Add a CG render context to the iOS runtime

Diffs=
42f393436 Add a CG render context to the iOS runtime (#5998)

Co-authored-by: Chris Dalton <[email protected]>

.rive_head

@@ -1 +1 @@
-2c2ea44922f91b784ec16549ce1cda0346438fd0
+42f39343647f68371989628c3c24da8f2ba31171

.rive_renderer

@@ -1 +1 @@
-4bc1e5c1d5af8327b4d5afc8f53afd6d0a7a7d45
+01aa67c9996f1fa96ac8091040dfc91d432192e9

RiveRuntime.xcodeproj/project.pbxproj

@@ -51,6 +51,7 @@
 		83DE4CA02AAA072B00B88B72 /* PlatformCGImage.mm in Sources */ = {isa = PBXBuildFile; fileRef = 83DE4C9F2AAA072B00B88B72 /* PlatformCGImage.mm */; };
 		83DE4CA22AAA077200B88B72 /* PlatformCGImage.h in Headers */ = {isa = PBXBuildFile; fileRef = 83DE4CA12AAA077200B88B72 /* PlatformCGImage.h */; };
 		83DE4CA72AAAE72100B88B72 /* RenderContext.hh in Headers */ = {isa = PBXBuildFile; fileRef = 83DE4CA62AAAE72000B88B72 /* RenderContext.hh */; };
+		83DE4CBA2AB4B26D00B88B72 /* AutoCF.h in Headers */ = {isa = PBXBuildFile; fileRef = 83DE4CB92AB4B26D00B88B72 /* AutoCF.h */; };
 		C34609FC27FF9114002DBCB7 /* RiveFile+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = C34609FB27FF9114002DBCB7 /* RiveFile+Extensions.swift */; };
 		C3468E5827EB9887008652FD /* RiveView.swift in Sources */ = {isa = PBXBuildFile; fileRef = C3468E5727EB9887008652FD /* RiveView.swift */; };
 		C3468E5A27ECC7C6008652FD /* RiveViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = C3468E5927ECC7C6008652FD /* RiveViewModel.swift */; };
@@ -130,6 +131,7 @@
 		83DE4C9F2AAA072B00B88B72 /* PlatformCGImage.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = PlatformCGImage.mm; sourceTree = "<group>"; };
 		83DE4CA12AAA077200B88B72 /* PlatformCGImage.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = PlatformCGImage.h; sourceTree = "<group>"; };
 		83DE4CA62AAAE72000B88B72 /* RenderContext.hh */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = RenderContext.hh; sourceTree = "<group>"; };
+		83DE4CB92AB4B26D00B88B72 /* AutoCF.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = AutoCF.h; sourceTree = "<group>"; };
 		C34609FB27FF9114002DBCB7 /* RiveFile+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "RiveFile+Extensions.swift"; sourceTree = "<group>"; };
 		C3468E5727EB9887008652FD /* RiveView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RiveView.swift; sourceTree = "<group>"; };
 		C3468E5927ECC7C6008652FD /* RiveViewModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RiveViewModel.swift; sourceTree = "<group>"; };
@@ -178,6 +180,7 @@
 		046FB801264EB632000129B1 /* include */ = {
 			isa = PBXGroup;
 			children = (
+				83DE4CB92AB4B26D00B88B72 /* AutoCF.h */,
 				83DE4CA12AAA077200B88B72 /* PlatformCGImage.h */,
 				C9C741F224FC510200EF9516 /* Rive.h */,
 				046FB7E7264EAA5F000129B1 /* RiveFile.h */,
@@ -248,7 +251,6 @@
 				E57798A52A72C9C500FF25C3 /* RiveTextValueRun.mm */,
 				04BE5431264D243D00427B39 /* LayerState.mm */,
 				83DE4C902AA8DD7B00B88B72 /* RenderContextManager.mm */,
-				274175FC286DB9CE000A60D1 /* cg_skia_factory.cpp */,
 				E5964A972A9697B600140479 /* RiveEvent.mm */,
 			);
 			path = Renderer;
@@ -321,6 +323,7 @@
 			isa = PBXHeadersBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				83DE4CBA2AB4B26D00B88B72 /* AutoCF.h in Headers */,
 				046FB7F7264EAA60000129B1 /* RiveFile.h in Headers */,
 				046FB7FC264EAA61000129B1 /* RiveArtboard.h in Headers */,
 				2A7079352726277C00C035A1 /* rive_renderer_view.hh in Headers */,

Source/Renderer/PlatformCGImage.mm

@@ -3,33 +3,9 @@
  */
 
 #import <PlatformCGImage.h>
+#import <AutoCF.h>
 #include "rive/core/type_conversions.hpp"
 
-#if defined(RIVE_BUILD_FOR_OSX)
-#include <ApplicationServices/ApplicationServices.h>
-#elif defined(RIVE_BUILD_FOR_IOS)
-#include <CoreGraphics/CoreGraphics.h>
-#include <ImageIO/ImageIO.h>
-#endif
-
-// Helper that remembers to call CFRelease when an object goes out of scope.
-template <typename T> class AutoCF
-{
-    T m_Obj;
-
-public:
-    AutoCF(T obj) : m_Obj(obj) {}
-    ~AutoCF()
-    {
-        if (m_Obj)
-            CFRelease(m_Obj);
-    }
-
-    operator T() const { return m_Obj; }
-    operator bool() const { return m_Obj != nullptr; }
-    T get() const { return m_Obj; }
-};
-
 bool PlatformCGImageDecode(const uint8_t* encodedBytes,
                            size_t encodedSizeInBytes,
                            PlatformCGImage* platformImage)

Source/Renderer/RenderContextManager.mm

@@ -5,6 +5,7 @@
 #import <RenderContextManager.h>
 #import <RenderContext.hh>
 
+#import <AutoCF.h>
 #import <PlatformCGImage.h>
 
 @implementation RenderContext
@@ -32,6 +33,8 @@ - (void)endFrame
 #include "include/gpu/mtl/GrMtlBackendContext.h"
 #include "skia_renderer.hpp"
 #include "skia_factory.hpp"
+#include "cg_factory.hpp"
+#include "cg_renderer.hpp"
 
 @interface SkiaContext : RenderContext
 - (rive::Factory*)factory;
@@ -95,8 +98,8 @@ - (instancetype)init
             return pixels;
         }
     };
-    static CGSkiaFactory gFactory;
-    return &gFactory;
+    static CGSkiaFactory factory;
+    return &factory;
 }
 
 static sk_sp<SkSurface> mtk_view_to_sk_surface(MTKView* mtkView, GrDirectContext* grContext)
@@ -250,6 +253,16 @@ - (void)dealloc
         return nullptr;
     }
 
+    switch (view.colorPixelFormat)
+    {
+        case MTLPixelFormatBGRA8Unorm:
+        case MTLPixelFormatRGBA8Unorm:
+            break;
+        default:
+            NSLog(@"error: unsupported colorPixelFormat on MTKView");
+            return nullptr;
+    }
+
     if (_renderTarget == nullptr || _renderTarget->width() != view.drawableSize.width ||
         _renderTarget->height() != view.drawableSize.height)
     {
@@ -274,12 +287,130 @@ - (void)endFrame
 
 #endif // !defined(RIVE_NO_PLS)
 
+@interface CGRendererContext : RenderContext
+- (rive::Renderer*)beginFrame:(MTKView*)view;
+- (void)endFrame;
+@end
+
+constexpr static int kBufferRingSize = 3;
+
+@implementation CGRendererContext
+{
+    id<MTLTexture> _renderTargetTexture;
+    id<MTLBuffer> _buffers[kBufferRingSize];
+    int _currentBufferIdx;
+    AutoCF<CGContextRef> _cgContext;
+    std::unique_ptr<rive::CGRenderer> _renderer;
+}
+
+- (instancetype)init
+{
+    self = [super init];
+
+    _renderTargetTexture = nil;
+    for (int i = 0; i < kBufferRingSize; ++i)
+    {
+        _buffers[i] = nil;
+    }
+    _currentBufferIdx = -1;
+
+    self.metalDevice = MTLCreateSystemDefaultDevice();
+    if (!self.metalDevice)
+    {
+        NSLog(@"Metal is not supported on this device");
+        return nil;
+    }
+    self.metalQueue = [self.metalDevice newCommandQueue];
+    self.depthStencilPixelFormat = MTLPixelFormatInvalid;
+    self.framebufferOnly = NO;
+    return self;
+}
+
+- (rive::Factory*)factory
+{
+    static rive::CGFactory factory;
+    return &factory;
+}
+
+- (rive::Renderer*)beginFrame:(MTKView*)view
+{
+    uint32_t cgBitmapInfo;
+    switch (view.colorPixelFormat)
+    {
+        case MTLPixelFormatBGRA8Unorm:
+            cgBitmapInfo = kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst;
+            break;
+        case MTLPixelFormatRGBA8Unorm:
+            cgBitmapInfo = kCGBitmapByteOrder32Big | kCGImageAlphaPremultipliedLast;
+            break;
+        default:
+            NSLog(@"error: unsupported colorPixelFormat on MTKView");
+            return nullptr;
+    }
+
+    id<CAMetalDrawable> surface = view.currentDrawable;
+    _renderTargetTexture = surface.texture;
+    if (!_renderTargetTexture)
+    {
+        NSLog(@"error: no surface texture on MTKView");
+        return nullptr;
+    }
+
+    _currentBufferIdx = (_currentBufferIdx + 1) % kBufferRingSize;
+    size_t bufferSize = _renderTargetTexture.height * _renderTargetTexture.width * 4;
+    if (_buffers[_currentBufferIdx] == nil ||
+        _buffers[_currentBufferIdx].allocatedSize != bufferSize)
+    {
+        _buffers[_currentBufferIdx] =
+            [self.metalDevice newBufferWithLength:bufferSize options:MTLResourceStorageModeShared];
+    }
+    AutoCF<CGColorSpaceRef> colorSpace = CGColorSpaceCreateDeviceRGB();
+    _cgContext.adopt(CGBitmapContextCreate(_buffers[_currentBufferIdx].contents,
+                                           _renderTargetTexture.width,
+                                           _renderTargetTexture.height,
+                                           8,
+                                           _renderTargetTexture.width * 4,
+                                           colorSpace,
+                                           cgBitmapInfo));
+
+    _renderer = std::make_unique<rive::CGRenderer>(
+        _cgContext, _renderTargetTexture.width, _renderTargetTexture.height);
+    return _renderer.get();
+}
+
+- (void)endFrame
+{
+    if (_cgContext != nil)
+    {
+        id<MTLCommandBuffer> commandBuffer = [self.metalQueue commandBuffer];
+        id<MTLBlitCommandEncoder> blitEncoder = [commandBuffer blitCommandEncoder];
+        [blitEncoder copyFromBuffer:_buffers[_currentBufferIdx]
+                       sourceOffset:0
+                  sourceBytesPerRow:_renderTargetTexture.width * 4
+                sourceBytesPerImage:_renderTargetTexture.height * _renderTargetTexture.width * 4
+                         sourceSize:MTLSizeMake(
+                                        _renderTargetTexture.width, _renderTargetTexture.height, 1)
+                          toTexture:_renderTargetTexture
+                   destinationSlice:0
+                   destinationLevel:0
+                  destinationOrigin:MTLOriginMake(0, 0, 0)];
+        [blitEncoder endEncoding];
+        [commandBuffer commit];
+    }
+    _renderTargetTexture = nil;
+    _renderer = nullptr;
+    _cgContext.adopt(nullptr);
+}
+
+@end
+
 @implementation RenderContextManager
 {
     __weak SkiaContext* _skiaContextWeakPtr;
 #if !defined(RIVE_NO_PLS)
     __weak RiveRendererContext* _riveRendererContextWeakPtr;
 #endif
+    __weak CGRendererContext* _cgContextWeakPtr;
 }
 
 // The context manager is a singleton.
@@ -301,8 +432,15 @@ - (instancetype)init
 
 - (RenderContext*)getDefaultContext
 {
-    return self.defaultRenderer == RendererType::skiaRenderer ? [self getSkiaContext]
-                                                              : [self getRiveRendererContext];
+    switch (self.defaultRenderer)
+    {
+        case RendererType::skiaRenderer:
+            return [self getSkiaContext];
+        case RendererType::riveRenderer:
+            return [self getRiveRendererContext];
+        case RendererType::cgRenderer:
+            return [self getCGRendererContext];
+    }
 }
 
 - (RenderContext*)getSkiaContext
@@ -341,4 +479,18 @@ - (RenderContext*)getRiveRendererContext
 #endif
 }
 
+- (RenderContext*)getCGRendererContext
+{
+    // Convert our weak reference to strong before trying to work with it. A weak pointer is liable
+    // to be released out from under us at any moment.
+    // https://stackoverflow.com/questions/15674320/understanding-weak-reference
+    CGRendererContext* strongPtr = _cgContextWeakPtr;
+    if (strongPtr == nil)
+    {
+        strongPtr = [[CGRendererContext alloc] init];
+        _cgContextWeakPtr = strongPtr;
+    }
+    return strongPtr;
+}
+
 @end

Source/Renderer/include/AutoCF.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2023 Rive
+ */
+
+#pragma once
+
+#include <TargetConditionals.h>
+
+#if TARGET_OS_IPHONE
+#include <CoreGraphics/CoreGraphics.h>
+#include <ImageIO/ImageIO.h>
+#elif TARGET_OS_MAC
+#include <ApplicationServices/ApplicationServices.h>
+#endif
+
+// Helper that remembers to call CFRelease when an object goes out of scope.
+template <typename T> class AutoCF
+{
+public:
+    AutoCF() = default;
+    AutoCF(T obj) : m_Obj(obj) {}
+    AutoCF(const AutoCF&) = delete;
+    AutoCF& operator=(const AutoCF&) = delete;
+    ~AutoCF() { adopt(nullptr); }
+
+    void adopt(T obj)
+    {
+        if (m_Obj)
+            CFRelease(m_Obj);
+        m_Obj = obj;
+    }
+
+    operator T() const { return m_Obj; }
+    operator bool() const { return m_Obj != nullptr; }
+    T get() const { return m_Obj; }
+
+private:
+    T m_Obj = nullptr;
+};

Source/Renderer/include/RenderContextManager.h

@@ -6,7 +6,7 @@
 
 #import <Foundation/Foundation.h>
 
-typedef NS_ENUM(NSInteger, RendererType) { skiaRenderer, riveRenderer };
+typedef NS_ENUM(NSInteger, RendererType) { skiaRenderer, riveRenderer, cgRenderer };
 
 @class RenderContext;
 
@@ -19,4 +19,5 @@ typedef NS_ENUM(NSInteger, RendererType) { skiaRenderer, riveRenderer };
 - (RenderContext*)getDefaultContext;
 - (RenderContext*)getSkiaContext;
 - (RenderContext*)getRiveRendererContext;
+- (RenderContext*)getCGRendererContext;
 @end

Source/Renderer/rive_renderer_view.mm

@@ -93,11 +93,14 @@ - (void)drawRect:(CGRect)rect
     }
 
     _renderer = [_renderContext beginFrame:self];
-    _renderer->save();
-    [self drawRive:rect size:self.drawableSize];
-    _renderer->restore();
+    if (_renderer != nil)
+    {
+        _renderer->save();
+        [self drawRive:rect size:self.drawableSize];
+        _renderer->restore();
+    }
     [_renderContext endFrame];
-    _renderer = nullptr;
+    _renderer = nil;
 
     id<MTLCommandBuffer> commandBuffer = [_renderContext.metalQueue commandBuffer];
     [commandBuffer presentDrawable:[self currentDrawable]];