如何围绕x轴旋转GLKView？

时间：2012-12-19 11:06:09

标签： iphone objective-c rotation opengl-es-2.0

我已经将GLKView子类化，我想围绕x轴旋转它。我试图在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GLKViewController（+它的委托）做了一切。所以我没有委托等的更新方法等。我几乎没有使用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];

MyGLKViewSubclass.m 

- (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);


}

这是我想要旋转对象的地方 

 -(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];

}

3 个答案:

答案 0 :(得分：0)

你似乎没有任何东西可以运行你的绘制循环。把它放在你的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（因为你不使用GLKViewController，所以不必是glkview）。

答案 1 :(得分：0)

旋转GLKView有四个要求： 1.与旋转相关的代码必须放在视图控制器内 2.必须在旋转中添加90°才能横向显示 3.与旋转相关的代码必须包含在UIView动画块中 4.度数应以弧度表示，并以负数表示

这是我成功使用的代码：

在GLKViewController实现文件（.m）中： 

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

。 。 

if (UIInterfaceOrientationIsPortrait([[UIApplication sharedApplication] statusBarOrientation]) || (UIInterfaceOrientationIsPortrait([[UIApplication sharedApplication] statusBarOrientation]))) {
    [UIView animateWithDuration:0.0 animations:^{
        ((PlayerView *)self.view).transform = CGAffineTransformMakeRotation(radians(-90.0));
        ((PlayerView *)self.view).frame = [[UIScreen mainScreen] bounds];
    } completion:^(BOOL finished) { }];
} else if (UIInterfaceOrientationIsLandscape([[UIApplication sharedApplication] statusBarOrientation]) || (UIInterfaceOrientationIsLandscape([[UIApplication sharedApplication] statusBarOrientation]))) {
    [UIView animateWithDuration:0.0 animations:^{
        ((PlayerView *)self.view).transform = CGAffineTransformMakeRotation(radians(-180.0));
        ((PlayerView *)self.view).frame = [[UIScreen mainScreen] bounds];
    } completion:^(BOOL finished) { }];
} else {
    NSLog(@"--------------------------- orientation could not be determined");
}

这些要求可能听起来有点怀疑;但是，我保证你不会以任何其他方式轮换它，并保持所有方向和所有方面的一致性。

答案 2 :(得分：0)

甚至比旋转视图更好的是旋转四边形纹理坐标;虽然Apple没有在任何示例代码或文档中进行演示，但他们的文档确实建议通过旋转GLKView来旋转输出。

以下是四元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AVBasicVideo ...示例应用中使用的GLKView中使用它，例如：

  1. 使用self.bounds.size代替self.presentationRect.size，这样无论轮换如何，输出都会填满整个屏幕：

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

  2. 对于值1.0，请使用max;对于0.0，使用min;

    GLfloat quadTextureData [] = { CGRectGetMaxX（textureSamplingRect），CGRectGetMinY（textureSamplingRect）， CGRectGetMaxX（textureSamplingRect），CGRectGetMaxY（textureSamplingRect）， CGRectGetMinX（textureSamplingRect），CGRectGetMinY（textureSamplingRect）， CGRectGetMinX（textureSamplingRect），CGRectGetMaxY（textureSamplingRect） };

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