1 files changed, 160 insertions, 0 deletions
diff --git a/backend/drm/main.c b/backend/drm/main.c
new file mode 100644
index 00000000..aab11e19
--- /dev/null
+++ b/backend/drm/main.c
@@ -0,0 +1,160 @@
+#include <stdio.h>
+#include <stdbool.h>
+#include <inttypes.h>
+#include <time.h>
+#include <GLES3/gl3.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdnoreturn.h>
+
+#include "otd.h"
+#include "drm.h"
+#include "event.h"
+
+// I know this is pretty crappy,
+// but it's just for the example's sake
+struct {
+	char *name;
+	char *mode;
+} displays[8];
+int num_displays = 0;
+
+noreturn void usage(const char *name, int ret)
+{
+	fprintf(stderr, "usage: %s [-o <name> [-m <mode>]]*\n"
+			"\n"
+			"  -h       \tDisplay this help text\n"
+			"  -o <name>\tWhich diplay to use. e.g. DVI-I-1.\n"
+			"  -m <mode>\tWhich mode to use. It must come after an -o option.\n"
+			"           \tMust be either 'preferred', 'current', widthxheight\n"
+			"           \tor widthxheight@rate. Defaults to 'preferred'.\n"
+			"\n"
+			"example: %s -o DVI-I-1 -m 1920x1080@60 -o DP-1 -m 1920x1200\n",
+			name, name);
+
+	exit(ret);
+}
+
+void parse_args(int argc, char *argv[])
+{
+	int c;
+	int i = -1;
+
+	while ((c = getopt(argc, argv, "ho:m:")) != -1) {
+		switch (c) {
+		case 'h':
+			usage(argv[0], 0);
+		case 'o':
+			i = num_displays++;
+
+			if (num_displays == 8) {
+				fprintf(stderr, "Too many displays\n");
+				exit(1);
+			}
+
+			displays[i].name = strdup(optarg);
+			break;
+		case 'm':
+			if (i == -1) {
+				fprintf(stderr, "A display is required first\n");
+				exit(1);
+			}
+
+			fprintf(stderr, "Assigned '%s' to '%s'\n", optarg, displays[i].name);
+			displays[i].mode = optarg;
+			i = -1;
+			break;
+		default:
+			usage(argv[0], 1);
+		}
+	}
+
+	// Trailing args
+	if (optind != argc) {
+		usage(argv[0], 1);
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	parse_args(argc, argv);
+
+	struct otd *otd = otd_start();
+	if (!otd)
+		return 1;
+
+	float colour[3] = {1.0, 0.0, 0.0};
+	int dec = 0;
+
+	struct timespec start, now;
+	clock_gettime(CLOCK_MONOTONIC, &start);
+	struct timespec last = start;
+
+	while (clock_gettime(CLOCK_MONOTONIC, &now) == 0 &&
+	       now.tv_sec < start.tv_sec + 10) {
+
+		struct otd_event ev;
+		if (!otd_get_event(otd, &ev))
+			continue;
+
+		struct otd_display *disp = ev.display;
+
+		switch (ev.type) {
+		case OTD_EV_RENDER:
+			rendering_begin(disp);
+
+			// This is all just calculating the colours.
+			// It's not particularly important.
+
+			long ms = (now.tv_sec - last.tv_sec) * 1000 +
+				(now.tv_nsec - last.tv_nsec) / 1000000;
+
+			int inc = (dec + 1) % 3;
+
+			colour[dec] -= ms / 2000.0f;
+			colour[inc] += ms / 2000.0f;
+
+			if (colour[dec] < 0.0f) {
+				colour[dec] = 0.0f;
+				colour[inc] = 1.0f;
+
+				dec = (dec + 1) % 3;
+			}
+
+			last = now;
+
+			glViewport(0, 0, disp->width, disp->height);
+			glClearColor(colour[0], colour[1], colour[2], 1.0f);
+			glClear(GL_COLOR_BUFFER_BIT);
+
+			rendering_end(disp);
+			break;
+		case OTD_EV_DISPLAY_REM:
+			printf("%s removed\n", disp->name);
+			break;
+		case OTD_EV_DISPLAY_ADD:
+			printf("%s added\n", disp->name);
+
+			const char *mode = NULL;
+			for (int i = 0; i < num_displays; ++i) {
+				if (strcmp(disp->name, displays[i].name) == 0) {
+					mode = displays[i].mode;
+				}
+			}
+			if (!mode)
+				mode = "preferred";
+
+			if (!modeset_str(otd, ev.display, mode)) {
+				fprintf(stderr, "Modesetting %s failed\n", disp->name);
+				goto out;
+			}
+			break;
+		default:
+			break;
+		}
+	}
+
+out:
+	otd_finish(otd);
+}