Swap buffers with damage

backend/drm/drm.c

@@ -190,7 +190,8 @@ static bool wlr_drm_connector_make_current(struct wlr_output *output,
 	return wlr_drm_surface_make_current(&conn->crtc->primary->surf, buffer_age);
 }
 
-static bool wlr_drm_connector_swap_buffers(struct wlr_output *output) {
+static bool wlr_drm_connector_swap_buffers(struct wlr_output *output,
+		pixman_region32_t *damage) {
 	struct wlr_drm_connector *conn = (struct wlr_drm_connector *)output;
 	struct wlr_drm_backend *drm = (struct wlr_drm_backend *)output->backend;
 	if (!drm->session->active) {
@@ -203,7 +204,7 @@ static bool wlr_drm_connector_swap_buffers(struct wlr_output *output) {
 	}
 	struct wlr_drm_plane *plane = crtc->primary;
 
-	struct gbm_bo *bo = wlr_drm_surface_swap_buffers(&plane->surf);
+	struct gbm_bo *bo = wlr_drm_surface_swap_buffers(&plane->surf, damage);
 	if (drm->parent) {
 		bo = wlr_drm_surface_mgpu_copy(&plane->mgpu_surf, bo);
 	}
@@ -635,7 +636,7 @@ static bool wlr_drm_connector_set_cursor(struct wlr_output *output,
 		GL_UNSIGNED_BYTE, bo_data);
 	glPixelStorei(GL_UNPACK_ROW_LENGTH_EXT, 0);
 
-	wlr_drm_surface_swap_buffers(&plane->surf);
+	wlr_drm_surface_swap_buffers(&plane->surf, NULL);
 
 	gbm_bo_unmap(bo, bo_data);
 

backend/drm/renderer.c

@@ -133,14 +133,13 @@ bool wlr_drm_surface_make_current(struct wlr_drm_surface *surf,
 	return wlr_egl_make_current(&surf->renderer->egl, surf->egl, buffer_damage);
 }
 
-struct gbm_bo *wlr_drm_surface_swap_buffers(struct wlr_drm_surface *surf) {
+struct gbm_bo *wlr_drm_surface_swap_buffers(struct wlr_drm_surface *surf,
+		pixman_region32_t *damage) {
 	if (surf->front) {
 		gbm_surface_release_buffer(surf->gbm, surf->front);
 	}
 
-	if (!eglSwapBuffers(surf->renderer->egl.display, surf->egl)) {
-		wlr_log(L_ERROR, "eglSwapBuffers failed");
-	}
+	wlr_egl_swap_buffers(&surf->renderer->egl, surf->egl, damage);
 
 	surf->front = surf->back;
 	surf->back = gbm_surface_lock_front_buffer(surf->gbm);
@@ -156,7 +155,7 @@ struct gbm_bo *wlr_drm_surface_get_front(struct wlr_drm_surface *surf) {
 	glViewport(0, 0, surf->width, surf->height);
 	glClearColor(0.0, 0.0, 0.0, 1.0);
 	glClear(GL_COLOR_BUFFER_BIT);
-	return wlr_drm_surface_swap_buffers(surf);
+	return wlr_drm_surface_swap_buffers(surf, NULL);
 }
 
 void wlr_drm_surface_post(struct wlr_drm_surface *surf) {
@@ -244,7 +243,7 @@ struct gbm_bo *wlr_drm_surface_mgpu_copy(struct wlr_drm_surface *dest,
 	glClear(GL_COLOR_BUFFER_BIT);
 	wlr_render_with_matrix(dest->renderer->wlr_rend, tex, &matrix);
 
-	return wlr_drm_surface_swap_buffers(dest);
+	return wlr_drm_surface_swap_buffers(dest, NULL);
 }
 
 bool wlr_drm_plane_surfaces_init(struct wlr_drm_plane *plane, struct wlr_drm_backend *drm,

backend/headless/output.c

@@ -55,7 +55,8 @@ static bool output_make_current(struct wlr_output *wlr_output, int *buffer_age)
 		buffer_age);
 }
 
-static bool output_swap_buffers(struct wlr_output *wlr_output) {
+static bool output_swap_buffers(struct wlr_output *wlr_output,
+		pixman_region32_t *damage) {
 	return true; // No-op
 }
 

backend/wayland/output.c

@@ -47,7 +47,8 @@ static bool wlr_wl_output_make_current(struct wlr_output *wlr_output,
 		buffer_age);
 }
 
-static bool wlr_wl_output_swap_buffers(struct wlr_output *wlr_output) {
+static bool wlr_wl_output_swap_buffers(struct wlr_output *wlr_output,
+		pixman_region32_t *damage) {
 	struct wlr_wl_backend_output *output =
 		(struct wlr_wl_backend_output *)wlr_output;
 
@@ -59,12 +60,8 @@ static bool wlr_wl_output_swap_buffers(struct wlr_output *wlr_output) {
 	output->frame_callback = wl_surface_frame(output->surface);
 	wl_callback_add_listener(output->frame_callback, &frame_listener, output);
 
-	if (!eglSwapBuffers(output->backend->egl.display, output->egl_surface)) {
-		wlr_log(L_ERROR, "eglSwapBuffers failed: %s", egl_error());
-		return false;
-	}
-
-	return true;
+	return wlr_egl_swap_buffers(&output->backend->egl, output->egl_surface,
+		damage);
 }
 
 static void wlr_wl_output_transform(struct wlr_output *_output,

backend/x11/backend.c

@@ -401,16 +401,12 @@ static bool output_make_current(struct wlr_output *wlr_output, int *buffer_age)
 	return wlr_egl_make_current(&x11->egl, output->surf, buffer_age);
 }
 
-static bool output_swap_buffers(struct wlr_output *wlr_output) {
+static bool output_swap_buffers(struct wlr_output *wlr_output,
+		pixman_region32_t *damage) {
 	struct wlr_x11_output *output = (struct wlr_x11_output *)wlr_output;
 	struct wlr_x11_backend *x11 = output->x11;
 
-	if (!eglSwapBuffers(x11->egl.display, output->surf)) {
-		wlr_log(L_ERROR, "eglSwapBuffers failed: %s", egl_error());
-		return false;
-	}
-
-	return true;
+	return wlr_egl_swap_buffers(&x11->egl, output->surf, damage);
 }
 
 static struct wlr_output_impl output_impl = {

include/backend/drm/renderer.h

@@ -41,14 +41,17 @@ bool wlr_drm_surface_init(struct wlr_drm_surface *surf,
 	struct wlr_drm_renderer *renderer, uint32_t width, uint32_t height,
 	uint32_t format, uint32_t flags);
 
-bool wlr_drm_plane_surfaces_init(struct wlr_drm_plane *plane, struct wlr_drm_backend *drm,
-		int32_t width, uint32_t height, uint32_t format);
+bool wlr_drm_plane_surfaces_init(struct wlr_drm_plane *plane,
+	struct wlr_drm_backend *drm, int32_t width, uint32_t height,
+	uint32_t format);
 
 void wlr_drm_surface_finish(struct wlr_drm_surface *surf);
 bool wlr_drm_surface_make_current(struct wlr_drm_surface *surf, int *buffer_age);
-struct gbm_bo *wlr_drm_surface_swap_buffers(struct wlr_drm_surface *surf);
+struct gbm_bo *wlr_drm_surface_swap_buffers(struct wlr_drm_surface *surf,
+	pixman_region32_t *damage);
 struct gbm_bo *wlr_drm_surface_get_front(struct wlr_drm_surface *surf);
 void wlr_drm_surface_post(struct wlr_drm_surface *surf);
-struct gbm_bo *wlr_drm_surface_mgpu_copy(struct wlr_drm_surface *dest, struct gbm_bo *src);
+struct gbm_bo *wlr_drm_surface_mgpu_copy(struct wlr_drm_surface *dest,
+	struct gbm_bo *src);
 
 #endif

include/wlr/interfaces/wlr_output.h

@@ -19,7 +19,7 @@ struct wlr_output_impl {
 	bool (*move_cursor)(struct wlr_output *output, int x, int y);
 	void (*destroy)(struct wlr_output *output);
 	bool (*make_current)(struct wlr_output *output, int *buffer_age);
-	bool (*swap_buffers)(struct wlr_output *output);
+	bool (*swap_buffers)(struct wlr_output *output, pixman_region32_t *damage);
 	void (*set_gamma)(struct wlr_output *output,
 		uint32_t size, uint16_t *r, uint16_t *g, uint16_t *b);
 	uint32_t (*get_gamma_size)(struct wlr_output *output);

include/wlr/render/egl.h

@@ -1,9 +1,10 @@
 #ifndef WLR_EGL_H
 #define WLR_EGL_H
 
+#include <stdbool.h>
 #include <EGL/egl.h>
 #include <EGL/eglext.h>
-#include <stdbool.h>
+#include <pixman.h>
 #include <wayland-server.h>
 
 struct wlr_egl {
@@ -16,6 +17,7 @@ struct wlr_egl {
 
 	struct {
 		bool buffer_age;
+		bool swap_buffers_with_damage;
 	} egl_exts;
 
 	struct wl_display *wl_display;
@@ -72,4 +74,7 @@ const char *egl_error(void);
 bool wlr_egl_make_current(struct wlr_egl *egl, EGLSurface surface,
 	int *buffer_age);
 
+bool wlr_egl_swap_buffers(struct wlr_egl *egl, EGLSurface surface,
+	pixman_region32_t *damage);
+
 #endif

render/egl.c

@@ -1,8 +1,8 @@
 #include <assert.h>
+#include <stdlib.h>
 #include <EGL/egl.h>
 #include <EGL/eglext.h>
 #include <GLES2/gl2.h>
-#include <stdlib.h>
 #include <wlr/util/log.h>
 #include <wlr/render/egl.h>
 #include "glapi.h"
@@ -143,6 +143,9 @@ bool wlr_egl_init(struct wlr_egl *egl, EGLenum platform, void *remote_display,
 
 	egl->egl_exts.buffer_age =
 		strstr(egl->egl_exts_str, "EGL_EXT_buffer_age") != NULL;
+	egl->egl_exts.swap_buffers_with_damage =
+		strstr(egl->egl_exts_str, "EGL_EXT_swap_buffers_with_damage") != NULL ||
+		strstr(egl->egl_exts_str, "EGL_KHR_swap_buffers_with_damage") != NULL;
 
 	return true;
 
@@ -242,3 +245,37 @@ bool wlr_egl_make_current(struct wlr_egl *egl, EGLSurface surface,
 	}
 	return true;
 }
+
+bool wlr_egl_swap_buffers(struct wlr_egl *egl, EGLSurface surface,
+		pixman_region32_t *damage) {
+	EGLBoolean ret;
+	if (damage != NULL && egl->egl_exts.swap_buffers_with_damage) {
+		int nrects;
+		pixman_box32_t *rects =
+			pixman_region32_rectangles(damage, &nrects);
+		EGLint egl_damage[4 * nrects];
+		for (int i = 0; i < nrects; ++i) {
+			egl_damage[4*i] = rects[i].x1;
+			egl_damage[4*i + 1] = rects[i].y1;
+			egl_damage[4*i + 2] = rects[i].x2 - rects[i].x1;
+			egl_damage[4*i + 3] = rects[i].y2 - rects[i].y1;
+		}
+
+		assert(eglSwapBuffersWithDamageEXT || eglSwapBuffersWithDamageKHR);
+		if (eglSwapBuffersWithDamageEXT) {
+			ret = eglSwapBuffersWithDamageEXT(egl->display, surface, egl_damage,
+				nrects);
+		} else {
+			ret = eglSwapBuffersWithDamageKHR(egl->display, surface, egl_damage,
+				nrects);
+		}
+	} else {
+		ret = eglSwapBuffers(egl->display, surface);
+	}
+
+	if (!ret) {
+		wlr_log(L_ERROR, "eglSwapBuffers failed: %s", egl_error());
+		return false;
+	}
+	return true;
+}

render/glapi.txt

@@ -6,3 +6,5 @@ eglCreatePlatformWindowSurfaceEXT
 -eglBindWaylandDisplayWL
 -eglUnbindWaylandDisplayWL
 -glEGLImageTargetTexture2DOES
+-eglSwapBuffersWithDamageEXT
+-eglSwapBuffersWithDamageKHR

types/wlr_output.c

@@ -507,8 +507,14 @@ bool wlr_output_swap_buffers(struct wlr_output *output, struct timespec *when,
 		}
 	}
 
-	// TODO: provide `damage` (not `render_damage`) to backend
-	if (!output->impl->swap_buffers(output)) {
+	// Transform damage into renderer coordinates, ie. upside down
+	enum wl_output_transform transform = wlr_output_transform_compose(
+		wlr_output_transform_invert(output->transform),
+		WL_OUTPUT_TRANSFORM_FLIPPED_180);
+	wlr_region_transform(&render_damage, &render_damage, transform, width,
+		height);
+
+	if (!output->impl->swap_buffers(output, damage ? &render_damage : NULL)) {
 		return false;
 	}