Merge pull request #1432 from ForTheReallys/relative-pointers

Relative pointers

2 files changed, 497 insertions, 0 deletions

diff --git a/examples/meson.build b/examples/meson.build
index 589a7326..0811d1a2 100644
--- a/examples/meson.build
+++ b/examples/meson.build
@@ -81,6 +81,10 @@ examples = {
 		'src': 'pointer-constraints.c',
 		'dep': [wayland_client, wlr_protos, wlroots],
 	},
+	'relative-pointer': {
+		'src': 'relative-pointer-unstable-v1.c',
+		'dep': [wayland_client, wlr_protos, wlroots],
+	},
 	'dmabuf-capture': {
 		'src': 'dmabuf-capture.c',
 		'dep': [
diff --git a/examples/relative-pointer-unstable-v1.c b/examples/relative-pointer-unstable-v1.c
new file mode 100644
index 00000000..ce671f99
--- /dev/null
+++ b/examples/relative-pointer-unstable-v1.c
@@ -0,0 +1,493 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <GLES2/gl2.h>
+#include <linux/input-event-codes.h>
+#include <wayland-egl.h>
+#include <wlr/render/egl.h>
+#include "pointer-constraints-unstable-v1-client-protocol.h"
+#include "relative-pointer-unstable-v1-client-protocol.h"
+#include "xdg-shell-client-protocol.h"
+
+
+/**
+ * structs storing global state
+ *
+ * These are passed around as user data in the wayland globals.
+ */
+
+struct egl_info {
+	struct wlr_egl *egl;
+	struct wl_egl_window *egl_window;
+	struct wlr_egl_surface *egl_surface;
+	uint32_t width;
+	uint32_t height;
+	struct wl_surface *surface;
+	struct wl_callback *frame_callback;
+};
+
+struct window {
+	struct egl_info *egl_info;
+	struct wl_pointer *pointer;
+	struct zwp_locked_pointer_v1 *locked_pointer;
+	struct zwp_relative_pointer_v1 *relative_pointer;
+	int32_t pointer_x, pointer_y;
+	uint32_t last_draw;
+};
+
+
+/**
+ * surface handling and helpers
+ *
+ * draw_cursor and draw_relative_cursor draw a small 5px by 5px box around the
+ * cursor and relative motion coordinates respectively. draw_background colors
+ * the background black.
+ *
+ * The functions are somewhat duplicated, but it doesn't really matter.
+ */
+
+static void surface_callback_handle_done(void *data,
+		struct wl_callback *callback, uint32_t time) {
+	wl_callback_destroy(callback);
+	struct egl_info *e = data;
+	e->frame_callback = NULL;
+}
+
+static struct wl_callback_listener surface_callback_listener = {
+	.done = surface_callback_handle_done,
+};
+
+static void draw_init(struct egl_info *e) {
+	eglMakeCurrent(e->egl->display, e->egl_surface,
+		e->egl_surface, e->egl->context);
+	glViewport(0, 0, e->width, e->height);
+}
+
+static void draw_cursor(struct egl_info *e, int32_t x, int32_t y) {
+	glEnable(GL_SCISSOR_TEST);
+	glScissor(x, e->height - y, 5, 5);
+	glClearColor(1.0f, 1.0f, 1.0f, 1.0f); /* white */
+	glClear(GL_COLOR_BUFFER_BIT);
+	glDisable(GL_SCISSOR_TEST);
+}
+
+static void draw_relative_cursor(struct egl_info *e, int32_t x, int32_t y) {
+	glEnable(GL_SCISSOR_TEST);
+	glScissor(x, e->height - y, 5, 5);
+	glClearColor(1.0f, 0.0f, 0.0f, 1.0f); /* red */
+	glClear(GL_COLOR_BUFFER_BIT);
+	glDisable(GL_SCISSOR_TEST);
+}
+
+static void draw_background(struct egl_info *e) {
+	glClearColor(0.0f, 0.0f, 0.0f, 1.0f); /* black */
+	glClear(GL_COLOR_BUFFER_BIT);
+}
+
+static void draw_end(struct egl_info *e) {
+	e->frame_callback = wl_surface_frame(e->surface);
+	wl_callback_add_listener(e->frame_callback, &surface_callback_listener, e);
+
+	eglSwapBuffers(e->egl->display, e->egl_surface);
+}
+
+
+/**
+ * registry and globals handling
+ */
+
+static struct wl_compositor *compositor = NULL;
+static struct wl_seat *seat = NULL;
+static struct xdg_wm_base *wm_base = NULL;
+static struct zwp_pointer_constraints_v1 *pointer_constraints = NULL;
+static struct zwp_relative_pointer_manager_v1 *relative_pointer_manager = NULL;
+
+static void registry_handle_global(void *data, struct wl_registry *registry,
+		uint32_t name, const char *interface, uint32_t version) {
+	if (strcmp(interface, wl_compositor_interface.name) == 0) {
+		compositor = wl_registry_bind(registry, name,
+			&wl_compositor_interface, version);
+	} else if (strcmp(interface, xdg_wm_base_interface.name) == 0) {
+		wm_base = wl_registry_bind(registry, name,
+			&xdg_wm_base_interface, version);
+	} else if (strcmp(interface, wl_seat_interface.name) == 0) {
+		seat = wl_registry_bind(registry, name,
+			&wl_seat_interface, version);
+	} else if (strcmp(interface, zwp_pointer_constraints_v1_interface.name) == 0) {
+		pointer_constraints = wl_registry_bind(registry, name,
+			&zwp_pointer_constraints_v1_interface, version);
+	} else if (strcmp(interface, zwp_relative_pointer_manager_v1_interface.name) == 0) {
+		relative_pointer_manager = wl_registry_bind(registry, name,
+			&zwp_relative_pointer_manager_v1_interface, version);
+	}
+}
+
+static void registry_handle_global_remove(void *data, struct wl_registry *registry,
+		uint32_t time) {
+	/* This space intentionally left blank */
+}
+
+static const struct wl_registry_listener registry_listener = {
+	.global = registry_handle_global,
+	.global_remove = registry_handle_global_remove,
+};
+
+
+/**
+ * xdg_surface handling
+ */
+
+static void xdg_surface_handle_configure(void *data,
+		struct xdg_surface *xdg_surface, uint32_t serial) {
+	struct egl_info *e = data;
+	xdg_surface_ack_configure(xdg_surface, serial);
+	wl_egl_window_resize(e->egl_window, e->width, e->height, 0, 0);
+	draw_init(e);
+	draw_background(e);
+	draw_end(e);
+}
+
+static const struct xdg_surface_listener xdg_surface_listener = {
+	.configure = xdg_surface_handle_configure,
+};
+
+
+/**
+ * xdg_toplevel handling
+ */
+
+static void xdg_toplevel_handle_configure(void *data,
+		struct xdg_toplevel *xdg_toplevel, int32_t width, int32_t height,
+		struct wl_array *states) {
+	struct egl_info *e = data;
+	// TODO: Why do we get 0,0 on initialization here? (in rootston)
+	if (width == 0 && height == 0) {
+		return;
+	}
+	e->width = width;
+	e->height = height;
+}
+
+static void xdg_toplevel_handle_close(void *data,
+		struct xdg_toplevel *xdg_toplevel) {
+	struct egl_info *e = data;
+	wlr_egl_finish(e->egl);
+	exit(EXIT_SUCCESS);
+}
+
+static const struct xdg_toplevel_listener xdg_toplevel_listener = {
+	.configure = xdg_toplevel_handle_configure,
+	.close = xdg_toplevel_handle_close,
+};
+
+
+/**
+ * zwp_locked_pointer handling
+ *
+ * Pointer unlocks need to be handled properly since the relative pointer needs
+ * to be released as well. Unlocks happen when the focus is changed, for
+ * example.
+ */
+
+static void locked_pointer_handle_locked(void *data,
+		struct zwp_locked_pointer_v1 *zwp_locked_pointer_v1) {
+	/* This space intentionally left blank */
+}
+
+static void locked_pointer_handle_unlocked(void *data,
+		struct zwp_locked_pointer_v1 *zwp_locked_pointer_v1) {
+	struct window *w = data;
+	/* The locked pointer doesn't need to be destroyed since it was oneshot */
+	w->locked_pointer = NULL;
+	if (w->relative_pointer) {
+		/* Destroy the relative pointer */
+		zwp_relative_pointer_v1_destroy(w->relative_pointer);
+		w->relative_pointer = NULL;
+	}
+	draw_init(w->egl_info);
+	draw_background(w->egl_info);
+	draw_end(w->egl_info);
+}
+
+static const struct zwp_locked_pointer_v1_listener locked_pointer_listener = {
+	.locked = locked_pointer_handle_locked,
+	.unlocked = locked_pointer_handle_unlocked,
+};
+
+
+/**
+ * zwp_relative_pointer handling
+ *
+ * Handling relative_motion events is the meat of the code. The handler simply
+ * tries to indicate what the deltas look like.
+ */
+
+static void relative_pointer_handle_relative_motion(void *data,
+		struct zwp_relative_pointer_v1 *zwp_relative_pointer_v1,
+		uint32_t utime_hi, uint32_t utime_lo,
+		wl_fixed_t dx, wl_fixed_t dy,
+		wl_fixed_t dx_unaccel, wl_fixed_t dy_unaccel) {
+	struct window *w = data;
+
+	/**
+	 * This renders the last location of the pointer (before it as locked), as
+	 * well as what the position would have been after the given relative
+	 * motion. Note that, if the device sends absolute motion events, the
+	 * cursor location after relative motion is always identical to the actual
+	 * cursor position.
+	 */
+	uint64_t utime = (((uint64_t) utime_hi << 32) + utime_lo) / 1000;
+	if (utime - w->last_draw > 30 && w->egl_info->frame_callback == NULL) {
+		w->last_draw = utime;
+
+		struct egl_info *e = w->egl_info;
+		draw_init(e);
+		draw_background(e);
+		draw_cursor(e, w->pointer_x, w->pointer_y);
+		draw_relative_cursor(e, w->pointer_x + wl_fixed_to_int(dx),
+			w->pointer_y + wl_fixed_to_int(dy));
+		draw_end(e);
+	}
+}
+
+static const struct zwp_relative_pointer_v1_listener relative_pointer_listener = {
+	.relative_motion = relative_pointer_handle_relative_motion,
+};
+
+
+/**
+ * wl_pointer handling
+ *
+ * The client toggles between locking the pointer and receiving relative motion
+ * events, and releasing the locked pointer and falling back to normal motion
+ * events, on a mouse button one (left mouse button) click.
+ *
+ * It additionally removes the cursor image, and indicates the pointer location
+ * via a small white box.
+ */
+
+static void pointer_handle_button(void *data, struct wl_pointer *pointer,
+		uint32_t serial, uint32_t time, uint32_t button, uint32_t state_w) {
+
+	struct window *w = data;
+	struct egl_info *e = w->egl_info;
+
+	if (button == BTN_LEFT && state_w == WL_POINTER_BUTTON_STATE_PRESSED) {
+		if (w->locked_pointer == NULL && w->relative_pointer == NULL) {
+			/* Get a locked pointer and add listener */
+			w->locked_pointer = zwp_pointer_constraints_v1_lock_pointer(
+				pointer_constraints, w->egl_info->surface, w->pointer, NULL,
+				ZWP_POINTER_CONSTRAINTS_V1_LIFETIME_ONESHOT);
+			zwp_locked_pointer_v1_add_listener(w->locked_pointer,
+				&locked_pointer_listener, w);
+
+			/* Get relative pointer and add listener */
+			w->relative_pointer = zwp_relative_pointer_manager_v1_get_relative_pointer(
+				relative_pointer_manager, w->pointer);
+			zwp_relative_pointer_v1_add_listener(w->relative_pointer,
+				&relative_pointer_listener, w);
+
+			/* Commit the surface and render */
+			wl_surface_commit(e->surface);
+
+			draw_init(e);
+			draw_background(e);
+			draw_cursor(e, w->pointer_x, w->pointer_y);
+			draw_end(e);
+		} else if (w->locked_pointer && w->relative_pointer) {
+			/* Destroy the locked pointer */
+			zwp_locked_pointer_v1_destroy(w->locked_pointer);
+			w->locked_pointer = NULL;
+
+			/* Destroy the relative pointer */
+			zwp_relative_pointer_v1_destroy(w->relative_pointer);
+			w->relative_pointer = NULL;
+
+			/* Render */
+			draw_init(e);
+			draw_background(e);
+			draw_cursor(e, w->pointer_x, w->pointer_y);
+			draw_end(e);
+		} else {
+			fprintf(stderr, "Unknown state!\n");
+			exit(EXIT_FAILURE);
+		}
+	}
+}
+
+static void pointer_handle_enter(void *data, struct wl_pointer *wl_pointer,
+		uint32_t serial, struct wl_surface *surface,
+		wl_fixed_t surface_x, wl_fixed_t surface_y) {
+	struct window *w = data;
+	wl_pointer_set_cursor(w->pointer, serial, NULL, 0, 0);
+}
+
+static void pointer_handle_leave(void *data, struct wl_pointer *wl_pointer,
+		uint32_t serial, struct wl_surface *surface) {
+	/* This space intentionally left blank */
+}
+
+static void pointer_handle_motion(void *data, struct wl_pointer *wl_pointer,
+		uint32_t time, wl_fixed_t surface_x, wl_fixed_t surface_y) {
+	struct window *w = data;
+	struct egl_info *e = w->egl_info;
+	w->pointer_x = wl_fixed_to_int(surface_x);
+	w->pointer_y = wl_fixed_to_int(surface_y);
+	if (time - w->last_draw > 30 && e->frame_callback == NULL) {
+		w->last_draw = time;
+		draw_init(e);
+		draw_background(e);
+		draw_cursor(e, w->pointer_x, w->pointer_y);
+		draw_end(e);
+	}
+}
+
+static void pointer_handle_axis(void *data, struct wl_pointer *wl_pointer,
+		uint32_t time, uint32_t axis, wl_fixed_t value) {
+	/* This space intentionally left blank */
+}
+
+static void pointer_handle_frame(void *data, struct wl_pointer *wl_pointer) {
+	/* This space intentionally left blank */
+}
+
+static void pointer_handle_axis_source(void *data,
+		struct wl_pointer *wl_pointer, uint32_t axis_source) {
+	/* This space intentionally left blank */
+}
+
+static void pointer_handle_axis_stop(void *data,
+		struct wl_pointer *wl_pointer, uint32_t time, uint32_t axis) {
+	/* This space intentionally left blank */
+}
+
+static void pointer_handle_axis_discrete(void *data,
+		struct wl_pointer *wl_pointer, uint32_t axis, int32_t discrete) {
+	/* This space intentionally left blank */
+}
+
+static const struct wl_pointer_listener pointer_listener = {
+	.enter = pointer_handle_enter,
+	.leave = pointer_handle_leave,
+	.motion = pointer_handle_motion,
+	.button = pointer_handle_button,
+	.axis = pointer_handle_axis,
+	.frame = pointer_handle_frame,
+	.axis_source = pointer_handle_axis_source,
+	.axis_stop = pointer_handle_axis_stop,
+	.axis_discrete = pointer_handle_axis_discrete,
+};
+
+
+/**
+ * relative-pointer:
+ *
+ * This client servers as an example for the relative-pointer-v1 protocol, and
+ * to some extent the pointer-constraints protocol as well (the locked_pointer
+ * interface).
+ *
+ * The intended behavior is the following. In the default state, the client
+ * shows a black background, and renders the pointer location as a small white
+ * box. No cursor is shown. In the locked state, the pointer is locked and the
+ * client only listens for relative motion events, which are rendered relative
+ * to the last unlocked pointer location by a small red box. Clicking with the
+ * left mouse button toggles the state.
+ *
+ * Most of the code is standard. The interesting stuff happens in "wl_pointer
+ * handling" (toggling states), and "zwp_relative_pointer handling" (rendering
+ * relative motion events).
+ */
+
+int main(int argc, char **argv) {
+
+	/* Connect to the display */
+
+	struct wl_display *display = wl_display_connect(NULL);
+	if (display == NULL) {
+		fprintf(stderr, "Could not connect to a Wayland display\n");
+		return EXIT_FAILURE;
+	}
+
+	/* Get the registry and set listeners */
+
+	struct wl_registry *registry = wl_display_get_registry(display);
+	wl_registry_add_listener(registry, &registry_listener, NULL);
+	wl_display_dispatch(display);
+	wl_display_roundtrip(display);
+
+	/* Check that all the global interfaces were captured */
+
+	if (compositor == NULL) {
+		fprintf(stderr, "wl_compositor not available\n");
+		return EXIT_FAILURE;
+	}
+	if (seat == NULL) {
+		fprintf(stderr, "wl_seat not available\n");
+		return EXIT_FAILURE;
+	}
+	if (wm_base == NULL) {
+		fprintf(stderr, "xdg_wm_base not available\n");
+		return EXIT_FAILURE;
+	}
+	if (pointer_constraints == NULL) {
+		fprintf(stderr, "zwp_pointer_constraints_v1 not available\n");
+		return EXIT_FAILURE;
+	}
+	if (relative_pointer_manager == NULL) {
+		fprintf(stderr, "zwp_relative_pointer_manager_v1 not available\n");
+		return EXIT_FAILURE;
+	}
+
+	/* Initialize EGL context */
+
+	struct egl_info *e = calloc(1, sizeof(struct egl_info));
+	e->egl = calloc(1, sizeof(struct wlr_egl));
+	e->width = e->height = 512;
+
+	wlr_egl_init(e->egl, EGL_PLATFORM_WAYLAND_EXT, display, NULL,
+		WL_SHM_FORMAT_ARGB8888);
+
+	/* Create the surface and xdg_toplevels, and set listeners */
+
+	struct wl_surface *surface = wl_compositor_create_surface(compositor);
+	struct xdg_surface *xdg_surface =
+		xdg_wm_base_get_xdg_surface(wm_base, surface);
+	struct xdg_toplevel *xdg_toplevel = xdg_surface_get_toplevel(xdg_surface);
+
+	xdg_surface_add_listener(xdg_surface, &xdg_surface_listener, e);
+	xdg_toplevel_add_listener(xdg_toplevel, &xdg_toplevel_listener, e);
+
+	/* Create the egl window and surface */
+
+	wl_surface_commit(surface);
+
+	e->egl_window = wl_egl_window_create(surface, e->width, e->height);
+	e->egl_surface = wlr_egl_create_surface(e->egl, e->egl_window);
+	e->surface = surface;
+
+	wl_display_roundtrip(display);
+
+	/* Setup global state and render */
+
+	struct window *w = calloc(1, sizeof(struct window));
+	w->egl_info = e;
+
+	draw_init(e);
+	draw_background(e);
+	draw_end(e);
+
+	/* Setup the pointer */
+
+	struct wl_pointer *pointer = wl_seat_get_pointer(seat);
+	wl_pointer_add_listener(pointer, &pointer_listener, w);
+
+	w->pointer = pointer;
+
+	/* Run display */
+
+	while (wl_display_dispatch(display) != -1) {
+		/* This space intentionally left blank */
+	}
+
+	return EXIT_SUCCESS;
+}