82 lines
3.6 KiB
Swift
82 lines
3.6 KiB
Swift
//
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// Terrain.swift
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// Terrain
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//
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// Created by Eryn Wells on 11/3/18.
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// Copyright © 2018 Eryn Wells. All rights reserved.
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//
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import Cocoa
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import MetalKit
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class Terrain: NSObject {
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/// Create 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.
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class func buildVertexDescriptor() -> MTLVertexDescriptor {
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let mtlVertexDescriptor = MTLVertexDescriptor()
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mtlVertexDescriptor.attributes[VertexAttribute.position.rawValue].format = MTLVertexFormat.float3
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mtlVertexDescriptor.attributes[VertexAttribute.position.rawValue].offset = 0
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mtlVertexDescriptor.attributes[VertexAttribute.position.rawValue].bufferIndex = BufferIndex.meshPositions.rawValue
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mtlVertexDescriptor.attributes[VertexAttribute.texcoord.rawValue].format = MTLVertexFormat.float2
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mtlVertexDescriptor.attributes[VertexAttribute.texcoord.rawValue].offset = 0
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mtlVertexDescriptor.attributes[VertexAttribute.texcoord.rawValue].bufferIndex = BufferIndex.meshGenerics.rawValue
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mtlVertexDescriptor.layouts[BufferIndex.meshPositions.rawValue].stride = 12
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mtlVertexDescriptor.layouts[BufferIndex.meshPositions.rawValue].stepRate = 1
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mtlVertexDescriptor.layouts[BufferIndex.meshPositions.rawValue].stepFunction = MTLVertexStepFunction.perVertex
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mtlVertexDescriptor.layouts[BufferIndex.meshGenerics.rawValue].stride = 8
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mtlVertexDescriptor.layouts[BufferIndex.meshGenerics.rawValue].stepRate = 1
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mtlVertexDescriptor.layouts[BufferIndex.meshGenerics.rawValue].stepFunction = MTLVertexStepFunction.perVertex
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return mtlVertexDescriptor
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}
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/// Create and condition mesh data to feed into a pipeline using the given vertex descriptor.
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/// @param dimensions Coordinate dimensions of the plane
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/// @param segments Number of segments to divide each dimension into
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/// @param device Metal device
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/// @param vertexDescriptor Description of how to lay out vertex data in GPU memory
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class func buildMesh(withDimensions dimensions: float2, segments: uint2, device: MTLDevice, vertexDescriptor: MTLVertexDescriptor) throws -> MTKMesh {
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let metalAllocator = MTKMeshBufferAllocator(device: device)
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let plane = MDLMesh.newPlane(withDimensions: dimensions,
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segments: segments,
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geometryType: .triangles,
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allocator: metalAllocator)
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let mdlVertexDescriptor = MTKModelIOVertexDescriptorFromMetal(vertexDescriptor)
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guard let attributes = mdlVertexDescriptor.attributes as? [MDLVertexAttribute] else {
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throw RendererError.badVertexDescriptor
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}
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attributes[VertexAttribute.position.rawValue].name = MDLVertexAttributePosition
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attributes[VertexAttribute.texcoord.rawValue].name = MDLVertexAttributeTextureCoordinate
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plane.vertexDescriptor = mdlVertexDescriptor
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return try MTKMesh(mesh:plane, device:device)
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}
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let dimensions: float2
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let segments: uint2
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let vertexDescriptor: MTLVertexDescriptor
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let mesh: MTKMesh
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init?(dimensions dim: float2, segments seg: uint2, device: MTLDevice) {
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dimensions = dim
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segments = seg
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vertexDescriptor = Terrain.buildVertexDescriptor()
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do {
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mesh = try Terrain.buildMesh(withDimensions: dimensions, segments: segments, device: device, vertexDescriptor: vertexDescriptor)
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} catch let e {
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print("Couldn't create mesh. Error: \(e)")
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return nil
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}
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super.init()
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}
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}
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