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/*********************************************************************
* kd-forest *
* Copyright (C) 2015 Tavian Barnes <tavianator@tavianator.com> *
* *
* This program is free software. It comes without any warranty, to *
* the extent permitted by applicable law. You can redistribute it *
* and/or modify it under the terms of the Do What The Fuck You Want *
* To Public License, Version 2, as published by Sam Hocevar. See *
* the COPYING file or http://www.wtfpl.net/ for more details. *
*********************************************************************/
#include "generate.h"
#include "color.h"
#include "util.h"
#include <stdlib.h>
uint32_t *
generate_colors(const options_t *options)
{
const unsigned int bit_depth = options->bit_depth;
mode_t mode = options->mode;
// Allocate bits from most to least perceptually important
unsigned int grb_bits[3];
for (unsigned int i = 0; i < 3; ++i) {
grb_bits[i] = (bit_depth + 2 - i)/3;
}
uint32_t *colors = xmalloc(options->ncolors*sizeof(uint32_t));
for (uint32_t i = 0; i < (1 << bit_depth); ++i) {
uint32_t n = i;
uint32_t grb[3] = {0, 0, 0};
switch (mode) {
case MODE_MORTON:
for (unsigned int j = 0; j < bit_depth; ++j) {
grb[j%3] |= (i & (1 << j)) >> (j - j/3);
}
break;
default:
for (unsigned int j = 0; j < 3; ++j) {
grb[j] = n & ((1 << grb_bits[j]) - 1);
n >>= grb_bits[j];
}
break;
}
// Pad out colors, and put them in RGB order
grb[0] <<= 16U - grb_bits[0];
grb[1] <<= 24U - grb_bits[1];
grb[2] <<= 8U - grb_bits[2];
colors[i] = grb[1] | grb[0] | grb[2];
}
switch (mode) {
case MODE_HUE_SORT:
qsort(colors, options->ncolors, sizeof(uint32_t), color_comparator);
break;
case MODE_RANDOM:
// Fisher-Yates shuffle
for (unsigned int i = options->ncolors; i-- > 0;) {
unsigned int j = xrand(i + 1);
uint32_t temp = colors[i];
colors[i] = colors[j];
colors[j] = temp;
}
break;
default:
break;
}
return colors;
}
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