Added multithreaded rendering

Source/Rampage.xcodeproj/project.pbxproj

@@ -64,6 +64,7 @@
 		01D0F5D922F80E1600682CA1 /* RampageTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 01D0F5D822F80E1600682CA1 /* RampageTests.swift */; };
 		01D0F5F122FF095E00682CA1 /* Door.swift in Sources */ = {isa = PBXBuildFile; fileRef = 01D0F5F022FF095E00682CA1 /* Door.swift */; };
 		01E3963A2342758D00D02236 /* Pushwall.swift in Sources */ = {isa = PBXBuildFile; fileRef = 01E396392342758D00D02236 /* Pushwall.swift */; };
+		01D0F5EF22FDF19A00682CA1 /* Bitmap+Rendering.swift in Sources */ = {isa = PBXBuildFile; fileRef = 01D0F5EE22FDF19900682CA1 /* Bitmap+Rendering.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -174,6 +175,7 @@
 		01D0F5DA22F80E1600682CA1 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		01D0F5F022FF095E00682CA1 /* Door.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Door.swift; sourceTree = "<group>"; };
 		01E396392342758D00D02236 /* Pushwall.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Pushwall.swift; sourceTree = "<group>"; };
+		01D0F5EE22FDF19900682CA1 /* Bitmap+Rendering.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Bitmap+Rendering.swift"; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -256,6 +258,7 @@
 			children = (
 				016E41B2228E9A5B00ACF137 /* AppDelegate.swift */,
 				016E41B4228E9A5B00ACF137 /* ViewController.swift */,
+				01D0F5EE22FDF19900682CA1 /* Bitmap+Rendering.swift */,
 				01D09AF422A482450052745A /* UIImage+Bitmap.swift */,
 				0199F57323E242D4003E3F08 /* SoundManager.swift */,
 				016E41B6228E9A5B00ACF137 /* Main.storyboard */,
@@ -544,6 +547,7 @@
 			files = (
 				01D09AF522A482450052745A /* UIImage+Bitmap.swift in Sources */,
 				0199F57423E242D4003E3F08 /* SoundManager.swift in Sources */,
+				01D0F5EF22FDF19A00682CA1 /* Bitmap+Rendering.swift in Sources */,
 				016E41B5228E9A5B00ACF137 /* ViewController.swift in Sources */,
 				016E41B3228E9A5B00ACF137 /* AppDelegate.swift in Sources */,
 			);

Source/Rampage.xcodeproj/xcshareddata/xcschemes/Rampage.xcscheme

@@ -50,7 +50,7 @@
       </Testables>
    </TestAction>
    <LaunchAction
-      buildConfiguration = "Debug"
+      buildConfiguration = "Release"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       launchStyle = "0"

Source/Rampage/Bitmap+Rendering.swift

@@ -0,0 +1,33 @@
+//
+//  ConcurrentRenderer.swift
+//  Rampage
+//
+//  Created by Nick Lockwood on 09/08/2019.
+//  Copyright © 2019 Nick Lockwood. All rights reserved.
+//
+
+import UIKit
+import Engine
+import Renderer
+
+public extension Bitmap {
+    init(width: Int, height: Int, world: World, textures: Textures) {
+        let cpuCores = ProcessInfo.processInfo.activeProcessorCount
+        var buffers = Array(repeating: [Color](), count: cpuCores)
+        let step = 1.0 / Double(cpuCores)
+        DispatchQueue.concurrentPerform(iterations: cpuCores) { i in
+            let offset = Double(i) * step
+            let range = offset ..< offset + step
+            var renderer = Renderer(
+                width: width,
+                height: height,
+                range: range,
+                textures: textures
+            )
+            renderer.draw(world)
+            buffers[i] = renderer.bitmap.pixels
+        }
+        let pixels = Array(buffers.joined())
+        self.init(height: height, pixels: pixels)
+    }
+}

Source/Rampage/ViewController.swift

@@ -128,10 +128,8 @@ class ViewController: UIViewController {
         lastFrameTime = displayLink.timestamp
 
         let width = Int(imageView.bounds.width), height = Int(imageView.bounds.height)
-        var renderer = Renderer(width: width, height: height, textures: textures)
-        renderer.draw(world)
-
-        imageView.image = UIImage(bitmap: renderer.bitmap)
+        let bitmap = Bitmap(width: width, height: height, world: world, textures: textures)
+        imageView.image = UIImage(bitmap: bitmap)
     }
 
     @objc func fire(_ gestureRecognizer: UITapGestureRecognizer) {

Source/RampageTests/RampageTests.swift

@@ -17,8 +17,7 @@ class RampageTests: XCTestCase {
 
     func testRenderFrame() {
         self.measure {
-            var renderer = Renderer(width: 1000, height: 1000, textures: textures)
-            renderer.draw(world)
+            _ = Bitmap(width: 1000, height: 1000, world: world, textures: textures)
         }
     }
 }

Source/Renderer/Bitmap.swift

@@ -89,9 +89,9 @@ public extension Bitmap {
     }
 
     mutating func drawImage(_ source: Bitmap, at point: Vector, size: Vector) {
-        let start = Int(point.x), end = Int(point.x + size.x)
+        let start = max(0, Int(point.x)), end = Int(point.x + size.x)
         let stepX = Double(source.width) / size.x
-        for x in max(0, start) ..< min(width, end) {
+        for x in start ..< max(start, min(width, end)) {
             let sourceX = (Double(x) - point.x) * stepX
             let outputPosition = Vector(x: Double(x), y: point.y)
             drawColumn(Int(sourceX), of: source, at: outputPosition, height: size.y)

Source/Renderer/Renderer.swift

@@ -12,27 +12,31 @@ private let fizzle = (0 ..< 10000).shuffled()
 
 public struct Renderer {
     public private(set) var bitmap: Bitmap
+    private let width: Int
+    private let range: Range<Double>
     private let textures: Textures
 
-    public init(width: Int, height: Int, textures: Textures) {
-        self.bitmap = Bitmap(width: width, height: height, color: .black)
+    public init(width: Int, height: Int, range: Range<Double>, textures: Textures) {
+        self.width = width
+        self.range = range
+        let columns = Int(Double(width) * (range.upperBound - range.lowerBound))
+        self.bitmap = Bitmap(width: columns, height: height, color: .clear)
         self.textures = textures
     }
 }
 
 public extension Renderer {
     mutating func draw(_ world: World) {
         let focalLength = 1.0
-        let viewWidth = Double(bitmap.width) / Double(bitmap.height)
+        let viewWidth = Double(width) / Double(bitmap.height)
         let viewPlane = world.player.direction.orthogonal * viewWidth
         let viewCenter = world.player.position + world.player.direction * focalLength
-        let viewStart = viewCenter - viewPlane / 2
+        let viewStart = viewCenter - viewPlane * (0.5 - range.lowerBound)
 
         // Cast rays
-        let columns = bitmap.width
-        let step = viewPlane / Double(columns)
+        let step = viewPlane / Double(width)
         var columnPosition = viewStart
-        for x in 0 ..< columns {
+        for x in 0 ..< bitmap.width {
             let rayDirection = columnPosition - world.player.position
             let viewPlaneDistance = rayDirection.length
             let ray = Ray(
@@ -130,7 +134,7 @@ public extension Renderer {
         let weaponWidth = screenHeight * aspectRatio
         bitmap.drawImage(
             weaponTexture,
-            at: Vector(x: Double(bitmap.width) / 2 - weaponWidth / 2, y: 0),
+            at: Vector(x: Double(width) * (0.5 - range.lowerBound) - weaponWidth / 2, y: 0),
             size: Vector(x: weaponWidth, y: screenHeight)
         )