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.
19 // Can alias on a float[2].
21 Point2D(float x, float y)
27 // Can alias on a float[3].
29 RGBTriplet(float r, float g, float b)
35 // Convenience functions that deal with prepending the prefix.
36 GLint get_uniform_location(GLuint glsl_program_num, const std::string &prefix, const std::string &key);
37 void set_uniform_int(GLuint glsl_program_num, const std::string &prefix, const std::string &key, int value);
38 void set_uniform_float(GLuint glsl_program_num, const std::string &prefix, const std::string &key, float value);
39 void set_uniform_float_array(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values, size_t num_values);
40 void set_uniform_vec2(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values);
41 void set_uniform_vec3(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values);
42 void set_uniform_vec4_array(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values, size_t num_values);
46 // Whether this effects expects its input (and output) to be in
47 // linear gamma, ie. without an applied gamma curve. Most effects
48 // will want this, although the ones that never actually look at
49 // the pixels, e.g. mirror, won't need to care, and can set this
50 // to false. If so, the input gamma will be undefined.
52 // Also see the note on needs_many_samples(), below.
53 virtual bool needs_linear_light() const { return true; }
55 // Whether this effect expects its input to be in the sRGB
56 // color space, ie. use the sRGB/Rec. 709 RGB primaries.
57 // (If not, it would typically come in as some slightly different
58 // set of RGB primaries; you would currently not get YCbCr
59 // or something similar).
61 // Again, most effects will want this.
62 virtual bool needs_srgb_primaries() const { return true; }
64 // Whether this effect expects to be sampling many times from
65 // its input. If this is true, the framework will not chain the
66 // input from other effects, but will store the results of the
67 // chain to a temporary (RGBA fp16) texture and let this effect
68 // sample directly from that.
70 // Note that if you do _not_ set this, and do not sample on
71 // whole pixels (ie. you request linear filtering), it is undefined
72 // whether that filtering happen in linear gamma or not.
73 // It _could_ be (for instance in the case where the input is sRGB
74 // and your GPU applies gamma expansion before filtering), but you
75 // have no such guarantee. For most uses, however, this will be fine.
76 virtual bool needs_many_samples() const { return false; }
78 // Whether this effect expects mipmaps or not. If you set this to
79 // true, you will be sampling with bilinear filtering; if not,
80 // you could be sampling with simple linear filtering and no mipmaps
81 // (although there is no guarantee; if a different effect in the chain
82 // needs mipmaps, you will also get them).
83 virtual bool needs_mipmaps() const { return false; }
85 // Requests that this effect adds itself to the given effect chain.
86 // For most effects, the default will be fine, but for effects that
87 // consist of multiple passes, it is often useful to replace this
88 // with something that adds completely different things to the chain.
89 virtual void add_self_to_effect_chain(std::vector<Effect *> *chain) {
90 chain->push_back(this);
93 // Outputs one GLSL uniform declaration for each registered parameter
94 // (see below), with the right prefix prepended to each uniform name.
95 // If you do not want this behavior, you can override this function.
96 virtual std::string output_convenience_uniforms() const;
98 // Returns the GLSL fragment shader string for this effect.
99 virtual std::string output_fragment_shader() = 0;
101 // Set all uniforms the shader needs in the current GL context.
102 // The default implementation sets one uniform per registered parameter.
104 // <sampler_num> is the first free texture sampler. If you want to use
105 // textures, you can bind a texture to GL_TEXTURE0 + <sampler_num>,
106 // and then increment the number (so that the next effect in the chain
107 // will use a different sampler).
109 // NOTE: Currently this is also abused a bit to set other GL state
110 // the effect might need.
111 virtual void set_uniforms(GLuint glsl_program_num, const std::string& prefix, unsigned *sampler_num);
113 // Set a parameter; intended to be called from user code.
114 // Neither of these take ownership of the pointer.
115 virtual bool set_int(const std::string&, int value);
116 virtual bool set_float(const std::string &key, float value);
117 virtual bool set_vec2(const std::string &key, const float *values);
118 virtual bool set_vec3(const std::string &key, const float *values);
121 // Register a parameter. Whenever set_*() is called with the same key,
122 // it will update the value in the given pointer (typically a pointer
123 // to some private member variable in your effect).
125 // Neither of these take ownership of the pointer.
127 // int is special since GLSL pre-1.30 doesn't have integer uniforms.
128 // Thus, ints that you register will _not_ be converted to GLSL uniforms.
129 void register_int(const std::string &key, int *value);
131 // These correspond directly to float/vec2/vec3 in GLSL.
132 void register_float(const std::string &key, float *value);
133 void register_vec2(const std::string &key, float *values);
134 void register_vec3(const std::string &key, float *values);
136 // This will register a 1D texture, which will be bound to a sampler
137 // when your GLSL code runs (so it corresponds 1:1 to a sampler2D uniform
140 // Note that if you change the contents of <values>, you will need to
141 // call invalidate_1d_texture() to have the picture re-uploaded on the
142 // next frame. This is in contrast to all the other parameters, which are
143 // set anew every frame.
144 void register_1d_texture(const std::string &key, float *values, size_t size);
145 void invalidate_1d_texture(const std::string &key);
155 std::map<std::string, int *> params_int;
156 std::map<std::string, float *> params_float;
157 std::map<std::string, float *> params_vec2;
158 std::map<std::string, float *> params_vec3;
159 std::map<std::string, Texture1D> params_tex_1d;
162 #endif // !defined(_EFFECT_H)