我正在尝试学习如何在Metal IOS中实现模板缓冲区。目前，未开启Metal验证时运行良好。但是一旦开启Metal验证，项目就会崩溃。
这是我的代码：- Metal视图：
import MetalKit
class DrawingView: MTKView {
//Renderer to handle all the rendering of the Drawing View
public var renderer: Renderer!
override init(frame frameRect: CGRect, device: MTLDevice?) {
super.init(frame: frameRect, device: device)
self.configDrawingView()
}
required init(coder: NSCoder) {
super.init(coder: coder)
self.configDrawingView()
}
private func configDrawingView() {
//Setting system default GPU
self.device = MTLCreateSystemDefaultDevice()
//Setting pixel format for the view
self.colorPixelFormat = MTLPixelFormat.bgra8Unorm
//Setting clear color of the view. View will be cleared in every frame
self.clearColor = MTLClearColorMake(1.0, 1.0, 1.0, 1.0)
//Setting sample count of drawing textures
self.sampleCount = 1
//Setting prefered frame rate
self.preferredFramesPerSecond = 120
//Setting auto resizing of the drawable to false. If the value is true, the currentDrawable object’s texture, depthStencilTexture object, and multisampleColorTexture object automatically resize as the view resizes. If the value is false, drawableSize does not change and neither does the size of these objects.
self.autoResizeDrawable = false
//Stencil
self.clearStencil = 0
self.depthStencilPixelFormat = MTLPixelFormat.depth32Float_stencil8
//Setting up Renderer
self.renderer = Renderer(withDevice: self.device!)
//Using renderer and the MTKView delegate. This will call draw method every frame
self.delegate = renderer
}
}
渲染器：-
import MetalKit
class Renderer: NSObject {
//Device
private var device: MTLDevice!
//CommandQueue
private var commandQueue: MTLCommandQueue!
//Mirror Vertex
private var paintData: [Vertex] = [
Vertex(position: float4(-0.75, -0.75, 0, 1), color: float4(1.0, 1.0, 0.0, 1.0)),
Vertex(position: float4(-0.75, 0.75, 0, 1), color: float4(1.0, 1.0, 0.0, 1.0)),
Vertex(position: float4(0.75, 0.75, 0, 1), color: float4(1.0, 1.0, 0.0, 1.0)),
Vertex(position: float4(0.75, -0.75, 0, 1), color: float4(1.0, 1.0, 0.0, 1.0))
]
//Mirror Indices
private var paintIndicies: [UInt32] = [0, 1, 2, 0, 2, 3]
//Mirror Vertex Buffer
private var paintVertexBuffer: MTLBuffer!
//Mirror Index Buffer
private var paintIndexBuffer: MTLBuffer!
//Paint Vertex
private var stencilData: [Vertex] = [
Vertex(position: float4(-1, 0, 0, 1), color: float4(0.0, 0.0, 1.0, 1.0)),
Vertex(position: float4(0, 1, 0, 1), color: float4(0.0, 0.0, 1.0, 1.0)),
Vertex(position: float4(0, -1, 0, 1), color: float4(0.0, 0.0, 1.0, 1.0)),
Vertex(position: float4(1, 0, 0, 1), color: float4(0.0, 0.0, 1.0, 1.0))
]
//Paint indices
private var stencilIndices: [UInt32] = [0, 1, 2, 2, 1, 3]
//Paint Vertex Buffer
private var stencilVertexBuffer: MTLBuffer!
//Paint Index Buffer
private var stencilIndexBuffer: MTLBuffer!
//Depth Stencil State
private var depthStencilState: MTLDepthStencilState!
private var maskStencilState: MTLDepthStencilState!
private var drawStencilState: MTLDepthStencilState!
private var library: MTLLibrary!
private var vertexFunction: MTLFunction!
private var fragmentFunction: MTLFunction!
private var stencilFragmentFunction: MTLFunction!
private var pipelineState: MTLRenderPipelineState!
private var stencilPipelineState: MTLRenderPipelineState!
init(withDevice device: MTLDevice) {
super.init()
self.device = device
self.configure()
}
private func configure() {
self.commandQueue = self.device.makeCommandQueue()
self.setupPipelines()
self.setupDepthStencil()
self.setupBuffers()
}
private func setupDepthStencil() {
var depthStencilStateDescriptor: MTLDepthStencilDescriptor = MTLDepthStencilDescriptor()
depthStencilStateDescriptor.depthCompareFunction = MTLCompareFunction.less
depthStencilStateDescriptor.isDepthWriteEnabled = true
self.depthStencilState = self.device.makeDepthStencilState(descriptor: depthStencilStateDescriptor)
depthStencilStateDescriptor = MTLDepthStencilDescriptor()
depthStencilStateDescriptor.depthCompareFunction = MTLCompareFunction.less
var stencilDescriptor: MTLStencilDescriptor = MTLStencilDescriptor()
stencilDescriptor.stencilCompareFunction = MTLCompareFunction.always
stencilDescriptor.depthStencilPassOperation = MTLStencilOperation.replace
depthStencilStateDescriptor.backFaceStencil = stencilDescriptor
depthStencilStateDescriptor.frontFaceStencil = stencilDescriptor
depthStencilStateDescriptor.isDepthWriteEnabled = false
self.drawStencilState = self.device.makeDepthStencilState(descriptor: depthStencilStateDescriptor)
depthStencilStateDescriptor = MTLDepthStencilDescriptor()
depthStencilStateDescriptor.depthCompareFunction = MTLCompareFunction.less
stencilDescriptor = MTLStencilDescriptor()
stencilDescriptor.stencilCompareFunction = MTLCompareFunction.equal
depthStencilStateDescriptor.frontFaceStencil = stencilDescriptor
depthStencilStateDescriptor.backFaceStencil = stencilDescriptor
depthStencilStateDescriptor.isDepthWriteEnabled = true
self.maskStencilState = self.device.makeDepthStencilState(descriptor: depthStencilStateDescriptor)
}
private func setupPipelines() {
self.library = self.device.makeDefaultLibrary()
self.vertexFunction = self.library.makeFunction(name: "vertexShader")
self.fragmentFunction = self.library.makeFunction(name: "fragmentShader")
self.stencilFragmentFunction = self.library.makeFunction(name: "stencilFragmentShader")
var renderPipelineDescriptor: MTLRenderPipelineDescriptor = MTLRenderPipelineDescriptor()
renderPipelineDescriptor.vertexFunction = self.vertexFunction
renderPipelineDescriptor.fragmentFunction = self.fragmentFunction
renderPipelineDescriptor.colorAttachments[0].pixelFormat = MTLPixelFormat.bgra8Unorm
renderPipelineDescriptor.depthAttachmentPixelFormat = MTLPixelFormat.depth32Float_stencil8
renderPipelineDescriptor.stencilAttachmentPixelFormat = MTLPixelFormat.depth32Float_stencil8
do {
self.pipelineState = try self.device.makeRenderPipelineState(descriptor: renderPipelineDescriptor)
} catch {
print("\(error)")
}
var renderPipelineDescriptorNoDraw: MTLRenderPipelineDescriptor = MTLRenderPipelineDescriptor()
renderPipelineDescriptorNoDraw.vertexFunction = self.vertexFunction
renderPipelineDescriptorNoDraw.fragmentFunction = self.stencilFragmentFunction
renderPipelineDescriptorNoDraw.depthAttachmentPixelFormat = MTLPixelFormat.depth32Float_stencil8
renderPipelineDescriptorNoDraw.stencilAttachmentPixelFormat = MTLPixelFormat.depth32Float_stencil8
renderPipelineDescriptorNoDraw.colorAttachments[0].pixelFormat = MTLPixelFormat.bgra8Unorm //Problem Here ---- (1)
renderPipelineDescriptorNoDraw.colorAttachments[0].writeMask = []
do {
self.stencilPipelineState = try self.device.makeRenderPipelineState(descriptor: renderPipelineDescriptorNoDraw)
} catch {
print("\(error)")
}
}
private func setupBuffers() {
self.stencilVertexBuffer = self.device.makeBuffer(bytes: self.stencilData, length: MemoryLayout<Vertex>.stride * self.stencilData.count, options: [])
self.stencilIndexBuffer = self.device.makeBuffer(bytes: self.stencilIndices, length: MemoryLayout<UInt32>.size * self.stencilIndices.count, options: [])
self.paintVertexBuffer = self.device.makeBuffer(bytes: self.paintData, length: MemoryLayout<Vertex>.stride * self.paintData.count, options: [])
self.paintIndexBuffer = self.device.makeBuffer(bytes: self.paintIndicies, length: MemoryLayout<UInt32>.size * self.paintIndicies.count, options: [])
}
}
extension Renderer: MTKViewDelegate {
func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) {
}
func draw(in view: MTKView) {
let buffer: MTLCommandBuffer = self.commandQueue.makeCommandBuffer()!
let renderPassDescriptor = view.currentRenderPassDescriptor
renderPassDescriptor!.colorAttachments[0].clearColor = MTLClearColorMake(1.0, 1.0, 1.0, 1.0)
let encoderClear = buffer.makeRenderCommandEncoder(descriptor: renderPassDescriptor!)
encoderClear!.endEncoding()
let renderPassDescriptorOther = MTLRenderPassDescriptor()
renderPassDescriptorOther.colorAttachments[0].loadAction = MTLLoadAction.load
renderPassDescriptorOther.colorAttachments[0].storeAction = MTLStoreAction.store
renderPassDescriptorOther.colorAttachments[0].texture = view.currentDrawable?.texture
let commandEncoderOther = buffer.makeRenderCommandEncoder(descriptor: renderPassDescriptorOther)
Plane(withDevice: self.device, sizeOf: float2(100, 100), andPlaneCenterTo: float2(100, 100), withColor: float4(1.0, 0.0, 0.0, 1.0)).render(commandEncoder: commandEncoderOther!)
commandEncoderOther?.endEncoding()
let renderPassDescriptorOther1 = MTLRenderPassDescriptor()
renderPassDescriptorOther1.colorAttachments[0].loadAction = MTLLoadAction.load
renderPassDescriptorOther1.colorAttachments[0].storeAction = MTLStoreAction.store
renderPassDescriptorOther1.colorAttachments[0].texture = view.currentDrawable?.texture
let encoder: MTLRenderCommandEncoder = buffer.makeRenderCommandEncoder(descriptor: renderPassDescriptorOther1)!
//Stencil
encoder.setRenderPipelineState(self.stencilPipelineState)
encoder.setStencilReferenceValue(1)
encoder.setDepthStencilState(self.drawStencilState)
encoder.setVertexBuffer(self.stencilVertexBuffer, offset: 0, index: 0)
encoder.drawIndexedPrimitives(type: MTLPrimitiveType.triangle, indexCount: self.stencilIndices.count, indexType: MTLIndexType.uint32, indexBuffer: self.stencilIndexBuffer, indexBufferOffset: 0)
//Paint
encoder.setRenderPipelineState(self.pipelineState)
encoder.setDepthStencilState(self.maskStencilState)
encoder.setVertexBuffer(self.paintVertexBuffer, offset: 0, index: 0)
encoder.drawIndexedPrimitives(type: MTLPrimitiveType.triangle, indexCount: self.paintIndicies.count, indexType: MTLIndexType.uint32, indexBuffer: self.paintIndexBuffer, indexBufferOffset: 0)
encoder.endEncoding()
buffer.present(view.currentDrawable!)
buffer.commit()
}
}
这是我的着色器文件：
#include <metal_stdlib>
using namespace metal;
struct Vertex {
float4 position [[position]];
float4 color;
};
vertex Vertex vertexShader(const device Vertex *vertexArray [[buffer(0)]], unsigned int vid [[vertex_id]]) {
return vertexArray[vid];
}
fragment float4 fragmentShader(Vertex interpolated [[stage_in]]) {
return interpolated.color;
}
fragment float4 fragmentShader_stencil(Vertex v [[stage_in]])
{
return float4(1, 1, 1, 0.0);
}
当我开启Metal验证时，会出现以下错误：
[MTLDebugRenderCommandEncoder validateFramebufferWithRenderPipelineState:]:1236:
failed assertion `For depth attachment, the renderPipelineState pixelFormat
must be MTLPixelFormatInvalid, as no texture is set.'
然后我在 Renderer 中更改了 (1) 像素格式为 MTLPixelFormat.invalid，但是它给我另一个错误：-
[MTLDebugRenderCommandEncoder validateFramebufferWithRenderPipelineState:]:1196:
failed assertion `For color attachment 0, the render pipeline's pixelFormat
(MTLPixelFormatInvalid) does not match the framebuffer's pixelFormat
(MTLPixelFormatBGRA8Unorm).'
有办法修复这个问题吗？我想启用Metal验证，禁用验证时它可以正常工作。