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OpenGL OpenGL problem with shadows: I can't seem to disable writing to the color buffer

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I'm trying to get some shadows to be cast off of this cube in a scene. I've got GL_QUADS being extruded off the cube to the ground, but I don't want them being written to the color buffer, just the stencil buffer. I tried google and looking at NeHe's tutorials, but I can't figure out where I'm going wrong. I end up with some GL_QUADS appearing in the scene coming off the cube, when they should be invisible and only used for stcencil buffer calculations.
void drawShadows(Light* light)
    // Most of this stuff is straight from the NeHe tutorial on shadows

    // Prepare the GL stuff
	glDisable( GL_LIGHTING ); // No drawing the shadow volume quads
	glDepthMask( GL_FALSE ); // Don't keep track of their depth either
	glDepthFunc( GL_LEQUAL ); // Not sure what this is, but it was in the tutorial
    glEnable( GL_STENCIL_TEST ); // Prepare the stencil buffer
	glStencilFunc( GL_ALWAYS, 1, 0xFFFFFFFFL );

    // First Pass. Increase Stencil Value In The Shadow
	glStencilOp( GL_KEEP, GL_KEEP, GL_INCR );
	// Second Pass. Decrease Stencil Value In The Shadow
	glStencilOp( GL_KEEP, GL_KEEP, GL_DECR );

	glColorMask( GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE );	// Enable Rendering To Colour Buffer For All Components

void doShadowPass(Light* light)
    float vector1[3];
    float vector2[3];
    float normalizedVector1[3];
    float normalizedVector2[3];

    for (int i = 0; i < 4; i++)
        // Code ommited here
        // It's just where I get the edges for the edges[][] array
            glVertex3f(edges[0][0], edges[0][1], edges[0][2]);
            glVertex3f(edges[1][0], edges[1][1], edges[1][2]);
            glVertex3f(edges[1][0] + (normalizedVector2[0] * INFINITY), 
                       edges[1][1] + (normalizedVector2[1] * INFINITY), 
                       edges[1][2] + (normalizedVector2[2] * INFINITY));
            glVertex3f(edges[0][0] + (normalizedVector1[0] * INFINITY), 
                       edges[0][1] + (normalizedVector1[1] * INFINITY), 
                       edges[0][2] + (normalizedVector1[2] * INFINITY));
EDIT: Didn't realize there was a forum for OpenGL specifically. Can someone move this? [Edited by - Amablue on April 2, 2008 2:29:20 PM]

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