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.
31 // program_freelist_max_length is how many compiled programs that are unused to keep
32 // around after they are no longer in use (in case another EffectChain
33 // wants that exact program later). Shaders are expensive to compile and do not
34 // need a lot of resources to keep around, so this should be a reasonable number.
36 // texture_freelist_max_bytes is how many bytes of unused textures to keep around
37 // after they are no longer in use (in case a new texture of the same dimensions
38 // and format is needed). Note that the size estimate is very coarse; it does not
39 // take into account padding, metadata, and most importantly mipmapping.
40 // This means you should be prepared for actual memory usage of the freelist being
41 // twice this estimate or more.
42 ResourcePool(size_t program_freelist_max_length = 100,
43 size_t texture_freelist_max_bytes = 100 << 20); // 100 MB.
46 // All remaining functions are intended for calls from EffectChain only.
48 // Compile the given vertex+fragment shader pair, or fetch an already
49 // compiled program from the cache if possible. Keeps ownership of the
50 // program; you must call release_glsl_program() instead of deleting it
51 // when you no longer want it.
52 GLuint compile_glsl_program(const std::string& vertex_shader, const std::string& fragment_shader);
53 void release_glsl_program(GLuint glsl_program_num);
55 // Allocate a 2D texture of the given internal format and dimensions,
56 // or fetch a previous used if possible. Unbinds GL_TEXTURE_2D afterwards.
57 // Keeps ownership of the texture; you must call release_2d_texture() instead
58 // of deleting it when you no longer want it.
59 GLuint create_2d_texture(GLint internal_format, GLsizei width, GLsizei height);
60 void release_2d_texture(GLuint texture_num);
63 // Delete the given program and both its shaders.
64 void delete_program(GLuint program_num);
66 // Protects all the other elements in the class.
69 size_t program_freelist_max_length, texture_freelist_max_bytes;
71 // A mapping from vertex/fragment shader source strings to compiled program number.
72 std::map<std::pair<std::string, std::string>, GLuint> programs;
74 // A mapping from compiled program number to number of current users.
75 // Once this reaches zero, the program is taken out of this map and instead
76 // put on the freelist (after which it may be deleted).
77 std::map<GLuint, int> program_refcount;
79 // A mapping from program number to vertex and fragment shaders.
80 std::map<GLuint, std::pair<GLuint, GLuint> > program_shaders;
82 // A list of programs that are no longer in use, most recently freed first.
83 // Once this reaches <program_freelist_max_length>, the last element
85 std::list<GLuint> program_freelist;
88 GLint internal_format;
89 GLsizei width, height;
92 // A mapping from texture number to format details. This is filled if the
93 // texture is given out to a client or on the freelist, but not if it is
94 // deleted from the freelist.
95 std::map<GLuint, Texture2D> texture_formats;
97 // A list of all textures that are release but not freed (most recently freed
98 // first), and an estimate of their current memory usage. Once
99 // <texture_freelist_bytes> goes above <texture_freelist_max_bytes>,
100 // elements are deleted off the end of the list until we are under the limit
102 std::list<GLuint> texture_freelist;
103 size_t texture_freelist_bytes;
105 // See the caveats at the constructor.
106 static size_t estimate_texture_size(const Texture2D &texture_format);
111 #endif // !defined(_MOVIT_RESOURCE_POOL_H)