added GetSurfaceVector() to Math.c which can be used to get informations about the surface of the landscape at some point (f.e. for bouncing projectiles)

planet/System.ocg/Math.c

@@ -162,4 +162,25 @@ global func FindHeight(int x)
 	while (GBackSemiSolid(x, y) && y)
 		y--;
 	return y;
+}
+
+/*
+	Returns the normal vector of the (solid) landscape at a point relative to an object.
+	Can f.e. be used to bounce projectiles.
+*/
+global func GetSurfaceVector(int x, int y)
+{
+	var normal = {x = 0, y = 0};
+	
+	var fac = 1;
+	for(var fac = 1; fac <= 4; fac *= 2)
+	{
+		if(GBackSolid(x + fac, y)) {--normal.x;}
+		if(GBackSolid(x - fac, y)) {++normal.x;}
+	
+		if(GBackSolid(x, y + fac)) {--normal.y;}
+		if(GBackSolid(x, y - fac)) {++normal.y;}
+	}
+	
+	return normal;
 }