+
+GLuint ResourcePool::create_2d_texture(GLint internal_format, GLsizei width, GLsizei height)
+{
+ pthread_mutex_lock(&lock);
+ // See if there's a texture on the freelist we can use.
+ for (list<GLuint>::iterator freelist_it = texture_freelist.begin();
+ freelist_it != texture_freelist.end();
+ ++freelist_it) {
+ GLuint texture_num = *freelist_it;
+ map<GLuint, Texture2D>::const_iterator format_it = texture_formats.find(texture_num);
+ assert(format_it != texture_formats.end());
+ if (format_it->second.internal_format == internal_format &&
+ format_it->second.width == width &&
+ format_it->second.height == height) {
+ texture_freelist_bytes -= estimate_texture_size(format_it->second);
+ texture_freelist.erase(freelist_it);
+ pthread_mutex_unlock(&lock);
+ return texture_num;
+ }
+ }
+
+ // Find any reasonable format given the internal format; OpenGL validates it
+ // even though we give NULL as pointer.
+ GLenum format;
+ switch (internal_format) {
+ case GL_RGBA32F_ARB:
+ case GL_RGBA16F_ARB:
+ case GL_RGBA8:
+ case GL_SRGB8_ALPHA8:
+ format = GL_RGBA;
+ break;
+ case GL_RG32F:
+ case GL_RG16F:
+ format = GL_RG;
+ break;
+ case GL_R8:
+ format = GL_RED;
+ break;
+ default:
+ // TODO: Add more here as needed.
+ assert(false);
+ }
+
+ GLuint texture_num;
+ glGenTextures(1, &texture_num);
+ check_error();
+ glBindTexture(GL_TEXTURE_2D, texture_num);
+ check_error();
+ glTexImage2D(GL_TEXTURE_2D, 0, internal_format, width, height, 0, format, GL_UNSIGNED_BYTE, NULL);
+ check_error();
+ glBindTexture(GL_TEXTURE_2D, 0);
+ check_error();
+
+ Texture2D texture_format;
+ texture_format.internal_format = internal_format;
+ texture_format.width = width;
+ texture_format.height = height;
+ assert(texture_formats.count(texture_num) == 0);
+ texture_formats.insert(make_pair(texture_num, texture_format));
+
+ pthread_mutex_unlock(&lock);
+ return texture_num;
+}
+
+void ResourcePool::release_2d_texture(GLuint texture_num)
+{
+ pthread_mutex_lock(&lock);
+ texture_freelist.push_front(texture_num);
+ assert(texture_formats.count(texture_num) != 0);
+ texture_freelist_bytes += estimate_texture_size(texture_formats[texture_num]);
+
+ while (texture_freelist_bytes > texture_freelist_max_bytes) {
+ GLuint free_texture_num = texture_freelist.front();
+ texture_freelist.pop_front();
+ assert(texture_formats.count(free_texture_num) != 0);
+ texture_freelist_bytes -= estimate_texture_size(texture_formats[free_texture_num]);
+ texture_formats.erase(free_texture_num);
+ glDeleteTextures(1, &free_texture_num);
+ check_error();
+ }
+ pthread_mutex_unlock(&lock);
+}
+
+size_t ResourcePool::estimate_texture_size(const Texture2D &texture_format)
+{
+ size_t bytes_per_pixel;
+
+ switch (texture_format.internal_format) {
+ case GL_RGBA32F_ARB:
+ bytes_per_pixel = 16;
+ break;
+ case GL_RGBA16F_ARB:
+ bytes_per_pixel = 8;
+ break;
+ case GL_RGBA8:
+ case GL_SRGB8_ALPHA8:
+ bytes_per_pixel = 4;
+ break;
+ case GL_RG32F:
+ bytes_per_pixel = 8;
+ break;
+ case GL_RG16F:
+ bytes_per_pixel = 4;
+ break;
+ case GL_R8:
+ bytes_per_pixel = 1;
+ break;
+ default:
+ // TODO: Add more here as needed.
+ assert(false);
+ }
+
+ return texture_format.width * texture_format.height * bytes_per_pixel;
+}
+
+} // namespace movit