metal

问题 I tried: let scale = UIScreen.mainScreen().scale UIGraphicsBeginImageContextWithOptions(metalLayer.bounds.size,false,scale) // metalLayer.renderInContext(UIGraphicsGetCurrentContext()!) // self.view.layer ... metalLayer.presentationLayer()!.renderInContext(UIGraphicsGetCurrentContext()!) let image = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext(); UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil) But the result is a empty screenshot. Any help would be nice! Please

问题 What is the most efficient way to capture frames from a MTKView ? If possible, I would like to save a .mov file from the frames in realtime. Is it possible to render into an AVPlayer frame or something? It is currently drawing with this code (based on @warrenm PerformanceShaders project): func draw(in view: MTKView) { _ = inflightSemaphore.wait(timeout: DispatchTime.distantFuture) updateBuffers() let commandBuffer = commandQueue.makeCommandBuffer() commandBuffer.addCompletedHandler{ [weak

问题 I am creating UIImage from current drawable texture as follows. func createImageFromCurrentDrawable() ->(UIImage){ let context = CIContext() let texture = metalView.currentDrawable!.texture let kciOptions = [kCIContextWorkingColorSpace: CGColorSpace(name: CGColorSpace.sRGB)!, kCIContextOutputPremultiplied: true, kCIContextUseSoftwareRenderer: false] as [String : Any] let cImg = CIImage(mtlTexture: texture, options: kciOptions)! let cgImg = context.createCGImage(cImg, from: cImg.extent)! let

问题 I am trying to modify Apple's sample GLPaint (paint app using OpenGL) to use Metal instead of OpenGL. I am able to render a brush stroke to screen using Metal, but am having difficulties "erasing" it. In Metal, I am using the following blending parameters: renderPipelineDescriptor.colorAttachments[0].isBlendingEnabled = true renderPipelineDescriptor.colorAttachments[0].rgbBlendOperation = .add renderPipelineDescriptor.colorAttachments[0].alphaBlendOperation = .add renderPipelineDescriptor

问题 I am new to metal shading language.So your kind guidance would be so helpful. I just repeated texture using metal as shown on below image (Image sequence). But it seems not smoothy.How can I make it to be appeared as smoothy line as done in following link for metal points.(overlapping Metal Point primitives and blending) At the moment what I do is allocating memory for vertex buffer (MTLBuffer) at each touch point in my gesture. code: func allocateMemoryForVetexBuffer(vertices: Array<Vertex>)

问题 I have a supposedly simple task, but apparently I still don't understand how projections work in shaders. I need to do a 2D perspective transformation on a texture quad (2 triangles), but visually it doesn't look correct (e.g. trapezoid is slightly higher or more stretched than what it is in the CPU version). I have this struct: struct VertexInOut { float4 position [[position]]; float3 warp0; float3 warp1; float3 warp2; float3 warp3; }; And in the vertex shader I do something like ( texCoords

问题 I've got a question about constant buffers in Metal. Let's assume, that I've got something like: ...list of includes goes here... using namespace metal; struct ConstantBuffer { float ANY_VALUE; }; struct VS_INPUTS { float4 i_pos_ms [ [ attribute ( 0 ) ] ] ; } ; struct V2P_STRUCT { float4 v_pos_out [ [ position ] ] ; } ; float3 CalcSomething() { return float3(ANY_VALUE, ANY_VALUE, ANY_VALUE); // !!!!!!!! } vertex V2P_STRUCT VertexFunc(VS_INPUTS vs_inputs [ [ stage_in ] ] , constant

问题 I am passing a uniform buffer to both vertex and fragment shaders. let uniformBuffer = device.makeBuffer(length: 4096, options: []) renderEncoder.setVertexBuffer(uniformBuffer, offset: 0, at: 1) renderEncoder.setFragmentBuffer(uniformBuffer,offset:0, at: 1) Does this copy the uniformBuffer from CPU to GPU twice? Then I will instead pass the buffer from vertex shader to fragment shader which happens just inside the GPU. 回答1: There are no copies involved specifically with setVertexBuffer() or

问题 I'm reading a Metal tutorial on raywenderlich.com, where it introduces a pure Swift float4x4 helper class. 99% it's just wrapper around GLKit functions, except one function which really puzzles me: static func makePerspectiveViewAngle(_ fovyRadians: Float, aspectRatio: Float, nearZ: Float, farZ: Float) -> float4x4 { var q = unsafeBitCast(GLKMatrix4MakePerspective(fovyRadians, aspectRatio, nearZ, farZ), to: float4x4.self) let zs = farZ / (nearZ - farZ) q[2][2] = zs q[3][2] = zs * nearZ return

问题 Can I create a new MTLTexture of dimensions w2/h2 of an existing MTLTexture region x1/y1/w1/h1 ? PS: I thought about using MTLTexture.buffer?.makeTexture but the offset needs to be 64 bytes. Why? 回答1: Here's an example of how you might do this with MPSImageLanczosScale . Note that sourceRegion is expressed in the pixel coordinate system of the source texture, and destRegion should be equal to the full area of the destination texture (note that it specifically doesn't account for the origin of