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"
34 // For internal use within Node.
42 // Whether you want pre- or postmultiplied alpha in the output
43 // (see effect.h for a discussion of pre- versus postmultiplied alpha).
44 enum OutputAlphaFormat {
45 OUTPUT_ALPHA_FORMAT_PREMULTIPLIED,
46 OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED,
49 // A node in the graph; basically an effect and some associated information.
55 // Edges in the graph (forward and backward).
56 std::vector<Node *> outgoing_links;
57 std::vector<Node *> incoming_links;
60 // Logical size of the output of this effect, ie. the resolution
61 // you would get if you sampled it as a texture. If it is undefined
62 // (since the inputs differ in resolution), it will be 0x0.
63 // If both this and output_texture_{width,height} are set,
64 // they will be equal.
65 unsigned output_width, output_height;
67 // If output goes to RTT (otherwise, none of these are set).
68 // The Phase pointer is a but ugly; we should probably fix so
69 // that Phase takes other phases as inputs, instead of Node.
70 GLuint output_texture;
71 unsigned output_texture_width, output_texture_height;
74 // Used during the building of the effect chain.
75 Colorspace output_color_space;
76 GammaCurve output_gamma_curve;
77 AlphaType output_alpha_type;
79 friend class EffectChain;
82 // A rendering phase; a single GLSL program rendering a single quad.
84 GLuint glsl_program_num; // Owned by the resource_pool.
85 bool input_needs_mipmaps;
87 // Inputs are only inputs from other phases (ie., those that come from RTT);
88 // input textures are not counted here.
89 std::vector<Node *> inputs;
91 std::vector<Node *> effects; // In order.
92 unsigned output_width, output_height, virtual_output_width, virtual_output_height;
94 // Identifier used to create unique variables in GLSL.
95 // Unique per-phase to increase cacheability of compiled shaders.
96 std::map<Node *, std::string> effect_ids;
101 // Aspect: e.g. 16.0f, 9.0f for 16:9.
102 // resource_pool is a pointer to a ResourcePool with which to share shaders
103 // and other resources (see resource_pool.h). If NULL (the default),
104 // will create its own that is not shared with anything else. Does not take
105 // ownership of the passed-in ResourcePool, but will naturally take ownership
106 // of its own internal one if created.
107 EffectChain(float aspect_nom, float aspect_denom, ResourcePool *resource_pool = NULL);
111 // input, effects, output, finalize need to come in that specific order.
113 // EffectChain takes ownership of the given input.
114 // input is returned back for convenience.
115 Input *add_input(Input *input);
117 // EffectChain takes ownership of the given effect.
118 // effect is returned back for convenience.
119 Effect *add_effect(Effect *effect) {
120 return add_effect(effect, last_added_effect());
122 Effect *add_effect(Effect *effect, Effect *input) {
123 std::vector<Effect *> inputs;
124 inputs.push_back(input);
125 return add_effect(effect, inputs);
127 Effect *add_effect(Effect *effect, Effect *input1, Effect *input2) {
128 std::vector<Effect *> inputs;
129 inputs.push_back(input1);
130 inputs.push_back(input2);
131 return add_effect(effect, inputs);
133 Effect *add_effect(Effect *effect, const std::vector<Effect *> &inputs);
135 void add_output(const ImageFormat &format, OutputAlphaFormat alpha_format);
137 // Set number of output bits, to scale the dither.
138 // 8 is the right value for most outputs.
139 // The default, 0, is a special value that means no dither.
140 void set_dither_bits(unsigned num_bits)
142 this->num_dither_bits = num_bits;
148 //void render(unsigned char *src, unsigned char *dst);
149 void render_to_screen()
151 render_to_fbo(0, 0, 0);
154 // Render the effect chain to the given FBO. If width=height=0, keeps
155 // the current viewport.
156 void render_to_fbo(GLuint fbo, unsigned width, unsigned height);
158 Effect *last_added_effect() {
162 return nodes.back()->effect;
166 // API for manipulating the graph directly. Intended to be used from
167 // effects and by EffectChain itself.
169 // Note that for nodes with multiple inputs, the order of calls to
170 // connect_nodes() will matter.
171 Node *add_node(Effect *effect);
172 void connect_nodes(Node *sender, Node *receiver);
173 void replace_receiver(Node *old_receiver, Node *new_receiver);
174 void replace_sender(Node *new_sender, Node *receiver);
175 void insert_node_between(Node *sender, Node *middle, Node *receiver);
178 // Make sure the output rectangle is at least large enough to hold
179 // the given input rectangle in both dimensions, and is of the
180 // current aspect ratio (aspect_nom/aspect_denom).
181 void size_rectangle_to_fit(unsigned width, unsigned height, unsigned *output_width, unsigned *output_height);
183 // Compute the input sizes for all inputs for all effects in a given phase,
184 // and inform the effects about the results.
185 void inform_input_sizes(Phase *phase);
187 // Determine the preferred output size of a given phase.
188 // Requires that all input phases (if any) already have output sizes set.
189 void find_output_size(Phase *phase);
191 // Find all inputs eventually feeding into this effect that have
192 // output gamma different from GAMMA_LINEAR.
193 void find_all_nonlinear_inputs(Node *effect, std::vector<Node *> *nonlinear_inputs);
195 // Create a GLSL program computing the given effects in order.
196 Phase *compile_glsl_program(const std::vector<Node *> &inputs,
197 const std::vector<Node *> &effects);
199 // Create all GLSL programs needed to compute the given effect, and all outputs
200 // that depends on it (whenever possible).
201 void construct_glsl_programs(Node *output);
203 // Output the current graph to the given file in a Graphviz-compatible format;
204 // only useful for debugging.
205 void output_dot(const char *filename);
206 std::vector<std::string> get_labels_for_edge(const Node *from, const Node *to);
207 void output_dot_edge(FILE *fp,
208 const std::string &from_node_id,
209 const std::string &to_node_id,
210 const std::vector<std::string> &labels);
212 // Some of the graph algorithms assume that the nodes array is sorted
213 // topologically (inputs are always before outputs), but some operations
214 // (like graph rewriting) can change that. This function restores that order.
215 void sort_all_nodes_topologically();
217 // Do the actual topological sort. <nodes> must be a connected, acyclic subgraph;
218 // links that go to nodes not in the set will be ignored.
219 std::vector<Node *> topological_sort(const std::vector<Node *> &nodes);
221 // Utility function used by topological_sort() to do a depth-first search.
222 // The reason why we store nodes left to visit instead of a more conventional
223 // list of nodes to visit is that we want to be able to limit ourselves to
224 // a subgraph instead of all nodes. The set thus serves a dual purpose.
225 void topological_sort_visit_node(Node *node, std::set<Node *> *nodes_left_to_visit, std::vector<Node *> *sorted_list);
227 // Used during finalize().
228 void find_color_spaces_for_inputs();
229 void propagate_alpha();
230 void propagate_gamma_and_color_space();
231 Node *find_output_node();
233 bool node_needs_colorspace_fix(Node *node);
234 void fix_internal_color_spaces();
235 void fix_output_color_space();
237 bool node_needs_alpha_fix(Node *node);
238 void fix_internal_alpha(unsigned step);
239 void fix_output_alpha();
241 bool node_needs_gamma_fix(Node *node);
242 void fix_internal_gamma_by_asking_inputs(unsigned step);
243 void fix_internal_gamma_by_inserting_nodes(unsigned step);
244 void fix_output_gamma();
245 void add_dither_if_needed();
247 float aspect_nom, aspect_denom;
248 ImageFormat output_format;
249 OutputAlphaFormat output_alpha_format;
251 std::vector<Node *> nodes;
252 std::map<Effect *, Node *> node_map;
253 Effect *dither_effect;
255 std::vector<Input *> inputs; // Also contained in nodes.
256 std::vector<Phase *> phases;
258 unsigned num_dither_bits;
261 ResourcePool *resource_pool;
262 bool owns_resource_pool;
265 #endif // !defined(_MOVIT_EFFECT_CHAIN_H)