zoldar256

08-03-2001, 12:56 PM

So I have a model of a light that I draw that is in the same place as the light. I first disable lighting, then draw the object, re-enable it then draw everything else. Simple right?

Well... my light model shows up at 50 or something tranparency, but I don't have blending or anything enabled, nor is it colored with an alpha specified. Another weird thing is that I can't use the select buffer to pick it, it simple is unpickable.

It gets stranger, when I enable lighting. My object shows up at no transparency and is pickable throught the select buffer...

Ummmmm... Help?

zoldar256

08-03-2001, 01:21 PM

Originally posted by Michael Steinberg:

I need code

haha.. I knew this would be a problem. Unfortuanitly most of it is in an all sorts of proprietary app so it's tough.

Here's the routine that draws the object though:

void C3DMaskPlot: http://www.opengl.org/discussion_boards/ubb/biggrin.gifrawLightObject()

{

glPushMatrix();

glLoadIdentity();

// Draw the light object

glDisable(GL_LIGHTING);

glRotatef(lightRot[0], 1.0, 0.0, 0.0);

glRotatef(lightRot[1], 0.0, 1.0, 0.0);

glRotatef(lightRot[2], 0.0, 0.0, 1.0);

glTranslatef(0, (sqrt(height*height+length*length+width*width)*0.9 5), 0);

if (showLight == true)

{

// Ok, draw it

glLoadName(666);

// Ack! Lights are tools of the devil. ;-)

GLdouble size = sqrt(width*width + length*length + height*height) * 0.05;

// The cone.

glBegin(GL_TRIANGLES);

for (GLfloat t = 0; t <= 2*3.141592654 - (0.1 * 3.141592654); t+=(0.1 * 3.141592654))

{

glColor3f(0.90,0.90,0.90);

glVertex3f(size*cos(t + (0.1 * 3.141592654)), 0, size*sin(t + (0.1 * 3.141592654)));

glColor3f(0.90,0.90,0.90);

glVertex3f(size*cos(t), 0, size*sin(t));

glColor3f(1,0.85,0.85);

glVertex3f(0,size,0);

}

glColor3f(0.90,0.90,0.90);

glVertex3f(size*cos(0), 0, size*sin(0));

glColor3f(0.90,0.90,0.90);

glVertex3f(size*cos(0 - (0.1 * 3.141592654)), 0, size*sin(0 - (0.1 * 3.141592654)));

glColor3f(1,0.85,0.85);

glVertex3f(0,size,0);

glEnd();

// The Tube looking part.

glBegin(GL_QUADS);

for (GLfloat t = 0; t <= 2*3.141592654 - (0.1 * 3.141592654); t+=(0.1 * 3.141592654))

{

glColor3f(0.95,0.88,0.88);

glVertex3f((size/2.0)*cos(t), size + size*0.1, (size/2.0)*sin(t));

glColor3f(0.95,0.88,0.88);

glVertex3f((size/2.0)*cos(t + (0.1 * 3.141592654)), size + size*0.1, (size/2.0)*sin(t + (0.1 * 3.141592654)));

glColor3f(0.95,0.88,0.88);

glVertex3f((size/2.0)*cos(t + (0.1 * 3.141592654)), size/2.0, (size/2.0)*sin(t + (0.1 * 3.141592654)));

glColor3f(0.95,0.88,0.88);

glVertex3f((size/2.0)*cos(t), size/2.0, size*sin(t));

}

glColor3f(0.95,0.88,0.88);

glVertex3f((size/2.0)*cos(0 - (0.1 * 3.141592654)), size + size*0.1, (size/2.0)*sin(0 - (0.1 * 3.141592654)));

glColor3f(0.95,0.88,0.88);

glVertex3f((size/2.0)*cos(0), size + size*0.1, (size/2.0)*sin(0));

glColor3f(0.95,0.88,0.88);

glVertex3f((size/2.0)*cos(0), size/2.0, (size/2.0)*sin(0));

glColor3f(0.95,0.88,0.88);

glVertex3f((size/2.0)*cos(0 - (0.1 * 3.141592654)), size/2.0, (size/2.0)*sin(0 - (0.1 * 3.141592654)));

glEnd();

// The top of it.

glBegin(GL_TRIANGLES);

for (GLfloat t = 0; t <= 2*3.141592654 - (0.1 * 3.141592654); t+=(0.1 * 3.141592654))

{

glColor3f(1,0.85,0.85);

glVertex3f((size/2.0)*cos(t + (0.1 * 3.141592654)), size + size*0.1, (size/2.0)*sin(t + (0.1 * 3.141592654)));

glColor3f(1,0.85,0.85);

glVertex3f((size/2.0)*cos(t), size + size*0.1, (size/2.0)*sin(t));

glColor3f(1,0.85,0.85);

glVertex3f(0,size + size*0.1,0);

}

glColor3f(1,0.85,0.85);

glVertex3f((size/2.0)*cos(0), size + size*0.1, (size/2.0)*sin(0));

glColor3f(1,0.85,0.85);

glVertex3f((size/2.0)*cos(0 - (0.1 * 3.141592654)), size + size*0.1, (size/2.0)*sin(0 - (0.1 * 3.141592654)));

glColor3f(1,0.85,0.85);

glVertex3f(0,size + size*0.1,0);

glEnd();

}

// Reset Matrix

glEnable(GL_LIGHTING);

// Now do the actual light

glLightfv(GL_LIGHT0, GL_POSITION, lightPos);

glPopMatrix();

}

Michael Steinberg

08-03-2001, 01:25 PM

Hmmm, other than that you don't specify the matrix you're working on here I don't see anything. Could I have a look at the initialization code and the one to clear the screen?

Michael Steinberg

08-03-2001, 01:27 PM

Which lights did you enable after all?

zoldar256

08-03-2001, 01:36 PM

Originally posted by Michael Steinberg:

Which lights did you enable after all?

Hmmm... I don't know why this was affecting it. But I was using a translate in my projection matrix. And for some reason when drawn with lighting the piching worked, without it didn't. So I removed the translate fromt he projection matrix and all is well in the universe again.

Michael Steinberg

08-03-2001, 01:40 PM

No transformations to the projections matrix. That kills lighting. Never! http://www.opengl.org/discussion_boards/ubb/smile.gif

Transformations only belong into the modelview matrix.

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