render/texture: drop wlr_texture_is_opaque

Whether a texture is opaque or not doesn't depend on the renderer
at all, it just depends on the source buffer. Instead of forcing
all renderers to implement wlr_texture_impl.is_opaque, let's move
this in common code and use the wlr_buffer format to know whether
a texture will be opaque.

include/types/wlr_buffer.h

@@ -69,4 +69,13 @@ struct wlr_dmabuf_buffer *dmabuf_buffer_create(
  */
 bool dmabuf_buffer_drop(struct wlr_dmabuf_buffer *buffer);
 
+/**
+ * Check whether a buffer is fully opaque.
+ *
+ * When true is returned, the buffer is guaranteed to be fully opaque, but the
+ * reverse is not true: false may be returned in cases where the buffer is fully
+ * opaque.
+ */
+bool buffer_is_opaque(struct wlr_buffer *buffer);
+
 #endif

include/wlr/render/interface.h

@@ -54,7 +54,6 @@ void wlr_renderer_init(struct wlr_renderer *renderer,
 	const struct wlr_renderer_impl *impl);
 
 struct wlr_texture_impl {
-	bool (*is_opaque)(struct wlr_texture *texture);
 	bool (*write_pixels)(struct wlr_texture *texture,
 		uint32_t stride, uint32_t width, uint32_t height,
 		uint32_t src_x, uint32_t src_y, uint32_t dst_x, uint32_t dst_y,

include/wlr/render/wlr_texture.h

@@ -36,11 +36,6 @@ struct wlr_texture *wlr_texture_from_pixels(struct wlr_renderer *renderer,
 struct wlr_texture *wlr_texture_from_dmabuf(struct wlr_renderer *renderer,
 	struct wlr_dmabuf_attributes *attribs);
 
-/**
- * Returns true if this texture is using a fully opaque format.
- */
-bool wlr_texture_is_opaque(struct wlr_texture *texture);
-
 /**
   * Update a texture with raw pixels. The texture must be mutable, and the input
   * data must have the same pixel format that the texture was created with.

include/wlr/types/wlr_compositor.h

@@ -162,6 +162,8 @@ struct wlr_surface {
 		int width, height;
 		int buffer_width, buffer_height;
 	} previous;
+
+	bool opaque;
 };
 
 struct wlr_renderer;