[solved] Back half of cube is being clipped (using geometry shader).

ClickerMonkey · November 24, 2013, 4:49pm

I’m working on a geometry shader that takes points, color, rotation, scale and generates a 3d cube.

The code (including the GS, VS, and FS):

gist.github.com

https://gist.github.com/ClickerMonkey/7605059

PointToCube.java

package com.axe.sandbox.gs;

import java.io.InputStream;
import java.nio.ByteBuffer;
import java.util.HashMap;
import java.util.Map;

import org.lwjgl.BufferUtils;
import org.lwjgl.input.Keyboard;
import org.lwjgl.opengl.ARBBufferObject;

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shader.fs

#version 110
 
in vec4 frag_color;
 
void main()
{
    gl_FragColor = frag_color;
}

shader.gs

#version 330
 
layout(points) in;
layout(triangle_strip, max_vertices=24) out;
 
in vec4 v_color[];
in vec4 v_props[];
 
out vec4 frag_color;

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For some odd reason the back half of the rotating cubes are clipped… and they’re not clipped on the back plane (which is at 100) because I can move them closer and further and the back is STILL clipped.

I’m fairly sure it has to do with my geometry shader, but after googling for hours I can’t find anything =/

The only thing I suspect it could be would be gl_ClipDistance - something I could set to fix it? But there’s no good information online…

Thanks!

ClickerMonkey · November 24, 2013, 5:59pm

Here’s a picture of what it looks like:

http://i1150.photobucket.com/albums/o604/ClickerMonkey/Clipped_zpsfba5e54a.png

lcass · November 25, 2013, 12:13am

That doesn’t look like culling. How is it being rendered what type of polygon are you using.

Danny02 · November 25, 2013, 12:43am

use vec3 for the position and just a mat3 for the roation matrix. I guess your problem is that the w component of the corners is 0

ClickerMonkey · November 25, 2013, 3:39pm

That’s why I said clipping =P

Holy moly! You’re awesome =P I changed the w component of the corners to be 1.0 and not 0.0 and it worked! (derp they’re points not normals)

Very odd, I wonder how having them be 0.0 would cause the backside to be clipped…

Anywho, thanks!