Added example.

2 files changed, 117 insertions, 0 deletions

diff --git a/example/CMakeLists.txt b/example/CMakeLists.txt
index 73768393..dfb069b4 100644
--- a/example/CMakeLists.txt
+++ b/example/CMakeLists.txt
@@ -5,3 +5,11 @@ add_executable(example
 target_link_libraries(example
     wlr-backend
 )
+
+add_executable(example-drm
+    example-drm.c
+)
+
+target_link_libraries(example-drm
+    wlr-backend
+)
diff --git a/example/example-drm.c b/example/example-drm.c
new file mode 100644
index 00000000..4c944226
--- /dev/null
+++ b/example/example-drm.c
@@ -0,0 +1,109 @@
+#define _POSIX_C_SOURCE 199309L
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <wayland-server.h>
+#include <GLES3/gl3.h>
+
+#include <wlr/backend/drm.h>
+
+struct state {
+	float color[3];
+	int dec;
+
+	struct timespec last_frame;
+
+	struct wl_listener add;
+	struct wl_listener rem;
+	struct wl_listener render;
+};
+
+void display_add(struct wl_listener *listener, void *data)
+{
+	struct wlr_drm_display *disp = data;
+
+	fprintf(stderr, "Display added\n");
+	wlr_drm_display_modeset(disp, "preferred");
+}
+
+void display_rem(struct wl_listener *listener, void *data)
+{
+	fprintf(stderr, "Display removed\n");
+}
+
+void display_render(struct wl_listener *listener, void *data)
+{
+	struct wlr_drm_display *disp = data;
+	struct state *s = wl_container_of(listener, s, render);
+
+	struct timespec now;
+	clock_gettime(CLOCK_MONOTONIC, &now);
+
+	long ms = (now.tv_sec - s->last_frame.tv_sec) * 1000 +
+		(now.tv_nsec - s->last_frame.tv_nsec) / 1000000;
+	int inc = (s->dec + 1) % 3;
+
+	s->color[inc] += ms / 2000.0f;
+	s->color[s->dec] -= ms / 2000.0f;
+
+	if (s->color[s->dec] < 0.0f) {
+		s->color[inc] = 1.0f;
+		s->color[s->dec] = 0.0f;
+
+		s->dec = inc;
+	}
+
+	s->last_frame = now;
+
+	wlr_drm_display_begin(disp);
+
+	glClearColor(s->color[0], s->color[1], s->color[2], 1.0);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	wlr_drm_display_end(disp);
+}
+
+int timer_done(void *data)
+{
+	*(bool *)data = true;
+	return 1;
+}
+
+int main()
+{
+	if (getenv("DISPLAY")) {
+		fprintf(stderr, "Detected that X is running. Run this in its own virtual terminal.\n");
+		return 1;
+	} else if (getenv("WAYLAND_DISPLAY")) {
+		fprintf(stderr, "Detected that Wayland is running. Run this in its own virtual terminal.\n");
+		return 1;
+	}
+
+	struct state state = {
+		.color = { 1.0, 0.0, 0.0 },
+		.dec = 0,
+		.add = { .notify = display_add },
+		.rem = { .notify = display_rem },
+		.render = { .notify = display_render },
+	};
+
+	wl_list_init(&state.add.link);
+	wl_list_init(&state.rem.link);
+	wl_list_init(&state.render.link);
+	clock_gettime(CLOCK_MONOTONIC, &state.last_frame);
+
+	struct wlr_drm_backend *wlr = wlr_drm_backend_init(&state.add, &state.rem, &state.render);
+
+	bool done = false;
+	struct wl_event_loop *event_loop = wlr_drm_backend_get_event_loop(wlr);
+	struct wl_event_source *timer = wl_event_loop_add_timer(event_loop,
+		timer_done, &done);
+
+	wl_event_source_timer_update(timer, 10000);
+
+	while (!done)
+		wl_event_loop_dispatch(event_loop, 0);
+
+	wl_event_source_remove(timer);
+	wlr_drm_backend_free(wlr);
+}