mandelbrot

annotate src/palette.c @ 0:4d85805eb875

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mandelbrot initial import
author John Tsiombikas <nuclear@mutantstargoat.com>
date Tue, 19 Jun 2012 06:48:38 +0300
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nuclear@0 1 /*
nuclear@0 2 A simple interactive mandelbrot fractal explorer
nuclear@0 3 Copyright (C) John Tsiombikas <nuclear@member.fsf.org>
nuclear@0 4
nuclear@0 5 This program is free software: you can redistribute it and/or modify
nuclear@0 6 it under the terms of the GNU General Public License as published by
nuclear@0 7 the Free Software Foundation, either version 3 of the License, or
nuclear@0 8 (at your option) any later version.
nuclear@0 9
nuclear@0 10 This program is distributed in the hope that it will be useful,
nuclear@0 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@0 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
nuclear@0 13 GNU General Public License for more details.
nuclear@0 14
nuclear@0 15 You should have received a copy of the GNU General Public License
nuclear@0 16 along with this program. If not, see <http://www.gnu.org/licenses/>.
nuclear@0 17 */
nuclear@0 18 #include <stdio.h>
nuclear@0 19 #include <stdlib.h>
nuclear@0 20 #include <string.h>
nuclear@0 21 #include <errno.h>
nuclear@0 22 #include "palette.h"
nuclear@0 23
nuclear@0 24 struct palnode {
nuclear@0 25 double t;
nuclear@0 26 double r, g, b;
nuclear@0 27 struct palnode *next;
nuclear@0 28 };
nuclear@0 29
nuclear@0 30 static void fill_palette(struct palnode *list);
nuclear@0 31 static void free_list(struct palnode *list);
nuclear@0 32
nuclear@0 33 int load_palette(const char *fname)
nuclear@0 34 {
nuclear@0 35 FILE *fp;
nuclear@0 36 int res;
nuclear@0 37
nuclear@0 38 if(!(fp = fopen(fname, "r"))) {
nuclear@0 39 fprintf(stderr, "failed to open palette file: %s: %s\n", fname, strerror(errno));
nuclear@0 40 return -1;
nuclear@0 41 }
nuclear@0 42 res = load_palette_file(fp);
nuclear@0 43 fclose(fp);
nuclear@0 44 return res;
nuclear@0 45 }
nuclear@0 46
nuclear@0 47 int load_palette_file(FILE *fp)
nuclear@0 48 {
nuclear@0 49 char buf[256];
nuclear@0 50 struct palnode *palist = 0, *patail = 0;
nuclear@0 51
nuclear@0 52 if(!fgets(buf, sizeof buf, fp) || strstr(buf, "GRAD") != buf) {
nuclear@0 53 fprintf(stderr, "invalid palette file, lack of magic!\n");
nuclear@0 54 return -1;
nuclear@0 55 }
nuclear@0 56
nuclear@0 57 while(fgets(buf, sizeof buf, fp)) {
nuclear@0 58 struct palnode *node;
nuclear@0 59 float t, r, g, b;
nuclear@0 60
nuclear@0 61 if(sscanf(buf, "%f %f %f %f", &t, &r, &g, &b) != 4) {
nuclear@0 62 fprintf(stderr, "invalid palette file format\n");
nuclear@0 63 free_list(palist);
nuclear@0 64 return -1;
nuclear@0 65 }
nuclear@0 66
nuclear@0 67 if(!(node = malloc(sizeof *node))) {
nuclear@0 68 fprintf(stderr, "failed to allocate memory for list node\n");
nuclear@0 69 free_list(palist);
nuclear@0 70 return -1;
nuclear@0 71 }
nuclear@0 72 node->t = t;
nuclear@0 73 node->r = r;
nuclear@0 74 node->g = g;
nuclear@0 75 node->b = b;
nuclear@0 76 node->next = 0;
nuclear@0 77
nuclear@0 78 if(palist) {
nuclear@0 79 patail->next = node;
nuclear@0 80 patail = node;
nuclear@0 81 } else {
nuclear@0 82 palist = patail = node;
nuclear@0 83 }
nuclear@0 84 }
nuclear@0 85
nuclear@0 86 fill_palette(palist);
nuclear@0 87 free_list(palist);
nuclear@0 88 return 0;
nuclear@0 89 }
nuclear@0 90
nuclear@0 91 static void fill_palette(struct palnode *list)
nuclear@0 92 {
nuclear@0 93 int i;
nuclear@0 94 struct palnode *start, *end;
nuclear@0 95 static const struct palnode last = {1.0, 0.0, 0.0, 0.0, 0};
nuclear@0 96
nuclear@0 97 memset(palette, 0, sizeof palette);
nuclear@0 98 if(!list) {
nuclear@0 99 return;
nuclear@0 100 }
nuclear@0 101
nuclear@0 102 start = list;
nuclear@0 103 end = list->next;
nuclear@0 104
nuclear@0 105 while(start && start != &last) {
nuclear@0 106 int sidx, eidx, count;
nuclear@0 107 double r, g, b, dr, dg, db;
nuclear@0 108
nuclear@0 109 if(!end) {
nuclear@0 110 end = (struct palnode*)&last;
nuclear@0 111 }
nuclear@0 112
nuclear@0 113 sidx = (int)(start->t * PAL_SIZE);
nuclear@0 114 eidx = (int)(end->t * PAL_SIZE);
nuclear@0 115 count = eidx - sidx;
nuclear@0 116
nuclear@0 117 r = start->r;
nuclear@0 118 g = start->g;
nuclear@0 119 b = start->b;
nuclear@0 120 dr = (end->r - start->r) / count;
nuclear@0 121 dg = (end->g - start->g) / count;
nuclear@0 122 db = (end->b - start->b) / count;
nuclear@0 123
nuclear@0 124 for(i=0; i<count; i++) {
nuclear@0 125 palette[sidx + i].r = (int)(r * 255.0);
nuclear@0 126 palette[sidx + i].g = (int)(g * 255.0);
nuclear@0 127 palette[sidx + i].b = (int)(b * 255.0);
nuclear@0 128 r += dr;
nuclear@0 129 g += dg;
nuclear@0 130 b += db;
nuclear@0 131 }
nuclear@0 132
nuclear@0 133 start = end;
nuclear@0 134 end = end->next;
nuclear@0 135 }
nuclear@0 136 }
nuclear@0 137
nuclear@0 138 static void free_list(struct palnode *list)
nuclear@0 139 {
nuclear@0 140 while(list) {
nuclear@0 141 void *tmp = list;
nuclear@0 142 list = list->next;
nuclear@0 143 free(tmp);
nuclear@0 144 }
nuclear@0 145 }