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macOS NSOpenGLView code simple problem

Soulstorm

Soulstorm

macrumors 68000
Original poster
Feb 1, 2005
1,887
1
I have this code in a carbon application using Xcode and OpenGL with GLUT:

Code: 
#include <Carbon/Carbon.h>
#include <GLUT/glut.h>
#include <OpenGL/OpenGL.h>

float xRot;
float yRot;

///////////////////////////////////////////////////////////
// Called to draw scene
void RenderScene(void)
{
	// Clear the window with current clearing color
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glPushMatrix();
	
	glColor3f(0, 1.0, 0);
	glRotatef(xRot, 1.0f, 0.0f, 0.0f);
	glRotatef(yRot, 0.0f, 1.0f, 0.0f);
	
	glBegin(GL_TRIANGLES);					// Start Drawing The Pyramid
	
	glColor3f(1.0f,0.0f,0.0f);			// Red
	glVertex3f( 0.0f, 1.0f, 0.0f);			// Top Of Triangle (Front)
	glColor3f(0.0f,1.0f,0.0f);			// Green
	glVertex3f(-1.0f,-1.0f, 1.0f);			// Left Of Triangle (Front)
	glColor3f(0.0f,0.0f,1.0f);			// Blue
	glVertex3f( 1.0f,-1.0f, 1.0f);			// Right Of Triangle (Front)
	
	
	glColor3f(1.0f,0.0f,0.0f);			// Red
	glVertex3f( 0.0f, 1.0f, 0.0f);			// Top Of Triangle (Right)
	glColor3f(0.0f,0.0f,1.0f);			// Blue
	glVertex3f( 1.0f,-1.0f, 1.0f);			// Left Of Triangle (Right)
	glColor3f(0.0f,1.0f,0.0f);			// Green
	glVertex3f( 1.0f,-1.0f, -1.0f);			// Right Of Triangle (Right)
	
	glColor3f(1.0f,0.0f,0.0f);			// Red
	glVertex3f( 0.0f, 1.0f, 0.0f);			// Top Of Triangle (Back)
	glColor3f(0.0f,1.0f,0.0f);			// Green
	glVertex3f( 1.0f,-1.0f, -1.0f);			// Left Of Triangle (Back)
	glColor3f(0.0f,0.0f,1.0f);			// Blue
	glVertex3f(-1.0f,-1.0f, -1.0f);			// Right Of Triangle (Back)
	
	glColor3f(1.0f,0.0f,0.0f);			// Red
	glVertex3f( 0.0f, 1.0f, 0.0f);			// Top Of Triangle (Left)
	glColor3f(0.0f,0.0f,1.0f);			// Blue
	glVertex3f(-1.0f,-1.0f,-1.0f);			// Left Of Triangle (Left)
	glColor3f(0.0f,1.0f,0.0f);			// Green
	glVertex3f(-1.0f,-1.0f, 1.0f);			// Right Of Triangle (Left)
	glEnd();
	
	

	glPopMatrix();
    
	glFlush();
}


///////////////////////////////////////////////////////////
// Setup the rendering state
void SetupRC(void)
{
	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
	//cout << "hello! :";
	//cout << tgaFile.width;
	
	glShadeModel(GL_SMOOTH);
	glEnable(GL_DEPTH_TEST);
	
}



///////////////////////////////////////////////////////////
// Called by GLUT library when the window has chanaged size
void ChangeSize(int w, int h)
{
    GLfloat nRange = 2.0f;
    // Prevent a divide by zero
    if(h == 0)
        h = 1;
	
    // Set Viewport to window dimensions
    glViewport(0, 0, w, h);
	
    // Reset coordinate system
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
	
    // Establish clipping volume (left, right, bottom, top, near, far)
    if (w <= h) 
        glOrtho (-nRange, nRange, -nRange*h/w, nRange*h/w, -nRange, nRange);
    else 
        glOrtho (-nRange*w/h, nRange*w/h, -nRange, nRange, -nRange, nRange);
	
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}
//void TimerFunction(int value){
//	xRot += 0.5;
//	yRot += 0.5;
//	glutPostRedisplay();
//	glutTimerFunc(30,TimerFunction,4);
//}
//
void SpecialKeys(int key, int x, int y)
{
	//cout << "special key hit\n";
	if(key == GLUT_KEY_UP)
		xRot-= 5.0f;
	
	if(key == GLUT_KEY_DOWN)
		xRot += 5.0f;
	
	if(key == GLUT_KEY_LEFT)
		yRot -= 5.0f;
	
	if(key == GLUT_KEY_RIGHT)
		yRot += 5.0f;
	
	if(key > 356.0f)
		xRot = 0.0f;
	
	if(key < -1.0f)
		xRot = 355.0f;
	
	if(key > 356.0f)
		yRot = 0.0f;
	
	if(key < -1.0f)
		yRot = 355.0f;
	
	// Refresh the Window
	glutPostRedisplay();
}


// Program entry point
int main(int argc, char* argv[])
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH);
	glutInitWindowSize(800,600);
	glutCreateWindow("OpenGL Test");
	
	glutReshapeFunc(ChangeSize);
	glutDisplayFunc(RenderScene);
	glutSpecialFunc(SpecialKeys);
	//glutTimerFunc(33, TimerFunction, 1);
	SetupRC();
	
	glutMainLoop();
	
	SetupRC();
	return 0;
}

While porting this code to Cocoa OpenGL using an NSOpenGLView, my code looks something like this:

Code: 
#import "MyOpenGLView.h"

@implementation MyOpenGLView

- (void)prepareOpenGL
{
	yRot = 0.0;
	xRot = 0.0;
	
	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
	//cout << "hello! :";
	//cout << tgaFile.width;
	
	glShadeModel(GL_SMOOTH);
	glEnable(GL_DEPTH_TEST);
}

- (void)reshape
{
	//NSLog(@"reshaping...");
	[[self openGLContext]makeCurrentContext];
	NSRect bounds = [self bounds];
	//NSLog(@"reshaping: %f, %f", NSWidth(bounds), NSHeight(bounds));
	glViewport(0, 0, NSWidth(bounds), NSHeight(bounds));
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(-2, 2, -2, 2, -2, 2);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	
	[NSOpenGLContext clearCurrentContext];
}

- (void)drawRect:(NSRect)rect
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glPushMatrix();
	
	glColor3f(0, 1.0, 0);
	glRotatef(xRot, 1.0f, 0.0f, 0.0f);
	glRotatef(yRot, 0.0f, 1.0f, 0.0f);
	
	glBegin(GL_TRIANGLES);					// Start Drawing The Pyramid
		glColor3f(1.0f,0.0f,0.0f);			// Red
		glVertex3f( 0.0f, 1.0f, 0.0f);			// Top Of Triangle (Front)
		glColor3f(0.0f,1.0f,0.0f);			// Green
		glVertex3f(-1.0f,-1.0f, 1.0f);			// Left Of Triangle (Front)
		glColor3f(0.0f,0.0f,1.0f);			// Blue
		glVertex3f( 1.0f,-1.0f, 1.0f);			// Right Of Triangle (Front)
		
		
		glColor3f(1.0f,0.0f,0.0f);			// Red
		glVertex3f( 0.0f, 1.0f, 0.0f);			// Top Of Triangle (Right)
		glColor3f(0.0f,0.0f,1.0f);			// Blue
		glVertex3f( 1.0f,-1.0f, 1.0f);			// Left Of Triangle (Right)
		glColor3f(0.0f,1.0f,0.0f);			// Green
		glVertex3f( 1.0f,-1.0f, -1.0f);			// Right Of Triangle (Right)
		
		glColor3f(1.0f,0.0f,0.0f);			// Red
		glVertex3f( 0.0f, 1.0f, 0.0f);			// Top Of Triangle (Back)
		glColor3f(0.0f,1.0f,0.0f);			// Green
		glVertex3f( 1.0f,-1.0f, -1.0f);			// Left Of Triangle (Back)
		glColor3f(0.0f,0.0f,1.0f);			// Blue
		glVertex3f(-1.0f,-1.0f, -1.0f);			// Right Of Triangle (Back)
		
		glColor3f(1.0f,0.0f,0.0f);			// Red
		glVertex3f( 0.0f, 1.0f, 0.0f);			// Top Of Triangle (Left)
		glColor3f(0.0f,0.0f,1.0f);			// Blue
		glVertex3f(-1.0f,-1.0f,-1.0f);			// Left Of Triangle (Left)
		glColor3f(0.0f,1.0f,0.0f);			// Green
		glVertex3f(-1.0f,-1.0f, 1.0f);			// Right Of Triangle (Left)
	glEnd();
	
	glPopMatrix();
	
	[[self openGLContext]flushBuffer];
}

- (IBAction)rotateUp:(id)sender
{
	xRot-= 5.0f;
	if(xRot < 1.0f)
		xRot = 355.0f;
	[self setNeedsDisplay:YES];
}
- (IBAction)rotateDown:(id)sender
{
	xRot += 5.0f;
	if(xRot > 356.0f)
		yRot = 0.0f;
	[self setNeedsDisplay:YES];
}
- (IBAction)rotateLeft:(id)sender
{
	yRot -= 5.0f;
	if(yRot < 1.0f)
		yRot = 355.0f;
	[self setNeedsDisplay:YES];
}
- (IBAction)rotateRight:(id)sender
{
	yRot += 5.0f;
	if(yRot > 356.0f)
		yRot = 0.0f;
	[self setNeedsDisplay:YES];
}

- (void) dealloc
{
	[texture1 release];
	[super dealloc];
}

@end

However, using GLUT I get the expected result, which is a multicolored pyramid ,like the left one. But on the right, I get the same pyramid, only that you can see through some of the faces. I don't know why this is happening... Wasn't it supposed to look the same when I rotate the images? Note that the fault into the second project can only be seen when you rotate the object.
 

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Soulstorm

Soulstorm

macrumors 68000
Original poster
Feb 1, 2005
1,887
1
lazydog said:
Looks like you haven't got a depth buffer assigned to your view.

b e n
Click to expand...

Damn. It was so easy! I went into the interface builder and set a depth buffer (16 bits). That solved the problem. Thanks a lot.
 
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