[Renderer] Move OpenGLView to OpenGL directory

Renderer/OpenGL/OpenGLView.swift

@@ -0,0 +1,144 @@
+//
+//  OpenGLView.swift
+//  OpenGLRenderer
+//
+//  Created by Eryn Wells on 11/12/15.
+//  Copyright © 2015 Eryn Wells. All rights reserved.
+//
+
+import Foundation
+import Cocoa
+import OpenGL
+import CoreVideo
+
+public class OpenGLView: NSOpenGLView {
+    private var didSetupOpenGL = false
+    private var displayLink: CVDisplayLink? = nil
+
+    // TODO: Should this be weak?
+    public var renderer: FrameRenderer? = nil
+
+    deinit {
+        stopRenderingLoop()
+    }
+
+    override public func awakeFromNib() {
+        setupOpenGL()
+        startRenderingLoop()
+    }
+
+    override public func viewWillMoveToSuperview(newSuperview: NSView?) {
+        if newSuperview != nil {
+            setupOpenGL()
+            startRenderingLoop()
+        } else {
+            stopRenderingLoop()
+        }
+    }
+
+    private func setupOpenGL() {
+        guard !didSetupOpenGL else { return }
+        defer { didSetupOpenGL = true }
+
+        let attrs = [NSOpenGLPFAAccelerated,
+                     NSOpenGLPFADoubleBuffer,
+                     NSOpenGLPFADepthSize, 24,
+                     NSOpenGLPFAOpenGLProfile,
+                     NSOpenGLProfileVersion4_1Core]
+
+        let format = NSOpenGLPixelFormat(attributes: UnsafePointer<UInt32>(attrs))
+        guard format != nil else {
+            // TODO: Throw an error?
+            return
+        }
+        
+        let context = NSOpenGLContext(format: format!, shareContext: nil)
+        guard context != nil else {
+            // TODO: Throw an error?
+            return
+        }
+
+        CGLEnable(context!.CGLContextObj, kCGLCECrashOnRemovedFunctions)
+
+        pixelFormat = format
+        openGLContext = context
+        wantsBestResolutionOpenGLSurface = true
+    }
+
+    private func startRenderingLoop() {
+        var success = kCVReturnSuccess
+
+        success = CVDisplayLinkCreateWithActiveCGDisplays(&displayLink)
+        guard success == kCVReturnSuccess && displayLink != nil else {
+            // TODO: Throw an error?
+            return
+        }
+
+        let unsafeSelf = UnsafeMutablePointer<Void>(unsafeAddressOf(self))
+        success = CVDisplayLinkSetOutputCallback(displayLink!, displayLinkCallback, unsafeSelf)
+        guard success == kCVReturnSuccess else {
+            // TODO: Throw an error?
+            return
+        }
+
+        if let context = self.openGLContext?.CGLContextObj, format = self.pixelFormat?.CGLPixelFormatObj {
+            CVDisplayLinkSetCurrentCGDisplayFromOpenGLContext(displayLink!, context, format)
+        } else {
+            // TODO: Throw an error?
+            return
+        }
+
+        success = CVDisplayLinkStart(displayLink!)
+        guard success == kCVReturnSuccess else {
+            // TODO: Throw an error?
+            return
+        }
+    }
+
+    private func stopRenderingLoop() {
+        guard displayLink != nil else { return }
+        CVDisplayLinkStop(displayLink!)
+        displayLink = nil
+    }
+
+    private func renderAtTime(time: CVTimeStamp) -> CVReturn {
+        let context: NSOpenGLContext! = self.openGLContext
+
+        guard context != nil else {
+            // TODO: Throw an error? Log something?
+            return kCVReturnError
+        }
+        guard renderer != nil else {
+            // This is actually okay, we just don't render anything.
+            return kCVReturnSuccess
+        }
+
+        context.makeCurrentContext()
+        // TODO: OpenGLContext.clearCurrentContext()?
+
+        CGLLockContext(context.CGLContextObj)
+        defer { CGLUnlockContext(context.CGLContextObj) }
+
+        // Render the frame.
+        renderer!.renderAtTime(time)
+        context.flushBuffer()
+
+        return kCVReturnSuccess
+    }
+}
+
+private func displayLinkCallback(
+    displayLink: CVDisplayLink,
+    currentTime: UnsafePointer<CVTimeStamp>,
+    outputTime: UnsafePointer<CVTimeStamp>,
+    flags: CVOptionFlags,
+    flagsOut: UnsafeMutablePointer<CVOptionFlags>,
+    context: UnsafeMutablePointer<Void>) -> CVReturn
+{
+    var result = kCVReturnSuccess
+    autoreleasepool {
+        let glView = unsafeBitCast(context, OpenGLView.self)
+        result = glView.renderAtTime(currentTime.memory)
+    }
+    return result
+}