Re: White spot

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Brian Furtaw (brian++at++sgi.com)
Thu, 20 Mar 1997 15:42:52 -0500

You highlight is being blend with the textured color because textures are
applied after lighting. To get the effect you desire you need some kind of
texturing that emualates lighting, hence you need Projected Texture mapping and
it is already available in hardware on the RE2 and IR. The way you do this is
to create an intensity map of your light source, look at
/usr/demos/data/textures/spotlight.rgb to get an idea. Then in IRISGL we used
to set the repeat pfTexture::setRepeat(PFTEX_WRAP, TX_SELECT) was the key with
OpenGL however you need to set to ???? PFTEX_CLAMP maybe or
GL_CLAMP_TO_EDGE_SGIS , although clamping in IRISGL meant that the last row of
pixels in the texture map was smeared acrossed the remainder (U or V value > 1
) of the polygon, not what you want here. I'll have to ask around for the
answer in OpenGL or maybe someone else can help me out here.

Brian

On Mar 20, 3:30pm, Yann Andenmatten wrote:
> Subject: White spot
> Hi,
>
> I'm trying to have an shiny textured object. I have set a pfMaterial with
> specular light to (1.0,1.0,1.0) and shininess to 16.0. It's working, but the
> spot on the object isn't white (the color of the spot is defined by the
> texture). The light has also a specular light to (1.0,1.0,1.0).
>
> How can I get a very saturated spot ?
> Any idea ?
>
> Thanks for help.
>
> Yann Andenmatten
>
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