[WIP] Story collage

submodules/TelegramUI/Components/CameraScreen/Sources/CameraVideoSource.swift

@@ -0,0 +1,82 @@
+import AVFoundation
+import Metal
+import CoreVideo
+import Display
+import SwiftSignalKit
+import Camera
+import MetalEngine
+
+final class CameraVideoSource: VideoSource {
+    private var device: MTLDevice
+    private var textureCache: CVMetalTextureCache?
+        
+    private(set) var cameraVideoOutput: CameraVideoOutput!
+    
+    public private(set) var currentOutput: Output?
+    private var onUpdatedListeners = Bag<() -> Void>()
+        
+    public var sourceId: Int = 0
+    public var sizeMultiplicator: CGPoint = CGPoint(x: 1.0, y: 1.0)
+    
+    public init?() {
+        self.device = MetalEngine.shared.device
+                
+        self.cameraVideoOutput = CameraVideoOutput(sink: { [weak self] buffer in
+            self?.push(buffer)
+        })
+
+        CVMetalTextureCacheCreate(nil, nil, self.device, nil, &self.textureCache)
+    }
+    
+    public func addOnUpdated(_ f: @escaping () -> Void) -> Disposable {
+        let index = self.onUpdatedListeners.add(f)
+        
+        return ActionDisposable { [weak self] in
+            DispatchQueue.main.async {
+                guard let self else {
+                    return
+                }
+                self.onUpdatedListeners.remove(index)
+            }
+        }
+    }
+    
+    private func push(_ sampleBuffer: CMSampleBuffer) {
+        guard let buffer = CMSampleBufferGetImageBuffer(sampleBuffer) else {
+            return
+        }
+                  
+        let width = CVPixelBufferGetWidth(buffer)
+        let height = CVPixelBufferGetHeight(buffer)
+        
+        var cvMetalTextureY: CVMetalTexture?
+        var status = CVMetalTextureCacheCreateTextureFromImage(nil, self.textureCache!, buffer, nil, .r8Unorm, width, height, 0, &cvMetalTextureY)
+        guard status == kCVReturnSuccess, let yTexture = CVMetalTextureGetTexture(cvMetalTextureY!) else {
+            return
+        }
+        var cvMetalTextureUV: CVMetalTexture?
+        status = CVMetalTextureCacheCreateTextureFromImage(nil, self.textureCache!, buffer, nil, .rg8Unorm, width / 2, height / 2, 1, &cvMetalTextureUV)
+        guard status == kCVReturnSuccess, let uvTexture = CVMetalTextureGetTexture(cvMetalTextureUV!) else {
+            return
+        }
+
+        var resolution = CGSize(width: CGFloat(yTexture.width), height: CGFloat(yTexture.height))
+        resolution.width = floor(resolution.width * self.sizeMultiplicator.x)
+        resolution.height = floor(resolution.height * self.sizeMultiplicator.y)
+        
+        self.currentOutput = Output(
+            resolution: resolution,
+            textureLayout: .biPlanar(Output.BiPlanarTextureLayout(
+                y: yTexture,
+                uv: uvTexture
+            )),
+            dataBuffer: Output.NativeDataBuffer(pixelBuffer: buffer),
+            mirrorDirection: [],
+            sourceId: self.sourceId
+        )
+        
+        for onUpdated in self.onUpdatedListeners.copyItems() {
+            onUpdated()
+        }
+    }
+}