Scratch that! It appears that the issue arises by setting depthFunc or any other attribute before creating a window. On Thu, Apr 1, 2010 at 5:54 AM, Scott wrote:

Hello!

I have a problem when trying to run some code found on this tutorial page:

http://public.beuth-hochschule.de/~panitz/hopengl/skript.htmlhttp://public.beuth-hochschule.de/%7Epanitz/hopengl/skript.html

The demo is called "LightCube." The problem seems to have to do with the following line (which I've commented out in the provided source):

depthFunc $= Just Less

Uncommenting the line gives a Segmentation Fault when I run the executable generated by:

ghc --make -package GLUT -o LightCube LightCube.hs

Does anyone else have this problem? Here is the necessary code: * LightCube*

import Graphics.Rendering.OpenGL import Graphics.UI.GLUT as GLUT

import Cube

main = do (progName,_) <- getArgsAndInitialize

-- depthFunc $= Just Less

createWindow progName

lighting $= Enabled position (Light 0) $= Vertex4 1 0.4 0.8 1 light (Light 0) $= Enabled

displayCallback $= display mainLoop

display = do clear [ColorBuffer] rotate 40 (Vector3 1 1 (1::GLfloat)) cube 0.5 loadIdentity flush * Cube * module Cube where

import Graphics.Rendering.OpenGL import Graphics.UI.GLUT as GLUT

import PointsForRendering

cube l = renderAs Quads corners where corners = [(l,0,l),(0,0,l),(0,l,l),(l,l,l) ,(l,l,l),(l,l,0),(l,0,0),(l,0,l) ,(0,0,0),(l,0,0),(l,0,l),(0,0,l) ,(l,l,0),(0,l,0),(0,0,0),(l,0,0) ,(0,l,l),(l,l,l),(l,l,0),(0,l,0) ,(0,l,l),(0,l,0),(0,0,0),(0,0,l) ] * PointsForRendering*

module PointsForRendering where import Graphics.UI.GLUT import Graphics.Rendering.OpenGL

renderInWindow displayFunction = do (progName,_) <- getArgsAndInitialize createWindow progName displayCallback $= displayFunction mainLoop

displayPoints points primitiveShape = do renderAs primitiveShape points flush

renderAs figure ps = renderPrimitive figure$makeVertexes ps

makeVertexes = mapM_ (\(x,y,z)->vertex$Vertex3 x y z)

mainFor primitiveShape = renderInWindow (displayMyPoints primitiveShape)

displayMyPoints primitiveShape = do clear [ColorBuffer] currentColor $= Color4 1 1 0 1 displayPoints myPoints primitiveShape

myPoints = [(0.2,-0.4,0::GLfloat) ,(0.46,-0.26,0) ,(0.6,0,0) ,(0.6,0.2,0) ,(0.46,0.46,0) ,(0.2,0.6,0) ,(0.0,0.6,0) ,(-0.26,0.46,0) ,(-0.4,0.2,0) ,(-0.4,0,0) ,(-0.26,-0.26,0) ,(0,-0.4,0) ]