Delayed texture deletion (Fixes #28)

libvita2d/include/vita2d.h

@@ -105,8 +105,16 @@ vita2d_texture *vita2d_create_empty_texture(unsigned int w, unsigned int h);
 vita2d_texture *vita2d_create_empty_texture_format(unsigned int w, unsigned int h, SceGxmTextureFormat format);
 vita2d_texture *vita2d_create_empty_texture_rendertarget(unsigned int w, unsigned int h, SceGxmTextureFormat format);
 
+// Mark texture for deletion; will be deleted at next vita2d_swap_buffers() or
+// when vita2d_gc_textures() is called (to avoid GPU crashes when deleting
+// textures still required by the GPU to finish rendering the current frame)
 void vita2d_free_texture(vita2d_texture *texture);
 
+// This will be called automatically by vita2d_swap_buffers(), but you can call
+// it earlier in case you allocate/deallocate many textures in a single frame;
+// returns the number of texture objects freed
+int vita2d_gc_textures();
+
 unsigned int vita2d_texture_get_width(const vita2d_texture *texture);
 unsigned int vita2d_texture_get_height(const vita2d_texture *texture);
 unsigned int vita2d_texture_get_stride(const vita2d_texture *texture);

libvita2d/source/vita2d.c

@@ -738,6 +738,10 @@ int vita2d_fini()
 	// wait until rendering is done
 	sceGxmFinish(_vita2d_context);
 
+	// in case vita2d_free_texture() was called after the last vita2d_swap_buffers(),
+	// we need to GC textures here again, otherwise we would leak texture objects
+	vita2d_gc_textures();
+
 	// clean up allocations
 	sceGxmShaderPatcherReleaseFragmentProgram(shaderPatcher, clearFragmentProgram);
 	sceGxmShaderPatcherReleaseVertexProgram(shaderPatcher, clearVertexProgram);
@@ -844,6 +848,9 @@ void vita2d_swap_buffers()
 		frontBufferIndex = backBufferIndex;
 		backBufferIndex = (backBufferIndex + 1) % DISPLAY_BUFFER_COUNT;
 	}
+
+	// free any textures marked for deletion
+	vita2d_gc_textures();
 }
 
 void vita2d_start_drawing()

libvita2d/source/vita2d_texture.c

@@ -197,7 +197,7 @@ vita2d_texture * vita2d_create_empty_texture_rendertarget(unsigned int w, unsign
 	return _vita2d_create_empty_texture_format_advanced(w, h, format, 1);
 }
 
-void vita2d_free_texture(vita2d_texture *texture)
+static void _vita2d_free_texture_internal(vita2d_texture *texture)
 {
 	if (texture) {
 		if (texture->gxm_rtgt) {
@@ -214,6 +214,47 @@ void vita2d_free_texture(vita2d_texture *texture)
 	}
 }
 
+typedef struct texture_freelist_entry texture_freelist_entry;
+
+// TODO: If we store the "next" pointer in vita2d_texture, we can
+// use it for an intrusive linked list and don't need to malloc
+struct texture_freelist_entry {
+	vita2d_texture *texture;
+	texture_freelist_entry *next;
+};
+
+// Note: Operations on _texture_freelist are not threadsafe at the moment
+static texture_freelist_entry *_texture_freelist = NULL;
+
+void vita2d_free_texture(vita2d_texture *texture)
+{
+	texture_freelist_entry *entry = malloc(sizeof(texture_freelist_entry));
+	entry->texture = texture;
+	entry->next = _texture_freelist;
+	_texture_freelist = entry;
+}
+
+int vita2d_gc_textures()
+{
+	if (_texture_freelist == NULL) {
+		// Nothing to do, exit early without waiting
+		return 0;
+	}
+
+	// Need to free textures, wait for GPU first
+	vita2d_wait_rendering_done();
+
+	int res = 0;
+	while (_texture_freelist != NULL) {
+		texture_freelist_entry *entry = _texture_freelist;
+		_texture_freelist = entry->next;
+		_vita2d_free_texture_internal(entry->texture);
+		free(entry);
+		++res;
+	}
+	return res;
+}
+
 unsigned int vita2d_texture_get_width(const vita2d_texture *texture)
 {
 	return sceGxmTextureGetWidth(&texture->gxm_tex);