1 files changed, 88 insertions, 0 deletions
diff --git a/demos/colors.c b/demos/colors.c
new file mode 100644
index 0000000..41712e1
--- /dev/null
+++ b/demos/colors.c
@@ -0,0 +1,88 @@
+/* Simplistic demo that just makes the window colorful, including alpha
+ * transparency if supported by the windowing system.
+ *
+ * License: CC0 / Public Domain
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <math.h>
+#include <string.h>
+
+#include "common.h"
+#include "pl_clock.h"
+#include "window.h"
+
+static pl_log logger;
+static struct window *win;
+
+static void uninit(int ret)
+{
+    window_destroy(&win);
+    pl_log_destroy(&logger);
+    exit(ret);
+}
+
+int main(int argc, char **argv)
+{
+    logger = pl_log_create(PL_API_VER, pl_log_params(
+        .log_cb = pl_log_color,
+        .log_level = PL_LOG_DEBUG,
+    ));
+
+    win = window_create(logger, &(struct window_params) {
+        .title = "colors demo",
+        .width = 640,
+        .height = 480,
+        .alpha = true,
+    });
+    if (!win)
+        uninit(1);
+
+    pl_clock_t ts_start, ts;
+    if ((ts_start = pl_clock_now()) == 0) {
+        uninit(1);
+    }
+
+    while (!win->window_lost) {
+        if (window_get_key(win, KEY_ESC))
+            break;
+
+        struct pl_swapchain_frame frame;
+        bool ok = pl_swapchain_start_frame(win->swapchain, &frame);
+        if (!ok) {
+            // Something unexpected happened, perhaps the window is not
+            // visible? Wait for events and try again.
+            window_poll(win, true);
+            continue;
+        }
+
+        if ((ts = pl_clock_now()) == 0)
+            uninit(1);
+
+        const double period = 10.; // in seconds
+        double secs = fmod(pl_clock_diff(ts, ts_start), period);
+
+        double pos = 2 * M_PI * secs / period;
+        float alpha = (cos(pos) + 1.0) / 2.0;
+
+        assert(frame.fbo->params.blit_dst);
+        pl_tex_clear(win->gpu, frame.fbo, (float[4]) {
+            alpha * (sinf(2 * pos + 0.0) + 1.0) / 2.0,
+            alpha * (sinf(2 * pos + 2.0) + 1.0) / 2.0,
+            alpha * (sinf(2 * pos + 4.0) + 1.0) / 2.0,
+            alpha,
+        });
+
+        ok = pl_swapchain_submit_frame(win->swapchain);
+        if (!ok) {
+            fprintf(stderr, "libplacebo: failed submitting frame!\n");
+            uninit(3);
+        }
+
+        pl_swapchain_swap_buffers(win->swapchain);
+        window_poll(win, false);
+    }
+
+    uninit(0);
+}