1.使用AVAsset对象对视频进行逐帧读取
- (void)getImageWithAsset:(AVAsset *)videoAsset{
CGFloat durationSeconds = CMTimeGetSeconds(videoAsset.duration);
AVAssetImageGenerator *gen = [[AVAssetImageGenerator alloc] initWithAsset:videoAsset];
gen.appliesPreferredTrackTransform = YES;
gen.requestedTimeToleranceAfter = kCMTimeZero;
gen.requestedTimeToleranceBefore = kCMTimeZero;
NSMutableArray *times = [NSMutableArray arrayWithCapacity:0];
CGFloat totalFrames = durationSeconds * 10;
for (int i = 0; i < totalFrames; i++) {
CMTime timeframe = CMTimeMake(i, 10);
NSValue *timeValue = [NSValue valueWithCMTime:timeframe];
[times addObject:timeValue];
}
[gen generateCGImagesAsynchronouslyForTimes:times completionHandler:^(CMTime requestedTime, CGImageRef _Nullable image, CMTime actualTime, AVAssetImageGeneratorResult result, NSError * _Nullable error) {
if (result == AVAssetImageGeneratorSucceeded) {
UIImage *resultImage = [UIImage imageWithCGImage:image];
dispatch_async(dispatch_get_main_queue(), ^{
[self configTextWithImage:resultImage];
});
}
}];
}
其中configTextWithImage方法是对每帧数据进行加入对应的滤镜特征，可以是灵魂出窍、缩放、灵魂出窍、抖动、闪白、毛刺、幻觉等功能等
- (void)configTextWithImage:(UIImage *)image{
//将JPG图片转换成纹理图片
GLuint textureID = [self createTextureWithImage:image];
//设置纹理ID
self.textureID = textureID; // 将纹理 ID 保存，方便后面切换滤镜的时候重用
//7.设置视口
glViewport(0, 0, self.drawableWidth, self.drawableHeight);
//8.设置顶点缓存区
GLuint vertexBuffer;
glGenBuffers(1, &vertexBuffer);
glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
GLsizeiptr bufferSizeBytes = sizeof(SenceVertex) * 4;
glBufferData(GL_ARRAY_BUFFER, bufferSizeBytes, self.vertices, GL_STATIC_DRAW);
//9.设置默认着色器
//注意在此处更改着色器的读取文件
[self setupShaderProgramWithName:@"SplitScreen_out"]; // 一开始选用默认的着色器
//10.将顶点缓存保存，退出时才释放
self.vertexBuffer = vertexBuffer;
}
绑定渲染缓存区和帧缓存区
- (void)bindRenderLayer:(CALayer <EAGLDrawable> *)layer {
//1.渲染缓存区,帧缓存区对象
GLuint renderBuffer;
GLuint frameBuffer;
//2.获取帧渲染缓存区名称,绑定渲染缓存区以及将渲染缓存区与layer建立连接
glGenRenderbuffers(1, &renderBuffer);
glBindRenderbuffer(GL_RENDERBUFFER, renderBuffer);
[self.context renderbufferStorage:GL_RENDERBUFFER fromDrawable:layer];
//3.获取帧缓存区名称,绑定帧缓存区以及将渲染缓存区附着到帧缓存区上
glGenFramebuffers(1, &frameBuffer);
glBindFramebuffer(GL_FRAMEBUFFER, frameBuffer);
glFramebufferRenderbuffer(GL_FRAMEBUFFER,
GL_COLOR_ATTACHMENT0,
GL_RENDERBUFFER,
renderBuffer);
}
从图片中加载纹理
- (GLuint)createTextureWithImage:(UIImage *)image {
//1、将 UIImage 转换为 CGImageRef
CGImageRef cgImageRef = [image CGImage];
//判断图片是否获取成功
if (!cgImageRef) {
NSLog(@"Failed to load image");
exit(1);
}
//2、读取图片的大小，宽和高
GLuint width = (GLuint)CGImageGetWidth(cgImageRef);
GLuint height = (GLuint)CGImageGetHeight(cgImageRef);
//获取图片的rect
CGRect rect = CGRectMake(0, 0, width, height);
//获取图片的颜色空间
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
//3.获取图片字节数 宽*高*4（RGBA）
void *imageData = malloc(width * height * 4);
//4.创建上下文
/*
参数1：data,指向要渲染的绘制图像的内存地址
参数2：width,bitmap的宽度，单位为像素
参数3：height,bitmap的高度，单位为像素
参数4：bitPerComponent,内存中像素的每个组件的位数，比如32位RGBA，就设置为8
参数5：bytesPerRow,bitmap的没一行的内存所占的比特数
参数6：colorSpace,bitmap上使用的颜色空间 kCGImageAlphaPremultipliedLast：RGBA
*/
CGContextRef context = CGBitmapContextCreate(imageData, width, height, 8, width * 4, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
//将图片翻转过来(图片默认是倒置的)
CGContextTranslateCTM(context, 0, height);
CGContextScaleCTM(context, 1.0f, -1.0f);
CGColorSpaceRelease(colorSpace);
CGContextClearRect(context, rect);
//对图片进行重新绘制，得到一张新的解压缩后的位图
CGContextDrawImage(context, rect, cgImageRef);
//设置图片纹理属性
//5. 获取纹理ID
GLuint textureID;
glGenTextures(1, &textureID);
glBindTexture(GL_TEXTURE_2D, textureID);
//6.载入纹理2D数据
/*
参数1：纹理模式，GL_TEXTURE_1D、GL_TEXTURE_2D、GL_TEXTURE_3D
参数2：加载的层次，一般设置为0
参数3：纹理的颜色值GL_RGBA
参数4：宽
参数5：高
参数6：border，边界宽度
参数7：format
参数8：type
参数9：纹理数据
*/
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
//7.设置纹理属性
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
//8.绑定纹理
/*
参数1：纹理维度
参数2：纹理ID,因为只有一个纹理，给0就可以了。
*/
glBindTexture(GL_TEXTURE_2D, 0);
//9.释放context,imageData
CGContextRelease(context);
free(imageData);
//10.返回纹理ID
return textureID;
}
开始一个滤镜动画
- (void)startFilerAnimation {
//1.判断displayLink 是否为空
//CADisplayLink 定时器
if (self.displayLink) {
[self.displayLink invalidate];
self.displayLink = nil;
}
//2. 设置displayLink 的方法
self.startTimeInterval = 0;
self.displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(timeAction)];
//3.将displayLink 添加到runloop 运行循环
[self.displayLink addToRunLoop:[NSRunLoop mainRunLoop]
forMode:NSRunLoopCommonModes];
}
动画
- (void)timeAction {
//DisplayLink 的当前时间撮
if (self.startTimeInterval == 0) {
self.startTimeInterval = self.displayLink.timestamp;
}
//使用program
glUseProgram(self.program);
//绑定buffer
glBindBuffer(GL_ARRAY_BUFFER, self.vertexBuffer);
// 传入时间
CGFloat currentTime = self.displayLink.timestamp - self.startTimeInterval;
NSLog(@"currentTime = %f", currentTime);
GLuint time = glGetUniformLocation(self.program, "Time");
glUniform1f(time, currentTime);
// 清除画布
glClearColor(1, 1, 1, 1);
glClear(GL_COLOR_BUFFER_BIT);
// 重绘
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
//渲染到屏幕上
[self.context presentRenderbuffer:GL_RENDERBUFFER];
}
初始化着色器程序
- (void)setupShaderProgramWithName:(NSString *)name {
//1. 获取着色器program
GLuint program = [self programWithShaderName:name];
//2. use Program
glUseProgram(program);
//3. 获取Position,Texture,TextureCoords 的索引位置
GLuint positionSlot = glGetAttribLocation(program, "Position");
GLuint textureSlot = glGetUniformLocation(program, "Texture");
GLuint textureCoordsSlot = glGetAttribLocation(program, "TextureCoords");
//4.激活纹理,绑定纹理ID
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, self.textureID);
//5.纹理sample
glUniform1i(textureSlot, 0);
//6.打开positionSlot 属性并且传递数据到positionSlot中(顶点坐标)
glEnableVertexAttribArray(positionSlot);
glVertexAttribPointer(positionSlot, 3, GL_FLOAT, GL_FALSE, sizeof(SenceVertex), NULL + offsetof(SenceVertex, positionCoord));
//7.打开textureCoordsSlot 属性并传递数据到textureCoordsSlot(纹理坐标)
glEnableVertexAttribArray(textureCoordsSlot);
glVertexAttribPointer(textureCoordsSlot, 2, GL_FLOAT, GL_FALSE, sizeof(SenceVertex), NULL + offsetof(SenceVertex, textureCoord));
//8.保存program,界面销毁则释放
self.program = program;
}
初始化程序对象
- (GLuint)programWithShaderName:(NSString *)shaderName {
//1. 编译顶点着色器/片元着色器
GLuint vertexShader = [self compileShaderWithName:shaderName type:GL_VERTEX_SHADER];
GLuint fragmentShader = [self compileShaderWithName:shaderName type:GL_FRAGMENT_SHADER];
//2. 将顶点/片元附着到program
GLuint program = glCreateProgram();
glAttachShader(program, vertexShader);
glAttachShader(program, fragmentShader);
//3.linkProgram
glLinkProgram(program);
//4.检查是否link成功
GLint linkSuccess;
glGetProgramiv(program, GL_LINK_STATUS, &linkSuccess);
if (linkSuccess == GL_FALSE) {
GLchar messages[256];
glGetProgramInfoLog(program, sizeof(messages), 0, &messages[0]);
NSString *messageString = [NSString stringWithUTF8String:messages];
NSAssert(NO, @"program链接失败：%@", messageString);
exit(1);
}
//5.返回program
return program;
}
编译shader代码
- (GLuint)compileShaderWithName:(NSString *)name type:(GLenum)shaderType {
//1.获取shader 路径
NSString *shaderPath = [[NSBundle mainBundle] pathForResource:name ofType:shaderType == GL_VERTEX_SHADER ? @"vsh" : @"fsh"];
NSError *error;
NSString *shaderString = [NSString stringWithContentsOfFile:shaderPath encoding:NSUTF8StringEncoding error:&error];
if (!shaderString) {
NSAssert(NO, @"读取shader失败");
exit(1);
}
//2. 创建shader->根据shaderType
GLuint shader = glCreateShader(shaderType);
//3.获取shader source
const char *shaderStringUTF8 = [shaderString UTF8String];
int shaderStringLength = (int)[shaderString length];
glShaderSource(shader, 1, &shaderStringUTF8, &shaderStringLength);
//4.编译shader
glCompileShader(shader);
//5.查看编译是否成功
GLint compileSuccess;
glGetShaderiv(shader, GL_COMPILE_STATUS, &compileSuccess);
if (compileSuccess == GL_FALSE) {
GLchar messages[256];
glGetShaderInfoLog(shader, sizeof(messages), 0, &messages[0]);
NSString *messageString = [NSString stringWithUTF8String:messages];
NSAssert(NO, @"shader编译失败：%@", messageString);
exit(1);
}
//6.返回shader
return shader;
}
获取渲染缓存区的宽
- (GLint)drawableWidth {
GLint backingWidth;
glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &backingWidth);
return backingWidth;
}
获取渲染缓存区的高
- (GLint)drawableHeight {
GLint backingHeight;
glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &backingHeight);
return backingHeight;
}
最后附上github地址
https://github.com/LoveToday/VideoFilter.git
网友评论