115 lines
4.3 KiB
Swift
115 lines
4.3 KiB
Swift
//
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// Renderer.swift
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// Metaballs
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//
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// Created by Eryn Wells on 7/30/17.
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// Copyright © 2017 Eryn Wells. All rights reserved.
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//
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import Foundation
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import MetalKit
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public enum RendererError: Error {
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case MetalError(String)
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}
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public protocol RendererDelegate {
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var renderSize: Size { get set }
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var field: Field { get }
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var metalView: MTKView { get }
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}
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struct Vertex {
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let position: Point
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let textureCoordinate: Point
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}
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public class Renderer: NSObject, MTKViewDelegate {
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var delegate: RendererDelegate
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private var device: MTLDevice
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private var commandQueue: MTLCommandQueue
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private var renderPipelineState: MTLRenderPipelineState
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public init(delegate: RendererDelegate) throws {
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self.delegate = delegate
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guard let device = MTLCreateSystemDefaultDevice() else {
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throw RendererError.MetalError("Unable to create Metal system device")
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}
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let view = delegate.metalView
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self.device = device
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view.device = device
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try delegate.field.setupMetal(withDevice: device)
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let library = try device.makeDefaultLibrary(bundle: Bundle.main)
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let vertexShader = library.makeFunction(name: "passthroughVertexShader")
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let fragmentShader = library.makeFunction(name: "sampleToColorShader")
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let pipelineStateDescriptor = MTLRenderPipelineDescriptor()
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pipelineStateDescriptor.label = "Render Pipeline"
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pipelineStateDescriptor.vertexFunction = vertexShader
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pipelineStateDescriptor.fragmentFunction = fragmentShader
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if let renderAttachment = pipelineStateDescriptor.colorAttachments[0] {
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renderAttachment.pixelFormat = view.colorPixelFormat
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// Pulled all this from SO. I don't know what all this does...
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// https://stackoverflow.com/q/43727335/1174185
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renderAttachment.isBlendingEnabled = true
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renderAttachment.alphaBlendOperation = .add
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renderAttachment.rgbBlendOperation = .add
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renderAttachment.sourceRGBBlendFactor = .sourceAlpha
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renderAttachment.sourceAlphaBlendFactor = .sourceAlpha
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renderAttachment.destinationRGBBlendFactor = .oneMinusSourceAlpha
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renderAttachment.destinationAlphaBlendFactor = .oneMinusSourceAlpha
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}
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renderPipelineState = try device.makeRenderPipelineState(descriptor: pipelineStateDescriptor)
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commandQueue = device.makeCommandQueue()
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super.init()
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}
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/// MARK: - MTKViewDelegate
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public func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) {
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delegate.renderSize = Size(size: size)
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}
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public func draw(in view: MTKView) {
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let field = delegate.field
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// Two triangles, plus texture coordinates.
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let points: [Vertex] = [
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Vertex(position: Point(x: 1, y: -1), textureCoordinate: Point(x: 1, y: 0)),
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Vertex(position: Point(x: -1, y: -1), textureCoordinate: Point(x: 0, y: 0)),
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Vertex(position: Point(x: -1, y: 1), textureCoordinate: Point(x: 0, y: 1)),
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Vertex(position: Point(x: 1, y: -1), textureCoordinate: Point(x: 1, y: 0)),
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Vertex(position: Point(x: -1, y: 1), textureCoordinate: Point(x: 0, y: 1)),
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Vertex(position: Point(x: 1, y: 1), textureCoordinate: Point(x: 1, y: 1))
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]
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field.update()
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let buffer = commandQueue.makeCommandBuffer()
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buffer.label = "Render"
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if let renderPass = view.currentRenderPassDescriptor {
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let encoder = buffer.makeRenderCommandEncoder(descriptor: renderPass)
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encoder.label = "Render Pass"
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encoder.setViewport(MTLViewport(originX: 0.0, originY: 0.0, width: Double(view.drawableSize.width), height: Double(view.drawableSize.height), znear: -1.0, zfar: 1.0))
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encoder.setRenderPipelineState(renderPipelineState)
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encoder.setVertexBytes(points, length: points.count * MemoryLayout<Vertex>.stride, at: 0)
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encoder.setFragmentBuffer(field.parametersBuffer, offset: 0, at: 0)
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encoder.setFragmentBuffer(field.ballBuffer, offset: 0, at: 1)
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encoder.drawPrimitives(type: .triangle, vertexStart: 0, vertexCount: 6)
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encoder.endEncoding()
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if let drawable = view.currentDrawable {
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buffer.present(drawable)
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}
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}
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buffer.commit()
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}
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}
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