Iphone 如何绕x轴旋转GLKView？

我已经对GLKView进行了子类化，我想绕x轴旋转它。我曾尝试在raywenderlich的教程中应用该方法，但没有结果。不同的是，我有一个GLKView，他碰巧用一个GLKViewController（+它的委托）做任何事情。因此，我没有代理的更新方法等。我几乎没有OpenGL的经验（刚刚开始），所以我希望我在这里遇到一些启示

ViewController.m

    EAGLContext * context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2]; 
    BlogCell *view = [[BlogCell alloc] initWithFrame:CGRectMake(0, 200, 320, 80) context:context]; 
    view.drawableMultisample = GLKViewDrawableMultisample4X;
    view.context = context; 
    view.delegate = view; 
    [view setupGL];
    [self.view addSubview:view]; 

- (void)setupGL {

    [EAGLContext setCurrentContext:self.context];
    glEnable(GL_CULL_FACE);


    self.effect = [[GLKBaseEffect alloc] init];

    NSDictionary * options = [NSDictionary dictionaryWithObjectsAndKeys:
                              [NSNumber numberWithBool:YES],
                              GLKTextureLoaderOriginBottomLeft,
                              nil];

    NSError * error;
    NSString *path = [[NSBundle mainBundle] pathForResource:@"myImage" ofType:@"png"];
    GLKTextureInfo * info = [GLKTextureLoader textureWithContentsOfFile:path options:options error:&error];
    if (info == nil) {
        NSLog(@"Error loading file: %@", [error localizedDescription]);
    }
    self.effect.texture2d0.name = info.name;
    self.effect.texture2d0.enabled = true;

    glGenVertexArraysOES(1, &vertexArray);
    glBindVertexArrayOES(vertexArray);

    glGenBuffers(1, &vertexBuffer);
    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(Vertices), Vertices, GL_STATIC_DRAW);


    glGenBuffers(1, &indexBuffer);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(Indices), Indices, GL_STATIC_DRAW);

    glEnableVertexAttribArray(GLKVertexAttribColor);
    glVertexAttribPointer(GLKVertexAttribColor, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid *) offsetof(Vertex, Color));


    glEnableVertexAttribArray(GLKVertexAttribPosition);
    glVertexAttribPointer(GLKVertexAttribPosition, 
                          3,         
                          GL_FLOAT,   
                          GL_FALSE,    
                          sizeof(Vertex),   
                          (const GLvoid *) offsetof(Vertex, Position) 
                          );

    glEnableVertexAttribArray(GLKVertexAttribTexCoord0);
    glVertexAttribPointer(GLKVertexAttribTexCoord0, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid *) offsetof(Vertex, TexCoord));


    glBindVertexArrayOES(0);

    rotMatrix = GLKMatrix4Identity;

}




- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect {

    self.contentScaleFactor = 2.0;
    self.opaque = NO;
    self.drawableColorFormat = GLKViewDrawableColorFormatRGBA8888;
    glClearColor(1.0f, 1.0f, 1.0f, 1.0f);

    glClear(GL_COLOR_BUFFER_BIT);

    [self.effect prepareToDraw];

    glBindVertexArrayOES(vertexArray);
    glDrawElements(GL_TRIANGLES, sizeof(Indices)/sizeof(Indices[0]), GL_UNSIGNED_BYTE, 0);


}

MyGLKViewSubclass.m

    EAGLContext * context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2]; 
    BlogCell *view = [[BlogCell alloc] initWithFrame:CGRectMake(0, 200, 320, 80) context:context]; 
    view.drawableMultisample = GLKViewDrawableMultisample4X;
    view.context = context; 
    view.delegate = view; 
    [view setupGL];
    [self.view addSubview:view]; 

- (void)setupGL {

    [EAGLContext setCurrentContext:self.context];
    glEnable(GL_CULL_FACE);


    self.effect = [[GLKBaseEffect alloc] init];

    NSDictionary * options = [NSDictionary dictionaryWithObjectsAndKeys:
                              [NSNumber numberWithBool:YES],
                              GLKTextureLoaderOriginBottomLeft,
                              nil];

    NSError * error;
    NSString *path = [[NSBundle mainBundle] pathForResource:@"myImage" ofType:@"png"];
    GLKTextureInfo * info = [GLKTextureLoader textureWithContentsOfFile:path options:options error:&error];
    if (info == nil) {
        NSLog(@"Error loading file: %@", [error localizedDescription]);
    }
    self.effect.texture2d0.name = info.name;
    self.effect.texture2d0.enabled = true;

    glGenVertexArraysOES(1, &vertexArray);
    glBindVertexArrayOES(vertexArray);

    glGenBuffers(1, &vertexBuffer);
    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(Vertices), Vertices, GL_STATIC_DRAW);


    glGenBuffers(1, &indexBuffer);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(Indices), Indices, GL_STATIC_DRAW);

    glEnableVertexAttribArray(GLKVertexAttribColor);
    glVertexAttribPointer(GLKVertexAttribColor, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid *) offsetof(Vertex, Color));


    glEnableVertexAttribArray(GLKVertexAttribPosition);
    glVertexAttribPointer(GLKVertexAttribPosition, 
                          3,         
                          GL_FLOAT,   
                          GL_FALSE,    
                          sizeof(Vertex),   
                          (const GLvoid *) offsetof(Vertex, Position) 
                          );

    glEnableVertexAttribArray(GLKVertexAttribTexCoord0);
    glVertexAttribPointer(GLKVertexAttribTexCoord0, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid *) offsetof(Vertex, TexCoord));


    glBindVertexArrayOES(0);

    rotMatrix = GLKMatrix4Identity;

}




- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect {

    self.contentScaleFactor = 2.0;
    self.opaque = NO;
    self.drawableColorFormat = GLKViewDrawableColorFormatRGBA8888;
    glClearColor(1.0f, 1.0f, 1.0f, 1.0f);

    glClear(GL_COLOR_BUFFER_BIT);

    [self.effect prepareToDraw];

    glBindVertexArrayOES(vertexArray);
    glDrawElements(GL_TRIANGLES, sizeof(Indices)/sizeof(Indices[0]), GL_UNSIGNED_BYTE, 0);


}

这是我想旋转对象的地方

 -(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{

    UITouch * touch = [touches anyObject];
    CGPoint location = [touch locationInView:[touch view]];
    CGPoint lastLoc = [touch previousLocationInView:[touch view]];
    CGPoint diff = CGPointMake(lastLoc.x - location.x, lastLoc.y - location.y);

    float rotX = -1 * GLKMathDegreesToRadians(diff.y / 2.0);
    float rotY = -1 * GLKMathDegreesToRadians(diff.x / 2.0);

    GLKVector3 xAxis = GLKVector3Make(1, 0, 0);
    rotMatrix = GLKMatrix4Rotate(rotMatrix, rotX, xAxis.x, xAxis.y, xAxis.z);
    GLKVector3 yAxis = GLKVector3Make(0, 1, 0);
    rotMatrix = GLKMatrix4Rotate(rotMatrix, rotY, yAxis.x, yAxis.y, yAxis.z);
    [self update];

}

---

你似乎没有任何东西来运行你的绘图循环。将其放入您的viewDidLoad中：

displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(render:)];
displayLink.frameInterval = 2;
[displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];

---

将displayLink定义为标题中的属性，并将@selector（render:）更改为渲染函数（不必是glkview函数，因为您不使用GLKViewController）。

旋转glkview有四个要求： 1.与旋转相关的代码必须放置在视图控制器内 2.横向旋转必须增加90° 3.旋转相关代码必须包含在UIView动画块中 4.度应以弧度表示，并以负数表示

以下是我成功使用的代码：

GLKViewController实现文件（.m）中的：

static inline double radians (double degrees) { return degrees * M_PI/180; }

。 .

---

这些要求听起来可能有点可疑；但是，我向您保证，您不会以任何其他方式旋转它，并在所有方向和所有方面保持一致性。

比旋转视图更好的是旋转四边形纹理坐标；尽管苹果的任何示例代码或文档中都没有演示，但他们的文档确实建议旋转输出而不是旋转GLKView

以下是四边形纹理坐标设置的所有排列：

static const GLfloat noRotationTextureCoordinates[] = {
    0.0f, 0.0f,
    1.0f, 0.0f,
    0.0f, 1.0f,
    1.0f, 1.0f,
};

static const GLfloat rotateLeftTextureCoordinates[] = {
    1.0f, 0.0f,
    1.0f, 1.0f,
    0.0f, 0.0f,
    0.0f, 1.0f,
};

static const GLfloat rotateRightTextureCoordinates[] = {
    0.0f, 1.0f,
    0.0f, 0.0f,
    1.0f, 1.0f,
    1.0f, 0.0f,
};

static const GLfloat verticalFlipTextureCoordinates[] = {
    0.0f, 1.0f,
    1.0f, 1.0f,
    0.0f,  0.0f,
    1.0f,  0.0f,
};

static const GLfloat horizontalFlipTextureCoordinates[] = {
    1.0f, 0.0f,
    0.0f, 0.0f,
    1.0f,  1.0f,
    0.0f,  1.0f,
};

static const GLfloat rotateRightVerticalFlipTextureCoordinates[] = {
    0.0f, 0.0f,
    0.0f, 1.0f,
    1.0f, 0.0f,
    1.0f, 1.0f,
};

static const GLfloat rotateRightHorizontalFlipTextureCoordinates[] = {
    1.0f, 1.0f,
    1.0f, 0.0f,
    0.0f, 1.0f,
    0.0f, 0.0f,
};

static const GLfloat rotate180TextureCoordinates[] = {
    1.0f, 1.0f,
    0.0f, 1.0f,
    1.0f, 0.0f,
    0.0f, 0.0f,
};

要在其AVBasicVideo中使用的GLKView中使用此选项。。。示例应用程序，例如：

使用

self.bounds.size

而不是

self.presentationRect.size

，以便输出填充整个屏幕，而不考虑其旋转：

CGRect vertexSamplingRect = AVMakeRectWithAspectRatioInsideRect(self.bounds.size, self.eaglLayer.bounds);

对于1.0的值，使用max；对于0.0，使用最小值

GLfloat四纹理数据[]=     { CGRectGetMaxX（textureSamplingRect）、CGRectGetMinY（textureSamplingRect）， CGRectGetMaxX（textureSamplingRect）、CGRectGetMaxY（textureSamplingRect）， CGRectGetMinX（纹理采样RECT）、CGRectGetMinY（纹理采样RECT）， CGRectGetMinX（textureSamplingRect）、CGRectGetMaxY（textureSamplingRect）     };

---

谢谢你的回答。我试过你的代码，可惜没用。对我来说，每当我需要重新绘制GLKView时，都可以使用

[self display]

。顺便说一下，我将委托设置为GLKView本身，因此在调用其上的

display

方法时，将调用其委托方法。这是一种糟糕的方法吗？displayLink运行循环与GLKViewController/GLKView组合提供的运行循环相同。使用CADisplayLink，您可以精确查看自上次刷新以来发生的循环数；但是，这些信息与我认识的每个人都无关。使用GLKViewController，我可以设置给定视频的每秒帧数；以每秒15帧的速度播放的视频不需要以每秒60帧的速度渲染。能够降低fps比没有fps更有利于snappier应用。