50 lines
2 KiB
Swift
50 lines
2 KiB
Swift
//
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// Math.swift
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// Terrain2
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//
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// Created by Eryn Wells on 11/20/18.
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// Copyright © 2018 Eryn Wells. All rights reserved.
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//
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import Foundation
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import simd
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extension float4 {
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var xyz: float3 {
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return float3(x, y, z)
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}
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}
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// Generic matrix math utility functions
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func matrix4x4_rotation(radians: Float, axis: float3) -> matrix_float4x4 {
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let unitAxis = normalize(axis)
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let ct = cosf(radians)
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let st = sinf(radians)
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let ci = 1 - ct
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let x = unitAxis.x, y = unitAxis.y, z = unitAxis.z
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return matrix_float4x4.init(columns:(vector_float4( ct + x * x * ci, y * x * ci + z * st, z * x * ci - y * st, 0),
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vector_float4(x * y * ci - z * st, ct + y * y * ci, z * y * ci + x * st, 0),
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vector_float4(x * z * ci + y * st, y * z * ci - x * st, ct + z * z * ci, 0),
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vector_float4( 0, 0, 0, 1)))
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}
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func matrix4x4_translation(_ translationX: Float, _ translationY: Float, _ translationZ: Float) -> matrix_float4x4 {
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return matrix_float4x4.init(columns:(vector_float4(1, 0, 0, 0),
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vector_float4(0, 1, 0, 0),
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vector_float4(0, 0, 1, 0),
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vector_float4(translationX, translationY, translationZ, 1)))
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}
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func matrix_perspective_right_hand(fovyRadians fovy: Float, aspectRatio: Float, nearZ: Float, farZ: Float) -> matrix_float4x4 {
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let ys = 1 / tanf(fovy * 0.5)
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let xs = ys / aspectRatio
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let zs = farZ / (nearZ - farZ)
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return matrix_float4x4.init(columns:(vector_float4(xs, 0, 0, 0),
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vector_float4( 0, ys, 0, 0),
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vector_float4( 0, 0, zs, -1),
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vector_float4( 0, 0, zs * nearZ, 0)))
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}
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func radians_from_degrees(_ degrees: Float) -> Float {
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return (degrees / 180) * .pi
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}
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