#mapping UVs values from one texture to another

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deft bay
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This is the code I have so far, the output is green which is the first color of the palette

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float x = UV.x * 255.0;
float y = UV.y * 255.0;

//float rng = (x + (TextureSize.y - y - 1) * TextureSize.x) * 4;
float rng = (x + y * TextureSize.x) * 4;
float rngMapped = rng / 255.0;

float2 idx = float2(rng,0);

half4 pc = tex2D(PaletteTexture,idx);

teste = pc;```
placid wraith
#

Since the palette is only horizontal, you don't really have to care about the Y coord.
And for X, I would also add a half pixel offset, just to be sure.

Also, you probably don't want to map the XY coord of the source texture to the palette, this doesn't really make sense ?
Usually, for paletting, sample the sprite, take the pixel value and use it as index of the palette.

It gives something like this :

half colorIndex = tex2D(MainTexture, UV).r;

float x = ( floor( colorIndex * 255.0) + 0.5 ) / 255.0;
float y = 0.5;

half4 pc = tex2D( PaletteTexture, float2( x, y ) );