Clearing a previously set color

[kainjow]

I'm having a strange issue where I draw a texture and then draw a line afterwards in red. The texture draws fine, and so does the line, but if I redraw again, the texture draws with a shade of red.

(I'm working in Cocoa and am new to OpenGL, although I wrote a small cross-platform Tetris game back in 06 but have since forgotten everything. Currently trying to learn a little more by porting over an old 2D game.)

Here's the code:

- (void)drawRect:(NSRect)rect
{
	[[self openGLContext] makeCurrentContext];
 
	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glLoadIdentity();
 
	if (!bgImg)
		bgImg = [[GLImage alloc] initWithImageNamed:@"background.png"];
	[bgImg drawAtPoint:NSZeroPoint];
 
	glBegin(GL_LINES);
	glColor3d(1.0, 0.0, 0.0);
	glLineWidth(5.0);
	glVertex3f(0.0f, 0.0f, 0.0f);
	glVertex3f(mouseLoc.x, mouseLoc.y, 0.0f);
	glEnd();
 
	[[self openGLContext] flushBuffer];
}
 
- (void)mouseDragged:(NSEvent *)theEvent
{
	mouseLoc = [self convertPoint:[theEvent locationInWindow] fromView:nil];
	[self setNeedsDisplay:YES];
}

GLImage is just a separate class that handles loading and drawing an image.

[kainjow]

Ok this seems to fix it, although I'm confused as to why this isn't causing it to display solid white.

glColor3f(1.0, 1.0, 1.0);

[-Ekh-]

It seems your texture modulates with the color. It must be your texture environment (look at your glTexEnv funcs).

[kainjow]

Thanks. I looked into it and using glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE); fixes it without having to use glColor3f().