const float *values);
154 virtual bool set_vec3(const std::string &key, const float *values);
157 // Register a parameter. Whenever set_*() is called with the same key,
158 // it will update the value in the given pointer (typically a pointer
159 // to some private member variable in your effect).
161 // Neither of these take ownership of the pointer.
163 // int is special since GLSL pre-1.30 doesn't have integer uniforms.
164 // Thus, ints that you register will _not_ be converted to GLSL uniforms.
165 void register_int(const std::string &key, int *value);
167 // These correspond directly to float/vec2/vec3 in GLSL.
168 void register_float(const std::string &key, float *value);
169 void register_vec2(const std::string &key, float *values);
170 void register_vec3(const std::string &key, float *values);
172 // This will register a 1D texture, which will be bound to a sampler
173 // when your GLSL code runs (so it corresponds 1:1 to a sampler2D uniform
176 // Note that if you change the contents of <values>, you will need to
177 // call invalidate_1d_texture() to have the picture re-uploaded on the
178 // next frame. This is in contrast to all the other parameters, which are
179 // set anew every frame.
180 void register_1d_texture(const std::string &key, float *values, size_t size);
181 void invalidate_1d_texture(const std::string &key);
191 std::map<std::string, int *> params_int;
192 std::map<std::string, float *> params_float;
193 std::map<std::string, float *> params_vec2;
194 std::map<std::string, float *> params_vec3;
195 std::map<std::string, Texture1D> params_tex_1d;
198 #endif // !defined(_EFFECT_H)