GLSL Fragment Shader strange behaviour

Hi,

I’am trying to use GLSL and i’ve only reverted the x-coordinate in the vertex shader.

The problem is : When I try to keep the color used in the state machine, nothing is displayed.

E.g : gl_FragColor = vec4(1.0,1.0,0.0,1.0); displays the correct yellow color but gl_FragColor = gl_Color displays nothing.

Am I missing a point, or is there a driver / card problem
(Linux , NVidia FX5200 with latest drivers)

Thanks for any help!