1 files changed, 77 insertions, 0 deletions
diff --git a/generate.c b/generate.c
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index 0000000..6b7e925
--- /dev/null
+++ b/generate.c
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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;
+}