--- /dev/null
+/* 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.)
+ *
+ * written by Bruce Walter (bjw@graphics.cornell.edu) 5/26/95
+ * based on code written by Greg Ward
+ * minor modifications by John Tsiombikas (nuclear@member.fsf.org) apr.9 2007
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <ctype.h>
+#include <errno.h>
+#include "imago2.h"
+#include "ftmodule.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;
+
+
+static int check(struct img_io *io);
+static int read(struct img_pixmap *img, struct img_io *io);
+static int write(struct img_pixmap *img, struct img_io *io);
+
+static int rgbe_read_header(struct img_io *io, int *width, int *height, rgbe_header_info * info);
+static int rgbe_read_pixels_rle(struct img_io *io, float *data, int scanline_width, int num_scanlines);
+
+
+int img_register_rgbe(void)
+{
+ static struct ftype_module mod = {".rgbe", check, read, write};
+ return img_register_module(&mod);
+}
+
+
+static int check(struct img_io *io)
+{
+ int xsz, ysz, res;
+ long pos = io->seek(0, SEEK_CUR, io->uptr);
+
+ rgbe_header_info hdr;
+ res = rgbe_read_header(io, &xsz, &ysz, &hdr);
+
+ io->seek(pos, SEEK_SET, io->uptr);
+ return res;
+}
+
+static int read(struct img_pixmap *img, struct img_io *io)
+{
+ int xsz, ysz;
+ rgbe_header_info hdr;
+
+ if(rgbe_read_header(io, &xsz, &ysz, &hdr) == -1) {
+ return -1;
+ }
+
+ if(img_set_pixels(img, xsz, ysz, IMG_FMT_RGBF, 0) == -1) {
+ return -1;
+ }
+ if(rgbe_read_pixels_rle(io, img->pixels, xsz, ysz) == -1) {
+ return -1;
+ }
+ return 0;
+}
+
+static int write(struct img_pixmap *img, struct img_io *io)
+{
+ return -1; /* TODO */
+}
+
+
+static int iofgetc(struct img_io *io)
+{
+ char c;
+ return io->read(&c, 1, io->uptr) < 1 ? -1 : c;
+}
+
+static char *iofgets(char *buf, int size, struct img_io *io)
+{
+ int c;
+ char *ptr = buf;
+
+ while(--size > 0 && (c = iofgetc(io)) != -1) {
+ *ptr++ = c;
+ if(c == '\n') break;
+ }
+ *ptr = 0;
+
+ return ptr == buf ? 0 : buf;
+}
+
+
+/* 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
+
+
+#if defined(__cplusplus) || defined(GNUC) || __STDC_VERSION >= 199901L
+#define INLINE inline
+#else
+#define INLINE
+#endif
+
+/* 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
+
+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:
+ fprintf(stderr, "RGBE read error: %s\n", strerror(errno));
+ break;
+
+ case rgbe_write_error:
+ fprintf(stderr, "RGBE write error: %s\n", strerror(errno));
+ 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 */
+/*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 = 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 = 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;
+}
+
+#if 0
+/* default minimal header. modify if you want more information in header */
+static int rgbe_write_header(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;
+}
+#endif
+
+/* minimal header reading. modify if you want to parse more information */
+static int rgbe_read_header(struct img_io *io, 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(iofgets(buf, sizeof(buf) / sizeof(buf[0]), io) == NULL)
+ return RGBE_RETURN_FAILURE;/*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(iofgets(buf, sizeof(buf) / sizeof(buf[0]), io) == 0)
+ return rgbe_error(rgbe_read_error, NULL);
+ }
+ for(;;) {
+ if((buf[0] == 0) || (buf[0] == '\n'))
+ return RGBE_RETURN_FAILURE;/*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(iofgets(buf, sizeof(buf) / sizeof(buf[0]), io) == 0)
+ return RGBE_RETURN_FAILURE;/*rgbe_error(rgbe_read_error, NULL);*/
+ }
+ if(iofgets(buf, sizeof(buf) / sizeof(buf[0]), io) == 0)
+ return RGBE_RETURN_FAILURE;/*rgbe_error(rgbe_read_error, NULL);*/
+ if(strcmp(buf, "\n") != 0)
+ return RGBE_RETURN_FAILURE;/*rgbe_error(rgbe_format_error, "missing blank line after FORMAT specifier");*/
+ if(iofgets(buf, sizeof(buf) / sizeof(buf[0]), io) == 0)
+ return RGBE_RETURN_FAILURE;/*rgbe_error(rgbe_read_error, NULL);*/
+ if(sscanf(buf, "-Y %d +X %d", height, width) < 2)
+ return RGBE_RETURN_FAILURE;/*rgbe_error(rgbe_format_error, "missing image size specifier");*/
+ return RGBE_RETURN_SUCCESS;
+}
+
+#if 0
+/* 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 */
+static int rgbe_write_pixels(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;
+}
+#endif
+
+/* simple read routine. will not correctly handle run length encoding */
+static int rgbe_read_pixels(struct img_io *io, float *data, int numpixels)
+{
+ unsigned char rgbe[4];
+
+ while(numpixels-- > 0) {
+ if(io->read(rgbe, sizeof(rgbe), io->uptr) < 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;
+}
+
+#if 0
+/* 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_write_bytes_rle(struct img_io *io, 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
+}
+
+static int rgbe_write_pixels_rle(struct img_io *io, 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_write_pixels(io, 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_write_pixels(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_write_bytes_rle(fp, &buffer[i * scanline_width],
+ scanline_width)) != RGBE_RETURN_SUCCESS) {
+ free(buffer);
+ return err;
+ }
+ }
+ }
+ free(buffer);
+ return RGBE_RETURN_SUCCESS;
+}
+#endif
+
+static int rgbe_read_pixels_rle(struct img_io *io, 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_read_pixels(io, data, scanline_width * num_scanlines);
+ scanline_buffer = NULL;
+ /* read in each successive scanline */
+ while(num_scanlines > 0) {
+ if(io->read(rgbe, sizeof(rgbe), io->uptr) < 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_read_pixels(io, 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(io->read(buf, sizeof(buf[0]) * 2, io->uptr) < 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(io->read(ptr, sizeof(*ptr) * count, io->uptr) < 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;
+}
projects / eradicate / blobdiff