   Texture mapping causes lines to dull
  i want to simulate the orbit of a satellite over a sphere mapped with the earth terrain. When i use the texture , the orbit , which is a series of GL_LINE_STRIP, becomes very dullJust the addition of OpenGL.GL.glColorMaterial ( OpenGL.GL.GL_FRONT_AND_BACK, OpenGL.GL.GL_EMISSION ) OpenGL.GL.glEnable(OpenGL.GL.GL_TEXTURE_2D);OpenGL.GL.glTexParameteri(OpenGL.GL.GL_TEXTURE_2D, OpenGL.GL.GL_TEXTURE_WRAP_S, OpenGL.GL.GL_CLAMP);OpenGL.GL.glTexParameteri(OpenGL.GL.GL_TEXTURE_2D, OpenGL.GL.GL_TEXTURE_WRAP_T, OpenGL.GL.GL_CLAMP);OpenGL.GL.glTexParameterf(OpenGL.GL.GL_TEXTURE_2D, OpenGL.GL.GL_TEXTURE_MAG_FILTER, OpenGL.GL.GL_LINEAR);OpenGL.GL.glTexParameteri(OpenGL.GL.GL_TEXTURE_2D, OpenGL.GL.GL_TEXTURE_MIN_FILTER, OpenGL.GL.GL_LINEAR); causes a following line strip to dull. I am not using lighting.   
  I always disable texturemapping when drawing lines. I have experienced the same thing and that usually helps. Just enable texturemapping again when you are done drawing the line.   ;  This worked, thanks a lot, but i would still like o know why is this happening, intutively this should not be happening right?   ;  All OpenGL rendering functions support texture mapping, including GL_LINE_STRIP. If you don't set tex coords for the new vertexes, the renderer applies the tex coords you already had set last. So, it was blending the texcoord last set from your texture over the newly rendered line. Like O-san said, to stop this, just call glDisable(GL_TEXTURE_XD) where X is your 1 or 2, etc.It that clear and concise?   