Moved the drop shadow into its own scene node

Author: ErikReider

examples/scene-graph.c

@@ -100,10 +100,9 @@ static void surface_handle_commit(struct wl_listener *listener, void *data) {
 	wlr_scene_rect_set_size(surface->border,
 			surface->wlr->current.width + 2 * border_width,
 			surface->wlr->current.height + 2 * border_width);
-	const int blur_offset = wlr_scene_shadow_get_offset(surface->shadow);
 	wlr_scene_shadow_set_size(surface->shadow,
-			surface->wlr->current.width + 2 * (blur_offset + border_width),
-			surface->wlr->current.height + 2 * (blur_offset + border_width));
+			surface->wlr->current.width + 2 * (surface->shadow->blur_sigma + border_width),
+			surface->wlr->current.height + 2 * (surface->shadow->blur_sigma + border_width));
 }
 
 static void surface_handle_destroy(struct wl_listener *listener, void *data) {
@@ -140,9 +139,8 @@ static void server_handle_new_surface(struct wl_listener *listener,
 	float blur_sigma = 20.0f;
 	surface->shadow = wlr_scene_shadow_create(&server->scene->tree,
 			0, 0, corner_radius, blur_sigma, (float[4]){ 1.0f, 0.f, 0.f, 1.0f });
-	const int blur_offset = wlr_scene_shadow_get_offset(surface->shadow);
 	wlr_scene_node_set_position(&surface->shadow->node,
-			pos - blur_offset, pos - blur_offset);
+			pos - blur_sigma, pos - blur_sigma);
 	surface->scene_surface =
 		wlr_scene_surface_create(&server->scene->tree, wlr_surface);
 	wlr_scene_buffer_set_corner_radius(

include/scenefx/types/fx/blur_data.h

@@ -4,6 +4,7 @@
 #include <stdbool.h>
 #include <wlr/util/addon.h>
 
+// Calculate the drop-shadows blur sample size
 #define drop_shadow_calc_size(blur_sigma) (ceil(1.5f * blur_sigma) * 2)
 #define drop_shadow_downscale 0.5
 

include/scenefx/types/linked_node.h

@@ -16,6 +16,8 @@ struct linked_node {
 		.link = NULL \
 	})
 
+#define linked_node_initialized(node) ((node)->link != NULL)
+
 bool linked_nodes_are_linked(struct linked_node *node_1,
 		struct linked_node *node_2);
 

include/scenefx/types/wlr_scene.h

@@ -58,6 +58,7 @@ enum wlr_scene_node_type {
 	WLR_SCENE_NODE_TREE,
 	WLR_SCENE_NODE_RECT,
 	WLR_SCENE_NODE_SHADOW,
+	WLR_SCENE_NODE_DROP_SHADOW,
 	WLR_SCENE_NODE_BUFFER,
 	WLR_SCENE_NODE_OPTIMIZED_BLUR,
 	WLR_SCENE_NODE_BLUR,
@@ -162,9 +163,20 @@ struct wlr_scene_shadow {
 	float color[4];
 	float blur_sigma;
 
+	struct clipped_region clipped_region;
+};
+
+/** A scene-graph node displaying a dynamic drop-shadow */
+struct wlr_scene_drop_shadow {
+	struct wlr_scene_node node;
+	int width, height;
+	float color[4];
+	float blur_sigma;
+
 	struct {
-		// Used to draw a drop-shadow
-		struct linked_node buffer_link;
+		float blur_sample_size;
+		// Skips drawing if NULL
+		struct linked_node buffer_source;
 	} WLR_PRIVATE;
 
 	struct clipped_region clipped_region;
@@ -182,7 +194,9 @@ struct wlr_scene_blur {
 
 	bool should_only_blur_bottom_layer;
 
-	struct linked_node transparency_mask_source;
+	struct {
+		struct linked_node transparency_mask_source;
+	} WLR_PRIVATE;
 };
 
 /** A scene-graph node telling SceneFX to render the optimized blur */
@@ -261,7 +275,7 @@ struct wlr_scene_buffer {
 
 		struct linked_node blur;
 		// Used to know which shadow's linked to this scene_buffer
-		struct linked_node drop_shadow_link;
+		struct linked_node drop_shadow;
 	} WLR_PRIVATE;
 };
 
@@ -496,6 +510,16 @@ struct wlr_scene_rect *wlr_scene_rect_from_node(struct wlr_scene_node *node);
  */
 struct wlr_scene_shadow *wlr_scene_shadow_from_node(struct wlr_scene_node *node);
 
+/**
+ * If this node represents a wlr_scene_drop_shadow, that shadow will be returned. It
+ * is not legal to feed a node that does not represent a wlr_scene_drop_shadow.
+ */
+struct wlr_scene_drop_shadow *wlr_scene_drop_shadow_from_node(struct wlr_scene_node *node);
+
+/**
+ * If this node represents a wlr_scene_blur node, that blur node will be returned.
+ * It is not legal to feed a node that does not represent a wlr_scene_blur node.
+ */
 struct wlr_scene_blur *wlr_scene_blur_from_node(struct wlr_scene_node *node);
 
 /**
@@ -547,8 +571,7 @@ void wlr_scene_rect_set_clipped_region(struct wlr_scene_rect *rect,
 void wlr_scene_rect_set_color(struct wlr_scene_rect *rect, const float color[static 4]);
 
 /**
- * Add a node displaying a shadow to the scene-graph. The shadow type created is
- * a regular box-shadow.
+ * Add a node displaying a shadow to the scene-graph.
  */
 struct wlr_scene_shadow *wlr_scene_shadow_create(struct wlr_scene_tree *parent,
 		int width, int height, int corner_radius, float blur_sigma,
@@ -574,39 +597,97 @@ void wlr_scene_shadow_set_blur_sigma(struct wlr_scene_shadow *shadow, float blur
  */
 void wlr_scene_shadow_set_color(struct wlr_scene_shadow *shadow, const float color[static 4]);
 
+/**
+ * Sets the region where to clip the shadow.
+ *
+ * For there to be corner rounding of the clipped region, the corner radius and
+ * corners must be non-zero.
+ *
+ * NOTE: The positioning is node-relative.
+ */
+void wlr_scene_shadow_set_clipped_region(struct wlr_scene_shadow *shadow,
+		struct clipped_region clipped_region);
+
+/**
+ * Add a node displaying a drop shadow to the scene-graph.
+ *
+ * It's recommended to use `wlr_scene_drop_shadow_calculate_offset` when first
+ * setting the size and adjusting the nodes position.
+ *
+ * NOTE: A reference `wlr_scene_buffer` needs to be set using
+ * `wlr_scene_drop_shadow_set_reference_buffer` for the shadow to render.
+ */
+struct wlr_scene_drop_shadow *wlr_scene_drop_shadow_create(struct wlr_scene_tree *parent,
+		int width, int height, float blur_sigma, const float color[static 4]);
+
+/**
+ * Change the width and height of an existing drop shadow node.
+ *
+ * NOTE: The set size of the node doesn't include the blur sample size (offset),
+ * It's recommended to include the offset in the calculations by using
+ * `wlr_scene_drop_shadow_get_offset`.
+ *
+ * Proper Width example: `toplevel_width + offset * 2 = correctly_fitted_width`
+ * Proper X Position example: `toplevel_x - offset = correctly_x_positioned`
+ */
+void wlr_scene_drop_shadow_set_size(struct wlr_scene_drop_shadow *shadow, int width, int height);
+
+/**
+ * Change the blur_sigma of an existing drop shadow node.
+ *
+ * NOTE: This adjusts the drop-shadows offset, so it's recommended to also
+ * adjust the nodes size and position to compensate.
+ */
+void wlr_scene_drop_shadow_set_blur_sigma(struct wlr_scene_drop_shadow *shadow, float blur_sigma);
+
+/**
+ * Change the color of an existing drop shadow node.
+ */
+void wlr_scene_drop_shadow_set_color(struct wlr_scene_drop_shadow *shadow, const float color[static 4]);
+
 /**
  * Change the reference scene_buffer.
- * NOTE: Will fallback to a box-shadow if the provided buffer is NULL.
+ * NOTE: Will skip rendering if the provided buffer is NULL.
  */
-void wlr_scene_shadow_set_reference_buffer(struct wlr_scene_shadow *shadow,
+void wlr_scene_drop_shadow_set_reference_buffer(struct wlr_scene_drop_shadow *shadow,
 		struct wlr_scene_buffer *ref_buffer);
 
 /**
  * Get the reference scene_buffer.
  */
-struct wlr_scene_buffer *wlr_scene_shadow_get_reference_buffer(struct wlr_scene_shadow *shadow);
+struct wlr_scene_buffer *wlr_scene_drop_shadow_get_reference_buffer(struct wlr_scene_drop_shadow *shadow);
 
 /**
- * Gets the sample size of the shadow. Can be used when setting the size of
- * the shadow node. Returns the correct size offset used depending on the
- * shadow-type. A drop-shadow returns a larger integer compared to the
- * box-shadow, so this can be used to dynamically adjust the size and position
- * depending on the shadow-type. Eg:
+ * Gets the offset of a drop shadow, the recommended way. Can be used as an
+ * offset for setting the correct size and position relative to a toplevel.
+ * Proper Width example: `toplevel_width + offset * 2 = correctly_fitted_width`
+ * Proper X Position example: `toplevel_x - offset = correctly_x_positioned`
  *
- * Scene Buffer size: 100 x 100px
- * Proper Shadow Node size: 100px + offset x 100px + offset = the correct size
+ * This is the same as `wlr_scene_drop_shadow_calculate_offset`, but uses the
+ * already cached offset instead of recalculating the offset.
  */
-int wlr_scene_shadow_get_offset(struct wlr_scene_shadow *shadow);
+int wlr_scene_drop_shadow_get_offset(struct wlr_scene_drop_shadow *shadow);
 
 /**
- * Sets the region where to clip the shadow.
+ * Gets the sample size of a drop shadow.
+ *
+ * Tip: Recalculates the offset, so it's recommended to only use this function
+ * to calculate the initial size and position of the node while using
+ * `wlr_scene_drop_shadow_get_offset` in other cases.
+ */
+__always_inline float wlr_scene_drop_shadow_calculate_offset(int blur_sigma) {
+	return drop_shadow_calc_size(blur_sigma);
+}
+
+/**
+ * Sets the region where to clip the drop shadow.
  *
  * For there to be corner rounding of the clipped region, the corner radius and
  * corners must be non-zero.
  *
  * NOTE: The positioning is node-relative.
  */
-void wlr_scene_shadow_set_clipped_region(struct wlr_scene_shadow *shadow,
+void wlr_scene_drop_shadow_set_clipped_region(struct wlr_scene_drop_shadow *shadow,
 		struct clipped_region clipped_region);
 
 /**

render/fx_renderer/fx_framebuffer.c

@@ -79,7 +79,9 @@ void fx_framebuffer_get_or_create_custom(struct fx_renderer *renderer,
 	int height = output->height;
 	struct wlr_buffer *wlr_buffer = NULL;
 
-	// Try getting a format with alpha. One could use the outputs swapchain
+	// TODO: Configure to use non-alpha to save some GPU memory :)
+	// TODO: Cache this, don't find it at runtime
+	// Try getting a format with alpha. We could use the outputs swapchain
 	// format, but that one doesn't support alpha.
 	const struct fx_pixel_format *pix_fmt =
 		get_fx_format_from_gl(GL_RGBA, GL_UNSIGNED_BYTE, true);

tinywl/tinywl.c

@@ -613,13 +613,13 @@ static void xdg_toplevel_commit(struct wl_listener *listener, void *data) {
 			.area = { BORDER_THICKNESS, BORDER_THICKNESS, geometry->width, geometry->height }
 	});
 
-	const int blur_offset = wlr_scene_shadow_get_offset(toplevel->shadow);
+	int blur_sigma = toplevel->shadow->blur_sigma;
 	wlr_scene_shadow_set_size(toplevel->shadow,
-			border_width + (blur_offset * 2),
-			border_height + (blur_offset * 2));
+			border_width + (blur_sigma * 2),
+			border_height + (blur_sigma * 2));
 	wlr_scene_shadow_set_clipped_region(toplevel->shadow, (struct clipped_region) {
 			.corners = corner_radii_all(toplevel->corner_radius + BORDER_THICKNESS),
-			.area = { blur_offset, blur_offset, border_width, border_height }
+			.area = { blur_sigma, blur_sigma, border_width, border_height }
 	});
 }
 
@@ -966,9 +966,8 @@ static void server_new_xdg_toplevel(struct wl_listener *listener, void *data) {
 	float blur_sigma = 20.0f;
 	toplevel->shadow = wlr_scene_shadow_create(toplevel->scene_tree,
 			0, 0, toplevel->corner_radius, blur_sigma, (float[4]){ 0.f, 1.0f, 0.f, 1.0f });
-	const int blur_offset = wlr_scene_shadow_get_offset(toplevel->shadow);
-	wlr_scene_node_set_position(&toplevel->shadow->node, -BORDER_THICKNESS - blur_offset,
-			-BORDER_THICKNESS - blur_offset);
+	wlr_scene_node_set_position(&toplevel->shadow->node, -BORDER_THICKNESS - blur_sigma,
+			-BORDER_THICKNESS - blur_sigma);
 
 	// Lower the border below the XDG scene tree
 	wlr_scene_node_lower_to_bottom(&toplevel->border->node);

types/scene/linked_node.c

@@ -30,13 +30,13 @@ static struct link *link_init(struct linked_node *node_1,
 
 bool linked_nodes_are_linked(struct linked_node *node_1,
 		struct linked_node *node_2) {
-	return node_1->link != NULL && node_2->link != NULL
+	return linked_node_initialized(node_1) && linked_node_initialized(node_2)
 		&& node_1->link == node_2->link;
 }
 
 void linked_node_init_link(struct linked_node *node_1,
 		struct linked_node *node_2) {
-	if (node_1->link || node_2->link) {
+	if (linked_node_initialized(node_1) || linked_node_initialized(node_2)) {
 		assert(linked_nodes_are_linked(node_1, node_2));
 		return;
 	}
@@ -47,7 +47,7 @@ void linked_node_init_link(struct linked_node *node_1,
 }
 
 struct linked_node *linked_node_get_sibling(struct linked_node *node) {
-	if (node->link == NULL) {
+	if (!linked_node_initialized(node)) {
 		return NULL;
 	}
 	assert(node == node->link->node_1 || node == node->link->node_2);
@@ -70,7 +70,7 @@ void linked_node_unlink(struct linked_node *node_1,
 }
 
 void linked_node_destroy(struct linked_node *node) {
-	if (node->link == NULL) {
+	if (!linked_node_initialized(node)) {
 		return;
 	}
 	assert(node == node->link->node_1 || node == node->link->node_2);