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.
21 // Can alias on a float[2].
23 Point2D(float x, float y)
29 // Can alias on a float[3].
31 RGBTriplet(float r, float g, float b)
37 // Convenience functions that deal with prepending the prefix.
38 GLint get_uniform_location(GLuint glsl_program_num, const std::string &prefix, const std::string &key);
39 void set_uniform_int(GLuint glsl_program_num, const std::string &prefix, const std::string &key, int value);
40 void set_uniform_float(GLuint glsl_program_num, const std::string &prefix, const std::string &key, float value);
41 void set_uniform_float_array(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values, size_t num_values);
42 void set_uniform_vec2(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values);
43 void set_uniform_vec3(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values);
44 void set_uniform_vec4_array(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values, size_t num_values);
48 // Whether this effects expects its input (and output) to be in
49 // linear gamma, ie. without an applied gamma curve. Most effects
50 // will want this, although the ones that never actually look at
51 // the pixels, e.g. mirror, won't need to care, and can set this
52 // to false. If so, the input gamma will be undefined.
54 // Also see the note on needs_texture_bounce(), below.
55 virtual bool needs_linear_light() const { return true; }
57 // Whether this effect expects its input to be in the sRGB
58 // color space, ie. use the sRGB/Rec. 709 RGB primaries.
59 // (If not, it would typically come in as some slightly different
60 // set of RGB primaries; you would currently not get YCbCr
61 // or something similar).
63 // Again, most effects will want this.
64 virtual bool needs_srgb_primaries() const { return true; }
66 // Whether this effect expects its input to come directly from
67 // a texture. If this is true, the framework will not chain the
68 // input from other effects, but will store the results of the
69 // chain to a temporary (RGBA fp16) texture and let this effect
70 // sample directly from that.
72 // There are two good reasons why you might want to set this:
74 // 1. You are sampling more than once from the input,
75 // in which case computing all the previous steps might
76 // be more expensive than going to a memory intermediate.
77 // 2. You rely on previous effects, possibly including gamma
78 // expansion, to happen pre-filtering instead of post-filtering.
79 // (This is only relevant if you actually need the filtering; if
80 // you sample on whole input pixels only, it makes no difference.)
82 // Note that in some cases, you might get post-filtered gamma expansion
83 // even when setting this option. More specifically, if you are the
84 // first effect in the chain, and the GPU is doing sRGB gamma
85 // expansion, it is undefined (from OpenGL's side) whether expansion
86 // happens pre- or post-filtering. For most uses, however,
87 // either will be fine.
88 virtual bool needs_texture_bounce() const { return false; }
90 // Whether this effect expects mipmaps or not. If you set this to
91 // true, you will be sampling with bilinear filtering; if not,
92 // you could be sampling with simple linear filtering and no mipmaps
93 // (although there is no guarantee; if a different effect in the chain
94 // needs mipmaps, you will also get them).
95 virtual bool needs_mipmaps() const { return false; }
97 // How many inputs this effect will take (a fixed number).
98 // If you have only one input, it will be called INPUT() in GLSL;
99 // if you have several, they will be INPUT1(), INPUT2(), and so on.
100 virtual unsigned num_inputs() const { return 1; }
102 // Requests that this effect adds itself to the given effect chain.
103 // For most effects, the default will be fine, but for effects that
104 // consist of multiple passes, it is often useful to replace this
105 // with something that adds completely different things to the chain.
106 virtual void add_self_to_effect_chain(EffectChain *graph, const std::vector<Effect *> &inputs);
108 // Outputs one GLSL uniform declaration for each registered parameter
109 // (see below), with the right prefix prepended to each uniform name.
110 // If you do not want this behavior, you can override this function.
111 virtual std::string output_convenience_uniforms() const;
113 // Returns the GLSL fragment shader string for this effect.
114 virtual std::string output_fragment_shader() = 0;
116 // Set all uniforms the shader needs in the current GL context.
117 // The default implementation sets one uniform per registered parameter.
119 // <sampler_num> is the first free texture sampler. If you want to use
120 // textures, you can bind a texture to GL_TEXTURE0 + <sampler_num>,
121 // and then increment the number (so that the next effect in the chain
122 // will use a different sampler).
124 // NOTE: Currently this is also abused a bit to set other GL state
125 // the effect might need.
126 virtual void set_uniforms(GLuint glsl_program_num, const std::string& prefix, unsigned *sampler_num);
128 // Set a parameter; intended to be called from user code.
129 // Neither of these take ownership of the pointer.
130 virtual bool set_int(const std::string&, int value);
131 virtual bool set_float(const std::string &key, float value);
132 virtual bool set_vec2(const std::string &key, const float *values);
133 virtual bool set_vec3(const std::string &key, const float *values);
136 // Register a parameter. Whenever set_*() is called with the same key,
137 // it will update the value in the given pointer (typically a pointer
138 // to some private member variable in your effect).
140 // Neither of these take ownership of the pointer.
142 // int is special since GLSL pre-1.30 doesn't have integer uniforms.
143 // Thus, ints that you register will _not_ be converted to GLSL uniforms.
144 void register_int(const std::string &key, int *value);
146 // These correspond directly to float/vec2/vec3 in GLSL.
147 void register_float(const std::string &key, float *value);
148 void register_vec2(const std::string &key, float *values);
149 void register_vec3(const std::string &key, float *values);
151 // This will register a 1D texture, which will be bound to a sampler
152 // when your GLSL code runs (so it corresponds 1:1 to a sampler2D uniform
155 // Note that if you change the contents of <values>, you will need to
156 // call invalidate_1d_texture() to have the picture re-uploaded on the
157 // next frame. This is in contrast to all the other parameters, which are
158 // set anew every frame.
159 void register_1d_texture(const std::string &key, float *values, size_t size);
160 void invalidate_1d_texture(const std::string &key);
170 std::map<std::string, int *> params_int;
171 std::map<std::string, float *> params_float;
172 std::map<std::string, float *> params_vec2;
173 std::map<std::string, float *> params_vec3;
174 std::map<std::string, Texture1D> params_tex_1d;
177 #endif // !defined(_EFFECT_H)