IOS AR获得背景图

以你之姓@ 2022-06-01 13:55 112阅读 0赞

在ARSCNView中，有ARSession，在代码中增加ARSessionDelegate。代码如下：

- (void)session:(ARSession *)session didUpdateFrame:(ARFrame *)frame
    {
    
        CVPixelBufferRef pixelBuffer = frame.capturedImage;
        self.cubeTexture=[self textureCubeWithImage:[self uiImageFromPixelBuffer:pixelBuffer width:512 height:512] device:self.device]; 
    }

CVPixelBufferRef转成UIImage：

- (UIImage*)uiImageFromPixelBuffer:(CVPixelBufferRef)p width:(CGFloat)width height:(CGFloat)height {
        CIImage* ciImage = [CIImage imageWithCVPixelBuffer:p];
        
        CIContext* context = [CIContext contextWithOptions:@{kCIContextUseSoftwareRenderer : @(YES)}];
        
    //    CGRect rect = CGRectMake(0, 0, CVPixelBufferGetWidth(p), CVPixelBufferGetHeight(p));
       // NSLog(@"width%zu",CVPixelBufferGetWidth(p));1280
        //NSLog(@"height%zu",CVPixelBufferGetHeight(p));720
        CGRect rect = CGRectMake(0, 0, width, height);
        CGImageRef videoImage = [context createCGImage:ciImage fromRect:rect];
        
        UIImage* image = [UIImage imageWithCGImage:videoImage];
        CGImageRelease(videoImage);
        
        return image;
    }

另外两个方法：

- (id<MTLTexture>)textureCubeWithImage:(UIImage *)image device:(id<MTLDevice>)device
    {
        
        const CGFloat cubeSize = image.size.width * image.scale;
        
        const NSUInteger bytesPerPixel = 4;
        const NSUInteger bytesPerRow = bytesPerPixel * cubeSize;
        const NSUInteger bytesPerImage = bytesPerRow * cubeSize;
        
        MTLRegion region = MTLRegionMake2D(0, 0, cubeSize, cubeSize);
        
        MTLTextureDescriptor *textureDescriptor = [MTLTextureDescriptor textureCubeDescriptorWithPixelFormat:MTLPixelFormatRGBA8Unorm
                                                                                                        size:cubeSize
                                                                                                   mipmapped:NO];
        
        id<MTLTexture> texture = [device newTextureWithDescriptor:textureDescriptor];
         uint8_t *imageData = [self dataForImage:image];
        
        for (size_t slice = 0; slice < 6; ++slice)
        {
            NSAssert(image.size.width == cubeSize && image.size.height == cubeSize, @"Cube map images must be square and uniformly-sized");
            [texture replaceRegion:region
                       mipmapLevel:0
                             slice:slice
                         withBytes:imageData
                       bytesPerRow:bytesPerRow
                     bytesPerImage:bytesPerImage];
        }
         free(imageData);
        
        return texture;
    }

- (uint8_t *)dataForImage:(UIImage *)image
    {
        CGImageRef imageRef = [image CGImage];
        
        // Create a suitable bitmap context for extracting the bits of the image
        const NSUInteger width = CGImageGetWidth(imageRef);
        const NSUInteger height = CGImageGetHeight(imageRef);
        CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
        uint8_t *rawData = (uint8_t *)calloc(height * width * 4, sizeof(uint8_t));
        const NSUInteger bytesPerPixel = 4;
        const NSUInteger bytesPerRow = bytesPerPixel * width;
        const NSUInteger bitsPerComponent = 8;
        CGContextRef context = CGBitmapContextCreate(rawData, width, height,
                                                     bitsPerComponent, bytesPerRow, colorSpace,
                                                     kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
        CGColorSpaceRelease(colorSpace);
        
        CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);
        CGContextRelease(context);
        
        return rawData;
    }