vkcube: delta-time sensitivity

1 files changed, 14 insertions, 3 deletions

diff --git a/tools/Vulkan-Tools/cube/cube.c b/tools/Vulkan-Tools/cube/cube.c
index b67e31c2..a5854c5f 100644
--- a/tools/Vulkan-Tools/cube/cube.c
+++ b/tools/Vulkan-Tools/cube/cube.c
@@ -1025,9 +1025,20 @@ void demo_update_data_buffer(struct demo *demo, void *uniform_memory_ptr) {
 
     mat4x4_mul(VP, demo->projection_matrix, demo->view_matrix);
 
+    static struct timespec ts_old;
+    static bool ts_first = true;
+
+    struct timespec ts;
+    clock_gettime(CLOCK_REALTIME, &ts);
+
+    double dtime = ts_first ? false :
+        (double)(ts.tv_sec - ts_old.tv_sec) + (double) (ts.tv_nsec - ts_old.tv_nsec) / 1.0e9;
+    ts_old = ts;
+    ts_first = false;
+
     // Rotate around the Y axis
     mat4x4_dup(Model, demo->model_matrix);
-    mat4x4_rotate_Y(demo->model_matrix, Model, (float)degreesToRadians(demo->spin_angle));
+    mat4x4_rotate_Y(demo->model_matrix, Model, (float)degreesToRadians(dtime * demo->spin_angle));
     mat4x4_orthonormalize(demo->model_matrix, demo->model_matrix);
     mat4x4_mul(MVP, VP, demo->model_matrix);
 
@@ -4918,8 +4929,8 @@ static void demo_init(struct demo *demo, int argc, char **argv) {
 
     demo_init_vk(demo);
 
-    demo->spin_angle = 4.0f;
-    demo->spin_increment = 0.2f;
+    demo->spin_angle = 270.0f;
+    demo->spin_increment = 60.0f;
     demo->pause = false;
 
     mat4x4_perspective(demo->projection_matrix, (float)degreesToRadians(37.0f), 1.0f, 0.1f, 100.0f);