flak_m/zscript/dt_Gutamatics/GlobalMaths.zsc

class dt_GM_GlobalMaths {
	/// Returns the sign of s.
	static int sign(double s) {
		if (s > 0) return 1;
		if (s < 0) return -1;
		return 0;
	}

	/// Copies the sign from signSource to source.
	static int copySignInt(int source, int signSource) {
		return abs(source) * sign(signSource);
	}

	/// Copies the sign from signSource to source.
	static double copySignDouble(double source, double signSource) {
		return abs(source) * sign(signSource);
	}

	/// Remaps a value in a range to another range.
	static double remapRange(double value, double range1L, double range1H, double range2L, double range2H) {
		return range2L + (value - range1L) * (range2H - range1H) / (range1H - range1L);
	}

	/// Remaps a value in a range to another range.
	static int remapRangeInt(int value, int range1L, int range1H, int range2L, int range2H) {
		return int(range2L + (value - range1L) * (range2H - range1H) / double(range1H - range1L));
	}

	/// Returns if two values are close enough to be considered equal.
	static bool closeEnough(double a, double b, double epsilon = double.epsilon) {
		if (a == b) return true;
		return abs(a - b) <= epsilon;
	}

	// Creates a smoothed transition between edge0 and edge1.
	static double smoothStep(double x, double edge0 = 0, double edge1 = 1) {
		x = clamp((x - edge0) / (edge1 - edge0), 0, 1);
		return x * x * (3 - 2 * x);
	}

	// Creates a smoother transition between edge0 and edge1.
	static double smootherStep(double x, double edge0 = 0, double edge1 = 1) {
		x = clamp((x - edge0) / (edge1 - edge0), 0, 1);
		return x * x * x * (x * (x * 6 - 15) + 10);
	}

	/// Converts from horizontal FOV to vertical FOV, according to how GZDoom handles it.
	static double fovHToY(double fovH) {
		// this is how gzdoom does it internally, so i'm using it here
		double aspect = Screen.getAspectRatio();
		double fovratio = (aspect >= 1.3) ? 1.333333 : aspect;
		return 2 * atan(tan(clamp(fovH, 5, 170) / 2.0) / fovratio);
	}

	/// Linearly interpolates between two doubles, clamping the parameters.
	static double lerpDouble(double from, double to, double time) {
		time = clamp(time, 0, 1);
		return lerpUnclampedDouble(from, to, time);
	}

	/// Linearly interpolates between two doubles.
	static double lerpUnclampedDouble(double from, double to, double time) {
		double ret;
		double reverseTime = 1 - time;
		ret = reverseTime * from + time * to;
		return ret;
	}

	// Converts from Normalised Device Coordinates to Viewport coordinates.
	// This is `ui` scope to safely access `screenblocks`.
	static ui Vector2 ndcToViewport(Vector3 ndcCoords, bool useScreenblocks = true) {
		if (useScreenblocks) {
			int viewwindowx, viewwindowy, viewwidth, viewheight;
			[viewwindowx, viewwindowy, viewwidth, viewheight] = Screen.getViewWindow();
			int screenHeight = Screen.getHeight();
			int height = screenHeight;
			if (screenblocks < 10) {
				height = (screenblocks * screenHeight / 10) & ~7;
			}
			int bottom = screenHeight - (height + viewwindowy - ((height - viewheight) / 2));
			return (viewwindowx, screenHeight - bottom - height) + (((ndcCoords.x + 1) * viewwidth) / 2, ((-ndcCoords.y + 1) * height) / 2);
		}
		else {
			return (((ndcCoords.x + 1) * Screen.getWidth()) / 2, ((-ndcCoords.y + 1) * Screen.getHeight()) / 2);
		}
	}

	enum OutCode {
		OUT_Inside = 0,
		OUT_Left   = 1 << 0,
		OUT_Right  = 1 << 1,
		OUT_Bottom = 1 << 2,
		OUT_Top    = 1 << 3
	}

	/// Computes an outcode for a point in a rectangle.
	static OutCode computeOutcode(Vector2 point, Vector2 min, Vector2 max) {
		OutCode code = OUT_Inside;

		if (point.x < min.x) {
			code |= OUT_Left;
		}
		else if (point.x > max.x) {
			code |= OUT_Right;
		}
		if (point.y < min.y) {
			code |= OUT_Top;
		}
		else if (point.y > max.y) {
			code |= OUT_Bottom;
		}

		return code;
	}

	/// Clips a line to a rectangle.
	static bool, Vector2, Vector2 cohenSutherlandClip(Vector2 point0, Vector2 point1, Vector2 min, Vector2 max) {
		OutCode outcode0 = computeOutCode(point0, min, max);
		OutCode outcode1 = computeOutCode(point1, min, max);

		while (true) {
			// trivial accept - points are both on screen
			if ((outcode0 | outcode1) == 0) {
				return true, point0, point1;
			}
			// trivial reject - points are in the same region offscreen
			else if ((outcode0 & outcode1) != 0) {
				return false, point0, point1;
			}
			else {
				Vector2 new;
				OutCode outcodeOut = (outcode0 != 0) ? outcode0 : outcode1;

				if ((outcodeOut & OUT_Bottom) != 0) {
					new.x = point0.x + (point1.x - point0.x) * (max.y - point0.y) / (point1.y - point0.y);
					new.y = max.y;
				}
				else if ((outcodeOut & OUT_Top) != 0) {
					new.x = point0.x + (point1.x - point0.x) * (min.y - point0.y) / (point1.y - point0.y);
					new.y = min.y;
				}
				else if ((outcodeOut & OUT_Right) != 0) {
					new.y = point0.y + (point1.y - point0.y) * (max.x - point0.x) / (point1.x - point0.x);
					new.x = max.x;
				}
				else if ((outcodeOut & OUT_Left) != 0) {
					new.y = point0.y + (point1.y - point0.y) * (min.x - point0.x) / (point1.x - point0.x);
					new.x = min.x;
				}

				if (outcodeOut == outCode0) {
					point0.x = new.x;
					point0.y = new.y;
					outCode0 = computeOutCode(point0, min, max);
				}
				else {
					point1.x = new.x;
					point1.y = new.y;
					outCode1 = computeOutCode(point1, min, max);
				}
			}
		}
		return false, (0, 0), (0, 0);
	}

	// Normalizes an angle to (-180, 180]. Like Actor.normalize180, but callable in data scope.
	static double normalize180(double ang) {
		ang = ang % 360;
		ang = (ang + 360) % 360;
		if (ang > 180) ang -= 360;
		return ang;
	}
}