Issue in rendering multiple textures on multiple objects

Question

I am trying to render two objects - (void)glkView:(GLKView *)view drawInRect:(CGRect)rect method and there I am trying to bind separate textures for both the objects.

For first object following is the texture binding code

/************* texture binding for object 1 ****************/
glActiveTexture(GL_TEXTURE0);
err = CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault, 
                                                   _videoTextureCache,
                                                   pixelBuffer,
                                                   NULL,
                                                   GL_TEXTURE_2D,
                                                   GL_RED_EXT,
                                                   _textureWidth,
                                                   _textureHeight,
                                                   GL_RED_EXT,
                                                   GL_UNSIGNED_BYTE,
                                                   0,
                                                   &_lumaTexture);
if (err) 
{
    NSLog(@"Error at CVOpenGLESTextureCacheCreateTextureFromImage %d", err);
}   

glBindTexture(CVOpenGLESTextureGetTarget(_lumaTexture), CVOpenGLESTextureGetName(_lumaTexture));
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); 

glActiveTexture(GL_TEXTURE1);
err = CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault, 
                                                   _videoTextureCache,
                                                   pixelBuffer,
                                                   NULL,
                                                   GL_TEXTURE_2D,
                                                   GL_RG_EXT,
                                                   _textureWidth/2,
                                                   _textureHeight/2,
                                                   GL_RG_EXT,
                                                   GL_UNSIGNED_BYTE,
                                                   1,
                                                   &_chromaTexture);
if (err) 
{
    NSLog(@"Error at CVOpenGLESTextureCacheCreateTextureFromImage %d", err);
}

glBindTexture(CVOpenGLESTextureGetTarget(_chromaTexture), CVOpenGLESTextureGetName(_chromaTexture));
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

/************* rendering first object ****************/
[self renderFirstObject]; 

/************* texture binding for object 2 ****************/
glEnable(GL_TEXTURE_2D);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, _texture1);

/************* rendering second object ****************/
[self renderSecondObject]; 

Both now texture for first object getting disturbed whereas second object gets proper texture binding.

Code for loading _texture1 (executed once in start of the view controller) is below

NSDictionary* options = @{[NSNumber numberWithBool:YES] : GLKTextureLoaderOriginBottomLeft};

NSError* error;
NSString* path = [[NSBundle mainBundle] pathForResource:fileName ofType:nil];
GLKTextureInfo* texture = [GLKTextureLoader textureWithContentsOfFile:path options:options error:&error];
if(texture == nil)
    NSLog(@"Error loading file: %@", [error localizedDescription]);
_texture1 = texture.name;
glUseProgram(_program1);
glBindTexture(GL_TEXTURE_2D, _texture1);

Answer 1

I've solved this issue by setting the texture for first object agin after rendering second object. Check the updated code below.

/************* texture binding for object 1 ****************/
    glActiveTexture(GL_TEXTURE0);
    err = CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault,
                                                       _videoTextureCache,
                                                       pixelBuffer,
                                                       NULL,
                                                       GL_TEXTURE_2D,
                                                       GL_RED_EXT,
                                                       _textureWidth,
                                                       _textureHeight,
                                                       GL_RED_EXT,
                                                       GL_UNSIGNED_BYTE,
                                                       0,
                                                       &_lumaTexture);
    if (err)
    {
        NSLog(@"Error at CVOpenGLESTextureCacheCreateTextureFromImage %d", err);
    }

    glBindTexture(CVOpenGLESTextureGetTarget(_lumaTexture), CVOpenGLESTextureGetName(_lumaTexture));
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    glActiveTexture(GL_TEXTURE1);
    err = CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault,
                                                       _videoTextureCache,
                                                       pixelBuffer,
                                                       NULL,
                                                       GL_TEXTURE_2D,
                                                       GL_RG_EXT,
                                                       _textureWidth/2,
                                                       _textureHeight/2,
                                                       GL_RG_EXT,
                                                       GL_UNSIGNED_BYTE,
                                                       1,
                                                       &_chromaTexture);
    if (err)
    {
        NSLog(@"Error at CVOpenGLESTextureCacheCreateTextureFromImage %d", err);
    }

    glBindTexture(CVOpenGLESTextureGetTarget(_chromaTexture), CVOpenGLESTextureGetName(_chromaTexture));
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    /************* rendering first object ****************/
    [self renderFirstObject];

    /************* texture binding for object 2 ****************/
    glEnable(GL_TEXTURE_2D);
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, _texture1);

    /************* rendering second object ****************/
    [self renderSecondObject];


    /************* re-binding texture for object 1 ****************/
    glBindTexture(CVOpenGLESTextureGetTarget(_lumaTexture), CVOpenGLESTextureGetName(_lumaTexture));
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);