surface: fix wlr_surface_get_effective_damage to give surface coords

Transforms were applied, but scale wasn't.

include/wlr/types/wlr_surface.h

@@ -17,14 +17,14 @@
 #include <wlr/types/wlr_output.h>
 
 enum wlr_surface_state_field {
-	WLR_SURFACE_STATE_BUFFER = 1,
-	WLR_SURFACE_STATE_SURFACE_DAMAGE = 2,
-	WLR_SURFACE_STATE_BUFFER_DAMAGE = 4,
-	WLR_SURFACE_STATE_OPAQUE_REGION = 8,
-	WLR_SURFACE_STATE_INPUT_REGION = 16,
-	WLR_SURFACE_STATE_TRANSFORM = 32,
-	WLR_SURFACE_STATE_SCALE = 64,
-	WLR_SURFACE_STATE_FRAME_CALLBACK_LIST = 128,
+	WLR_SURFACE_STATE_BUFFER = 1 << 0,
+	WLR_SURFACE_STATE_SURFACE_DAMAGE = 1 << 1,
+	WLR_SURFACE_STATE_BUFFER_DAMAGE = 1 << 2,
+	WLR_SURFACE_STATE_OPAQUE_REGION = 1 << 3,
+	WLR_SURFACE_STATE_INPUT_REGION = 1 << 4,
+	WLR_SURFACE_STATE_TRANSFORM = 1 << 5,
+	WLR_SURFACE_STATE_SCALE = 1 << 6,
+	WLR_SURFACE_STATE_FRAME_CALLBACK_LIST = 1 << 7,
 };
 
 struct wlr_surface_state {
@@ -32,7 +32,7 @@ struct wlr_surface_state {
 
 	struct wl_resource *buffer_resource;
 	int32_t dx, dy; // relative to previous position
-	pixman_region32_t surface_damage, buffer_damage;
+	pixman_region32_t surface_damage, buffer_damage; // clipped to bounds
 	pixman_region32_t opaque, input;
 	enum wl_output_transform transform;
 	int32_t scale;
@@ -68,11 +68,12 @@ struct wlr_surface {
 	 * The last commit's buffer damage, in buffer-local coordinates. This
 	 * contains both the damage accumulated by the client via
 	 * `wlr_surface_state.surface_damage` and `wlr_surface_state.buffer_damage`.
-	 * If the buffer has changed its size or moved, the whole buffer is
-	 * damaged.
+	 * If the buffer has been resized, the whole buffer is damaged.
 	 *
 	 * This region needs to be scaled and transformed into output coordinates,
-	 * just like the buffer's texture.
+	 * just like the buffer's texture. In addition, if the buffer has shrunk the
+	 * old size needs to be damaged and if the buffer has moved the old and new
+	 * positions need to be damaged.
 	 */
 	pixman_region32_t buffer_damage;
 	/**

rootston/output.c

@@ -700,8 +700,7 @@ static void damage_from_surface(struct wlr_surface *surface, int sx, int sy,
 	pixman_region32_init(&damage);
 	wlr_surface_get_effective_damage(surface, &damage);
 
-	wlr_region_scale(&damage, &damage,
-		wlr_output->scale / (float)surface->current.scale);
+	wlr_region_scale(&damage, &damage, wlr_output->scale);
 	if (ceil(wlr_output->scale) > surface->current.scale) {
 		// When scaling up a surface, it'll become blurry so we need to
 		// expand the damage region

types/wlr_surface.c

@@ -183,16 +183,15 @@ static void surface_update_damage(pixman_region32_t *buffer_damage,
 		pixman_region32_t surface_damage;
 		pixman_region32_init(&surface_damage);
 
-		pixman_region32_union(buffer_damage, buffer_damage,
-			&pending->buffer_damage);
 		pixman_region32_copy(&surface_damage, &pending->surface_damage);
-
 		wlr_region_transform(&surface_damage, &surface_damage,
 			wlr_output_transform_invert(pending->transform),
 			pending->width, pending->height);
 		wlr_region_scale(&surface_damage, &surface_damage, pending->scale);
 
-		pixman_region32_union(buffer_damage, buffer_damage, &surface_damage);
+		pixman_region32_union(buffer_damage,
+			&pending->buffer_damage, &surface_damage);
+
 		pixman_region32_fini(&surface_damage);
 	}
 }
@@ -291,8 +290,8 @@ static void surface_apply_damage(struct wlr_surface *surface) {
 	}
 
 	if (surface->buffer != NULL && surface->buffer->released) {
-		struct wlr_buffer *updated_buffer =
-			wlr_buffer_apply_damage(surface->buffer, resource, &surface->buffer_damage);
+		struct wlr_buffer *updated_buffer = wlr_buffer_apply_damage(
+			surface->buffer, resource, &surface->buffer_damage);
 		if (updated_buffer != NULL) {
 			surface->buffer = updated_buffer;
 			return;
@@ -1029,6 +1028,7 @@ void wlr_surface_get_effective_damage(struct wlr_surface *surface,
 	wlr_region_transform(damage, &surface->buffer_damage,
 		surface->current.transform, surface->current.buffer_width,
 		surface->current.buffer_height);
+	wlr_region_scale(damage, damage, 1.0 / (float)surface->current.scale);
 
 	// On resize, damage the previous bounds of the surface. The current bounds
 	// have already been damaged in surface_update_damage.