GPUImageMovieWriter更改过滤器设置。何时以及如何？

Question

我无法弄清楚当我开始使用GPUImageMovieWriter录制时会发生什么。虽然它只是预览一切正常，但是当我按下录制按钮时，我的过滤器会崩溃。我无法找到GPUImageMovieWriter如何更改我的过滤器，帮助我。

我的开始记录操作：

- (void)cameraButton:(id)sender
{
    // Recording.
    NSString *pathToMovie = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/Movie.m4v"];
    unlink([pathToMovie UTF8String]);
    NSURL *movieURL = [NSURL fileURLWithPath:pathToMovie];
    self.movieWriter = [[GPUImageMovieWriter alloc] initWithMovieURL:movieURL size:CGSizeMake(1080.0, 1920.0)];
    self.movieWriter.encodingLiveVideo = YES;
    self.movieWriter.shouldPassthroughAudio = YES;
    [self.blendFilter addTarget:self.movieWriter];
    self.videoCamera.audioEncodingTarget = self.movieWriter;
    // Start recording.
    [self.movieWriter startRecording];
    double delayInSeconds = 10.0;
    dispatch_time_t stopTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
    dispatch_after(stopTime, dispatch_get_main_queue(), ^(void){
        [self.blendFilter removeTarget:self.movieWriter];
        self.videoCamera.audioEncodingTarget = nil;
        [self.movieWriter finishRecording];
        UISaveVideoAtPathToSavedPhotosAlbum(pathToMovie, nil, NULL, NULL);
        NSLog(@"Movie completed");

    });
}

我的滤镜按形状裁剪输入图像，均匀采样2D形状。

我的过滤器代码：

#import "GPUImageShapeCropFilter.h"

NSString *const kGPUImageShapeCropShaderString = SHADER_STRING
(
 varying highp vec2 textureCoordinate;

 uniform sampler2D inputImageTexture;

 uniform highp float aspectRatio;
 uniform highp vec2 center;
 uniform highp float radius;
 uniform highp float scale;

 uniform sampler2D shape;

 void main()
 {
     highp vec2 textureCoordinateToUse = vec2(textureCoordinate.x, (textureCoordinate.y * aspectRatio + 0.5 - 0.5 * aspectRatio));
     lowp vec4 shapeColor = texture2D(shape, textureCoordinateToUse);
     textureCoordinateToUse = textureCoordinate;

     textureCoordinateToUse -= center;
     textureCoordinateToUse = textureCoordinateToUse * scale;
     textureCoordinateToUse += center;

     if (shapeColor.w > 0.0) {
         lowp vec4 textureColor = texture2D(inputImageTexture, textureCoordinateToUse);
         textureColor.w = shapeColor.w;
         gl_FragColor = textureColor;
     } else {
         gl_FragColor = shapeColor;
     }
 }
);


@interface GPUImageShapeCropFilter ()
{
    GLint _aspectRatioUniform;
    GLint _radiusUniform;
    GLint _centerUniform;
    GLint _scaleUniform;
    GLuint _oldTextureIndex;
}
- (void)adjustAspectRatio;

@property (readwrite, nonatomic) CGFloat aspectRatio;

@end

@implementation GPUImageShapeCropFilter

@synthesize aspectRatio = _aspectRatio;
@synthesize center = _center;
@synthesize radius = _radius;
@synthesize scale = _scale;

#pragma mark -
#pragma mark Initialization and teardown

- (id)init
{
    self = [super initWithFragmentShaderFromString:kGPUImageShapeCropShaderString];
    if (!self) {
        return nil;
    }

    // Get uniforms.
    _aspectRatioUniform = [filterProgram uniformIndex: @"aspectRatio"];
    _radiusUniform = [filterProgram uniformIndex: @"radius"];
    _scaleUniform = [filterProgram uniformIndex: @"scale"];
    _centerUniform = [filterProgram uniformIndex: @"center"];

    // Set default values.
    self.scale = 0.5;
    self.center = CGPointMake(0.5, 0.5);
    [self setShape:[UIImage imageNamed:@"circle"]];

    return self;
}

- (void)setShape:(UIImage *)shape
{
    [self setTexture:shape forUniform:@"shape"];
}

- (void)setTexture:(UIImage *)image forUniform:(NSString *)uniform
{
    // Find texture size.
    CGSize sizeOfImage = [image size];
    CGFloat scaleOfImage = [image scale];
    CGSize pixelSizeOfImage = CGSizeMake(scaleOfImage * sizeOfImage.width, scaleOfImage * sizeOfImage.height);

    // Create context.
    GLubyte * spriteData = (GLubyte *)malloc(pixelSizeOfImage.width * pixelSizeOfImage.height * 4 * sizeof(GLubyte));
    CGContextRef spriteContext = CGBitmapContextCreate(spriteData, pixelSizeOfImage.width, pixelSizeOfImage.height, 8, pixelSizeOfImage.width * 4, CGImageGetColorSpace(image.CGImage), (CGBitmapInfo)kCGImageAlphaPremultipliedLast);

    // Draw image into context.
    CGContextDrawImage(spriteContext, CGRectMake(0.0, 0.0, pixelSizeOfImage.width, pixelSizeOfImage.height), image.CGImage);

    // Get uniform of texture
    GLuint uniformIndex = [filterProgram uniformIndex:uniform];

    // Generate texture.
    GLuint textureIndex;
    glGenTextures(1, &textureIndex);
    glBindTexture(GL_TEXTURE_2D, textureIndex);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    // Create texture.
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, pixelSizeOfImage.width, pixelSizeOfImage.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, spriteData);

    glActiveTexture(GL_TEXTURE1);
    glBindTexture(GL_TEXTURE_2D, textureIndex);
    // "Send" to shader.
    glUniform1i(uniformIndex, 1);

    // Remove old texture if it is.
    if (_oldTextureIndex) {
        glDeleteTextures(1, &_oldTextureIndex);
    }
    _oldTextureIndex = textureIndex;

    free(spriteData);
    CGContextRelease(spriteContext);
}

#pragma mark -
#pragma mark Accessors

- (void)adjustAspectRatio;
{
    if (GPUImageRotationSwapsWidthAndHeight(inputRotation)) {
        [self setAspectRatio:inputTextureSize.width / inputTextureSize.height];
    } else {
        [self setAspectRatio:inputTextureSize.height / inputTextureSize.width];
    }
}

- (void)forceProcessingAtSize:(CGSize)frameSize;
{
    [super forceProcessingAtSize:frameSize];
    [self adjustAspectRatio];
}

- (void)setInputSize:(CGSize)newSize atIndex:(NSInteger)textureIndex
{
    CGSize oldInputSize = inputTextureSize;
    [super setInputSize:newSize atIndex:textureIndex];

    if ( (!CGSizeEqualToSize(oldInputSize, inputTextureSize)) && (!CGSizeEqualToSize(newSize, CGSizeZero)) ) {
        [self adjustAspectRatio];
    }
}

- (void)setAspectRatio:(CGFloat)newValue
{
    _aspectRatio = newValue;
    [self setFloat:self.aspectRatio forUniform:_aspectRatioUniform program:filterProgram];
}

- (void)setInputRotation:(GPUImageRotationMode)newInputRotation atIndex:(NSInteger)textureIndex;
{
    [super setInputRotation:newInputRotation atIndex:textureIndex];
    [self setCenter:self.center];
    [self adjustAspectRatio];
}

- (void)setScale: (CGFloat)newValue;
{
    _scale = newValue;
    [self setFloat:self.scale forUniform:_scaleUniform program:filterProgram];
}

- (void)setCenter: (CGPoint)newValue;
{
    _center = newValue;
    CGPoint rotatedPoint = [self rotatedPoint:self.center forRotation:inputRotation];
    [self setPoint:rotatedPoint forUniform:_centerUniform program:filterProgram];
}

@end