Re: Difficulty with the shaders tutorial

On Fri, Feb 17, 2012 at 12:39 AM, Nicolas Rougier
<[email protected]> wrote:
>
>
> No need to go for OpenGL 3.0 to use shaders.
>
> Here is code that do what you want (translated from glumpy):
>
> Color are transformed using the alpha channel of the image (see fragment code) and the color lookup table is a 1d texture. Fill it with any color sequence you want.
>
> Nicolas
>

That did it! I have working false-color now; all that remains is to
integrate it into the rest of my program.

For what it's worth, the color sequence I used does the following
ramps (percentages indicate distance along the texture):

Red: 0 at 35% to 1 at 67%, held through to 86%, down to .5 at 100%
Green: 0 at 10% to 1 at 39%, held through to 61%, down to 0 at 90%
Blue: .5 at 0% to 1 at 10%, held through to 31%, down tot 0 at 65%

This starts at dark blue, then goes to cyan, green, yellow, orange,
red. I got the percentages by manually examining the output of using
matplotlib's savefig function.

-Chris

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