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.
28 // program_freelist_max_length is how many compiled programs that are unused to keep
29 // around after they are no longer in use (in case another EffectChain
30 // wants that exact program later). Shaders are expensive to compile and do not
31 // need a lot of resources to keep around, so this should be a reasonable number.
32 ResourcePool(size_t program_freelist_max_length = 100);
35 // All remaining functions are intended for calls from EffectChain only.
37 // Compile the given vertex+fragment shader pair, or fetch an already
38 // compiled program from the cache if possible. Keeps ownership of the
39 // program; you must call release_glsl_program() instead of deleting it
40 // when you no longer want it.
41 GLuint compile_glsl_program(const std::string& vertex_shader, const std::string& fragment_shader);
42 void release_glsl_program(GLuint glsl_program_num);
45 // Delete the given program and both its shaders.
46 void delete_program(GLuint program_num);
48 // Protects all the other elements in the class.
51 size_t program_freelist_max_length;
53 // A mapping from vertex/fragment shader source strings to compiled program number.
54 std::map<std::pair<std::string, std::string>, GLuint> programs;
56 // A mapping from compiled program number to number of current users.
57 // Once this reaches zero, the program is taken out of this map and instead
58 // put on the freelist (after which it may be deleted).
59 std::map<GLuint, int> program_refcount;
61 // A mapping from program number to vertex and fragment shaders.
62 std::map<GLuint, std::pair<GLuint, GLuint> > program_shaders;
64 // A list of programs that are no longer in use, most recently freed first.
65 // Once this reaches <program_freelist_max_length>,
66 std::list<GLuint> program_freelist;
69 #endif // !defined(_MOVIT_RESOURCE_POOL_H)