1 #ifndef _MOVIT_RESOURCE_POOL_H
2 #define _MOVIT_RESOURCE_POOL_H 1
4 // A ResourcePool governs resources that are shared between multiple EffectChains;
5 // in particular, resources that might be expensive to acquire or hold. Thus,
6 // if you have many EffectChains, hooking them up to the same ResourcePool is
7 // probably a good idea.
9 // However, hooking an EffectChain to a ResourcePool extends the OpenGL context
10 // demands (see effect_chain.h) to that of the ResourcePool; all chains must then
11 // only be used in OpenGL contexts sharing resources with each other. This is
12 // the reason why there isn't just one global ResourcePool singleton (although
13 // most practical users will just want one).
15 // Thread-safety: All functions except the constructor and destructor can be
16 // safely called from multiple threads at the same time, provided they have
17 // separate (but sharing) OpenGL contexts.
19 // Memory management (only relevant if you use multiple contexts): Some objects,
20 // like FBOs, are not shareable across contexts, and can only be deleted from
21 // the context they were created in. Thus, you will need to tell the
22 // ResourcePool explicitly if you delete a context, or they will leak (and the
23 // ResourcePool destructor will assert-fail). See clean_context().
40 // program_freelist_max_length is how many compiled programs that are unused to keep
41 // around after they are no longer in use (in case another EffectChain
42 // wants that exact program later). Shaders are expensive to compile and do not
43 // need a lot of resources to keep around, so this should be a reasonable number.
45 // texture_freelist_max_bytes is how many bytes of unused textures to keep around
46 // after they are no longer in use (in case a new texture of the same dimensions
47 // and format is needed). Note that the size estimate is very coarse; it does not
48 // take into account padding, metadata, and most importantly mipmapping.
49 // This means you should be prepared for actual memory usage of the freelist being
50 // twice this estimate or more.
51 ResourcePool(size_t program_freelist_max_length = 100,
52 size_t texture_freelist_max_bytes = 100 << 20, // 100 MB.
53 size_t fbo_freelist_max_length = 100, // Per context.
54 size_t vao_freelist_max_length = 100); // Per context.
57 // All remaining functions are intended for calls from EffectChain only.
59 // Compile the given vertex+fragment shader pair, or fetch an already
60 // compiled program from the cache if possible. Keeps ownership of the
61 // program; you must call release_glsl_program() instead of deleting it
62 // when you no longer want it.
64 // If <fragment_shader_outputs> contains more than one value, the given
65 // outputs will be bound to fragment shader output colors in the order
66 // they appear in the vector. Otherwise, output order is undefined and
67 // determined by the OpenGL driver.
68 GLuint compile_glsl_program(const std::string& vertex_shader,
69 const std::string& fragment_shader,
70 const std::vector<std::string>& frag_shader_outputs);
71 void release_glsl_program(GLuint glsl_program_num);
73 // Same as the previous, but for compile shaders instead. There is currently
74 // no support for binding multiple outputs.
75 GLuint compile_glsl_compute_program(const std::string& compile_shader);
76 void release_glsl_compute_program(GLuint glsl_program_num);
78 // Since uniforms belong to the program and not to the context,
79 // a given GLSL program number can't be used by more than one thread
80 // at a time. Thus, if two threads want to use the same program
81 // (usually because two EffectChains share them via caching),
82 // we will need to make a clone. use_glsl_program() makes such
83 // a clone if needed, calls glUseProgram(), and returns the real
84 // program number that was used; this must be given to
85 // unuse_glsl_program() to release it. unuse_glsl_program() does not
86 // actually change any OpenGL state, though.
87 GLuint use_glsl_program(GLuint glsl_program_num);
88 void unuse_glsl_program(GLuint instance_program_num);
90 // Allocate a 2D texture of the given internal format and dimensions,
91 // or fetch a previous used if possible. Unbinds GL_TEXTURE_2D afterwards.
92 // Keeps ownership of the texture; you must call release_2d_texture() instead
93 // of deleting it when you no longer want it.
94 GLuint create_2d_texture(GLint internal_format, GLsizei width, GLsizei height);
95 void release_2d_texture(GLuint texture_num);
97 // Allocate an FBO with the the given texture(s) bound as framebuffer attachment(s),
98 // or fetch a previous used if possible. Unbinds GL_FRAMEBUFFER afterwards.
99 // Keeps ownership of the FBO; you must call release_fbo() of deleting
100 // it when you no longer want it.
102 // NOTE: In principle, the FBO doesn't have a resolution or pixel format;
103 // you can bind almost whatever texture you want to it. However, changing
104 // textures can have an adverse effect on performance due to validation,
105 // in particular on NVidia cards. Also, keep in mind that FBOs are not
106 // shareable across contexts, so you must have the context that's supposed
107 // to own the FBO current when you create or release it.
108 GLuint create_fbo(GLuint texture0_num,
109 GLuint texture1_num = 0,
110 GLuint texture2_num = 0,
111 GLuint texture3_num = 0);
112 void release_fbo(GLuint fbo_num);
114 // Create a VAO of a very specific form: All the given attribute indices
115 // are bound to start of the given VBO and contain two-component floats.
116 // Keeps ownership of the VAO; you must call release_vec2_vao() of deleting
117 // it when you no longer want it. VAOs are not sharable across contexts.
119 // These are not cached primarily for performance, but rather to work
120 // around an NVIDIA driver bug where glVertexAttribPointer() is thread-hostile
121 // (ie., simultaneous GL work in unrelated contexts can cause the driver
122 // to free() memory that was never malloc()-ed).
123 GLuint create_vec2_vao(const std::set<GLint> &attribute_indices,
125 void release_vec2_vao(const GLuint vao_num);
127 // Informs the ResourcePool that the current context is going away soon,
128 // and that any resources held for it in the freelist should be deleted.
130 // You do not need to do this for the last context; the regular destructor
131 // will take care of that. This means that if you only ever use one
132 // thread/context, you never need to call this function.
133 void clean_context();
136 // Delete the given program and both its shaders.
137 void delete_program(GLuint program_num);
139 // Deletes all FBOs for the given context that belong to deleted textures.
140 void cleanup_unlinked_fbos(void *context);
142 // Remove FBOs off the end of the freelist for <context>, until it
143 // is no more than <max_length> elements long.
144 void shrink_fbo_freelist(void *context, size_t max_length);
147 void shrink_vao_freelist(void *context, size_t max_length);
149 // Increment the refcount, or take it off the freelist if it's zero.
150 void increment_program_refcount(GLuint program_num);
152 // If debugging is on, output shader to a temporary file, for easier debugging.
153 void output_debug_shader(const std::string &shader_src, const std::string &suffix);
155 // For a new program that's not a clone of anything, insert it into the right
156 // structures: Give it a refcount, and set up the program_masters / program_instances lists.
157 void add_master_program(GLuint program_num);
159 // Link the given vertex and fragment shaders into a full GLSL program.
160 // See compile_glsl_program() for explanation of <fragment_shader_outputs>.
161 static GLuint link_program(GLuint vs_obj,
163 const std::vector<std::string>& fragment_shader_outputs);
165 static GLuint link_compute_program(GLuint cs_obj);
167 // Protects all the other elements in the class.
168 pthread_mutex_t lock;
170 size_t program_freelist_max_length, texture_freelist_max_bytes, fbo_freelist_max_length, vao_freelist_max_length;
172 // A mapping from vertex/fragment shader source strings to compiled program number.
173 std::map<std::pair<std::string, std::string>, GLuint> programs;
175 // A mapping from compute shader source string to compiled program number.
176 std::map<std::string, GLuint> compute_programs;
178 // A mapping from compiled program number to number of current users.
179 // Once this reaches zero, the program is taken out of this map and instead
180 // put on the freelist (after which it may be deleted).
181 std::map<GLuint, int> program_refcount;
183 // A mapping from program number to vertex and fragment shaders.
184 // Contains everything needed to re-link the program.
186 GLuint vs_obj, fs_obj;
187 std::vector<std::string> fragment_shader_outputs;
189 std::map<GLuint, ShaderSpec> program_shaders;
191 struct ComputeShaderSpec {
194 std::map<GLuint, ComputeShaderSpec> compute_program_shaders;
196 // For each program, a list of other programs that are exactly like it.
197 // By default, will only contain the program itself, but due to cloning
198 // (see use_glsl_program()), may grow. Programs are taken off this list
199 // while they are in use (by use_glsl_program()).
200 std::map<GLuint, std::stack<GLuint>> program_instances;
202 // For each program, the master program that created it
203 // (inverse of program_instances).
204 std::map<GLuint, GLuint> program_masters;
206 // A list of programs that are no longer in use, most recently freed first.
207 // Once this reaches <program_freelist_max_length>, the last element
209 std::list<GLuint> program_freelist;
212 GLint internal_format;
213 GLsizei width, height;
216 // A mapping from texture number to format details. This is filled if the
217 // texture is given out to a client or on the freelist, but not if it is
218 // deleted from the freelist.
219 std::map<GLuint, Texture2D> texture_formats;
221 // A list of all textures that are release but not freed (most recently freed
222 // first), and an estimate of their current memory usage. Once
223 // <texture_freelist_bytes> goes above <texture_freelist_max_bytes>,
224 // elements are deleted off the end of the list until we are under the limit
226 std::list<GLuint> texture_freelist;
227 size_t texture_freelist_bytes;
229 static const unsigned num_fbo_attachments = 4;
232 // GL_INVALID_INDEX means associated to a texture that has since been deleted.
233 // 0 means the output isn't bound.
234 GLuint texture_num[num_fbo_attachments];
237 // For each context, a mapping from FBO number to format details. This is
238 // filled if the FBO is given out to a client or on the freelist, but
239 // not if it is deleted from the freelist.
240 std::map<std::pair<void *, GLuint>, FBO> fbo_formats;
241 typedef std::map<std::pair<void *, GLuint>, FBO>::iterator FBOFormatIterator;
243 // For each context, a list of all FBOs that are released but not freed
244 // (most recently freed first). Once this reaches <fbo_freelist_max_length>,
245 // the last element will be deleted.
247 // We store iterators directly into <fbo_format> for efficiency.
248 std::map<void *, std::list<FBOFormatIterator>> fbo_freelist;
250 // Very similar, for VAOs.
253 std::set<GLint> attribute_indices;
256 std::map<std::pair<void *, GLuint>, VAO> vao_formats;
257 typedef std::map<std::pair<void *, GLuint>, VAO>::iterator VAOFormatIterator;
258 std::map<void *, std::list<VAOFormatIterator>> vao_freelist;
260 // See the caveats at the constructor.
261 static size_t estimate_texture_size(const Texture2D &texture_format);
266 #endif // !defined(_MOVIT_RESOURCE_POOL_H)