added read-support for RADIANCE / RGBE files

README.TXT

@@ -8,6 +8,7 @@ Included third-party software:
 * Includes OpenGL loader code created by a modified glLoadGen by Jason McKesson.
 * Includes GLM by Christophe Riccio.
 * Includes data type definitions from libspnav header originally by John Tsiombikas (see mini_spnav.h for details).
+* Includes RGBE/Radiance image import by Bruce Walter (code provided 'as-is').
 
 See LICENSE.TXT for licensing information.
 

include/ACGL/OpenGL/Data/TextureDataLoadStore.hh

@@ -51,6 +51,8 @@ SharedTextureData loadTextureDataFromLodepng(const std::string &_filename);
 SharedTextureData loadTextureDataFromQT(const std::string &_filename);
 #endif
 
+SharedTextureData loadTextureDataFromRGBE(const std::string &_filename);
+
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 //                                                                           library specific save
 ///////////////////////////////////////////////////////////////////////////////////////////////////

include/rgbe/rgbe.hh

+#ifndef _H_RGBE
+#define _H_RGBE
+/* THIS CODE CARRIES NO GUARANTEE OF USABILITY OR FITNESS FOR ANY PURPOSE.
+ * WHILE THE AUTHORS HAVE TRIED TO ENSURE THE PROGRAM WORKS CORRECTLY,
+ * IT IS STRICTLY USE AT YOUR OWN RISK.  */
+
+/* utility for reading and writing Ward's rgbe image format.
+   See rgbe.txt file for more details.
+*/
+
+#include <stdio.h>
+
+typedef struct {
+  int valid;            /* indicate which fields are valid */
+  char programtype[16]; /* listed at beginning of file to identify it 
+                         * after "#?".  defaults to "RGBE" */ 
+  float gamma;          /* image has already been gamma corrected with 
+                         * given gamma.  defaults to 1.0 (no correction) */
+  float exposure;       /* a value of 1.0 in an image corresponds to
+			 * <exposure> watts/steradian/m^2. 
+			 * defaults to 1.0 */
+} rgbe_header_info;
+
+/* flags indicating which fields in an rgbe_header_info are valid */
+#define RGBE_VALID_PROGRAMTYPE 0x01
+#define RGBE_VALID_GAMMA       0x02
+#define RGBE_VALID_EXPOSURE    0x04
+
+/* return codes for rgbe routines */
+#define RGBE_RETURN_SUCCESS 0
+#define RGBE_RETURN_FAILURE -1
+
+/* read or write headers */
+/* you may set rgbe_header_info to null if you want to */
+int RGBE_WriteHeader(FILE *fp, int width, int height, rgbe_header_info *info);
+int RGBE_ReadHeader(FILE *fp, int *width, int *height, rgbe_header_info *info);
+
+/* read or write pixels */
+/* can read or write pixels in chunks of any size including single pixels*/
+int RGBE_WritePixels(FILE *fp, float *data, int numpixels);
+int RGBE_ReadPixels(FILE *fp, float *data, int numpixels);
+
+/* read or write run length encoded files */
+/* must be called to read or write whole scanlines */
+int RGBE_WritePixels_RLE(FILE *fp, float *data, int scanline_width,
+			 int num_scanlines);
+int RGBE_ReadPixels_RLE(FILE *fp, float *data, int scanline_width,
+			int num_scanlines);
+
+#endif /* _H_RGBE */
+
+
+

src/ACGL/OpenGL/Data/TextureDataLoadStore.cc

@@ -16,6 +16,7 @@
 
 #include <fstream>
 #include "lodepng/lodepng.h"
+#include "rgbe/rgbe.hh"
 
 #ifdef ACGL_COMPILE_WITH_QT
 #include <QImage>
@@ -42,6 +43,8 @@ SharedTextureData loadTextureData(const std::string &_filename)
 
     if (fileEnding == "png") {
         return loadTextureDataFromLodepng( _filename );
+    } else if (fileEnding == "hdr") {
+        return loadTextureDataFromRGBE( _filename );
     }
 #ifdef ACGL_COMPILE_WITH_QT
     else if (   fileEnding == "bmp" || fileEnding == "jpg" || fileEnding == "jpeg"
@@ -209,6 +212,27 @@ SharedTextureData loadTextureDataFromQT(const std::string &_filename)
 }
 #endif
 
+SharedTextureData loadTextureDataFromRGBE(const std::string &_filename)
+{
+    SharedTextureData data = SharedTextureData( new TextureData() );
+
+    FILE* f = fopen(_filename.c_str(), "rb");
+
+    int texWidth, texHeight;
+    RGBE_ReadHeader(f, &texWidth, &texHeight, NULL);
+    GLubyte* tempdata = new GLubyte[ sizeof(GL_FLOAT) * 3 * texWidth * texHeight];
+    RGBE_ReadPixels_RLE(f, (float*)tempdata, texWidth, texHeight);
+    fclose(f);
+
+    data->setData(   tempdata  );
+    data->setHeight( texHeight );
+    data->setWidth(  texWidth  );
+    data->setFormat( GL_RGB );
+    data->setType(   GL_FLOAT  );
+
+    return data;
+}
+
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 //                                                                           library specific save
 ///////////////////////////////////////////////////////////////////////////////////////////////////

src/rgbe/rgbe.cc

+/* THIS CODE CARRIES NO GUARANTEE OF USABILITY OR FITNESS FOR ANY PURPOSE.
+ * WHILE THE AUTHORS HAVE TRIED TO ENSURE THE PROGRAM WORKS CORRECTLY,
+ * IT IS STRICTLY USE AT YOUR OWN RISK.  */
+
+/* Copyright (c) 1995 Bruce Walter <bjw@graphics.cornell.edu>
+   The license of these files has been clarified by Bruce Walter during
+   a private email conversation.  These files are public domain. */
+
+#include "rgbe/rgbe.hh"
+#include <math.h>
+#include <stdlib.h>
+#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.
+
+ (Place notice here if you modified the code.)
+ 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
+*/
+
+/* offsets to red, green, and blue components in a data (float) pixel */
+#define RGBE_DATA_RED    0
+#define RGBE_DATA_GREEN  1
+#define RGBE_DATA_BLUE   2
+/* number of floats per pixel */
+#define RGBE_DATA_SIZE   3
+
+#define INLINE inline
+
+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, char *msg)
+{
+  switch (rgbe_error_code) {
+  case rgbe_read_error:
+    perror("RGBE read error");
+    break;
+  case rgbe_write_error:
+    perror("RGBE write error");
+    break;
+  case rgbe_format_error:
+    fprintf(stderr,"RGBE bad file format: %s\n",msg);
+    break;
+  default:
+  case rgbe_memory_error:
+    fprintf(stderr,"RGBE error: %s\n",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 */
+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 = (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].            */
+INLINE void
+rgbe2float(float *red, float *green, float *blue, unsigned char rgbe[4])
+{
+  float f;
+
+  if (rgbe[3]) {   /*nonzero pixel*/
+    f = (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)
+{
+  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];
+  int found_format;
+  float tempf;
+  int i;
+
+  found_format = 0;
+  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<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 0
+  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");
+#endif
+
+  for(;;) {
+    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)
+      break;
+  }
+
+  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;
+}
+
+
+int RGBE_ReadPixels_Raw(FILE *fp, unsigned char *data, size_t numpixels)
+{
+  if (fread(data, 4, numpixels, fp) < numpixels)
+    return rgbe_error(rgbe_read_error,NULL);
+
+  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] = 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] = 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] = 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] = 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[0],&data[1],&data[2],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;
+}
+
+
+int RGBE_ReadPixels_Raw_RLE(FILE *fp, unsigned char *data, int scanline_width,
+                        size_t 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_Raw(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 */
+      data[0] = rgbe[0];
+      data[1] = rgbe[1];
+      data[2] = rgbe[2];
+      data[3] = rgbe[3];
+      data += RGBE_DATA_SIZE;
+      free(scanline_buffer);
+      return RGBE_ReadPixels_Raw(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 {