Extract Terrain into its own class

Terrain.xcodeproj/project.pbxproj

@@ -23,6 +23,7 @@
 		C0C15AB9218E2A90007494E2 /* Shaders.metal in Sources */ = {isa = PBXBuildFile; fileRef = C0C15AB8218E2A90007494E2 /* Shaders.metal */; };
 		C0C15ABC218E2A90007494E2 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = C0C15ABB218E2A90007494E2 /* Assets.xcassets */; };
 		C0C15ABF218E2A90007494E2 /* Main.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = C0C15ABD218E2A90007494E2 /* Main.storyboard */; };
+		C0C15AC6218E32B3007494E2 /* Terrain.swift in Sources */ = {isa = PBXBuildFile; fileRef = C0C15AC5218E32B2007494E2 /* Terrain.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -49,6 +50,7 @@
 		C0C15ABE218E2A90007494E2 /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/Main.storyboard; sourceTree = "<group>"; };
 		C0C15AC0218E2A90007494E2 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		C0C15AC1218E2A90007494E2 /* Terrain2.entitlements */ = {isa = PBXFileReference; lastKnownFileType = text.plist.entitlements; path = Terrain2.entitlements; sourceTree = "<group>"; };
+		C0C15AC5218E32B2007494E2 /* Terrain.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Terrain.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -122,6 +124,7 @@
 				C0C15AB2218E2A90007494E2 /* AppDelegate.swift */,
 				C0C15AB4218E2A90007494E2 /* GameViewController.swift */,
 				C0C15AB6218E2A90007494E2 /* Renderer.swift */,
+				C0C15AC5218E32B2007494E2 /* Terrain.swift */,
 				C0C15AB8218E2A90007494E2 /* Shaders.metal */,
 				C0C15ABA218E2A90007494E2 /* ShaderTypes.h */,
 				C0C15ABB218E2A90007494E2 /* Assets.xcassets */,
@@ -247,6 +250,7 @@
 			files = (
 				C0C15AB9218E2A90007494E2 /* Shaders.metal in Sources */,
 				C0C15AB5218E2A90007494E2 /* GameViewController.swift in Sources */,
+				C0C15AC6218E32B3007494E2 /* Terrain.swift in Sources */,
 				C0C15AB7218E2A90007494E2 /* Renderer.swift in Sources */,
 				C0C15AB3218E2A90007494E2 /* AppDelegate.swift in Sources */,
 			);

Terrain2/Renderer.swift

@@ -42,7 +42,7 @@ class Renderer: NSObject, MTKViewDelegate {
 
     var rotation: Float = 0
 
-    var mesh: MTKMesh
+    var terrain: Terrain
 
     init?(metalKitView: MTKView) {
         self.device = metalKitView.device!
@@ -61,12 +61,12 @@ class Renderer: NSObject, MTKViewDelegate {
         metalKitView.colorPixelFormat = MTLPixelFormat.bgra8Unorm_srgb
         metalKitView.sampleCount = 1
 
-        let mtlVertexDescriptor = Renderer.buildMetalVertexDescriptor()
+        terrain = Terrain(dimensions: float2(8, 8), segments: uint2(20, 20), device: device)!
 
         do {
             pipelineState = try Renderer.buildRenderPipelineWithDevice(device: device,
                                                                        metalKitView: metalKitView,
-                                                                       mtlVertexDescriptor: mtlVertexDescriptor)
+                                                                       mtlVertexDescriptor: terrain.vertexDescriptor)
         } catch {
             print("Unable to compile render pipeline state.  Error info: \(error)")
             return nil
@@ -77,13 +77,6 @@ class Renderer: NSObject, MTKViewDelegate {
         depthStateDesciptor.isDepthWriteEnabled = true
         self.depthState = device.makeDepthStencilState(descriptor:depthStateDesciptor)!
 
-        do {
-            mesh = try Renderer.buildMesh(device: device, mtlVertexDescriptor: mtlVertexDescriptor)
-        } catch {
-            print("Unable to build MetalKit Mesh. Error info: \(error)")
-            return nil
-        }
-
         do {
             colorMap = try Renderer.loadTexture(device: device, textureName: "ColorMap")
         } catch {
@@ -95,31 +88,6 @@ class Renderer: NSObject, MTKViewDelegate {
 
     }
 
-    class func buildMetalVertexDescriptor() -> MTLVertexDescriptor {
-        // Creete a Metal vertex descriptor specifying how vertices will by laid out for input into our render
-        //   pipeline and how we'll layout our Model IO vertices
-
-        let mtlVertexDescriptor = MTLVertexDescriptor()
-
-        mtlVertexDescriptor.attributes[VertexAttribute.position.rawValue].format = MTLVertexFormat.float3
-        mtlVertexDescriptor.attributes[VertexAttribute.position.rawValue].offset = 0
-        mtlVertexDescriptor.attributes[VertexAttribute.position.rawValue].bufferIndex = BufferIndex.meshPositions.rawValue
-
-        mtlVertexDescriptor.attributes[VertexAttribute.texcoord.rawValue].format = MTLVertexFormat.float2
-        mtlVertexDescriptor.attributes[VertexAttribute.texcoord.rawValue].offset = 0
-        mtlVertexDescriptor.attributes[VertexAttribute.texcoord.rawValue].bufferIndex = BufferIndex.meshGenerics.rawValue
-
-        mtlVertexDescriptor.layouts[BufferIndex.meshPositions.rawValue].stride = 12
-        mtlVertexDescriptor.layouts[BufferIndex.meshPositions.rawValue].stepRate = 1
-        mtlVertexDescriptor.layouts[BufferIndex.meshPositions.rawValue].stepFunction = MTLVertexStepFunction.perVertex
-
-        mtlVertexDescriptor.layouts[BufferIndex.meshGenerics.rawValue].stride = 8
-        mtlVertexDescriptor.layouts[BufferIndex.meshGenerics.rawValue].stepRate = 1
-        mtlVertexDescriptor.layouts[BufferIndex.meshGenerics.rawValue].stepFunction = MTLVertexStepFunction.perVertex
-
-        return mtlVertexDescriptor
-    }
-
     class func buildRenderPipelineWithDevice(device: MTLDevice,
                                              metalKitView: MTKView,
                                              mtlVertexDescriptor: MTLVertexDescriptor) throws -> MTLRenderPipelineState {
@@ -144,30 +112,6 @@ class Renderer: NSObject, MTKViewDelegate {
         return try device.makeRenderPipelineState(descriptor: pipelineDescriptor)
     }
 
-    class func buildMesh(device: MTLDevice,
-                         mtlVertexDescriptor: MTLVertexDescriptor) throws -> MTKMesh {
-        /// Create and condition mesh data to feed into a pipeline using the given vertex descriptor
-
-        let metalAllocator = MTKMeshBufferAllocator(device: device)
-
-        let plane = MDLMesh.newPlane(withDimensions: float2(6, 6),
-                                     segments: uint2(20, 20),
-                                     geometryType: .triangles,
-                                     allocator: metalAllocator)
-
-        let mdlVertexDescriptor = MTKModelIOVertexDescriptorFromMetal(mtlVertexDescriptor)
-
-        guard let attributes = mdlVertexDescriptor.attributes as? [MDLVertexAttribute] else {
-            throw RendererError.badVertexDescriptor
-        }
-        attributes[VertexAttribute.position.rawValue].name = MDLVertexAttributePosition
-        attributes[VertexAttribute.texcoord.rawValue].name = MDLVertexAttributeTextureCoordinate
-
-        plane.vertexDescriptor = mdlVertexDescriptor
-
-        return try MTKMesh(mesh:plane, device:device)
-    }
-
     class func loadTexture(device: MTLDevice,
                            textureName: String) throws -> MTLTexture {
         /// Load texture data with optimal parameters for sampling
@@ -248,20 +192,20 @@ class Renderer: NSObject, MTKViewDelegate {
                     renderEncoder.setVertexBuffer(dynamicUniformBuffer, offset:uniformBufferOffset, index: BufferIndex.uniforms.rawValue)
                     renderEncoder.setFragmentBuffer(dynamicUniformBuffer, offset:uniformBufferOffset, index: BufferIndex.uniforms.rawValue)
                     
-                    for (index, element) in mesh.vertexDescriptor.layouts.enumerated() {
+                    for (index, element) in terrain.mesh.vertexDescriptor.layouts.enumerated() {
                         guard let layout = element as? MDLVertexBufferLayout else {
                             return
                         }
                         
                         if layout.stride != 0 {
-                            let buffer = mesh.vertexBuffers[index]
+                            let buffer = terrain.mesh.vertexBuffers[index]
                             renderEncoder.setVertexBuffer(buffer.buffer, offset:buffer.offset, index: index)
                         }
                     }
                     
                     renderEncoder.setFragmentTexture(colorMap, index: TextureIndex.color.rawValue)
                     
-                    for submesh in mesh.submeshes {
+                    for submesh in terrain.mesh.submeshes {
                         renderEncoder.drawIndexedPrimitives(type: submesh.primitiveType,
                                                             indexCount: submesh.indexCount,
                                                             indexType: submesh.indexType,

Terrain2/Terrain.swift

@@ -0,0 +1,79 @@
+//
+//  Terrain.swift
+//  Terrain
+//
+//  Created by Eryn Wells on 11/3/18.
+//  Copyright © 2018 Eryn Wells. All rights reserved.
+//
+
+import Cocoa
+import MetalKit
+
+class Terrain: NSObject {
+
+    /// Creete a Metal vertex descriptor specifying how vertices will by laid out for input into our render pipeline and how we'll layout our Model IO vertices.
+    class func buildVertexDescriptor() -> MTLVertexDescriptor {
+        let mtlVertexDescriptor = MTLVertexDescriptor()
+
+        mtlVertexDescriptor.attributes[VertexAttribute.position.rawValue].format = MTLVertexFormat.float3
+        mtlVertexDescriptor.attributes[VertexAttribute.position.rawValue].offset = 0
+        mtlVertexDescriptor.attributes[VertexAttribute.position.rawValue].bufferIndex = BufferIndex.meshPositions.rawValue
+
+        mtlVertexDescriptor.attributes[VertexAttribute.texcoord.rawValue].format = MTLVertexFormat.float2
+        mtlVertexDescriptor.attributes[VertexAttribute.texcoord.rawValue].offset = 0
+        mtlVertexDescriptor.attributes[VertexAttribute.texcoord.rawValue].bufferIndex = BufferIndex.meshGenerics.rawValue
+
+        mtlVertexDescriptor.layouts[BufferIndex.meshPositions.rawValue].stride = 12
+        mtlVertexDescriptor.layouts[BufferIndex.meshPositions.rawValue].stepRate = 1
+        mtlVertexDescriptor.layouts[BufferIndex.meshPositions.rawValue].stepFunction = MTLVertexStepFunction.perVertex
+
+        mtlVertexDescriptor.layouts[BufferIndex.meshGenerics.rawValue].stride = 8
+        mtlVertexDescriptor.layouts[BufferIndex.meshGenerics.rawValue].stepRate = 1
+        mtlVertexDescriptor.layouts[BufferIndex.meshGenerics.rawValue].stepFunction = MTLVertexStepFunction.perVertex
+
+        return mtlVertexDescriptor
+    }
+
+    /// Create and condition mesh data to feed into a pipeline using the given vertex descriptor.
+    class func buildMesh(withDimensions dimensions: float2, segments: uint2, device: MTLDevice, vertexDescriptor: MTLVertexDescriptor) throws -> MTKMesh {
+        let metalAllocator = MTKMeshBufferAllocator(device: device)
+
+        let plane = MDLMesh.newPlane(withDimensions: dimensions,
+                                     segments: segments,
+                                     geometryType: .triangles,
+                                     allocator: metalAllocator)
+
+        let mdlVertexDescriptor = MTKModelIOVertexDescriptorFromMetal(vertexDescriptor)
+
+        guard let attributes = mdlVertexDescriptor.attributes as? [MDLVertexAttribute] else {
+            throw RendererError.badVertexDescriptor
+        }
+        attributes[VertexAttribute.position.rawValue].name = MDLVertexAttributePosition
+        attributes[VertexAttribute.texcoord.rawValue].name = MDLVertexAttributeTextureCoordinate
+
+        plane.vertexDescriptor = mdlVertexDescriptor
+
+        return try MTKMesh(mesh:plane, device:device)
+    }
+
+    let dimensions: float2
+    let segments: uint2
+
+    let vertexDescriptor: MTLVertexDescriptor
+    let mesh: MTKMesh
+
+    init?(dimensions dim: float2, segments seg: uint2, device: MTLDevice) {
+        dimensions = dim
+        segments = seg
+        vertexDescriptor = Terrain.buildVertexDescriptor()
+
+        do {
+            mesh = try Terrain.buildMesh(withDimensions: dimensions, segments: segments, device: device, vertexDescriptor: vertexDescriptor)
+        } catch let e {
+            print("Couldn't create mesh. Error: \(e)")
+            return nil
+        }
+
+        super.init()
+    }
+}