1 #ifndef _MOVIT_EFFECT_CHAIN_H
2 #define _MOVIT_EFFECT_CHAIN_H 1
4 // An EffectChain is the largest basic entity in Movit; it contains everything
5 // needed to connects a series of effects, from inputs to outputs, and render
6 // them. Generally you set up your effect chain once and then call its render
7 // functions once per frame; setting one up can be relatively expensive,
8 // but rendering is fast.
10 // Threading considerations: EffectChain is “thread-compatible”; you can use
11 // different EffectChains in multiple threads at the same time (assuming the
12 // threads do not use the same OpenGL context, but this is a good idea anyway),
13 // but you may not use one EffectChain from multiple threads simultaneously.
14 // You _are_ allowed to use one EffectChain from multiple threads as long as
15 // you only use it from one at a time (possibly by doing your own locking),
16 // but if so, the threads' contexts need to be set up to share resources, since
17 // the EffectChain holds textures and other OpenGL objects that are tied to the
27 #include "image_format.h"
36 // For internal use within Node.
44 // Whether you want pre- or postmultiplied alpha in the output
45 // (see effect.h for a discussion of pre- versus postmultiplied alpha).
46 enum OutputAlphaFormat {
47 OUTPUT_ALPHA_FORMAT_PREMULTIPLIED,
48 OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED,
51 // A node in the graph; basically an effect and some associated information.
57 // Edges in the graph (forward and backward).
58 std::vector<Node *> outgoing_links;
59 std::vector<Node *> incoming_links;
62 // Logical size of the output of this effect, ie. the resolution
63 // you would get if you sampled it as a texture. If it is undefined
64 // (since the inputs differ in resolution), it will be 0x0.
65 // If both this and output_texture_{width,height} are set,
66 // they will be equal.
67 unsigned output_width, output_height;
69 // If the effect has is_single_texture(), or if the output went to RTT
70 // and that texture has been bound to a sampler, the sampler number
71 // will be stored here.
73 // TODO: Can an RTT texture be used as inputs to multiple effects
74 // within the same phase? If so, we have a problem with modifying
75 // sampler state here.
76 int bound_sampler_num;
78 // Used during the building of the effect chain.
79 Colorspace output_color_space;
80 GammaCurve output_gamma_curve;
81 AlphaType output_alpha_type;
83 friend class EffectChain;
86 // A rendering phase; a single GLSL program rendering a single quad.
90 GLuint glsl_program_num; // Owned by the resource_pool.
91 bool input_needs_mipmaps;
93 // Inputs are only inputs from other phases (ie., those that come from RTT);
94 // input textures are counted as part of <effects>.
95 std::vector<Phase *> inputs;
96 std::vector<Node *> effects; // In order.
97 unsigned output_width, output_height, virtual_output_width, virtual_output_height;
99 // Identifier used to create unique variables in GLSL.
100 // Unique per-phase to increase cacheability of compiled shaders.
101 std::map<Node *, std::string> effect_ids;
103 // The geometry needed to draw this quad, bound to the vertex array
104 // object. (Seemingly it's actually a win not to upload geometry every
105 // frame, even for something as small as a quad, due to fewer state
108 GLuint position_vbo, texcoord_vbo;
113 // Aspect: e.g. 16.0f, 9.0f for 16:9.
114 // resource_pool is a pointer to a ResourcePool with which to share shaders
115 // and other resources (see resource_pool.h). If NULL (the default),
116 // will create its own that is not shared with anything else. Does not take
117 // ownership of the passed-in ResourcePool, but will naturally take ownership
118 // of its own internal one if created.
119 EffectChain(float aspect_nom, float aspect_denom, ResourcePool *resource_pool = NULL);
123 // input, effects, output, finalize need to come in that specific order.
125 // EffectChain takes ownership of the given input.
126 // input is returned back for convenience.
127 Input *add_input(Input *input);
129 // EffectChain takes ownership of the given effect.
130 // effect is returned back for convenience.
131 Effect *add_effect(Effect *effect) {
132 return add_effect(effect, last_added_effect());
134 Effect *add_effect(Effect *effect, Effect *input) {
135 std::vector<Effect *> inputs;
136 inputs.push_back(input);
137 return add_effect(effect, inputs);
139 Effect *add_effect(Effect *effect, Effect *input1, Effect *input2) {
140 std::vector<Effect *> inputs;
141 inputs.push_back(input1);
142 inputs.push_back(input2);
143 return add_effect(effect, inputs);
145 Effect *add_effect(Effect *effect, Effect *input1, Effect *input2, Effect *input3) {
146 std::vector<Effect *> inputs;
147 inputs.push_back(input1);
148 inputs.push_back(input2);
149 inputs.push_back(input3);
150 return add_effect(effect, inputs);
152 Effect *add_effect(Effect *effect, const std::vector<Effect *> &inputs);
154 void add_output(const ImageFormat &format, OutputAlphaFormat alpha_format);
156 // Set number of output bits, to scale the dither.
157 // 8 is the right value for most outputs.
158 // The default, 0, is a special value that means no dither.
159 void set_dither_bits(unsigned num_bits)
161 this->num_dither_bits = num_bits;
167 //void render(unsigned char *src, unsigned char *dst);
168 void render_to_screen()
170 render_to_fbo(0, 0, 0);
173 // Render the effect chain to the given FBO. If width=height=0, keeps
174 // the current viewport.
175 void render_to_fbo(GLuint fbo, unsigned width, unsigned height);
177 Effect *last_added_effect() {
181 return nodes.back()->effect;
185 // API for manipulating the graph directly. Intended to be used from
186 // effects and by EffectChain itself.
188 // Note that for nodes with multiple inputs, the order of calls to
189 // connect_nodes() will matter.
190 Node *add_node(Effect *effect);
191 void connect_nodes(Node *sender, Node *receiver);
192 void replace_receiver(Node *old_receiver, Node *new_receiver);
193 void replace_sender(Node *new_sender, Node *receiver);
194 void insert_node_between(Node *sender, Node *middle, Node *receiver);
195 Node *find_node_for_effect(Effect *effect) { return node_map[effect]; }
197 // Get the OpenGL sampler (GL_TEXTURE0, GL_TEXTURE1, etc.) for the
198 // input of the given node, so that one can modify the sampler state
199 // directly. Only valid to call during set_gl_state().
201 // Also, for this to be allowed, <node>'s effect must have
202 // needs_texture_bounce() set, so that it samples directly from a
203 // single-sampler input, or from an RTT texture.
204 GLenum get_input_sampler(Node *node, unsigned input_num) const;
206 // Get the current resource pool assigned to this EffectChain.
207 // Primarily to let effects allocate textures as needed.
208 // Any resources you get from the pool must be returned to the pool
209 // no later than in the Effect's destructor.
210 ResourcePool *get_resource_pool() { return resource_pool; }
213 // Make sure the output rectangle is at least large enough to hold
214 // the given input rectangle in both dimensions, and is of the
215 // current aspect ratio (aspect_nom/aspect_denom).
216 void size_rectangle_to_fit(unsigned width, unsigned height, unsigned *output_width, unsigned *output_height);
218 // Compute the input sizes for all inputs for all effects in a given phase,
219 // and inform the effects about the results.
220 void inform_input_sizes(Phase *phase);
222 // Determine the preferred output size of a given phase.
223 // Requires that all input phases (if any) already have output sizes set.
224 void find_output_size(Phase *phase);
226 // Find all inputs eventually feeding into this effect that have
227 // output gamma different from GAMMA_LINEAR.
228 void find_all_nonlinear_inputs(Node *effect, std::vector<Node *> *nonlinear_inputs);
230 // Create a GLSL program computing the effects for this phase in order.
231 void compile_glsl_program(Phase *phase);
233 // Create all GLSL programs needed to compute the given effect, and all outputs
234 // that depend on it (whenever possible). Returns the phase that has <output>
235 // as the last effect. Also pushes all phases in order onto <phases>.
236 Phase *construct_phase(Node *output, std::map<Node *, Phase *> *completed_effects);
238 // Execute one phase, ie. set up all inputs, effects and outputs, and render the quad.
239 void execute_phase(Phase *phase, bool last_phase, std::map<Phase *, GLuint> *output_textures, std::set<Phase *> *generated_mipmaps);
241 // Set up the given sampler number for sampling from an RTT texture,
242 // and bind it to "tex_" plus the given GLSL variable.
243 void setup_rtt_sampler(GLuint glsl_program_num, int sampler_num, const std::string &effect_id, bool use_mipmaps);
245 // Output the current graph to the given file in a Graphviz-compatible format;
246 // only useful for debugging.
247 void output_dot(const char *filename);
248 std::vector<std::string> get_labels_for_edge(const Node *from, const Node *to);
249 void output_dot_edge(FILE *fp,
250 const std::string &from_node_id,
251 const std::string &to_node_id,
252 const std::vector<std::string> &labels);
254 // Some of the graph algorithms assume that the nodes array is sorted
255 // topologically (inputs are always before outputs), but some operations
256 // (like graph rewriting) can change that. This function restores that order.
257 void sort_all_nodes_topologically();
259 // Do the actual topological sort. <nodes> must be a connected, acyclic subgraph;
260 // links that go to nodes not in the set will be ignored.
261 std::vector<Node *> topological_sort(const std::vector<Node *> &nodes);
263 // Utility function used by topological_sort() to do a depth-first search.
264 // The reason why we store nodes left to visit instead of a more conventional
265 // list of nodes to visit is that we want to be able to limit ourselves to
266 // a subgraph instead of all nodes. The set thus serves a dual purpose.
267 void topological_sort_visit_node(Node *node, std::set<Node *> *nodes_left_to_visit, std::vector<Node *> *sorted_list);
269 // Used during finalize().
270 void find_color_spaces_for_inputs();
271 void propagate_alpha();
272 void propagate_gamma_and_color_space();
273 Node *find_output_node();
275 bool node_needs_colorspace_fix(Node *node);
276 void fix_internal_color_spaces();
277 void fix_output_color_space();
279 bool node_needs_alpha_fix(Node *node);
280 void fix_internal_alpha(unsigned step);
281 void fix_output_alpha();
283 bool node_needs_gamma_fix(Node *node);
284 void fix_internal_gamma_by_asking_inputs(unsigned step);
285 void fix_internal_gamma_by_inserting_nodes(unsigned step);
286 void fix_output_gamma();
287 void add_dither_if_needed();
289 float aspect_nom, aspect_denom;
290 ImageFormat output_format;
291 OutputAlphaFormat output_alpha_format;
293 std::vector<Node *> nodes;
294 std::map<Effect *, Node *> node_map;
295 Effect *dither_effect;
297 std::vector<Input *> inputs; // Also contained in nodes.
298 std::vector<Phase *> phases;
300 unsigned num_dither_bits;
303 ResourcePool *resource_pool;
304 bool owns_resource_pool;
309 #endif // !defined(_MOVIT_EFFECT_CHAIN_H)