var spr = argument0;
sprite_set_offset(spr,0,0);
sprh = sprite_get_height(spr);
sprw = sprite_get_width(spr);

for(var i = 0; i < sprh ; i++)
{
    for(var j = 0; j < sprw; j++)
    {
        cArray[i,j] = -1;
    }
}

var palSurf = surface_create(sprw,sprh);

//create surface and draw pallete to it
if (!surface_exists(palSurf))
{
    var palSurf = surface_create(sprw,sprh);
}

surface_set_target(palSurf);
draw_clear_alpha(c_black, 0);
draw_sprite(spr,0,0,0);
for(var i = 0; i < sprh; i++)
{
    for(var j = 0; j < sprw; j++)
    {
        cArray[i,j] = surface_getpixel(palSurf,j,i);
    }
}
surface_free(palSurf);

//
colNum = array_length_2d(cArray,0);
pos = 0;
posPrev = -1;
posMAX = array_height_2d(cArray);
con = 255;
myShader = argument1;

passToShader(myShader);