OpenGL ES 2 on iOS: NULL Fragment and Vertex Shaders

Question

In attempt to figure out why I have zero attached shaders to my program. I have come across another problem. My fragment and vertex shaders are equal to zero (they're NULL)

NSString *vertexShaderPath = [[NSBundle mainBundle] pathForResource:@"VertexShader" ofType:@"glsl"];
NSString *vertexShaderString = [NSString stringWithContentsOfFile:vertexShaderPath encoding:NSUTF8StringEncoding error:nil];
const char * vertexShaderCString = [vertexShaderString cStringUsingEncoding:NSUTF8StringEncoding];
NSLog(@"%s",vertexShaderCString);

NSString *fragmentShaderPath = [[NSBundle mainBundle]pathForResource:@"FragmentShader" ofType:@"glsl"];
NSString *fragmentShaderString = [NSString stringWithContentsOfFile:fragmentShaderPath encoding:NSUTF8StringEncoding error:nil];
const char* fragmentShaderCString = [fragmentShaderString cStringUsingEncoding:NSUTF8StringEncoding];
NSLog(@"%s", fragmentShaderCString);

int vertexShaderCStringLength = strlen(vertexShaderCString);
NSLog(@"%i",vertexShaderCStringLength);

vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexShaderCString, &vertexShaderCStringLength);
glCompileShader(vertexShader);


 int fragmentShaderCStringLength = strlen(fragmentShaderCString);
 NSLog(@"%i",fragmentShaderCStringLength);

fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentShaderCString, &fragmentShaderCStringLength);
glCompileShader(fragmentShader);


programHandle = glCreateProgram();
glAttachShader(programHandle, vertexShader);
glAttachShader(programHandle, fragmentShader);
glLinkProgram(programHandle);

glGetProgramiv(programHandle, GL_ATTACHED_SHADERS, &attachedShaders);
NSLog(@"Attched shaders: %i",attachedShaders);

if (fragmentShader == 0 ) {
    NSLog(@"Some sort of fragment error");
}

if(vertexShader == 0){

NSLog(@"Some sort of vertex error");
}

The above code is in the viewDidLoad of a GLKViewController. Before I had coding looking for compiling errors (removed for readability) -- which there were none and I am also printing out the Fragment and Vertex Shader in an NSLog, so I know my paths are correct.

I have no idea why my vertex and fragment shaders are equal to zero. I've spent so much time on this program and I don't want to start over.

Any help at all is extremely and gratefully appreciated!

Thanks!

Answer 1

As seen here - http://developer.apple.com/library/ios/#documentation/3DDrawing/Conceptual/OpenGLES_ProgrammingGuide/DeterminingOpenGLESCapabilities/DeterminingOpenGLESCapabilities.html#//apple_ref/doc/uid/TP40008793-CH102-SW1

Check for Extensions Before Using Them

Is the encoding (for shader files) ASCII or UTF-8?

Call glGetError to Test for Errors

Because your code seems perfectly normal, try calling glGetError(...) in place of NSLog(...) to find more about errors (if there are any).