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Math APIs (Geometry)

This is not an introduction to the math functions of the standard JavaScript library. Instead, this is a set of useful classes provided by NTE/JCM to perform transformations for model rendering and other things.

Vector3f#

A three-dimensional vector, that is, the coordinates (x, y, z).

Difference between NTE and JCM's implementation
  • In NTE, Vector3f uses float. In JCM, Vector3f is a wrapper around Vector3d for the underlying implementation and casts back to a float.
  • In NTE, operation methods does not return anything (void). In JCM, they now return an instance of itself (Vector3f), allowing method chaining to be used.
Functions Description
new Vector3f(x: float, y: float, z: float): Vector3f Creates an instance of the Vector3f class.
new Vector3f(tscVec: Vector): Vector3f Creates an instance of the Vector3f class from the Vector class from MTR's Transport Simulation Core.
Vector3f.x(): float Returns the X coordinate
Vector3f.y(): float Returns the Y coordinate
Vector3f.z(): float Returns the Z coordinate
Vector3f.copy(): Vector3f Returns a copy of the vector that can be independently modified.
Vector3f.normalize(): Vector3f Normalizes to a unit vector, that is, it preserves its direction, but its length is 1.
Vector3f.add(x: float, y: float, z: float): Vector3f Adds the given vector from an x y z coordinate
Vector3f.add(other: Vector3f): Vector3f Adds the given vector from another Vector3f
Vector3f.sub(other: Vector3f): Vector3f Subtract the given vector from another Vector3f
Vector3f.mul(x: float, y: float, z: float): Vector3f Multiplies each coordinate by the specified numbers respectively.
Vector3f.mul(n: float): Vector3f Multiplies each coordinate by the specified number.
Vector3f.rotX(rad: float): Vector3f Rotates along the X axis, the angle is specified in radians.
Vector3f.rotY(rad: float): Vector3f Rotates along the Y axis, the angle is specified in radians.
Vector3f.rotZ(rad: float): Vector3f Rotates along the Z axis, the angle is specified in radians.
Vector3f.cross(other: Vector3f): Vector3f Performs a vector product with another vector. The result will be perpendicular to both vectors.
Vector3f.distance(other: Vector3f): float Returns the distance to the coordinates represented by the other vector.
Vector3f.distanceSq(other: Vector3f): float Returns the square of the distance to the coordinates represented by the other vector. The calculation is somewhat faster than in the previous case.
Vector3f.rawBlockPos(): BlockPos Returns BlockPos from Minecraft with rounded vector values.
static Vector3f.ZERO: Vector3f Zero vector. Do not operate/manipulate this object.
static Vector3f.XP: Vector3f Vector with value (1, 0, 0). Do not operate/manipulate this object.
static Vector3f.YP: Vector3f Vector with value (0, 1, 0). Do not operate/manipulate this object.
static Vector3f.ZP: Vector3f Vector with value (0, 0, 1). Do not operate/manipulate this object.

Matrices#

When rendering, there is often a need to “restore the transformation state to the previous step”.

For example, let's say I want to add a "move down" transformation to render the bogie. But after the rendering I need to return to the transformation before the move in order to render other parts of the car.

Matrices implements a stack where multiple transformations can be stored. push and pop are performed in pairs.

Functions Description
new Matrices(): Matrices Returns Matrices. Initially there is only one unit matrix.
Matrices.translate(x: float, y: float, z: float): void Adds a (x,y,z) translation transformation to the current state.
Matrices.rotateX(xRad: float): void Rotates along the X axis, in radian
Matrices.rotateY(yRad: float): void Rotates along the Y axis, in radian
Matrices.rotateZ(zRad: float): void Rotates along the Z axis, in radian
Matrices.rotateXDegrees(xDeg: float): void Rotates along the X axis, in degrees
Matrices.rotateYDegrees(yDeg: float): void Rotates along the Y axis, in degrees
Matrices.rotateZDegrees(zDeg: float): void Rotates along the Z axis, in degrees
Matrices.pushPose(): void Places a copy of the current state on the stack. That is, a copy of the current state is saved.
Matrices.popPose(): void Deletes the last element of the stack. That is, it resets the current state and then restores the last saved state as the last state.
Matrices.popPushPose(): void It deletes first and then makes a copy of the saved state.