Hello!
I am following the along with the OpenGL Redbook and one example describes how to draw lines. The book uses the aux library to draw, but I prefer to use Cocoa for my GUI. (I am using Xcode and Mac OS X) I get no errors but the lines don’t draw here is my code:
#import "LineView.h"
#import <OpenGL/gl.h>
#define drawOneLine(x1,y1,x2,y2) glBegin(GL_LINES); \
glVertex2f ((x1),(y1)); glVertex2f ((x2),(y2)); glEnd();
@implementation LineView
static void drawAnObject(){
int i;
// Draw all lines in white
glColor3f(1.0, 1.0, 1.0);
//In 1st row, 3 lines, each with a different stipple
glEnable(GL_LINE_STIPPLE);
glLineStipple(1, 0x0101); //Dotted
drawOneLine(50.0, 125.0, 150.0, 125.0);
glLineStipple (1, 0x00FF); /* dashed */
drawOneLine (150.0, 125.0, 250.0, 125.0);
glLineStipple (1, 0x1C47); /* dash/dot/dash */
drawOneLine (250.0, 125.0, 350.0, 125.0);
/* in 2nd row, 3 wide lines, each with different stipple */
glLineWidth (5.0);
glLineStipple (1, 0x0101);
drawOneLine (50.0, 100.0, 150.0, 100.0);
glLineStipple (1, 0x00FF);
drawOneLine (150.0, 100.0, 250.0, 100.0);
glLineStipple (1, 0x1C47);
drawOneLine (250.0, 100.0, 350.0, 100.0);
glLineWidth (1.0);
/* in 3rd row, 6 lines, with dash/dot/dash stipple, */
/* as part of a single connected line strip */
glLineStipple (1, 0x1C47);
glBegin (GL_LINE_STRIP);
for (i = 0; i < 7; i++)
glVertex2f (50.0 + ((GLfloat) i * 50.0), 75.0);
glEnd ();
/* in 4th row, 6 independent lines, */
/* with dash/dot/dash stipple */
for (i = 0; i < 6; i++) {
drawOneLine (50.0 + ((GLfloat) i * 50.0),
50.0, 50.0 + ((GLfloat)(i+1) * 50.0), 50.0);
}
/* in 5th row, 1 line, with dash/dot/dash stipple */
/* and repeat factor of 5 */
glLineStipple (5, 0x1C47);
drawOneLine (50.0, 25.0, 350.0, 25.0);
glFlush ();
}
- (void) drawRect: (NSRect) bounds{
glClearColor(0.0, 0.0, 0.0, 0.0);
glClear(GL_COLOR_BUFFER_BIT);
glShadeModel(GL_FLAT);
drawAnObject();
}
-(void)reshape{
NSRect rectView = [self bounds];
glViewport(0, 0, rectView.size.width, rectView.size.height);
}
@end
What’s causing the lines not to draw?
Thanks!