Demonstrate pointer button event in example

example/pointer.c

@@ -23,6 +23,7 @@ struct sample_state {
 	struct wlr_renderer *renderer;
 	struct wlr_surface *cat_texture;
 	int cur_x, cur_y;
+	float clear_color[4];
 };
 
 static void handle_output_frame(struct output_state *output, struct timespec *ts) {
@@ -31,6 +32,9 @@ static void handle_output_frame(struct output_state *output, struct timespec *ts
 	struct wlr_output *wlr_output = output->output;
 
 	wlr_renderer_begin(sample->renderer, wlr_output);
+	glClearColor(sample->clear_color[0], sample->clear_color[1],
+			sample->clear_color[2], sample->clear_color[3]);
+	glClear(GL_COLOR_BUFFER_BIT);
 
 	float matrix[16];
 	wlr_surface_get_matrix(sample->cat_texture, &matrix,
@@ -55,14 +59,32 @@ static void handle_pointer_motion(struct pointer_state *pstate,
 	state->cur_y += d_y;
 }
 
+static void handle_pointer_button(struct pointer_state *pstate,
+		uint32_t button, enum wlr_button_state state) {
+	struct sample_state *sample = pstate->compositor->data;
+	float (*color)[4];
+	if (state == WLR_BUTTON_RELEASED) {
+		float _default[4] = { 0.25f, 0.25f, 0.25f, 1 };
+		color = &_default;
+	} else {
+		float red[4] = { 0.25f, 0.25f, 0.25f, 1 };
+		red[button % 3] = 1;
+		color = &red;
+	}
+	memcpy(&sample->clear_color, color, sizeof(*color));
+}
+
 int main(int argc, char *argv[]) {
-	struct sample_state state = { 0 };
+	struct sample_state state = {
+		.clear_color = { 0.25f, 0.25f, 0.25f, 1 }
+	};
 	struct compositor_state compositor;
 
 	compositor_init(&compositor);
 	compositor.output_frame_cb = handle_output_frame;
-	compositor.pointer_motion_cb = handle_pointer_motion;
 	compositor.keyboard_key_cb = handle_keyboard_key;
+	compositor.pointer_motion_cb = handle_pointer_motion;
+	compositor.pointer_button_cb = handle_pointer_button;
 
 	state.renderer = wlr_gles3_renderer_init();
 	state.cat_texture = wlr_render_surface_init(state.renderer);

example/shared.c

@@ -74,7 +74,17 @@ static void pointer_motion_notify(struct wl_listener *listener, void *data) {
 	struct wlr_pointer_motion *event = data;
 	struct pointer_state *pstate = wl_container_of(listener, pstate, motion);
 	if (pstate->compositor->pointer_motion_cb) {
-		pstate->compositor->pointer_motion_cb(pstate, event->delta_x, event->delta_y);
+		pstate->compositor->pointer_motion_cb(pstate,
+				event->delta_x, event->delta_y);
+	}
+}
+
+static void pointer_button_notify(struct wl_listener *listener, void *data) {
+	struct wlr_pointer_button *event = data;
+	struct pointer_state *pstate = wl_container_of(listener, pstate, button);
+	if (pstate->compositor->pointer_button_cb) {
+		pstate->compositor->pointer_button_cb(pstate,
+				event->button, event->state);
 	}
 }
 
@@ -87,7 +97,9 @@ static void pointer_add(struct wlr_input_device *device, struct compositor_state
 	wl_list_init(&pstate->button.link);
 	wl_list_init(&pstate->axis.link);
 	pstate->motion.notify = pointer_motion_notify;
+	pstate->button.notify = pointer_button_notify;
 	wl_signal_add(&device->pointer->events.motion, &pstate->motion);
+	wl_signal_add(&device->pointer->events.button, &pstate->button);
 	wl_list_insert(&state->pointers, &pstate->link);
 }
 

example/shared.h

@@ -47,7 +47,10 @@ struct compositor_state {
 	void (*keyboard_remove_cb)(struct keyboard_state *s);
 	void (*keyboard_key_cb)(struct keyboard_state *s, xkb_keysym_t sym,
 			enum wlr_key_state key_state);
-	void (*pointer_motion_cb)(struct pointer_state *s, double d_x, double d_y);
+	void (*pointer_motion_cb)(struct pointer_state *s,
+			double d_x, double d_y);
+	void (*pointer_button_cb)(struct pointer_state *s,
+			uint32_t button, enum wlr_button_state state);
 
 	struct wl_display *display;
 	struct wl_event_loop *event_loop;