Remove shadow direction quantization, increase shadow update frames i…

…nstead (luanti-org#15665)

* This removes shadow direction quantization and defaults shadow_update_frames to 16 instead.

builtin/settingtypes.txt

@@ -1899,7 +1899,7 @@ shadow_poisson_filter (Poisson filtering) bool true
 #    Minimum value: 1; maximum value: 16
 #
 #    Requires: enable_dynamic_shadows, opengl
-shadow_update_frames (Map shadows update frames) int 8 1 16
+shadow_update_frames (Map shadows update frames) int 16 1 32
 
 #    Set to true to render debugging breakdown of the bloom effect.
 #    In debug mode, the screen is split into 4 quadrants:

src/client/shadows/dynamicshadows.cpp

@@ -13,18 +13,6 @@
 
 using m4f = core::matrix4;
 
-static v3f quantizeDirection(v3f direction, float step)
-{
-
-	float yaw = std::atan2(direction.Z, direction.X);
-	float pitch = std::asin(direction.Y); // assume look is normalized
-
-	yaw = std::floor(yaw / step) * step;
-	pitch = std::floor(pitch / step) * step;
-
-	return v3f(std::cos(yaw)*std::cos(pitch), std::sin(pitch), std::sin(yaw)*std::cos(pitch));
-}
-
 void DirectionalLight::createSplitMatrices(const Camera *cam)
 {
 	static const float COS_15_DEG = 0.965926f;
@@ -74,7 +62,7 @@ void DirectionalLight::createSplitMatrices(const Camera *cam)
 	v3f boundVec = (cam_pos_scene + farCorner * sfFar) - center_scene;
 	float radius = boundVec.getLength();
 	float length = radius * 3.0f;
-	v3f eye_displacement = quantizeDirection(direction, M_PI / 2880 /*15 seconds*/) * length;
+	v3f eye_displacement = direction * length;
 
 	// we must compute the viewmat with the position - the camera offset
 	// but the future_frustum position must be the actual world position

src/defaultsettings.cpp

@@ -341,7 +341,7 @@ void set_default_settings()
 	settings->setDefault("shadow_map_color", "false");
 	settings->setDefault("shadow_filters", "1");
 	settings->setDefault("shadow_poisson_filter", "true");
-	settings->setDefault("shadow_update_frames", "8");
+	settings->setDefault("shadow_update_frames", "16");
 	settings->setDefault("shadow_soft_radius", "5.0");
 	settings->setDefault("shadow_sky_body_orbit_tilt", "0.0");