1 #ifndef _MOVIT_EFFECT_H
2 #define _MOVIT_EFFECT_H 1
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.
28 // Can alias on a float[2].
31 Point2D(float x, float y)
37 // Can alias on a float[3].
40 RGBTriplet(float r, float g, float b)
46 // Can alias on a float[4].
49 RGBATuple(float r, float g, float b, float a)
50 : r(r), g(g), b(b), a(a) {}
55 // Represents a registered uniform.
58 std::string name; // Without prefix.
59 const T *value; // Owner by the effect.
60 size_t num_values; // Number of elements; for arrays only. _Not_ the vector length.
61 std::string prefix; // Filled in only after phases have been constructed.
62 GLint location; // Filled in only after phases have been constructed. -1 if no location.
69 // An identifier for this type of effect, mostly used for debug output
70 // (but some special names, like "ColorspaceConversionEffect", holds special
71 // meaning). Same as the class name is fine.
72 virtual std::string effect_type_id() const = 0;
74 // Whether this effects expects its input (and output) to be in
75 // linear gamma, ie. without an applied gamma curve. Most effects
76 // will want this, although the ones that never actually look at
77 // the pixels, e.g. mirror, won't need to care, and can set this
78 // to false. If so, the input gamma will be undefined.
80 // Also see the note on needs_texture_bounce(), below.
81 virtual bool needs_linear_light() const { return true; }
83 // Whether this effect expects its input to be in the sRGB
84 // color space, ie. use the sRGB/Rec. 709 RGB primaries.
85 // (If not, it would typically come in as some slightly different
86 // set of RGB primaries; you would currently not get YCbCr
87 // or something similar).
89 // Again, most effects will want this, but you can set it to false
90 // if you process each channel independently, equally _and_
91 // in a linear fashion.
92 virtual bool needs_srgb_primaries() const { return true; }
94 // How this effect handles alpha, ie. what it outputs in its
95 // alpha channel. The choices are basically blank (alpha is always 1.0),
96 // premultiplied and postmultiplied.
98 // Premultiplied alpha is when the alpha value has been be multiplied
99 // into the three color components, so e.g. 100% red at 50% alpha
100 // would be (0.5, 0.0, 0.0, 0.5) instead of (1.0, 0.0, 0.0, 0.5)
101 // as it is stored in most image formats (postmultiplied alpha).
102 // The multiplication is taken to have happened in linear light.
103 // This is the most natural format for processing, and the default in
104 // most of Movit (just like linear light is).
106 // If you set INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA or
107 // INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK, all of your inputs
108 // (if any) are guaranteed to also be in premultiplied alpha.
109 // Otherwise, you can get postmultiplied or premultiplied alpha;
110 // you won't know. If you have multiple inputs, you will get the same
111 // (pre- or postmultiplied) for all inputs, although most likely,
112 // you will want to combine them in a premultiplied fashion anyway
115 // Always outputs blank alpha (ie. alpha=1.0). Only appropriate
116 // for inputs that do not output an alpha channel.
117 // Blank alpha is special in that it can be treated as both
118 // pre- and postmultiplied.
121 // Always outputs postmultiplied alpha. Only appropriate for inputs.
122 OUTPUT_POSTMULTIPLIED_ALPHA,
124 // Always outputs premultiplied alpha. As noted above,
125 // you will then also get all inputs in premultiplied alpha.
126 // If you set this, you should also set needs_linear_light().
127 INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA,
129 // Like INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA, but also guarantees
130 // that if you get blank alpha in, you also keep blank alpha out.
131 // This is a somewhat weaker guarantee than DONT_CARE_ALPHA_TYPE,
132 // but is still useful in many situations, and appropriate when
133 // e.g. you don't touch alpha at all.
135 // Does not make sense for inputs.
136 INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK,
138 // Keeps the type of alpha (premultiplied, postmultiplied, blank)
139 // unchanged from input to output. Usually appropriate if you
140 // process all color channels in a linear fashion, do not change
141 // alpha, and do not produce any new pixels thare have alpha != 1.0.
143 // Does not make sense for inputs.
144 DONT_CARE_ALPHA_TYPE,
146 virtual AlphaHandling alpha_handling() const { return INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA; }
148 // Whether this effect expects its input to come directly from
149 // a texture. If this is true, the framework will not chain the
150 // input from other effects, but will store the results of the
151 // chain to a temporary (RGBA fp16) texture and let this effect
152 // sample directly from that.
154 // There are two good reasons why you might want to set this:
156 // 1. You are sampling more than once from the input,
157 // in which case computing all the previous steps might
158 // be more expensive than going to a memory intermediate.
159 // 2. You rely on previous effects, possibly including gamma
160 // expansion, to happen pre-filtering instead of post-filtering.
161 // (This is only relevant if you actually need the filtering; if
162 // you sample 1:1 between pixels and texels, it makes no difference.)
164 // Note that in some cases, you might get post-filtered gamma expansion
165 // even when setting this option. More specifically, if you are the
166 // first effect in the chain, and the GPU is doing sRGB gamma
167 // expansion, it is undefined (from OpenGL's side) whether expansion
168 // happens pre- or post-filtering. For most uses, however,
169 // either will be fine.
170 virtual bool needs_texture_bounce() const { return false; }
172 // Whether this effect expects mipmaps or not. If you set this to
173 // true, you will be sampling with bilinear filtering; if not,
174 // you could be sampling with simple linear filtering and no mipmaps
175 // (although there is no guarantee; if a different effect in the chain
176 // needs mipmaps, you will also get them).
177 virtual bool needs_mipmaps() const { return false; }
179 // Whether there is a direct correspondence between input and output
180 // texels. Specifically, the effect must not:
182 // 1. Try to sample in the border (ie., outside the 0.0 to 1.0 area).
183 // 2. Try to sample between texels.
184 // 3. Sample with an x- or y-derivative different from -1 or 1.
185 // (This also means needs_mipmaps() and one_to_one_sampling()
186 // together would make no sense.)
188 // The most common case for this would be an effect that has an exact
189 // 1:1-correspondence between input and output texels, e.g. SaturationEffect.
190 // However, more creative things, like mirroring/flipping or padding,
191 // would also be allowed.
193 // The primary gain from setting this is that you can sample directly
194 // from an effect that changes output size (see changes_output_size() below),
195 // without going through a bounce texture. It won't work for effects that
196 // set sets_virtual_output_size(), though.
198 // Does not make a lot of sense together with needs_texture_bounce().
199 virtual bool one_to_one_sampling() const { return false; }
201 // Whether this effect wants to output to a different size than
202 // its input(s) (see inform_input_size(), below). See also
203 // sets_virtual_output_size() below.
204 virtual bool changes_output_size() const { return false; }
206 // Whether your get_output_size() function (see below) intends to ever set
207 // virtual_width different from width, or similar for height.
208 // It does not make sense to set this to true if changes_output_size() is false.
209 virtual bool sets_virtual_output_size() const { return changes_output_size(); }
211 // Whether this effect is effectively sampling from a a single texture.
212 // If so, it will override needs_texture_bounce(); however, there are also
213 // two demands it needs to fulfill:
215 // 1. It needs to be an Input, ie. num_inputs() == 0.
216 // 2. It needs to allocate exactly one sampler in set_gl_state(),
217 // and allow dependent effects to change that sampler state.
218 virtual bool is_single_texture() const { return false; }
220 // If changes_output_size() is true, you must implement this to tell
221 // the framework what output size you want. Also, you can set a
222 // virtual width/height, which is the size the next effect (if any)
223 // will _think_ your data is in. This is primarily useful if you are
224 // relying on getting OpenGL's bilinear resizing for free; otherwise,
225 // your virtual_width/virtual_height should be the same as width/height.
227 // Note that it is explicitly allowed to change width and height
228 // from frame to frame; EffectChain will reallocate textures as needed.
229 virtual void get_output_size(unsigned *width, unsigned *height,
230 unsigned *virtual_width, unsigned *virtual_height) const {
234 // Tells the effect the resolution of each of its input.
235 // This will be called every frame, and always before get_output_size(),
236 // so you can change your output size based on the input if so desired.
238 // Note that in some cases, an input might not have a single well-defined
239 // resolution (for instance if you fade between two inputs with
240 // different resolutions). In this case, you will get width=0 and height=0
241 // for that input. If you cannot handle that, you will need to set
242 // needs_texture_bounce() to true, which will force a render to a single
243 // given resolution before you get the input.
244 virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height) {}
246 // How many inputs this effect will take (a fixed number).
247 // If you have only one input, it will be called INPUT() in GLSL;
248 // if you have several, they will be INPUT1(), INPUT2(), and so on.
249 virtual unsigned num_inputs() const { return 1; }
251 // Inform the effect that it has been just added to the EffectChain.
252 // The primary use for this is to store the ResourcePool uesd by
253 // the chain; for modifications to it, rewrite_graph() below
254 // is probably a better fit.
255 virtual void inform_added(EffectChain *chain) {}
257 // Let the effect rewrite the effect chain as it sees fit.
258 // Most effects won't need to do this, but this is very useful
259 // if you have an effect that consists of multiple sub-effects
260 // (for instance, two passes). The effect is given to its own
261 // pointer, and it can add new ones (by using add_node()
262 // and connect_node()) as it sees fit. This is called at
263 // EffectChain::finalize() time, when the entire graph is known,
264 // in the order that the effects were originally added.
266 // Note that if the effect wants to take itself entirely out
267 // of the chain, it must set “disabled” to true and then disconnect
268 // itself from all other effects.
269 virtual void rewrite_graph(EffectChain *graph, Node *self) {}
271 // Returns the GLSL fragment shader string for this effect.
272 virtual std::string output_fragment_shader() = 0;
274 // Set all OpenGL state that this effect needs before rendering.
275 // The default implementation sets one uniform per registered parameter,
276 // but no other state.
278 // <sampler_num> is the first free texture sampler. If you want to use
279 // textures, you can bind a texture to GL_TEXTURE0 + <sampler_num>,
280 // and then increment the number (so that the next effect in the chain
281 // will use a different sampler).
282 virtual void set_gl_state(GLuint glsl_program_num, const std::string& prefix, unsigned *sampler_num);
284 // If you set any special OpenGL state in set_gl_state(), you can clear it
285 // after rendering here. The default implementation does nothing.
286 virtual void clear_gl_state();
288 // Set a parameter; intended to be called from user code.
289 // Neither of these take ownership of the pointer.
290 virtual bool set_int(const std::string&, int value) MUST_CHECK_RESULT;
291 virtual bool set_float(const std::string &key, float value) MUST_CHECK_RESULT;
292 virtual bool set_vec2(const std::string &key, const float *values) MUST_CHECK_RESULT;
293 virtual bool set_vec3(const std::string &key, const float *values) MUST_CHECK_RESULT;
294 virtual bool set_vec4(const std::string &key, const float *values) MUST_CHECK_RESULT;
297 // Register a parameter. Whenever set_*() is called with the same key,
298 // it will update the value in the given pointer (typically a pointer
299 // to some private member variable in your effect). It will also
300 // register a uniform of the same name (plus an arbitrary prefix
301 // which you can access using the PREFIX macro) that you can access.
303 // Neither of these take ownership of the pointer.
305 // int is special since GLSL pre-1.30 doesn't have integer uniforms.
306 // Thus, ints that you register will _not_ be converted to GLSL uniforms.
307 void register_int(const std::string &key, int *value);
309 // These correspond directly to float/vec2/vec3/vec4 in GLSL.
310 void register_float(const std::string &key, float *value);
311 void register_vec2(const std::string &key, float *values);
312 void register_vec3(const std::string &key, float *values);
313 void register_vec4(const std::string &key, float *values);
315 // Register uniforms, such that they will automatically be set
316 // before the shader runs. This is more efficient than set_uniform_*
317 // in effect_util.h, because it doesn't need to do name lookups
318 // every time. Also, in the future, it will use uniform buffer objects
319 // (UBOs) if available to reduce the number of calls into the driver.
321 // May not be called after output_fragment_shader() has returned.
322 // The pointer must be valid for the entire lifetime of the Effect,
323 // since the value is pulled from it each execution. The value is
324 // guaranteed to be read after set_gl_state() for the effect has
325 // returned, so you can safely update its value from there.
327 // Note that this will also declare the uniform in the shader for you,
328 // so you should not do that yourself. (This is so it can be part of
329 // the right uniform block.) However, it is probably a good idea to
330 // have a commented-out declaration so that it is easier to see the
331 // type and thus understand the shader on its own.
333 // Calling register_* will automatically imply register_uniform_*,
334 // except for register_int as noted above.
335 void register_uniform_sampler2d(const std::string &key, const int *value);
336 void register_uniform_bool(const std::string &key, const bool *value);
337 void register_uniform_int(const std::string &key, const int *value); // Note: Requires GLSL 1.30 or newer.
338 void register_uniform_float(const std::string &key, const float *value);
339 void register_uniform_vec2(const std::string &key, const float *values);
340 void register_uniform_vec3(const std::string &key, const float *values);
341 void register_uniform_vec4(const std::string &key, const float *values);
342 void register_uniform_vec2_array(const std::string &key, const float *values, size_t num_values);
343 void register_uniform_vec4_array(const std::string &key, const float *values, size_t num_values);
344 void register_uniform_mat3(const std::string &key, const Eigen::Matrix3d *matrix);
347 std::map<std::string, int *> params_int;
348 std::map<std::string, float *> params_float;
349 std::map<std::string, float *> params_vec2;
350 std::map<std::string, float *> params_vec3;
351 std::map<std::string, float *> params_vec4;
353 // Picked out by EffectChain during finalization.
354 std::vector<Uniform<int> > uniforms_sampler2d;
355 std::vector<Uniform<bool> > uniforms_bool;
356 std::vector<Uniform<int> > uniforms_int;
357 std::vector<Uniform<float> > uniforms_float;
358 std::vector<Uniform<float> > uniforms_vec2;
359 std::vector<Uniform<float> > uniforms_vec3;
360 std::vector<Uniform<float> > uniforms_vec4;
361 std::vector<Uniform<float> > uniforms_vec2_array;
362 std::vector<Uniform<float> > uniforms_vec4_array;
363 std::vector<Uniform<Eigen::Matrix3d> > uniforms_mat3;
364 friend class EffectChain;
369 #endif // !defined(_MOVIT_EFFECT_H)