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// For Open Source Computer Vision Library
//
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#include "precomp.hpp"
#include "rgbe.hpp"
#include <math.h>
#if !defined(__APPLE__)
#include <malloc.h>
#endif
#include <string.h>
#include <ctype.h>
// This file contains code to read and write four byte rgbe file format
// developed by Greg Ward. It handles the conversions between rgbe and
// pixels consisting of floats. The data is assumed to be an array of floats.
// By default there are three floats per pixel in the order red, green, blue.
// (RGBE_DATA_??? values control this.) Only the mimimal header reading and
// writing is implemented. Each routine does error checking and will return
// a status value as defined below. This code is intended as a skeleton so
// feel free to modify it to suit your needs.
// Some opencv specific changes have been added:
// inline define specified, error handler uses CV_Error,
// defines changed to work in bgr color space.
//
// posted to http://www.graphics.cornell.edu/~bjw/
// written by Bruce Walter (bjw@graphics.cornell.edu) 5/26/95
// based on code written by Greg Ward
#define INLINE inline
/* offsets to red, green, and blue components in a data (float) pixel */
#define RGBE_DATA_RED 2
#define RGBE_DATA_GREEN 1
#define RGBE_DATA_BLUE 0
/* number of floats per pixel */
#define RGBE_DATA_SIZE 3
enum rgbe_error_codes {
rgbe_read_error,
rgbe_write_error,
rgbe_format_error,
rgbe_memory_error
};
/* default error routine. change this to change error handling */
static int rgbe_error(int rgbe_error_code, const char *msg)
{
switch (rgbe_error_code) {
case rgbe_read_error:
CV_Error(cv::Error::StsError, "RGBE read error");
break;
case rgbe_write_error:
CV_Error(cv::Error::StsError, "RGBE write error");
break;
case rgbe_format_error:
CV_Error(cv::Error::StsError, cv::String("RGBE bad file format: ") +
cv::String(msg));
break;
default:
case rgbe_memory_error:
CV_Error(cv::Error::StsError, cv::String("RGBE error: \n") +
cv::String(msg));
}
return RGBE_RETURN_FAILURE;
}
/* standard conversion from float pixels to rgbe pixels */
/* note: you can remove the "inline"s if your compiler complains about it */
static INLINE void
float2rgbe(unsigned char rgbe[4], float red, float green, float blue)
{
float v;
int e;
v = red;
if (green > v) v = green;
if (blue > v) v = blue;
if (v < 1e-32) {
rgbe[0] = rgbe[1] = rgbe[2] = rgbe[3] = 0;
}
else {
v = static_cast<float>(frexp(v,&e) * 256.0/v);
rgbe[0] = (unsigned char) (red * v);
rgbe[1] = (unsigned char) (green * v);
rgbe[2] = (unsigned char) (blue * v);
rgbe[3] = (unsigned char) (e + 128);
}
}
/* standard conversion from rgbe to float pixels */
/* note: Ward uses ldexp(col+0.5,exp-(128+8)). However we wanted pixels */
/* in the range [0,1] to map back into the range [0,1]. */
static INLINE void
rgbe2float(float *red, float *green, float *blue, unsigned char rgbe[4])
{
float f;
if (rgbe[3]) { /*nonzero pixel*/
f = static_cast<float>(ldexp(1.0,rgbe[3]-(int)(128+8)));
*red = rgbe[0] * f;
*green = rgbe[1] * f;
*blue = rgbe[2] * f;
}
else
*red = *green = *blue = 0.0;
}
/* default minimal header. modify if you want more information in header */
int RGBE_WriteHeader(FILE *fp, int width, int height, rgbe_header_info *info)
{
const char *programtype = "RGBE";
if (info && (info->valid & RGBE_VALID_PROGRAMTYPE))
programtype = info->programtype;
if (fprintf(fp,"#?%s\n",programtype) < 0)
return rgbe_error(rgbe_write_error,NULL);
/* The #? is to identify file type, the programtype is optional. */
if (info && (info->valid & RGBE_VALID_GAMMA)) {
if (fprintf(fp,"GAMMA=%g\n",info->gamma) < 0)
return rgbe_error(rgbe_write_error,NULL);
}
if (info && (info->valid & RGBE_VALID_EXPOSURE)) {
if (fprintf(fp,"EXPOSURE=%g\n",info->exposure) < 0)
return rgbe_error(rgbe_write_error,NULL);
}
if (fprintf(fp,"FORMAT=32-bit_rle_rgbe\n\n") < 0)
return rgbe_error(rgbe_write_error,NULL);
if (fprintf(fp, "-Y %d +X %d\n", height, width) < 0)
return rgbe_error(rgbe_write_error,NULL);
return RGBE_RETURN_SUCCESS;
}
/* minimal header reading. modify if you want to parse more information */
int RGBE_ReadHeader(FILE *fp, int *width, int *height, rgbe_header_info *info)
{
char buf[128];
float tempf;
int i;
if (info) {
info->valid = 0;
info->programtype[0] = 0;
info->gamma = info->exposure = 1.0;
}
if (fgets(buf,sizeof(buf)/sizeof(buf[0]),fp) == NULL)
return rgbe_error(rgbe_read_error,NULL);
if ((buf[0] != '#')||(buf[1] != '?')) {
/* if you want to require the magic token then uncomment the next line */
/*return rgbe_error(rgbe_format_error,"bad initial token"); */
}
else if (info) {
info->valid |= RGBE_VALID_PROGRAMTYPE;
for(i=0;i<static_cast<int>(sizeof(info->programtype)-1);i++) {
if ((buf[i+2] == 0) || isspace(buf[i+2]))
break;
info->programtype[i] = buf[i+2];
}
info->programtype[i] = 0;
if (fgets(buf,sizeof(buf)/sizeof(buf[0]),fp) == 0)
return rgbe_error(rgbe_read_error,NULL);
}
for(;;) {
if ((buf[0] == 0)||(buf[0] == '\n'))
return rgbe_error(rgbe_format_error,"no FORMAT specifier found");
else if (strcmp(buf,"FORMAT=32-bit_rle_rgbe\n") == 0)
break; /* format found so break out of loop */
else if (info && (sscanf(buf,"GAMMA=%g",&tempf) == 1)) {
info->gamma = tempf;
info->valid |= RGBE_VALID_GAMMA;
}
else if (info && (sscanf(buf,"EXPOSURE=%g",&tempf) == 1)) {
info->exposure = tempf;
info->valid |= RGBE_VALID_EXPOSURE;
}
if (fgets(buf,sizeof(buf)/sizeof(buf[0]),fp) == 0)
return rgbe_error(rgbe_read_error,NULL);
}
if (fgets(buf,sizeof(buf)/sizeof(buf[0]),fp) == 0)
return rgbe_error(rgbe_read_error,NULL);
if (strcmp(buf,"\n") != 0)
return rgbe_error(rgbe_format_error,
"missing blank line after FORMAT specifier");
if (fgets(buf,sizeof(buf)/sizeof(buf[0]),fp) == 0)
return rgbe_error(rgbe_read_error,NULL);
if (sscanf(buf,"-Y %d +X %d",height,width) < 2)
return rgbe_error(rgbe_format_error,"missing image size specifier");
return RGBE_RETURN_SUCCESS;
}
/* simple write routine that does not use run length encoding */
/* These routines can be made faster by allocating a larger buffer and
fread-ing and fwrite-ing the data in larger chunks */
int RGBE_WritePixels(FILE *fp, float *data, int numpixels)
{
unsigned char rgbe[4];
while (numpixels-- > 0) {
float2rgbe(rgbe,data[RGBE_DATA_RED],
data[RGBE_DATA_GREEN],data[RGBE_DATA_BLUE]);
data += RGBE_DATA_SIZE;
if (fwrite(rgbe, sizeof(rgbe), 1, fp) < 1)
return rgbe_error(rgbe_write_error,NULL);
}
return RGBE_RETURN_SUCCESS;
}
/* simple read routine. will not correctly handle run length encoding */
int RGBE_ReadPixels(FILE *fp, float *data, int numpixels)
{
unsigned char rgbe[4];
while(numpixels-- > 0) {
if (fread(rgbe, sizeof(rgbe), 1, fp) < 1)
return rgbe_error(rgbe_read_error,NULL);
rgbe2float(&data[RGBE_DATA_RED],&data[RGBE_DATA_GREEN],
&data[RGBE_DATA_BLUE],rgbe);
data += RGBE_DATA_SIZE;
}
return RGBE_RETURN_SUCCESS;
}
/* The code below is only needed for the run-length encoded files. */
/* Run length encoding adds considerable complexity but does */
/* save some space. For each scanline, each channel (r,g,b,e) is */
/* encoded separately for better compression. */
static int RGBE_WriteBytes_RLE(FILE *fp, unsigned char *data, int numbytes)
{
#define MINRUNLENGTH 4
int cur, beg_run, run_count, old_run_count, nonrun_count;
unsigned char buf[2];
cur = 0;
while(cur < numbytes) {
beg_run = cur;
/* find next run of length at least 4 if one exists */
run_count = old_run_count = 0;
while((run_count < MINRUNLENGTH) && (beg_run < numbytes)) {
beg_run += run_count;
old_run_count = run_count;
run_count = 1;
while( (beg_run + run_count < numbytes) && (run_count < 127)
&& (data[beg_run] == data[beg_run + run_count]))
run_count++;
}
/* if data before next big run is a short run then write it as such */
if ((old_run_count > 1)&&(old_run_count == beg_run - cur)) {
buf[0] = static_cast<unsigned char>(128 + old_run_count); /*write short run*/
buf[1] = data[cur];
if (fwrite(buf,sizeof(buf[0])*2,1,fp) < 1)
return rgbe_error(rgbe_write_error,NULL);
cur = beg_run;
}
/* write out bytes until we reach the start of the next run */
while(cur < beg_run) {
nonrun_count = beg_run - cur;
if (nonrun_count > 128)
nonrun_count = 128;
buf[0] = static_cast<unsigned char>(nonrun_count);
if (fwrite(buf,sizeof(buf[0]),1,fp) < 1)
return rgbe_error(rgbe_write_error,NULL);
if (fwrite(&data[cur],sizeof(data[0])*nonrun_count,1,fp) < 1)
return rgbe_error(rgbe_write_error,NULL);
cur += nonrun_count;
}
/* write out next run if one was found */
if (run_count >= MINRUNLENGTH) {
buf[0] = static_cast<unsigned char>(128 + run_count);
buf[1] = data[beg_run];
if (fwrite(buf,sizeof(buf[0])*2,1,fp) < 1)
return rgbe_error(rgbe_write_error,NULL);
cur += run_count;
}
}
return RGBE_RETURN_SUCCESS;
#undef MINRUNLENGTH
}
int RGBE_WritePixels_RLE(FILE *fp, float *data, int scanline_width,
int num_scanlines)
{
unsigned char rgbe[4];
unsigned char *buffer;
int i, err;
if ((scanline_width < 8)||(scanline_width > 0x7fff))
/* run length encoding is not allowed so write flat*/
return RGBE_WritePixels(fp,data,scanline_width*num_scanlines);
buffer = (unsigned char *)malloc(sizeof(unsigned char)*4*scanline_width);
if (buffer == NULL)
/* no buffer space so write flat */
return RGBE_WritePixels(fp,data,scanline_width*num_scanlines);
while(num_scanlines-- > 0) {
rgbe[0] = 2;
rgbe[1] = 2;
rgbe[2] = static_cast<unsigned char>(scanline_width >> 8);
rgbe[3] = scanline_width & 0xFF;
if (fwrite(rgbe, sizeof(rgbe), 1, fp) < 1) {
free(buffer);
return rgbe_error(rgbe_write_error,NULL);
}
for(i=0;i<scanline_width;i++) {
float2rgbe(rgbe,data[RGBE_DATA_RED],
data[RGBE_DATA_GREEN],data[RGBE_DATA_BLUE]);
buffer[i] = rgbe[0];
buffer[i+scanline_width] = rgbe[1];
buffer[i+2*scanline_width] = rgbe[2];
buffer[i+3*scanline_width] = rgbe[3];
data += RGBE_DATA_SIZE;
}
/* write out each of the four channels separately run length encoded */
/* first red, then green, then blue, then exponent */
for(i=0;i<4;i++) {
if ((err = RGBE_WriteBytes_RLE(fp,&buffer[i*scanline_width],
scanline_width)) != RGBE_RETURN_SUCCESS) {
free(buffer);
return err;
}
}
}
free(buffer);
return RGBE_RETURN_SUCCESS;
}
int RGBE_ReadPixels_RLE(FILE *fp, float *data, int scanline_width,
int num_scanlines)
{
unsigned char rgbe[4], *scanline_buffer, *ptr, *ptr_end;
int i, count;
unsigned char buf[2];
if ((scanline_width < 8)||(scanline_width > 0x7fff))
/* run length encoding is not allowed so read flat*/
return RGBE_ReadPixels(fp,data,scanline_width*num_scanlines);
scanline_buffer = NULL;
/* read in each successive scanline */
while(num_scanlines > 0) {
if (fread(rgbe,sizeof(rgbe),1,fp) < 1) {
free(scanline_buffer);
return rgbe_error(rgbe_read_error,NULL);
}
if ((rgbe[0] != 2)||(rgbe[1] != 2)||(rgbe[2] & 0x80)) {
/* this file is not run length encoded */
rgbe2float(&data[RGBE_DATA_RED],&data[RGBE_DATA_GREEN],&data[RGBE_DATA_BLUE],rgbe);
data += RGBE_DATA_SIZE;
free(scanline_buffer);
return RGBE_ReadPixels(fp,data,scanline_width*num_scanlines-1);
}
if ((((int)rgbe[2])<<8 | rgbe[3]) != scanline_width) {
free(scanline_buffer);
return rgbe_error(rgbe_format_error,"wrong scanline width");
}
if (scanline_buffer == NULL)
scanline_buffer = (unsigned char *)
malloc(sizeof(unsigned char)*4*scanline_width);
if (scanline_buffer == NULL)
return rgbe_error(rgbe_memory_error,"unable to allocate buffer space");
ptr = &scanline_buffer[0];
/* read each of the four channels for the scanline into the buffer */
for(i=0;i<4;i++) {
ptr_end = &scanline_buffer[(i+1)*scanline_width];
while(ptr < ptr_end) {
if (fread(buf,sizeof(buf[0])*2,1,fp) < 1) {
free(scanline_buffer);
return rgbe_error(rgbe_read_error,NULL);
}
if (buf[0] > 128) {
/* a run of the same value */
count = buf[0]-128;
if ((count == 0)||(count > ptr_end - ptr)) {
free(scanline_buffer);
return rgbe_error(rgbe_format_error,"bad scanline data");
}
while(count-- > 0)
*ptr++ = buf[1];
}
else {
/* a non-run */
count = buf[0];
if ((count == 0)||(count > ptr_end - ptr)) {
free(scanline_buffer);
return rgbe_error(rgbe_format_error,"bad scanline data");
}
*ptr++ = buf[1];
if (--count > 0) {
if (fread(ptr,sizeof(*ptr)*count,1,fp) < 1) {
free(scanline_buffer);
return rgbe_error(rgbe_read_error,NULL);
}
ptr += count;
}
}
}
}
/* now convert data from buffer into floats */
for(i=0;i<scanline_width;i++) {
rgbe[0] = scanline_buffer[i];
rgbe[1] = scanline_buffer[i+scanline_width];
rgbe[2] = scanline_buffer[i+2*scanline_width];
rgbe[3] = scanline_buffer[i+3*scanline_width];
rgbe2float(&data[RGBE_DATA_RED],&data[RGBE_DATA_GREEN],
&data[RGBE_DATA_BLUE],rgbe);
data += RGBE_DATA_SIZE;
}
num_scanlines--;
}
free(scanline_buffer);
return RGBE_RETURN_SUCCESS;
}