iOS Symbol(s) not found

[Limb]

Hello all,

Having a bit of trouble here, trying to take the GLSprite texture loading code and transform it into a class, but im getting some strange build errors (Symbol(s) not found) that I can't figure out why I'm getting. Would appreciate it if anyone could take a look at it and tell me what I'm doing wrong, as my searches so far have turned up nothing.

Code and errors are as follows:

Texture.h

#import <UIKit/UIKit.h>
#import <OpenGLES/EAGL.h>
#import <OpenGLES/ES1/gl.h>
#import <OpenGLES/ES1/glext.h>

@interface Texture : NSObject {

	GLuint spriteTexture;
}

- (GLuint) initWithImage:(NSString *)image;

@end

Texture.m

#import <QuartzCore/QuartzCore.h>
#import <OpenGLES/EAGLDrawable.h>

#import "Texture.h"

@implementation Texture

- (GLuint)initWithImage:(NSString *) Image
{
	CGImageRef spriteImage;
	CGContextRef spriteContext;
	GLubyte *spriteData;
	size_t	width, height;
	
	// Creates a Core Graphics image from an image file
	spriteImage = [UIImage imageNamed:Image].CGImage;
	// Get the width and height of the image
	width = CGImageGetWidth(spriteImage);
	height = CGImageGetHeight(spriteImage);
	// Texture dimensions must be a power of 2. If you write an application that allows users to supply an image,
	// you'll want to add code that checks the dimensions and takes appropriate action if they are not a power of 2.
	
	if(spriteImage) {
		// Allocated memory needed for the bitmap context
		spriteData = (GLubyte *) malloc(width * height * 4);
		// Uses the bitmatp creation function provided by the Core Graphics framework. 
		spriteContext = CGBitmapContextCreate(spriteData, width, height, 8, width * 4, CGImageGetColorSpace(spriteImage), kCGImageAlphaPremultipliedLast);
		// After you create the context, you can draw the sprite image to the context.
		CGContextDrawImage(spriteContext, CGRectMake(0.0, 0.0, (CGFloat)width, (CGFloat)height), spriteImage);
		// You don't need the context at this point, so you need to release it to avoid memory leaks.
		CGContextRelease(spriteContext);
		
		// Use OpenGL ES to generate a name for the texture.
		glGenTextures(1, &spriteTexture);
		// Bind the texture name. 
		glBindTexture(GL_TEXTURE_2D, spriteTexture);
		// Speidfy a 2D texture image, provideing the a pointer to the image data in memory
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, spriteData);
		// Release the image data
		free(spriteData);
		
		// Set the texture parameters to use a minifying filter and a linear filer (weighted average)
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
		
		// Enable use of the texture
		glEnable(GL_TEXTURE_2D);
		// Set a blending function to use
		glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
		// Enable blending
		glEnable(GL_BLEND);
	}
		return spriteTexture;
}

@end

Error Output:

Undefined symbols:
  "_CGContextRelease", referenced from:
      -[Texture initWithImage:] in Texture.o
  "_CGContextDrawImage", referenced from:
      -[Texture initWithImage:] in Texture.o
  "_CGBitmapContextCreate", referenced from:
      -[Texture initWithImage:] in Texture.o
  "_CGImageGetColorSpace", referenced from:
      -[Texture initWithImage:] in Texture.o
  "_CGImageGetWidth", referenced from:
      -[Texture initWithImage:] in Texture.o
  "_CGImageGetHeight", referenced from:
      -[Texture initWithImage:] in Texture.o
ld: symbol(s) not found
collect2: ld returned 1 exit status

Again, any help would be greatly appreciated.
Thanks,
-Limb

 

[ayasin]

You're missing a library reference. You need to add the openGL libraries to your project.

 

[kainjow]

Those symbols are Quartz symbols. Make sure you've linked in the QuartzCore/Quartz frameworks (which should be from UIKit). It is strange.

 

[Limb]

Turned out I didn't have the CoreGraphics framework included. Thanks for the suggestions, as they made me realize i should check which frameworks were in GLSprite that I didn't have.

Thanks!
-Limb