Haik Aslanyan
58 lines
2.9 KiB
Swift
58 lines
2.9 KiB
Swift
// MIT License
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// Copyright (c) 2020 Haik Aslanyan
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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import simd
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import QuartzCore
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struct RCTransformation {
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private let vectors: [SIMD3<Double>]
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private static let zeroColumnBeforeLast: double4x3 = {
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let identity = double3x3(diagonal: SIMD3<Double>(repeating: 1))
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var columns = (0 ... (SIMD3<Double>.scalarCount - 1)).map {identity[$0]}
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columns.insert(SIMD3<Double>(repeating: 0), at: SIMD3<Double>.scalarCount - 1)
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return .init(columns)
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}()
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private static let zeroRowBeforeLast: double3x4 = zeroColumnBeforeLast.transpose
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init(_ points: [CGPoint]) {
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self.vectors = points.map {SIMD3<Double>(Double($0.x), Double($0.y), 1)}
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}
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func perspectiveTransform(to destination: RCTransformation) -> CATransform3D {
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let destinationBaseVectors = double3x3(Array(destination.vectors[0 ... (SIMD3<Double>.scalarCount - 1)]))
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let destinationVectors = destinationBaseVectors.inverse * destination.vectors[SIMD3<Double>.scalarCount]
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let destinationScale = double3x3(diagonal: destinationVectors)
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let destinationPoints = destinationBaseVectors * destinationScale
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let currentBaseVectors = double3x3(Array(vectors[0 ... (SIMD3<Double>.scalarCount - 1)]))
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let currentVectors = currentBaseVectors.inverse * vectors[SIMD3<Double>.scalarCount]
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let currentScale = double3x3(diagonal: currentVectors)
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let currentPoints = currentBaseVectors * currentScale
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let perspective = destinationPoints * currentPoints.inverse
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let zNormalized = 1 / perspective[SIMD3<Double>.scalarCount - 1, SIMD3<Double>.scalarCount - 1] * perspective
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var matrix = (RCTransformation.zeroRowBeforeLast * zNormalized) * RCTransformation.zeroColumnBeforeLast
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matrix[SIMD3<Double>.scalarCount - 1, SIMD3<Double>.scalarCount - 1] = 1
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return unsafeBitCast(matrix, to: CATransform3D.self)
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}
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}
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