Add native osx backend v1 (with bitmap support)

rendercanvas/MetalIOSurfaceHelper.m

@@ -0,0 +1,90 @@
+/*
+
+clang -dynamiclib -fobjc-arc \
+  -framework Foundation -framework Metal -framework IOSurface \
+  -arch x86_64 -arch arm64 \
+  -mmacosx-version-min=10.13 \
+  -o libMetalIOSurfaceHelper.dylib MetalIOSurfaceHelper.m
+
+  maybe add '-framework MetalKit' too
+
+*/
+#import <Foundation/Foundation.h>
+#import <Metal/Metal.h>
+#import <IOSurface/IOSurface.h>
+
+@interface MetalIOSurfaceHelper : NSObject
+@property (nonatomic, readonly) id<MTLDevice> device;
+@property (nonatomic, readonly) id<MTLTexture> texture;
+
+- (instancetype)initWithWidth:(NSUInteger)width
+                       height:(NSUInteger)height;
+
+- (void *)baseAddress;
+- (NSUInteger)bytesPerRow;
+@end
+
+
+@implementation MetalIOSurfaceHelper {
+    IOSurfaceRef _surf;
+}
+
+- (instancetype)initWithWidth:(NSUInteger)width
+                       height:(NSUInteger)height
+{
+    if ((self = [super init])) {
+        // Create Metal device
+        _device = MTLCreateSystemDefaultDevice();
+        if (!_device) {
+            NSLog(@"❌ Failed to create Metal device");
+            return nil;
+        }
+
+        // Create IOSurface properties
+        NSDictionary *props = @{
+            (id)kIOSurfaceWidth: @(width),
+            (id)kIOSurfaceHeight: @(height),
+            (id)kIOSurfaceBytesPerElement: @(4),
+            (id)kIOSurfacePixelFormat: @(0x42475241) // 'BGRA'
+        };
+
+        _surf = IOSurfaceCreate((__bridge CFDictionaryRef)props);
+        if (!_surf) {
+            NSLog(@"❌ Failed to create IOSurface");
+            return nil;
+        }
+
+        // Create texture from IOSurface
+        MTLTextureDescriptor *desc =
+            [MTLTextureDescriptor texture2DDescriptorWithPixelFormat:MTLPixelFormatBGRA8Unorm
+                                                                width:width
+                                                               height:height
+                                                            mipmapped:NO];
+        desc.storageMode = MTLStorageModeShared;
+
+        _texture = [_device newTextureWithDescriptor:desc iosurface:_surf plane:0];
+        if (!_texture) {
+            NSLog(@"❌ Failed to create MTLTexture from IOSurface");
+            CFRelease(_surf);
+            return nil;
+        }
+    }
+    return self;
+}
+
+- (void *)baseAddress {
+    return IOSurfaceGetBaseAddress(_surf);
+}
+
+- (NSUInteger)bytesPerRow {
+    return IOSurfaceGetBytesPerRow(_surf);
+}
+
+- (void)dealloc {
+    if (_surf) {
+        CFRelease(_surf);
+        _surf = NULL;
+    }
+}
+
+@end