我是新来的金属和我很困惑...金属中的二次渲染 - 这很容易吗?
我有一组顶点,我从主纹理“平铺”出来。我正在使用顶点着色器和片段采样着色器来执行此操作。
我想叠加第一个绘图通过一个额外的绘图通过使用不同的纹理。我开始强调必须进行加载/存储操作等。唉,没有 - 下面是我在Swift渲染循环中所做的。我应该说覆盖层中的绘图数量不到第一遍中绘制的数量的5%。
This Works。 这真的很简单吗?
我只是有这种唠叨的感觉,我失去了一些东西。另一方面,我可能错误地认为在渲染循环中只有一次机会,例如设置渲染编码器的顶点缓冲区。
let renderEncoder : MTLRenderCommandEncoder = (commandBuffer?.makeRenderCommandEncoder(descriptor: renderPassDescriptor!))!
renderEncoder.label = "MyRenderEncoder"
renderEncoder.setViewport(MTLViewport.init(originX: 0.0, originY: 0.0, width: Double(self.drawableSize.width), height: Double(self.drawableSize.height), znear: -1.0, zfar: 1.0))
renderEncoder.setRenderPipelineState(self.pipelineState)
// draw main content
let vertices = ...
let vCount = vertices?.count
let vSize = vCount!*MemoryLayout.size(ofValue: vertices?[0])
let mBuff = self.device!.makeBuffer(bytes: vertices!, length: vSize, options: [])
renderEncoder.setVertexBuffer(mBuff, offset: 0, at: 0)
renderEncoder.setVertexBytes(&self.viewportSize, length: MemoryLayout.size(ofValue: self.viewportSize), at: 1)
renderEncoder.setFragmentTexture(inputTexture, at: 0)
renderEncoder.drawPrimitives(type: MTLPrimitiveType.triangle, vertexStart: 0, vertexCount: vCount!)
// draw overlaying content
let vertices2 = ...
let vCount2 = vertices2?.count
let vSize2 = vCount2!*MemoryLayout.size(ofValue: vertices2?[0])
let mBuff2 = self.device!.makeBuffer(bytes: vertices2!, length: vSize2, options: [])
renderEncoder.setVertexBuffer(mBuff2, offset: 0, at: 0)
renderEncoder.setVertexBytes(&self.viewportSize, length: MemoryLayout.size(ofValue: self.viewportSize), at: 1)
renderEncoder.setFragmentTexture(inputTexture2, at: 0)
renderEncoder.drawPrimitives(type: MTLPrimitiveType.triangle, vertexStart: 0, vertexCount: vCount2!)
// done drawing
renderEncoder.endEncoding()
commandBuffer?.present(view.currentDrawable!)
commandBuffer?.commit()