Merge pull request #1261 from arandomhuman/damage-control

Fix damage tracking for surfaces with transforms

3 files changed, 73 insertions, 67 deletions

diff --git a/include/wlr/types/wlr_surface.h b/include/wlr/types/wlr_surface.h
index bfbfbcc8..b8f8c02a 100644
--- a/include/wlr/types/wlr_surface.h
+++ b/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;
 	/**
@@ -234,4 +235,12 @@ struct wlr_surface *wlr_surface_from_resource(struct wl_resource *resource);
 void wlr_surface_for_each_surface(struct wlr_surface *surface,
 	wlr_surface_iterator_func_t iterator, void *user_data);
 
+/**
+ * Get the effective damage to the surface in terms of surface local
+ * coordinates. This includes damage induced by resizing and moving the
+ * surface. The damage is not expected to be bounded by the surface itself.
+ */
+void wlr_surface_get_effective_damage(struct wlr_surface *surface,
+	pixman_region32_t *damage);
+
 #endif
diff --git a/rootston/output.c b/rootston/output.c
index bd38f3ab..9aa7de65 100644
--- a/rootston/output.c
+++ b/rootston/output.c
@@ -708,16 +708,11 @@ static void damage_from_surface(struct wlr_surface *surface, int sx, int sy,
 	int center_x = box.x + box.width/2;
 	int center_y = box.y + box.height/2;
 
-	enum wl_output_transform transform =
-		wlr_output_transform_invert(surface->current.transform);
-
 	pixman_region32_t damage;
 	pixman_region32_init(&damage);
-	pixman_region32_copy(&damage, &surface->buffer_damage);
-	wlr_region_transform(&damage, &damage, transform,
-		surface->current.buffer_width, surface->current.buffer_height);
-	wlr_region_scale(&damage, &damage,
-		wlr_output->scale / (float)surface->current.scale);
+	wlr_surface_get_effective_damage(surface, &damage);
+
+	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
diff --git a/types/wlr_surface.c b/types/wlr_surface.c
index 408f38d1..b19387c8 100644
--- a/types/wlr_surface.c
+++ b/types/wlr_surface.c
@@ -7,6 +7,7 @@
 #include <wlr/types/wlr_matrix.h>
 #include <wlr/types/wlr_region.h>
 #include <wlr/types/wlr_surface.h>
+#include <wlr/types/wlr_output.h>
 #include <wlr/util/log.h>
 #include <wlr/util/region.h>
 #include "util/signal.h"
@@ -167,38 +168,28 @@ static void surface_state_finalize(struct wlr_surface *surface,
 }
 
 static void surface_update_damage(pixman_region32_t *buffer_damage,
-		struct wlr_surface_state *previous, struct wlr_surface_state *current) {
+		struct wlr_surface_state *current, struct wlr_surface_state *pending) {
 	pixman_region32_clear(buffer_damage);
 
-	if (current->buffer_width != previous->buffer_width ||
-			current->buffer_height != previous->buffer_height ||
-			current->dx != 0 || current->dy != 0) {
-		// Damage the whole surface on resize or move
-		int prev_x = -current->dx;
-		int prev_y = -current->dy;
-		if ((previous->transform & WL_OUTPUT_TRANSFORM_90) != 0) {
-			int tmp = prev_x;
-			prev_x = prev_y;
-			prev_y = tmp;
-		}
-
-		pixman_region32_union_rect(buffer_damage, buffer_damage,
-			prev_x * previous->scale, prev_y * previous->scale,
-			previous->buffer_width, previous->buffer_height);
+	if (pending->width != current->width ||
+			pending->height != current->height) {
+		// Damage the whole buffer on resize
 		pixman_region32_union_rect(buffer_damage, buffer_damage, 0, 0,
-			current->buffer_width, current->buffer_height);
+			pending->buffer_width, pending->buffer_height);
 	} else {
 		// Copy over surface damage + buffer damage
-		pixman_region32_union(buffer_damage, buffer_damage,
-			&current->buffer_damage);
-
 		pixman_region32_t surface_damage;
 		pixman_region32_init(&surface_damage);
-		pixman_region32_copy(&surface_damage, &current->surface_damage);
+
+		pixman_region32_copy(&surface_damage, &pending->surface_damage);
 		wlr_region_transform(&surface_damage, &surface_damage,
-			current->transform, current->buffer_width, current->buffer_height);
-		wlr_region_scale(&surface_damage, &surface_damage, current->scale);
-		pixman_region32_union(buffer_damage, buffer_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,
+			&pending->buffer_damage, &surface_damage);
+
 		pixman_region32_fini(&surface_damage);
 	}
 }
@@ -297,29 +288,8 @@ static void surface_apply_damage(struct wlr_surface *surface) {
 	}
 
 	if (surface->buffer != NULL && surface->buffer->released) {
-		pixman_region32_t damage;
-		pixman_region32_init(&damage);
-		pixman_region32_copy(&damage, &surface->current.buffer_damage);
-
-		pixman_region32_t surface_damage;
-		pixman_region32_init(&surface_damage);
-		pixman_region32_copy(&surface_damage, &surface->current.surface_damage);
-		wlr_region_transform(&surface_damage, &surface_damage,
-			surface->current.transform,
-			surface->current.buffer_width, surface->current.buffer_height);
-		wlr_region_scale(&surface_damage, &surface_damage,
-			surface->current.scale);
-		pixman_region32_union(&damage, &damage, &surface_damage);
-		pixman_region32_fini(&surface_damage);
-
-		pixman_region32_intersect_rect(&damage, &damage, 0, 0,
-			surface->current.buffer_width, surface->current.buffer_height);
-
-		struct wlr_buffer *updated_buffer =
-			wlr_buffer_apply_damage(surface->buffer, resource, &damage);
-
-		pixman_region32_fini(&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;
@@ -1055,3 +1025,35 @@ void wlr_surface_get_extends(struct wlr_surface *surface, struct wlr_box *box) {
 	box->width = acc.max_x - acc.min_x;
 	box->height = acc.max_y - acc.min_y;
 }
+
+void wlr_surface_get_effective_damage(struct wlr_surface *surface,
+		pixman_region32_t *damage) {
+	pixman_region32_clear(damage);
+
+	// Transform and copy the buffer damage in terms of surface coordinates.
+	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.
+	if (surface->previous.width > surface->current.width ||
+			surface->previous.height > surface->current.height) {
+		pixman_region32_union_rect(damage, damage, 0, 0,
+			surface->previous.width, surface->previous.height);
+	}
+
+	// On move, damage where the surface was with its old dimensions.
+	if (surface->current.dx != 0 || surface->current.dy != 0) {
+		int prev_x = -surface->current.dx;
+		int prev_y = -surface->current.dy;
+		if ((surface->previous.transform & WL_OUTPUT_TRANSFORM_90) != 0) {
+			int temp = prev_x;
+			prev_x = prev_y;
+			prev_y = temp;
+		}
+		pixman_region32_union_rect(damage, damage, prev_x, prev_y,
+			surface->previous.width, surface->previous.height);
+	}
+}