Rewrite in Swift

VisionCamera.podspec

@@ -20,7 +20,7 @@ Pod::Spec.new do |s|
   s.license      = package["license"]
   s.authors      = package["author"]
 
-  s.platforms    = { :ios => "12.4" }
+  s.platforms    = { :ios => "13.0" }
   s.source       = { :git => "https://github.com/mrousavy/react-native-vision-camera.git", :tag => "#{s.version}" }
 
   s.pod_target_xcconfig = {
@@ -53,7 +53,7 @@ Pod::Spec.new do |s|
 
     # Skia Frame Processors
     hasSkia ? "ios/Skia Render Layer/*.{m,mm,swift}" : "",
-    hasSkia ? "ios/Skia Render Layer/SkiaPreviewView.h" : "",
+    hasSkia ? "ios/Skia Render Layer/SkiaRenderer.h" : "",
   ]
   # Any private headers that are not globally unique should be mentioned here.
   # Otherwise there will be a nameclash, since CocoaPods flattens out any header directories

example/ios/Podfile.lock

@@ -713,7 +713,7 @@ SPEC CHECKSUMS:
   RNStaticSafeAreaInsets: 055ddbf5e476321720457cdaeec0ff2ba40ec1b8
   RNVectorIcons: fcc2f6cb32f5735b586e66d14103a74ce6ad61f8
   SocketRocket: f32cd54efbe0f095c4d7594881e52619cfe80b17
-  VisionCamera: f3cbd24bba0067a3dece6d88ac4b8b9d44787e87
+  VisionCamera: c935274ff3da0e443b4fcad23e349715c4416991
   Yoga: 65286bb6a07edce5e4fe8c90774da977ae8fc009
 
 PODFILE CHECKSUM: ab9c06b18c63e741c04349c0fd630c6d3145081c

ios/CameraQueues.swift

@@ -23,11 +23,18 @@ public class CameraQueues: NSObject {
                                                      attributes: [],
                                                      autoreleaseFrequency: .inherit,
                                                      target: nil)
-
+  
   /// The serial execution queue for output processing of audio buffers.
   @objc public static let audioQueue = DispatchQueue(label: "mrousavy/VisionCamera.audio",
                                                      qos: .userInteractive,
                                                      attributes: [],
                                                      autoreleaseFrequency: .inherit,
                                                      target: nil)
+
+  /// The serial execution queue for rendering the Skia preview.
+  @objc public static let previewQueue = DispatchQueue(label: "mrousavy/VisionCamera.preview",
+                                                       qos: .userInteractive,
+                                                       attributes: [],
+                                                       autoreleaseFrequency: .inherit,
+                                                       target: nil)
 }

ios/Skia Render Layer/SkiaFrameProcessor.h

@@ -10,18 +10,7 @@
 
 #import <Foundation/Foundation.h>
 #import "FrameProcessor.h"
-#import "SkiaMetalRenderContext.h"
-
-typedef void (^render_block_t)(const OffscreenRenderContext&);
 
 @interface SkiaFrameProcessor : FrameProcessor
 
-/**
- Render the latest Frame from the Camera.
- The callback (`render_block_t`) will be invoked with a read-access
- texture that can be used for rendering.
- */
-- (void)renderLatestFrame:(render_block_t _Nonnull)callback;
-- (bool)hasNewFrame;
-
 @end

ios/Skia Render Layer/SkiaFrameProcessor.mm

@@ -8,128 +8,24 @@
 
 #import <Foundation/Foundation.h>
 #import "SkiaFrameProcessor.h"
-#import <Metal/Metal.h>
+#import "SkiaRenderer.h"
 
-#import <include/core/SkSurface.h>
-#import <include/core/SkCanvas.h>
-#import <include/core/SkColorSpace.h>
-#import "SkImageHelpers.h"
-
-@implementation SkiaFrameProcessor {
-  // Metal/Skia Context
-  OffscreenRenderContext _offscreenContext;
-
-  // For synchronization between the two Threads/Contexts
-  std::mutex _textureMutex;
-  std::atomic<bool> _hasNewFrame;
-}
+@implementation SkiaFrameProcessor
 
 - (instancetype)init {
   if (self = [super init]) {
-    _offscreenContext = OffscreenRenderContext();
-    _hasNewFrame = false;
+    // TODO: init?
   }
   return self;
 }
 
-- (bool)hasNewFrame {
-  return _hasNewFrame;
-}
-
-- (void)renderLatestFrame:(render_block_t)callback {
-  // Lock the Mutex so we can operate on the Texture atomically without
-  // renderFrameToCanvas() overwriting in between from a different thread
-  std::unique_lock lock(_textureMutex);
-
-  // Call the callback
-  callback(_offscreenContext);
-
-  // Set flag back to false
-  _hasNewFrame = false;
-  lock.unlock();
-}
-
-- (id<MTLTexture>)getTexture:(NSUInteger)width height:(NSUInteger)height {
-  if (_offscreenContext.texture == nil
-      || _offscreenContext.texture.width != width
-      || _offscreenContext.texture.height != height) {
-    // Create new texture with the given width and height
-    MTLTextureDescriptor* textureDescriptor = [MTLTextureDescriptor texture2DDescriptorWithPixelFormat:MTLPixelFormatBGRA8Unorm
-                                                                                                 width:width
-                                                                                                height:height
-                                                                                             mipmapped:NO];
-    textureDescriptor.usage = MTLTextureUsageRenderTarget | MTLTextureUsageShaderRead;
-    _offscreenContext.texture = [_offscreenContext.device newTextureWithDescriptor:textureDescriptor];
-  }
-  return _offscreenContext.texture;
-}
-
 - (void)call:(Frame*)frame {
-  // Wrap in auto release pool since we want the system to clean up after rendering
-  // and not wait until later - we've seen some example of memory usage growing very
-  // fast in the simulator without this.
-  @autoreleasepool {
-    // Get the Frame's PixelBuffer
-    CVImageBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(frame.buffer);
-    if (pixelBuffer == nil) {
-      throw std::runtime_error("Frame Processor: Pixel Buffer is corrupt/empty.");
-    }
-
-    // Lock Mutex to block the runLoop from overwriting the _currentDrawable
-    std::unique_lock lock(_textureMutex);
-
-    // Get the Metal Texture we use for in-memory drawing
-    auto texture = [self getTexture:CVPixelBufferGetWidth(pixelBuffer)
-                             height:CVPixelBufferGetHeight(pixelBuffer)];
-
-    // Get & Lock the writeable Texture from the Metal Drawable
-    GrMtlTextureInfo textureInfo;
-    textureInfo.fTexture.retain((__bridge void*)texture);
-    GrBackendRenderTarget backendRenderTarget((int)texture.width,
-                                              (int)texture.height,
-                                              1,
-                                              textureInfo);
-
-    auto context = _offscreenContext.skiaContext.get();
-
-    // Create a Skia Surface from the writable Texture
-    auto surface = SkSurface::MakeFromBackendRenderTarget(context,
-                                                          backendRenderTarget,
-                                                          kTopLeft_GrSurfaceOrigin,
-                                                          kBGRA_8888_SkColorType,
-                                                          SkColorSpace::MakeSRGB(),
-                                                          nullptr);
-
-    if (surface == nullptr || surface->getCanvas() == nullptr) {
-      throw std::runtime_error("Skia surface could not be created from parameters.");
-    }
-
-    // Converts the CMSampleBuffer to an SkImage - RGB.
-    CVPixelBufferLockBaseAddress(pixelBuffer, kCVPixelBufferLock_ReadOnly);
-    auto image = SkImageHelpers::convertCMSampleBufferToSkImage(context, frame.buffer);
-
-    auto canvas = surface->getCanvas();
-
-    // Clear everything so we keep it at a clean state
-    canvas->clear(SkColors::kBlack);
-
-    // Draw the Image into the Frame (aspectRatio: cover)
-    // The Frame Processor might draw the Frame again (through render()) to pass a custom paint/shader,
-    // but that'll just overwrite the existing one - no need to worry.
-    canvas->drawImage(image, 0, 0);
-
-// TODO: How to pass SkCanvas here?
-    // Call the JS Frame Processor.
+  // TODO: Get SkiaRenderer somehow...
+  SkiaRenderer* renderer = nil;
+  [renderer renderCameraFrameToOffscreenCanvas:frame.buffer withDrawCallback:^(SkiaCanvas _Nonnull) {
+    // TODO: Pass SkiaCanvas along here...
     [super call:frame];
-
-    // Flush all appended operations on the canvas and commit it to the SkSurface
-    surface->flushAndSubmit();
-
-    _hasNewFrame = true;
-
-    lock.unlock();
-    CVPixelBufferUnlockBaseAddress(pixelBuffer, kCVPixelBufferLock_ReadOnly);
-  }
+  }];
 }
 
 @end