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 // Since uniforms belong to the program and not to the context,
74 // a given GLSL program number can't be used by more than one thread
75 // at a time. Thus, if two threads want to use the same program
76 // (usually because two EffectChains share them via caching),
77 // we will need to make a clone. use_glsl_program() makes such
78 // a clone if needed, calls glUseProgram(), and returns the real
79 // program number that was used; this must be given to
80 // unuse_glsl_program() to release it. unuse_glsl_program() does not
81 // actually change any OpenGL state, though.
82 GLuint use_glsl_program(GLuint glsl_program_num);
83 void unuse_glsl_program(GLuint instance_program_num);
85 // Allocate a 2D texture of the given internal format and dimensions,
86 // or fetch a previous used if possible. Unbinds GL_TEXTURE_2D afterwards.
87 // Keeps ownership of the texture; you must call release_2d_texture() instead
88 // of deleting it when you no longer want it.
89 GLuint create_2d_texture(GLint internal_format, GLsizei width, GLsizei height);
90 void release_2d_texture(GLuint texture_num);
92 // Allocate an FBO with the the given texture(s) bound as framebuffer attachment(s),
93 // or fetch a previous used if possible. Unbinds GL_FRAMEBUFFER afterwards.
94 // Keeps ownership of the FBO; you must call release_fbo() of deleting
95 // it when you no longer want it.
97 // NOTE: In principle, the FBO doesn't have a resolution or pixel format;
98 // you can bind almost whatever texture you want to it. However, changing
99 // textures can have an adverse effect on performance due to validation,
100 // in particular on NVidia cards. Also, keep in mind that FBOs are not
101 // shareable across contexts, so you must have the context that's supposed
102 // to own the FBO current when you create or release it.
103 GLuint create_fbo(GLuint texture0_num,
104 GLuint texture1_num = 0,
105 GLuint texture2_num = 0,
106 GLuint texture3_num = 0);
107 void release_fbo(GLuint fbo_num);
109 // Create a VAO of a very specific form: All the given attribute indices
110 // are bound to start of the given VBO and contain two-component floats.
111 // Keeps ownership of the VAO; you must call release_vec2_vao() of deleting
112 // it when you no longer want it. VAOs are not sharable across contexts.
114 // These are not cached primarily for performance, but rather to work
115 // around an NVIDIA driver bug where glVertexAttribPointer() is thread-hostile
116 // (ie., simultaneous GL work in unrelated contexts can cause the driver
117 // to free() memory that was never malloc()-ed).
118 GLuint create_vec2_vao(const std::set<GLint> &attribute_indices,
120 void release_vec2_vao(const GLuint vao_num);
122 // Informs the ResourcePool that the current context is going away soon,
123 // and that any resources held for it in the freelist should be deleted.
125 // You do not need to do this for the last context; the regular destructor
126 // will take care of that. This means that if you only ever use one
127 // thread/context, you never need to call this function.
128 void clean_context();
131 // Delete the given program and both its shaders.
132 void delete_program(GLuint program_num);
134 // Deletes all FBOs for the given context that belong to deleted textures.
135 void cleanup_unlinked_fbos(void *context);
137 // Remove FBOs off the end of the freelist for <context>, until it
138 // is no more than <max_length> elements long.
139 void shrink_fbo_freelist(void *context, size_t max_length);
142 void shrink_vao_freelist(void *context, size_t max_length);
144 // Link the given vertex and fragment shaders into a full GLSL program.
145 // See compile_glsl_program() for explanation of <fragment_shader_outputs>.
146 static GLuint link_program(GLuint vs_obj,
148 const std::vector<std::string>& fragment_shader_outputs);
150 // Protects all the other elements in the class.
151 pthread_mutex_t lock;
153 size_t program_freelist_max_length, texture_freelist_max_bytes, fbo_freelist_max_length, vao_freelist_max_length;
155 // A mapping from vertex/fragment shader source strings to compiled program number.
156 std::map<std::pair<std::string, std::string>, GLuint> programs;
158 // A mapping from compiled program number to number of current users.
159 // Once this reaches zero, the program is taken out of this map and instead
160 // put on the freelist (after which it may be deleted).
161 std::map<GLuint, int> program_refcount;
163 // A mapping from program number to vertex and fragment shaders.
164 // Contains everything needed to re-link the program.
166 GLuint vs_obj, fs_obj;
167 std::vector<std::string> fragment_shader_outputs;
169 std::map<GLuint, ShaderSpec> program_shaders;
171 // For each program, a list of other programs that are exactly like it.
172 // By default, will only contain the program itself, but due to cloning
173 // (see use_glsl_program()), may grow. Programs are taken off this list
174 // while they are in use (by use_glsl_program()).
175 std::map<GLuint, std::stack<GLuint> > program_instances;
177 // For each program, the master program that created it
178 // (inverse of program_instances).
179 std::map<GLuint, GLuint> program_masters;
181 // A list of programs that are no longer in use, most recently freed first.
182 // Once this reaches <program_freelist_max_length>, the last element
184 std::list<GLuint> program_freelist;
187 GLint internal_format;
188 GLsizei width, height;
191 // A mapping from texture number to format details. This is filled if the
192 // texture is given out to a client or on the freelist, but not if it is
193 // deleted from the freelist.
194 std::map<GLuint, Texture2D> texture_formats;
196 // A list of all textures that are release but not freed (most recently freed
197 // first), and an estimate of their current memory usage. Once
198 // <texture_freelist_bytes> goes above <texture_freelist_max_bytes>,
199 // elements are deleted off the end of the list until we are under the limit
201 std::list<GLuint> texture_freelist;
202 size_t texture_freelist_bytes;
204 static const unsigned num_fbo_attachments = 4;
207 // GL_INVALID_INDEX means associated to a texture that has since been deleted.
208 // 0 means the output isn't bound.
209 GLuint texture_num[num_fbo_attachments];
212 // For each context, a mapping from FBO number to format details. This is
213 // filled if the FBO is given out to a client or on the freelist, but
214 // not if it is deleted from the freelist.
215 std::map<std::pair<void *, GLuint>, FBO> fbo_formats;
216 typedef std::map<std::pair<void *, GLuint>, FBO>::iterator FBOFormatIterator;
218 // For each context, a list of all FBOs that are released but not freed
219 // (most recently freed first). Once this reaches <fbo_freelist_max_length>,
220 // the last element will be deleted.
222 // We store iterators directly into <fbo_format> for efficiency.
223 std::map<void *, std::list<FBOFormatIterator> > fbo_freelist;
225 // Very similar, for VAOs.
228 std::set<GLint> attribute_indices;
231 std::map<std::pair<void *, GLuint>, VAO> vao_formats;
232 typedef std::map<std::pair<void *, GLuint>, VAO>::iterator VAOFormatIterator;
233 std::map<void *, std::list<VAOFormatIterator> > vao_freelist;
235 // See the caveats at the constructor.
236 static size_t estimate_texture_size(const Texture2D &texture_format);
241 #endif // !defined(_MOVIT_RESOURCE_POOL_H)