Fix improper use of unsafe pointers

Many, many thanks to TylerTheCompiler at SO!

Foil/FoilViewController.swift

@@ -52,7 +52,7 @@ class FoilViewController: NSViewController {
 
     // Command queue used when simulation and renderer are using the same device.
     // Set to nil when using different devices
-    var commandQueue: MTLCommandQueue!
+    var viewControllerCommandQueue: MTLCommandQueue!
 
     // When true, stop running any more simulations (such as when the window closes).
     var terminateAllSimulations = false
@@ -111,6 +111,8 @@ class FoilViewController: NSViewController {
         renderer = FoilRenderer(self, rendererDevice)
 
         NSLog("New render device: \"\(rendererDevice.name)\"")
+
+        renderer.drawableSizeWillChange()
     }
 
     func beginSimulation() {
@@ -123,7 +125,7 @@ class FoilViewController: NSViewController {
 
         renderer.setRenderScale(renderScale: config.renderScale)
 
-        commandQueue = renderer.device.makeCommandQueue()
+        viewControllerCommandQueue = renderer.device.makeCommandQueue()
 
         NSLog("Starting Simulation Config: \(configNum)")
     }
@@ -184,8 +186,8 @@ class FoilViewController: NSViewController {
 
         // If the simulation and device are using the same device _commandQueue will be set
         // Create a command buffer to both execute a simulation frame and render an update
-        guard let commandQueue = self.commandQueue,
-              let simulate_render_commandBuffer = commandQueue.makeCommandBuffer()
+        guard let vcCommandQueue = self.viewControllerCommandQueue,
+              let simulate_render_commandBuffer = vcCommandQueue.makeCommandBuffer()
             else { fatalError() }
 
         simulate_render_commandBuffer.label = "simulate_render_commandBuffer"

Renderer/FoilRenderer.swift

@@ -59,11 +59,7 @@ class FoilRenderer: NSObject, MTKViewDelegate {
         updateProjectionMatrix()
     }
 
-    /// Update the projection matrix with a new drawable size
-    func drawableSizeWillChange(size: CGSize) {
-        print("dswc(CGSize)")
-        updateProjectionMatrix()
-    }
+    func drawableSizeWillChange() { updateProjectionMatrix() }
 
     /// Draw particles at the supplied positions using the given command buffer to the given view
     func draw(
@@ -201,7 +197,7 @@ class FoilRenderer: NSObject, MTKViewDelegate {
         pipelineDescriptor.colorAttachments[0].isBlendingEnabled = true
         pipelineDescriptor.colorAttachments[0].pixelFormat = view.colorPixelFormat
         pipelineDescriptor.colorAttachments[0].rgbBlendOperation = MTLBlendOperation.add
-        pipelineDescriptor.colorAttachments[0].sourceAlphaBlendFactor  = MTLBlendFactor.sourceAlpha
+        pipelineDescriptor.colorAttachments[0].sourceAlphaBlendFactor = MTLBlendFactor.sourceAlpha
         pipelineDescriptor.colorAttachments[0].sourceRGBBlendFactor = MTLBlendFactor.sourceAlpha
 
         guard let rp = try? device.makeRenderPipelineState(descriptor: pipelineDescriptor)
@@ -229,10 +225,12 @@ class FoilRenderer: NSObject, MTKViewDelegate {
     /// Update any render state (including updating dynamically changing Metal buffers)
     func updateState() {
         let uniforms = dynamicUniformBuffer.contents()
-        var u = uniforms.assumingMemoryBound(to: FoilUniforms.self).pointee
 
-        u.pointSize = FoilRenderer.bodyPointSize
-        u.mvpMatrix = projectionMatrix
+        let u = FoilUniforms(
+            mvpMatrix: projectionMatrix, pointSize: FoilRenderer.bodyPointSize
+        )
+
+        uniforms.assumingMemoryBound(to: FoilUniforms.self).pointee = u
     }
 
     func providePositionData(data: NSData) {
@@ -289,16 +287,23 @@ class FoilRenderer: NSObject, MTKViewDelegate {
     func updateProjectionMatrix() {
         // React to resize of the draw rect.  In particular update the perspective matrix.
         // Update the aspect ratio and projection matrix since the view orientation or size has changed
-        let aspect: Float = Float(view.drawableSize.height) / Float(view.drawableSize.width)
-        let left: Float   = renderScale
-        let right: Float  = -renderScale
-        let bottom: Float = renderScale * aspect
-        let top: Float    = -renderScale * aspect
-        let near: Float   = 5000
-        let far: Float    = -5000
-
-        projectionMatrix = FoilMath.matrixOrthoLeftHand(
-            left: left, right: right, bottom: bottom, top: top, nearZ: near, farZ: far
+//        let aspect: Float = Float(view.drawableSize.height) / Float(view.drawableSize.width)
+//        let left: Float   = renderScale
+//        let right: Float  = -renderScale
+//        let bottom: Float = renderScale * aspect
+//        let top: Float    = -renderScale * aspect
+//        let near: Float   = 5000
+//        let far: Float    = -5000
+//
+//        projectionMatrix = FoilMath.matrixOrthoLeftHand(
+//            left: left, right: right, bottom: bottom, top: top, nearZ: near, farZ: far
+//        )
+
+        projectionMatrix = FoilMath.matriMakeRows(
+            1, 0, 0, 0,
+            0, 1, 0, 0,
+            0, 0, 1, 0,
+            0, 0, 0, 1
         )
     }
 }

Renderer/FoilShaders.metal

@@ -35,7 +35,7 @@ vertex ColorInOut vertexShader(uint                    vertexID  [[ vertex_id ]]
     out.color = half4(color[vertexID]) / 255.0h;
 
     out.pointSize = half(uniforms.pointSize);
-
+    assert(false);
     return out;
 }
 

Simulation/FoilSimulation.swift

@@ -183,11 +183,12 @@ class FoilSimulation {
 
         let c_ = UnsafeMutableRawPointer(mutating: sp.contents())
 
-        var c = c_.assumingMemoryBound(to: FoilSimParams.self).pointee
-        c.timestep = config.simInterval
-        c.damping = config.damping
-        c.softeningSqr = config.softeningSqr
-        c.numBodies = UInt32(config.numBodies)
+        let c = FoilSimParams(timestep: config.simInterval,
+                              damping: config.damping,
+                              softeningSqr: config.softeningSqr,
+                              numBodies: UInt32(config.numBodies))
+
+        c_.assumingMemoryBound(to: FoilSimParams.self).pointee = c
 
         simulationParams.didModifyRange(0..<sp.length)
 
@@ -252,9 +253,12 @@ class FoilSimulation {
             let position = nrpos * (inner + (length * rpos))
 
             var p = positions[i]
-            p.x = position.x; p.y = position.x; p.z = position.z
+
+            p.x = position.x; p.y = position.y; p.z = position.z
             p.w = 1
 
+            positions[i] = p
+
             var axis = vector_float3(0.0, 0.0, 1.0)
             let scalar = simd_dot(nrpos, axis)
 
@@ -271,6 +275,8 @@ class FoilSimulation {
             v.x = velocity.x * vscale
             v.y = velocity.y * vscale
             v.z = velocity.z * vscale
+
+            velocities[i] = v
         }
 
         let fullPRange = 0..<self.positions[oldBufferIndex].length