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 GLuint location; // Filled in only after phases have been constructed. GL_INVALID_INDEX if no location, or if using UBOs.
63 GLint ubo_offset; // Same. -1 if no location or if not using UBOs.
64 GLint ubo_num_elem; // Same. 0 if no location or if not using UBOs.
71 // An identifier for this type of effect, mostly used for debug output
72 // (but some special names, like "ColorspaceConversionEffect", holds special
73 // meaning). Same as the class name is fine.
74 virtual std::string effect_type_id() const = 0;
76 // Whether this effects expects its input (and output) to be in
77 // linear gamma, ie. without an applied gamma curve. Most effects
78 // will want this, although the ones that never actually look at
79 // the pixels, e.g. mirror, won't need to care, and can set this
80 // to false. If so, the input gamma will be undefined.
82 // Also see the note on needs_texture_bounce(), below.
83 virtual bool needs_linear_light() const { return true; }
85 // Whether this effect expects its input to be in the sRGB
86 // color space, ie. use the sRGB/Rec. 709 RGB primaries.
87 // (If not, it would typically come in as some slightly different
88 // set of RGB primaries; you would currently not get YCbCr
89 // or something similar).
91 // Again, most effects will want this, but you can set it to false
92 // if you process each channel independently, equally _and_
93 // in a linear fashion.
94 virtual bool needs_srgb_primaries() const { return true; }
96 // How this effect handles alpha, ie. what it outputs in its
97 // alpha channel. The choices are basically blank (alpha is always 1.0),
98 // premultiplied and postmultiplied.
100 // Premultiplied alpha is when the alpha value has been be multiplied
101 // into the three color components, so e.g. 100% red at 50% alpha
102 // would be (0.5, 0.0, 0.0, 0.5) instead of (1.0, 0.0, 0.0, 0.5)
103 // as it is stored in most image formats (postmultiplied alpha).
104 // The multiplication is taken to have happened in linear light.
105 // This is the most natural format for processing, and the default in
106 // most of Movit (just like linear light is).
108 // If you set INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA or
109 // INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK, all of your inputs
110 // (if any) are guaranteed to also be in premultiplied alpha.
111 // Otherwise, you can get postmultiplied or premultiplied alpha;
112 // you won't know. If you have multiple inputs, you will get the same
113 // (pre- or postmultiplied) for all inputs, although most likely,
114 // you will want to combine them in a premultiplied fashion anyway
117 // Always outputs blank alpha (ie. alpha=1.0). Only appropriate
118 // for inputs that do not output an alpha channel.
119 // Blank alpha is special in that it can be treated as both
120 // pre- and postmultiplied.
123 // Always outputs postmultiplied alpha. Only appropriate for inputs.
124 OUTPUT_POSTMULTIPLIED_ALPHA,
126 // Always outputs premultiplied alpha. As noted above,
127 // you will then also get all inputs in premultiplied alpha.
128 // If you set this, you should also set needs_linear_light().
129 INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA,
131 // Like INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA, but also guarantees
132 // that if you get blank alpha in, you also keep blank alpha out.
133 // This is a somewhat weaker guarantee than DONT_CARE_ALPHA_TYPE,
134 // but is still useful in many situations, and appropriate when
135 // e.g. you don't touch alpha at all.
137 // Does not make sense for inputs.
138 INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK,
140 // Keeps the type of alpha (premultiplied, postmultiplied, blank)
141 // unchanged from input to output. Usually appropriate if you
142 // process all color channels in a linear fashion, do not change
143 // alpha, and do not produce any new pixels thare have alpha != 1.0.
145 // Does not make sense for inputs.
146 DONT_CARE_ALPHA_TYPE,
148 virtual AlphaHandling alpha_handling() const { return INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA; }
150 // Whether this effect expects its input to come directly from
151 // a texture. If this is true, the framework will not chain the
152 // input from other effects, but will store the results of the
153 // chain to a temporary (RGBA fp16) texture and let this effect
154 // sample directly from that.
156 // There are two good reasons why you might want to set this:
158 // 1. You are sampling more than once from the input,
159 // in which case computing all the previous steps might
160 // be more expensive than going to a memory intermediate.
161 // 2. You rely on previous effects, possibly including gamma
162 // expansion, to happen pre-filtering instead of post-filtering.
163 // (This is only relevant if you actually need the filtering; if
164 // you sample 1:1 between pixels and texels, it makes no difference.)
166 // Note that in some cases, you might get post-filtered gamma expansion
167 // even when setting this option. More specifically, if you are the
168 // first effect in the chain, and the GPU is doing sRGB gamma
169 // expansion, it is undefined (from OpenGL's side) whether expansion
170 // happens pre- or post-filtering. For most uses, however,
171 // either will be fine.
172 virtual bool needs_texture_bounce() const { return false; }
174 // Whether this effect expects mipmaps or not. If you set this to
175 // true, you will be sampling with bilinear filtering; if not,
176 // you could be sampling with simple linear filtering and no mipmaps
177 // (although there is no guarantee; if a different effect in the chain
178 // needs mipmaps, you will also get them).
179 virtual bool needs_mipmaps() const { return false; }
181 // Whether there is a direct correspondence between input and output
182 // texels. Specifically, the effect must not:
184 // 1. Try to sample in the border (ie., outside the 0.0 to 1.0 area).
185 // 2. Try to sample between texels.
186 // 3. Sample with an x- or y-derivative different from -1 or 1.
187 // (This also means needs_mipmaps() and one_to_one_sampling()
188 // together would make no sense.)
190 // The most common case for this would be an effect that has an exact
191 // 1:1-correspondence between input and output texels, e.g. SaturationEffect.
192 // However, more creative things, like mirroring/flipping or padding,
193 // would also be allowed.
195 // The primary gain from setting this is that you can sample directly
196 // from an effect that changes output size (see changes_output_size() below),
197 // without going through a bounce texture. It won't work for effects that
198 // set sets_virtual_output_size(), though.
200 // Does not make a lot of sense together with needs_texture_bounce().
201 virtual bool one_to_one_sampling() const { return false; }
203 // Whether this effect wants to output to a different size than
204 // its input(s) (see inform_input_size(), below). See also
205 // sets_virtual_output_size() below.
206 virtual bool changes_output_size() const { return false; }
208 // Whether your get_output_size() function (see below) intends to ever set
209 // virtual_width different from width, or similar for height.
210 // It does not make sense to set this to true if changes_output_size() is false.
211 virtual bool sets_virtual_output_size() const { return changes_output_size(); }
213 // Whether this effect is effectively sampling from a a single texture.
214 // If so, it will override needs_texture_bounce(); however, there are also
215 // two demands it needs to fulfill:
217 // 1. It needs to be an Input, ie. num_inputs() == 0.
218 // 2. It needs to allocate exactly one sampler in set_gl_state(),
219 // and allow dependent effects to change that sampler state.
220 virtual bool is_single_texture() const { return false; }
222 // If set, this effect should never be bounced to an output, even if a
223 // dependent effect demands texture bounce.
225 // Note that setting this can invoke undefined behavior, up to and including crashing,
226 // so you should only use it if you have deep understanding of your entire chain
227 // and Movit's processing of it. The most likely use case is if you have an input
228 // that's cheap to compute but not a single texture (e.g. YCbCrInput), and want
229 // to run a ResampleEffect directly from it. Normally, this would require a bounce,
230 // but it's faster not to. (However, also note that in this case, effective texel
231 // subpixel precision will be too optimistic, since chroma is already subsampled.)
233 // Has no effect if is_single_texture() is set.
234 virtual bool override_disable_bounce() const { return false; }
236 // If changes_output_size() is true, you must implement this to tell
237 // the framework what output size you want. Also, you can set a
238 // virtual width/height, which is the size the next effect (if any)
239 // will _think_ your data is in. This is primarily useful if you are
240 // relying on getting OpenGL's bilinear resizing for free; otherwise,
241 // your virtual_width/virtual_height should be the same as width/height.
243 // Note that it is explicitly allowed to change width and height
244 // from frame to frame; EffectChain will reallocate textures as needed.
245 virtual void get_output_size(unsigned *width, unsigned *height,
246 unsigned *virtual_width, unsigned *virtual_height) const {
250 // Tells the effect the resolution of each of its input.
251 // This will be called every frame, and always before get_output_size(),
252 // so you can change your output size based on the input if so desired.
254 // Note that in some cases, an input might not have a single well-defined
255 // resolution (for instance if you fade between two inputs with
256 // different resolutions). In this case, you will get width=0 and height=0
257 // for that input. If you cannot handle that, you will need to set
258 // needs_texture_bounce() to true, which will force a render to a single
259 // given resolution before you get the input.
260 virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height) {}
262 // How many inputs this effect will take (a fixed number).
263 // If you have only one input, it will be called INPUT() in GLSL;
264 // if you have several, they will be INPUT1(), INPUT2(), and so on.
265 virtual unsigned num_inputs() const { return 1; }
267 // Inform the effect that it has been just added to the EffectChain.
268 // The primary use for this is to store the ResourcePool uesd by
269 // the chain; for modifications to it, rewrite_graph() below
270 // is probably a better fit.
271 virtual void inform_added(EffectChain *chain) {}
273 // Let the effect rewrite the effect chain as it sees fit.
274 // Most effects won't need to do this, but this is very useful
275 // if you have an effect that consists of multiple sub-effects
276 // (for instance, two passes). The effect is given to its own
277 // pointer, and it can add new ones (by using add_node()
278 // and connect_node()) as it sees fit. This is called at
279 // EffectChain::finalize() time, when the entire graph is known,
280 // in the order that the effects were originally added.
282 // Note that if the effect wants to take itself entirely out
283 // of the chain, it must set “disabled” to true and then disconnect
284 // itself from all other effects.
285 virtual void rewrite_graph(EffectChain *graph, Node *self) {}
287 // Returns the GLSL fragment shader string for this effect.
288 virtual std::string output_fragment_shader() = 0;
290 // Set all OpenGL state that this effect needs before rendering.
291 // The default implementation sets one uniform per registered parameter,
292 // but no other state.
294 // <sampler_num> is the first free texture sampler. If you want to use
295 // textures, you can bind a texture to GL_TEXTURE0 + <sampler_num>,
296 // and then increment the number (so that the next effect in the chain
297 // will use a different sampler).
298 virtual void set_gl_state(GLuint glsl_program_num, const std::string& prefix, unsigned *sampler_num);
300 // If you set any special OpenGL state in set_gl_state(), you can clear it
301 // after rendering here. The default implementation does nothing.
302 virtual void clear_gl_state();
304 // Set a parameter; intended to be called from user code.
305 // Neither of these take ownership of the pointer.
306 virtual bool set_int(const std::string&, int value) MUST_CHECK_RESULT;
307 virtual bool set_float(const std::string &key, float value) MUST_CHECK_RESULT;
308 virtual bool set_vec2(const std::string &key, const float *values) MUST_CHECK_RESULT;
309 virtual bool set_vec3(const std::string &key, const float *values) MUST_CHECK_RESULT;
310 virtual bool set_vec4(const std::string &key, const float *values) MUST_CHECK_RESULT;
313 // Register a parameter. Whenever set_*() is called with the same key,
314 // it will update the value in the given pointer (typically a pointer
315 // to some private member variable in your effect). It will also
316 // register a uniform of the same name (plus an arbitrary prefix
317 // which you can access using the PREFIX macro) that you can access.
319 // Neither of these take ownership of the pointer.
321 // These correspond directly to int/float/vec2/vec3/vec4 in GLSL.
322 void register_int(const std::string &key, int *value);
323 void register_float(const std::string &key, float *value);
324 void register_vec2(const std::string &key, float *values);
325 void register_vec3(const std::string &key, float *values);
326 void register_vec4(const std::string &key, float *values);
328 // Register uniforms, such that they will automatically be set
329 // before the shader runs. This is more efficient than set_uniform_*
330 // in effect_util.h, because it doesn't need to do name lookups
331 // every time. Also, in the future, it will use uniform buffer objects
332 // (UBOs) if available to reduce the number of calls into the driver.
334 // May not be called after output_fragment_shader() has returned.
335 // The pointer must be valid for the entire lifetime of the Effect,
336 // since the value is pulled from it each execution. The value is
337 // guaranteed to be read after set_gl_state() for the effect has
338 // returned, so you can safely update its value from there.
340 // Note that this will also declare the uniform in the shader for you,
341 // so you should not do that yourself. (This is so it can be part of
342 // the right uniform block.) However, it is probably a good idea to
343 // have a commented-out declaration so that it is easier to see the
344 // type and thus understand the shader on its own.
346 // Calling register_* will automatically imply register_uniform_*,
347 // except for register_int as noted above.
348 void register_uniform_sampler2d(const std::string &key, const int *value);
349 void register_uniform_bool(const std::string &key, const bool *value);
350 void register_uniform_int(const std::string &key, const int *value); // Note: Requires GLSL 1.30 or newer.
351 void register_uniform_float(const std::string &key, const float *value);
352 void register_uniform_vec2(const std::string &key, const float *values);
353 void register_uniform_vec3(const std::string &key, const float *values);
354 void register_uniform_vec4(const std::string &key, const float *values);
355 void register_uniform_float_array(const std::string &key, const float *values, size_t num_values);
356 void register_uniform_vec2_array(const std::string &key, const float *values, size_t num_values);
357 void register_uniform_vec3_array(const std::string &key, const float *values, size_t num_values);
358 void register_uniform_vec4_array(const std::string &key, const float *values, size_t num_values);
359 void register_uniform_mat3(const std::string &key, const Eigen::Matrix3d *matrix);
362 std::map<std::string, int *> params_int;
363 std::map<std::string, float *> params_float;
364 std::map<std::string, float *> params_vec2;
365 std::map<std::string, float *> params_vec3;
366 std::map<std::string, float *> params_vec4;
368 // Picked out by EffectChain during finalization.
369 std::vector<Uniform<int> > uniforms_sampler2d;
370 std::vector<Uniform<bool> > uniforms_bool;
371 std::vector<Uniform<int> > uniforms_int;
372 std::vector<Uniform<float> > uniforms_float;
373 std::vector<Uniform<float> > uniforms_vec2;
374 std::vector<Uniform<float> > uniforms_vec3;
375 std::vector<Uniform<float> > uniforms_vec4;
376 std::vector<Uniform<float> > uniforms_float_array;
377 std::vector<Uniform<float> > uniforms_vec2_array;
378 std::vector<Uniform<float> > uniforms_vec3_array;
379 std::vector<Uniform<float> > uniforms_vec4_array;
380 std::vector<Uniform<Eigen::Matrix3d> > uniforms_mat3;
381 friend class EffectChain;
386 #endif // !defined(_MOVIT_EFFECT_H)