(iOS) OpenGL ES (2.0) Application, comment déplacer l'objet dans Z?

Question

Je joue avec le code source OpenGL ES (2.0) Application (iOS) en XCode et essayait de faire bouger le carré coloré dans la coordonnée Z, donc j'ai essayé de changer le code shader de

gl_Position.y + = sin (traduire)/2.0;

à

gl_Position.z + = sin (traduire)/2,0; sans succès.

Le carré ne bouge pas du tout. Il se déplace bien dans X et Y pensait ... Existe-t-il une option que je dois activer lors de l'initialisation d'OpenGL? Merci!

MISE À JOUR: J'ai téléchargé un exemple. C'est à peu près le template OpenGL ES que génère XCode, j'ai juste ajouté les appels pour créer le buffer de profondeur, et gl_Position.x pour gl_Position.z + = sin (translate)/2.0f dans le Shader.vsh. Je souhaite voir le carré se déplacer dans une forme sinusoïdale sur la coordonnée Z, mais ce ne sera pas le cas. Soit il reste immobile, soit, si je multiplie le péché(), il apparaîtra et disparaîtra dans un cycle.

Si quelqu'un peut me aider je serai très reconnaissant, car sincèrement je ne sais pas quoi faire d'autre, et croyez-moi j'ai essayé beaucoup ...

La source est dans un zip à: http://cl.ly/24240x2D1t2A3I0c1l1P

Merci!

Answer 1

L'exemple que vous regardez n'a pas de tampon de profondeur et une matrice de perspective destinée à 2D GL. Regardez plutôt l'exemple aurioTouch. Dans la classe EAGLView, vous remarquerez une option pour implémenter le buffer de profondeur. Les deux combinés (puisque aurioTouch n'implémente pas les shaders) devraient permettre une meilleure compréhension.

Je pense que l'ordre des opérations que vous avez dans votre méthode cause le problème. Voici le code que j'utilise dans mon application « Live Effects Cam » qui place la caméra en direct comme texture GL sur les formes:

#define DEGREES_TO_RADIANS(__ANGLE__) ((__ANGLE__)/180.0 * M_PI) 



@interface GLView : UIView 
    { 
@private 
    /* The pixel dimensions of the backbuffer */ 
    GLint backingWidth; 
    GLint backingHeight; 

    EAGLContext *context; 

    /* OpenGL names for the renderbuffer and framebuffers used to render to this view */ 
    GLuint viewRenderbuffer; 
    GLuint viewFramebuffer; 
    GLuint depthRenderbuffer; 

    /* OpenGL name for the sprite texture */ 
    GLuint spriteTexture; 
    } 

@property (readonly) GLint backingWidth; 
@property (readonly) GLint backingHeight; 
@property (readonly) EAGLContext *context; 


- (void) drawView; 
- (BOOL) createFramebuffer; 
- (void) destroyFramebuffer; 
+ (UIImage *) snapshot:(GLView *)eaglview; 

@end 




@implementation GLView 


@synthesize backingWidth; 
@synthesize backingHeight; 
@synthesize context; 


+ (Class) layerClass 
    { 
    return [CAEAGLLayer class]; 
    } 



- (id)init 
    { 
    self = [[super init] initWithFrame:CGRectMake(0.0, 0.0, 480.0, 640.0)];  // size of the camera image being captures 

    if (self==nil) 
     return self; 


    // Set Content Scaling 
    // 
    if (HIRESDEVICE) 
     { 
     self.contentScaleFactor = (CGFloat)2.0; 
     } 

    // Get our backing layer 
    // 
    CAEAGLLayer *eaglLayer = (CAEAGLLayer*) self.layer; 

    // Configure it so that it is opaque, does not retain the contents of the backbuffer when displayed, and uses RGBA8888 color. 
    // 
    eaglLayer.opaque = YES; 

    eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys: 
             [NSNumber numberWithBool:FALSE], kEAGLDrawablePropertyRetainedBacking, 
             kEAGLColorFormatRGBA8, kEAGLDrawablePropertyColorFormat, 
             nil]; 

    // Create our EAGLContext, and if successful make it current and create our framebuffer. 
    // 
    context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1]; 

    if(!context || ![EAGLContext setCurrentContext:context] || ![self createFramebuffer]) 
     { 
     [self release]; 
     return nil; 
     } 

    // Final View Settings 
    // 
    [self setOpaque:YES]; 
    self.multipleTouchEnabled = YES; 
    self.backgroundColor = [UIColor clearColor]; 

    [EAGLContext setCurrentContext:context]; 

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer); 
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer); 

    glMatrixMode(GL_PROJECTION); 
    glLoadIdentity(); 

    GLfloat zNear = 1.0; 
    GLfloat zFar = 1000.0; 
    GLfloat fieldOfView = 90;  // Lens Angle of View 
    GLfloat size = zNear * tanf(DEGREES_TO_RADIANS(fieldOfView)/2.0); 
    CGRect rect = CGRectMake((CGFloat)0.0, (CGFloat)0.0, backingWidth, backingHeight); 

    glFrustumf(-size, size, -size/(rect.size.width/rect.size.height), size/(rect.size.width/rect.size.height), zNear, zFar); 

    glViewport(0, 0, backingWidth, backingHeight); 

    glClearColor(0.0f, 0.0f, 0.0f, 0.0f); 
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 

    glEnable(GL_DEPTH_TEST); 
    glDepthFunc(GL_LESS); 
    glEnable(GL_MULTISAMPLE); 
    glEnable(GL_LINE_SMOOTH); 
    glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); 
    glHint(GL_LINE_SMOOTH_HINT, GL_NICEST); 
    glHint(GL_POINT_SMOOTH_HINT, GL_NICEST); 
    glDisable(GL_ALPHA_TEST); 

    // Turn Translucent Textures: OFF 
    // 
    glDisable(GL_BLEND); 

// // Turn Translucent Textures: ON 
// // 
// glEnable(GL_BLEND); 
// glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA); 

    return self; 
    } 



- (void) drawView 
    { 
    [context presentRenderbuffer:GL_RENDERBUFFER_OES]; 
    } 




- (BOOL)createFramebuffer 
    { 
    // Generate IDs for a framebuffer object and a color renderbuffer 
    // 
    glGenFramebuffersOES(1, &viewFramebuffer); 
    glGenRenderbuffersOES(1, &viewRenderbuffer); 

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer); 
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer); 

    // This call associates the storage for the current render buffer with the EAGLDrawable (our CAEAGLLayer) 
    // allowing us to draw into a buffer that will later be rendered to screen whereever the layer is (which corresponds with our view). 
    // 
    [context renderbufferStorage:GL_RENDERBUFFER_OES fromDrawable:(CAEAGLLayer*)self.layer]; 

    glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, viewRenderbuffer); 

    glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &backingWidth); 
    glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight); 

    // If this app uses a depth buffer, we'll create and attach one via another renderbuffer. 
    // 
    if (YES) 
     { 
     glGenRenderbuffersOES(1, &depthRenderbuffer); 
     glBindRenderbufferOES(GL_RENDERBUFFER_OES, depthRenderbuffer); 
     glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_DEPTH_COMPONENT16_OES, backingWidth, backingHeight); 
     glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, depthRenderbuffer); 
     } 

    if(glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES) != GL_FRAMEBUFFER_COMPLETE_OES) 
     { 
     NSLog(@"failed to make complete framebuffer object %x", glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES)); 
     return NO; 
     } 

    return YES; 
    } 


- (void) destroyFramebuffer 
    { 
    glDeleteFramebuffersOES(1, &viewFramebuffer); 
    viewFramebuffer = 0; 

    glDeleteRenderbuffersOES(1, &viewRenderbuffer); 
    viewRenderbuffer = 0; 

    if(depthRenderbuffer) 
     { 
     glDeleteRenderbuffersOES(1, &depthRenderbuffer); 
     depthRenderbuffer = 0; 
     } 
    } 




+ (UIImage *) snapshot:(GLView *)eaglview 
    { 
    NSInteger x = 0; 
    NSInteger y = 0; 
    NSInteger width = [eaglview backingWidth]; 
    NSInteger height = [eaglview backingHeight]; 
    NSInteger dataLength = width * height * 4; 

// Need to do this to get it to flush before taking the snapshit 
// 
    NSUInteger i; 
    for (i=0; i<100; i++) 
     { 
     glFlush(); 
     CFRunLoopRunInMode(kCFRunLoopDefaultMode, (float)1.0/(float)60.0, FALSE); 
     } 

    GLubyte *data = (GLubyte*)malloc(dataLength * sizeof(GLubyte)); 

    // Read pixel data from the framebuffer 
    // 
    glPixelStorei(GL_PACK_ALIGNMENT, 4); 
    glReadPixels(x, y, width, height, GL_RGBA, GL_UNSIGNED_BYTE, data); 

    // Create a CGImage with the pixel data 
    // If your OpenGL ES content is opaque, use kCGImageAlphaNoneSkipLast to ignore the alpha channel 
    // otherwise, use kCGImageAlphaPremultipliedLast 
    // 
    CGDataProviderRef ref = CGDataProviderCreateWithData(NULL, data, dataLength, NULL); 
    CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceRGB(); 
    CGImageRef iref = CGImageCreate(width, height, 8, 32, width * 4, colorspace, kCGBitmapByteOrder32Big | kCGImageAlphaPremultipliedLast, ref, NULL, true, kCGRenderingIntentDefault); 

    // OpenGL ES measures data in PIXELS 
    // Create a graphics context with the target size measured in POINTS 
    // 
    NSInteger widthInPoints; 
    NSInteger heightInPoints; 

    if (NULL != UIGraphicsBeginImageContextWithOptions) 
     { 
     // On iOS 4 and later, use UIGraphicsBeginImageContextWithOptions to take the scale into consideration 
     // Set the scale parameter to your OpenGL ES view's contentScaleFactor 
     // so that you get a high-resolution snapshot when its value is greater than 1.0 
     // 
     CGFloat scale = eaglview.contentScaleFactor; 
     widthInPoints = width/scale; 
     heightInPoints = height/scale; 
     UIGraphicsBeginImageContextWithOptions(CGSizeMake(widthInPoints, heightInPoints), NO, scale); 
     } 
    else 
     { 
     // On iOS prior to 4, fall back to use UIGraphicsBeginImageContext 
     // 
     widthInPoints = width; 
     heightInPoints = height; 
     UIGraphicsBeginImageContext(CGSizeMake(widthInPoints, heightInPoints)); 
     } 

    CGContextRef cgcontext = UIGraphicsGetCurrentContext(); 

    // UIKit coordinate system is upside down to GL/Quartz coordinate system 
    // Flip the CGImage by rendering it to the flipped bitmap context 
    // The size of the destination area is measured in POINTS 
    // 
    CGContextSetBlendMode(cgcontext, kCGBlendModeCopy); 
    CGContextDrawImage(cgcontext, CGRectMake(0.0, 0.0, widthInPoints, heightInPoints), iref); 

    // Retrieve the UIImage from the current context 
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext(); // autoreleased image 

    UIGraphicsEndImageContext(); 

    // Clean up 
    free(data); 
    CFRelease(ref); 
    CFRelease(colorspace); 
    CGImageRelease(iref); 

    return image; 
    } 


@end 

Answer 2

// Create default framebuffer object. 
    glGenFramebuffers(1, &defaultFramebuffer); 
    glBindFramebuffer(GL_FRAMEBUFFER, defaultFramebuffer); 

    // Create color render buffer and allocate backing store. 
    glGenRenderbuffers(1, &depthRenderbuffer); <---- 
    glGenRenderbuffers(1, &colorRenderbuffer); 

    glBindRenderbuffer(GL_RENDERBUFFER, depthRenderbuffer); <---- 
    glBindRenderbuffer(GL_RENDERBUFFER, colorRenderbuffer); 

    [context renderbufferStorage:GL_RENDERBUFFER fromDrawable:(CAEAGLLayer *)self.layer]; 

    glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &framebufferWidth); 
    glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &framebufferHeight); 

    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, framebufferWidth, framebufferHeight); <---- 

    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, colorRenderbuffer); 
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthRenderbuffer); <---- 

J'ai ajouté que mon code (... < ----) et maintenant je reçois un écran rose (lol). Des idées? C'est vraiment frustrant. Ne devrais-je pas faire quelque chose dans le setFrame .. presentFrame ..?