wlr_raster: Introduce new abstraction

include/wlr/render/wlr_texture.h

@@ -13,6 +13,7 @@
 #include <stdint.h>
 #include <wayland-server-core.h>
 #include <wlr/render/dmabuf.h>
+#include <wlr/types/wlr_raster.h>
 
 struct wlr_buffer;
 struct wlr_renderer;
@@ -21,6 +22,9 @@ struct wlr_texture_impl;
 struct wlr_texture {
 	const struct wlr_texture_impl *impl;
 	uint32_t width, height;
+
+	struct wlr_raster *raster;
+	struct wl_list link;
 };
 
 /**

include/wlr/types/wlr_raster.h

@@ -0,0 +1,78 @@
+/*
+ * This an unstable interface of wlroots. No guarantees are made regarding the
+ * future consistency of this API.
+ */
+#ifndef WLR_USE_UNSTABLE
+#error "Add -DWLR_USE_UNSTABLE to enable unstable wlroots features"
+#endif
+
+#ifndef WLR_TYPES_WLR_RASTER_H
+#define WLR_TYPES_WLR_RASTER_H
+
+#include <stdbool.h>
+#include <stdlib.h>
+#include <wayland-server-core.h>
+
+struct wlr_buffer;
+struct wlr_texture;
+
+struct wlr_raster {
+	// May be NULL
+	struct wlr_buffer *buffer;
+	uint32_t width, height;
+
+	struct wl_list sources; // struct wlr_texture
+
+	struct {
+		struct wl_signal destroy;
+	} events;
+
+	// private state
+
+	size_t n_locks;
+};
+
+/**
+ * Creates a new wlr_raster being backed by the given buffer.
+ * The creation funciton is referenced: once the creator is done with the raster,
+ * wlr_raster_unlock must be called.
+ */
+struct wlr_raster *wlr_raster_create(struct wlr_buffer *buffer);
+
+/**
+ * Removes and unlocks the buffer assolated with this raster. A raster must be
+ * created with a buffer so that there is a source of information for textures
+ * to be created from it, but once there is a texture, that can be used
+ * as the source of truth and so the buffer can be removed early for other
+ * purposes.
+ */
+void wlr_raster_remove_buffer(struct wlr_raster *raster);
+
+/**
+ * Lock the raster for use. As long as the raster has at least one lock, it
+ * will not be destroyed. The raster will be created with a reference count at 1
+ * meaning that whatever produced the raster, must call this funciton.
+ */
+struct wlr_raster *wlr_raster_lock(struct wlr_raster *raster);
+
+/**
+ * Unlock the raster. This must be called after wlr_raster_lock once the raster
+ * has been finished being used.
+ */
+void wlr_raster_unlock(struct wlr_raster *raster);
+
+/**
+ * Attaches a wlr_texture to the raster. Consumers of the raster can use the
+ * given texture for their rendering if needed. The pixel contents of the texture
+ * must be the same as the source buffer and other textures in the raster.
+ */
+void wlr_raster_attach(struct wlr_raster *raster, struct wlr_texture *texture);
+
+/**
+ * Detaches a wlr_texture from the raster. Once the texture is detached, ownership
+ * of the texture is given to the caller such that the caller may mutate the
+ * raster if it wishes.
+ */
+void wlr_raster_detach(struct wlr_raster *raster, struct wlr_texture *texture);
+
+#endif