Introduce wlr_output_damage

types/meson.build

@@ -11,6 +11,7 @@ lib_wlr_types = static_library(
 		'wlr_keyboard.c',
 		'wlr_list.c',
 		'wlr_output.c',
+		'wlr_output_damage.c',
 		'wlr_output_layout.c',
 		'wlr_pointer.c',
 		'wlr_primary_selection.c',

types/wlr_output_damage.c

@@ -0,0 +1,164 @@
+#include <stdlib.h>
+#include <stddef.h>
+#include <time.h>
+#include <wayland-server.h>
+#include <wlr/types/wlr_box.h>
+#include <wlr/types/wlr_output.h>
+#include <wlr/types/wlr_output_damage.h>
+
+static void output_handle_destroy(struct wl_listener *listener, void *data) {
+	struct wlr_output_damage *output_damage =
+		wl_container_of(listener, output_damage, output_destroy);
+	wlr_output_damage_destroy(output_damage);
+}
+
+static void output_handle_mode(struct wl_listener *listener, void *data) {
+	struct wlr_output_damage *output_damage =
+		wl_container_of(listener, output_damage, output_mode);
+	wlr_output_damage_add_whole(output_damage);
+}
+
+static void output_handle_needs_swap(struct wl_listener *listener, void *data) {
+	struct wlr_output_damage *output_damage =
+		wl_container_of(listener, output_damage, output_needs_swap);
+	pixman_region32_union(&output_damage->current, &output_damage->current,
+		&output_damage->output->damage);
+	wlr_output_schedule_frame(output_damage->output);
+}
+
+static void output_handle_frame(struct wl_listener *listener, void *data) {
+	struct wlr_output_damage *output_damage =
+		wl_container_of(listener, output_damage, output_frame);
+
+	if (!output_damage->output->enabled) {
+		return;
+	}
+
+	wl_signal_emit(&output_damage->events.frame, output_damage);
+}
+
+struct wlr_output_damage *wlr_output_damage_create(struct wlr_output *output) {
+	struct wlr_output_damage *output_damage =
+		calloc(1, sizeof(struct wlr_output_damage));
+	if (output_damage == NULL) {
+		return NULL;
+	}
+
+	output_damage->output = output;
+	wl_signal_init(&output_damage->events.frame);
+	wl_signal_init(&output_damage->events.destroy);
+
+	pixman_region32_init(&output_damage->current);
+	for (size_t i = 0; i < WLR_OUTPUT_DAMAGE_PREVIOUS_LEN; ++i) {
+		pixman_region32_init(&output_damage->previous[i]);
+	}
+
+	wl_signal_add(&output->events.destroy, &output_damage->output_destroy);
+	output_damage->output_destroy.notify = output_handle_destroy;
+	wl_signal_add(&output->events.mode, &output_damage->output_mode);
+	output_damage->output_mode.notify = output_handle_mode;
+	wl_signal_add(&output->events.needs_swap, &output_damage->output_needs_swap);
+	output_damage->output_needs_swap.notify = output_handle_needs_swap;
+	wl_signal_add(&output->events.frame, &output_damage->output_frame);
+	output_damage->output_frame.notify = output_handle_frame;
+
+	return output_damage;
+}
+
+void wlr_output_damage_destroy(struct wlr_output_damage *output_damage) {
+	if (output_damage == NULL) {
+		return;
+	}
+	wl_signal_emit(&output_damage->events.destroy, output_damage);
+	wl_list_remove(&output_damage->output_destroy.link);
+	wl_list_remove(&output_damage->output_mode.link);
+	wl_list_remove(&output_damage->output_needs_swap.link);
+	wl_list_remove(&output_damage->output_frame.link);
+	pixman_region32_fini(&output_damage->current);
+	for (size_t i = 0; i < WLR_OUTPUT_DAMAGE_PREVIOUS_LEN; ++i) {
+		pixman_region32_fini(&output_damage->previous[i]);
+	}
+	free(output_damage);
+}
+
+bool wlr_output_damage_make_current(struct wlr_output_damage *output_damage,
+		bool *needs_swap, pixman_region32_t *damage) {
+	struct wlr_output *output = output_damage->output;
+
+	int buffer_age = -1;
+	if (!wlr_output_make_current(output, &buffer_age)) {
+		return false;
+	}
+
+	// Check if we can use damage tracking
+	if (buffer_age <= 0 || buffer_age - 1 > WLR_OUTPUT_DAMAGE_PREVIOUS_LEN) {
+		int width, height;
+		wlr_output_transformed_resolution(output, &width, &height);
+
+		// Buffer new or too old, damage the whole output
+		pixman_region32_union_rect(damage, damage, 0, 0, width, height);
+	} else {
+		pixman_region32_copy(damage, &output_damage->current);
+
+		// Accumulate damage from old buffers
+		size_t idx = output_damage->previous_idx;
+		for (int i = 0; i < buffer_age - 1; ++i) {
+			int j = (idx + i) % WLR_OUTPUT_DAMAGE_PREVIOUS_LEN;
+			pixman_region32_union(damage, damage, &output_damage->previous[j]);
+		}
+	}
+
+	*needs_swap = output->needs_swap || pixman_region32_not_empty(damage);
+	return true;
+}
+
+bool wlr_output_damage_swap_buffers(struct wlr_output_damage *output_damage,
+		struct timespec *when, pixman_region32_t *damage) {
+	if (!wlr_output_swap_buffers(output_damage->output, when, damage)) {
+		return false;
+	}
+
+	// same as decrementing, but works on unsigned integers
+	output_damage->previous_idx += WLR_OUTPUT_DAMAGE_PREVIOUS_LEN - 1;
+	output_damage->previous_idx %= WLR_OUTPUT_DAMAGE_PREVIOUS_LEN;
+
+	pixman_region32_copy(&output_damage->previous[output_damage->previous_idx],
+		&output_damage->current);
+	pixman_region32_clear(&output_damage->current);
+
+	return true;
+}
+
+void wlr_output_damage_add(struct wlr_output_damage *output_damage,
+		pixman_region32_t *damage) {
+	int width, height;
+	wlr_output_transformed_resolution(output_damage->output, &width, &height);
+
+	pixman_region32_union(&output_damage->current, &output_damage->current,
+		damage);
+	pixman_region32_intersect_rect(&output_damage->current,
+		&output_damage->current, 0, 0, width, height);
+	wlr_output_schedule_frame(output_damage->output);
+}
+
+void wlr_output_damage_add_whole(struct wlr_output_damage *output_damage) {
+	int width, height;
+	wlr_output_transformed_resolution(output_damage->output, &width, &height);
+
+	pixman_region32_union_rect(&output_damage->current, &output_damage->current,
+		0, 0, width, height);
+
+	wlr_output_schedule_frame(output_damage->output);
+}
+
+void wlr_output_damage_add_box(struct wlr_output_damage *output_damage,
+		struct wlr_box *box) {
+	int width, height;
+	wlr_output_transformed_resolution(output_damage->output, &width, &height);
+
+	pixman_region32_union_rect(&output_damage->current, &output_damage->current,
+		box->x, box->y, box->width, box->height);
+	pixman_region32_intersect_rect(&output_damage->current,
+		&output_damage->current, 0, 0, width, height);
+	wlr_output_schedule_frame(output_damage->output);
+}