add sane-ish defaults to avoid ub

ui/src/api.hxx

@@ -8,18 +8,18 @@ namespace ffi {
 struct Core;
 
 struct SphericalPosition {
-	float yaw;
-	float pitch;
-	float distance;
+	float yaw = 0.;
+	float pitch = 0.;
+	float distance = 1.;
 };
 
 struct RedrawArgs {
 	SphericalPosition camera_position;
 	SphericalPosition light_position;
-	float light_radius;
-	float light_spread;
-	float accum_sigma;
-	float accum_scale;
+	float light_radius = 1.;
+	float light_spread = 0.;
+	float accum_sigma = 1.;
+	float accum_scale = 1.;
 };
 } // namespace ffi