Use the ResourcePool to allocate RTT textures in EffectChain.

[movit] / resource_pool.h

diff --git a/resource_pool.h b/resource_pool.h
index a6e4327b2e953ca5747f6b6dfac8d6e8811426f3..50e0da2c1207755c29c8eee56ec373d141c3275a 100644 (file)
--- a/resource_pool.h
+++ b/resource_pool.h
@@ -29,7 +29,15 @@ public:
        // around after they are no longer in use (in case another EffectChain
        // wants that exact program later). Shaders are expensive to compile and do not
        // need a lot of resources to keep around, so this should be a reasonable number.
-       ResourcePool(size_t program_freelist_max_length = 100);
+       //
+       // texture_freelist_max_bytes is how many bytes of unused textures to keep around
+       // after they are no longer in use (in case a new texture of the same dimensions
+       // and format is needed). Note that the size estimate is very coarse; it does not
+       // take into account padding, metadata, and most importantly mipmapping.
+       // This means you should be prepared for actual memory usage of the freelist being
+       // twice this estimate or more.
+       ResourcePool(size_t program_freelist_max_length = 100,
+                    size_t texture_freelist_max_bytes = 100 << 20);  // 100 MB.
        ~ResourcePool();
 
        // All remaining functions are intended for calls from EffectChain only.
@@ -41,6 +49,15 @@ public:
        GLuint compile_glsl_program(const std::string& vertex_shader, const std::string& fragment_shader);
        void release_glsl_program(GLuint glsl_program_num);
 
+       // Allocate a 2D texture of the given internal format and dimensions,
+       // or fetch a previous used if possible. Unbinds GL_TEXTURE_2D afterwards.
+       // Keeps ownership of the texture; you must call release_2d_texture() instead
+       // of deleting it when you no longer want it.
+       //
+       // Note: Currently we do not actually have a freelist, but this will change soon.
+       GLuint create_2d_texture(GLint internal_format, GLsizei width, GLsizei height);
+       void release_2d_texture(GLuint texture_num);
+
 private:
        // Delete the given program and both its shaders.
        void delete_program(GLuint program_num);
@@ -48,7 +65,7 @@ private:
        // Protects all the other elements in the class.
        pthread_mutex_t lock;
 
-       size_t program_freelist_max_length;
+       size_t program_freelist_max_length, texture_freelist_max_bytes;
                
        // A mapping from vertex/fragment shader source strings to compiled program number.
        std::map<std::pair<std::string, std::string>, GLuint> programs;
@@ -62,8 +79,30 @@ private:
        std::map<GLuint, std::pair<GLuint, GLuint> > program_shaders;
 
        // A list of programs that are no longer in use, most recently freed first.
-       // Once this reaches <program_freelist_max_length>, 
+       // Once this reaches <program_freelist_max_length>, the last element
+       // will be deleted.
        std::list<GLuint> program_freelist;
+
+       struct Texture2D {
+               GLint internal_format;
+               GLsizei width, height;
+       };
+
+       // A mapping from texture number to format details. This is filled if the
+       // texture is given out to a client or on the freelist, but not if it is
+       // deleted from the freelist.
+       std::map<GLuint, Texture2D> texture_formats;
+
+       // A list of all textures that are release but not freed (most recently freed
+       // first), and an estimate of their current memory usage. Once
+       // <texture_freelist_bytes> goes above <texture_freelist_max_bytes>,
+       // elements are deleted off the end of the list until we are under the limit
+       // again.
+       std::list<GLuint> texture_freelist;
+       size_t texture_freelist_bytes;
+
+       // See the caveats at the constructor.
+       static size_t estimate_texture_size(const Texture2D &texture_format);
 };
 
 #endif  // !defined(_MOVIT_RESOURCE_POOL_H)