1 // -*- mode: c++; c-set-style: "stroustrup"; tab-width: 4; -*-
2 //
3 // CReaderHDR.c
4 //
5 // Copyright (C) 2004 Koji Nakamaru
6 //
7 // This program is free software; you can redistribute it and/or modify
8 // it under the terms of the GNU General Public License as published by
9 // the Free Software Foundation; either version 2, or (at your option)
10 // any later version.
11 //
12 // This program is distributed in the hope that it will be useful,
13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 // GNU General Public License for more details.
16 //
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software Foundation,
19 // Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20 //
21
22 //
23 // NOTE: The following code is based on the code provided by Bruce
24 // Jonathan Walter at http://www.graphics.cornell.edu/~bjw/rgbe.html
25 //
26
27 #include "common.h"
28 #include "CReaderHDR.h"
29
30 static const char *_magic[] = {
31 "#?",
32 NULL,
33 };
34
35 static bool readData(CFile *fp, CImage<float, 4> *image, float *data, int num);
36 static void rgbe2float(uint8_t rgbe[4], float *red, float *green, float *blue);
37 #if 0
38 static void float2rgbe(float red, float green, float blue, uint8_t rgbe[4]);
39 #endif
40
41 // public functions
42
CReaderHDR()43 CReaderHDR::CReaderHDR()
44 : CReader()
45 {
46 magic = _magic;
47 }
48
~CReaderHDR()49 CReaderHDR::~CReaderHDR()
50 {
51 }
52
initialize(CFile * fp,char * magic)53 bool CReaderHDR::initialize(
54 CFile *fp,
55 char *magic)
56 {
57 float gamma = 1.0;
58 float exposure = 1.0;
59 char buf[256];
60 bool is_format_found;
61 if (fp->gets(buf, sizeof(buf)) == NULL
62 || buf[0] == '\0'
63 || buf[strlen(buf) - 1] != '\n') {
64 return false;
65 }
66 is_format_found = false;
67 for (;;) {
68 if (fp->gets(buf, sizeof(buf)) == NULL) {
69 return false;
70 }
71 if (buf[0] == '#') {
72 continue;
73 } else if (buf[0] == '\n') {
74 break;
75 } else if (strcmp(buf, "FORMAT=32-bit_rle_rgbe\n") == 0) {
76 is_format_found = true;
77 } else if (sscanf(buf, "GAMMA=%g", &gamma) == 1) {
78 continue;
79 } else if (sscanf(buf, "EXPOSURE=%g", &exposure) == 1) {
80 continue;
81 } else if (buf[strlen(buf) - 1] != '\n') { // too long line, something wrong
82 return false;
83 }
84 }
85 if (! is_format_found
86 || fp->gets(buf, sizeof(buf)) == NULL
87 || sscanf(buf, "-Y %d +X %d", &_h, &_w) != 2
88 || _h <= 0
89 || _w <= 0) {
90 return false;
91 }
92 return true;
93 }
94
read(CFile * fp,CImage<float,4> * image)95 void CReaderHDR::read(
96 CFile *fp,
97 CImage<float, 4> *image)
98 {
99 float *data = image->pixel(0, 0);
100 if (_w < 8 || _w > 0x7fff) {
101 // non-rle
102 readData(fp, image, data, _w * _h);
103 }
104 uint8_t rgbe[4], scanline[4 * _w];
105 for (int y = 0; y < _h; y++) {
106 if (fp->read(rgbe, sizeof(rgbe)) != sizeof(rgbe)) {
107 return;
108 }
109 if (rgbe[0] != 2 || rgbe[1] != 2 || rgbe[2] & 0x80) {
110 // non-rle
111 rgbe2float(rgbe, &data[0], &data[1], &data[2]);
112 data[3] = 1.0;
113 data += 4;
114 readData(fp, image, data, _w * _h - 1);
115 break;
116 }
117 if (((int)rgbe[2] << 8 | rgbe[3]) != _w) {
118 return;
119 }
120 uint8_t *ptr = &scanline[0];
121 // read each of the four channels for the scanline into the buffer
122 for (int i = 0; i < 4; i++) {
123 uint8_t *ptr_end = &scanline[(i + 1) * _w];
124 while (ptr < ptr_end) {
125 uint8_t buf[2];
126 if (fp->read(buf, 2) != 2) {
127 return;
128 }
129 if (buf[0] > 128) {
130 // a run of the same value
131 int count = buf[0] - 128;
132 if (count == 0 || count > ptr_end - ptr) {
133 return;
134 }
135 while (count-- > 0) {
136 *ptr++ = buf[1];
137 }
138 } else {
139 // a non-run
140 int count = buf[0];
141 if (count == 0 || count > ptr_end - ptr) {
142 return;
143 }
144 *ptr++ = buf[1];
145 if (--count > 0) {
146 if (fp->read(ptr, count) != (size_t)count) {
147 return;
148 }
149 ptr += count;
150 }
151 }
152 }
153 }
154 // now convert data from buffer into floats
155 image->lock();
156 for (int x = 0; x < _w; x++) {
157 rgbe[0] = scanline[x + 0 * _w];
158 rgbe[1] = scanline[x + 1 * _w];
159 rgbe[2] = scanline[x + 2 * _w];
160 rgbe[3] = scanline[x + 3 * _w];
161 rgbe2float(rgbe, &data[0], &data[1], &data[2]);
162 data[3] = 1.0;
163 data += 4;
164 }
165 image->setChanged(true);
166 image->unlock();
167 }
168 }
169
170 // protected functions
171 // private functions
172 // local functions
173
readData(CFile * fp,CImage<float,4> * image,float * data,int num)174 static bool readData(
175 CFile *fp,
176 CImage<float, 4> *image,
177 float *data,
178 int num)
179 {
180 uint8_t rgbe[4];
181
182 while (num-- > 0) {
183 if (fp->read(rgbe, sizeof(rgbe)) == sizeof(rgbe)) {
184 image->lock();
185 rgbe2float(rgbe, &data[0], &data[1], &data[2]);
186 data[3] = 1.0;
187 data += 4;
188 image->setChanged(true);
189 image->unlock();
190 } else {
191 return false;
192 }
193 }
194 return true;
195 }
196
rgbe2float(uint8_t rgbe[4],float * red,float * green,float * blue)197 static void rgbe2float(
198 uint8_t rgbe[4],
199 float *red,
200 float *green,
201 float *blue)
202 {
203 if (rgbe[3]) {
204 float f = ldexp(1.0, rgbe[3] - (int)(128 + 8));
205 *red = rgbe[0] * f;
206 *green = rgbe[1] * f;
207 *blue = rgbe[2] * f;
208 } else {
209 *red = *green = *blue = 0.0;
210 }
211 }
212
213 #if 0
214 static void float2rgbe(
215 float red,
216 float green,
217 float blue,
218 uint8_t rgbe[4])
219 {
220 float v = max(max(red, green), blue);
221 if (v < 1e-32) {
222 rgbe[0] = rgbe[1] = rgbe[2] = rgbe[3] = 0;
223 } else {
224 int e;
225 v = frexp(v, &e) * 256.0 / v;
226 rgbe[0] = (uint8_t)(red * v);
227 rgbe[1] = (uint8_t)(green * v);
228 rgbe[2] = (uint8_t)(blue * v);
229 rgbe[3] = (uint8_t)(e + 128);
230 }
231 }
232 #endif
233