/* dem2tga.c (c) 1997 Jon Larimer * * This is a program to convert USGS Digital Elevation Model (DEM) data * into a .TGA file, viewable by many graphics applications. This program * is public domain, do whatever you want with it, except claim it as your * own or sell it. If you find a way to make money from my work, I want a * piece of the action. * * This should compile with any ANSI standard compiler, including Unix * and DOS versions of gcc and many other C compilers. If you have any * questions or comments email jonl@alltel.net. * */ #include #include #include #include typedef struct _tagTGAHDR { char tgaID; /* number of chars in ID field */ char tgaMapType; /* color map (0=no map; 1=map present) */ char tgaImageType; /* codes: 0 - No image data included. 1 - Uncompressed, color-mapped images. 2 - Uncompressed, RGB images. 3 - Uncompressed, black and white images. 9 - Runlength encoded color-mapped images. 10 - Runlength encoded RGB images. 11 - Compressed, black and white images. 32 - Compressed color-mapped data, using Huffman, Delta, and runlength encoding. 33 - Compressed color-mapped data, using Huffman, Delta, and runlength encoding. 4-pass quadtree-type process. */ int tgaMapOrigin; /* Origin of colormap */ int tgaMapLen; /* number of entries in map */ char tgaMapEntry; /* length of map entry size in bits */ int tgaImgX; /* X origin of image (lower left) */ int tgaIMGY; /* Y origin of image (lower left) */ int tgaIMGW; /* width of image */ int tgaIMGH; /* height of image */ char tgaPixelSize; /* pixel size (number of bits per pixel) */ char tgaImgDesc; /* image descriptor (should be 0) */ char tgaDesc[255]; /* image description (may be less than 255 chars) */ } TGAHEADER; int writetgaheader(FILE *fptr, int r, int c) { int i; fputc(0, fptr); /* chars in ID field */ fputc(1, fptr); /* color map type */ fputc(1, fptr); /* image type (1=uncompressed colormap) */ fputc(0, fptr); /* colormap origin (int) */ fputc(0, fptr); /* colormap origin (int) */ fputc(0, fptr); /* num colormap entries (int) */ fputc(1, fptr); /* num colormap entries (int) */ fputc(24, fptr); /* colormap entry size (in bits) */ fputc(0, fptr); /* X origin of image (lower left corner) (int) */ fputc(0, fptr); /* X origin of image (lower left corner) (int) */ fputc(0, fptr); /* Y origin of image (lower left corner) (int) */ fputc(0, fptr); /* Y origin of image (lower left corner) (int) */ fputc((char)(c & 0x00ff), fptr); /* pixel width of image (int) */ fputc((char)((c & 0xff00) >> 8), fptr); /* pixel width of image (int) */ fputc((char)(r & 0x00ff), fptr); /* pixel height of image (int) */ fputc((char)((r & 0xff00) >> 8), fptr); /* pixel height of image (int) */ fputc(8, fptr); /* number of bits per pixel */ fputc(0, fptr); /* image descriptor */ for(i=0; i<=255; i++) { /* color map data */ fputc(i, fptr); /* in blue-green-red order for 24-bit images */ fputc(i, fptr); fputc(i, fptr); } fflush(fptr); return 0; } int writetgaheader24(FILE *fptr, int r, int c) { int i; fputc(0, fptr); /* chars in ID field */ fputc(0, fptr); /* color map type */ fputc(2, fptr); /* image type (2=uncompressed RGB) */ fputc(0, fptr); /* colormap origin (int) */ fputc(0, fptr); /* colormap origin (int) */ fputc(0, fptr); /* num colormap entries (int) */ fputc(0, fptr); /* num colormap entries (int) */ fputc(0, fptr); /* colormap entry size (in bits) */ fputc(0, fptr); /* X origin of image (lower left corner) (int) */ fputc(0, fptr); /* X origin of image (lower left corner) (int) */ fputc(0, fptr); /* Y origin of image (lower left corner) (int) */ fputc(0, fptr); /* Y origin of image (lower left corner) (int) */ fputc((char)(c & 0x00ff), fptr); /* pixel width of image (int) */ fputc((char)((c & 0xff00) >> 8), fptr); /* pixel width of image (int) */ fputc((char)(r & 0x00ff), fptr); /* pixel height of image (int) */ fputc((char)((r & 0xff00) >> 8), fptr); /* pixel height of image (int) */ fputc(24, fptr); /* number of bits per pixel */ fputc(0, fptr); /* image descriptor */ /* the storage for POV-Ray is the red and green for high and low bytes of the 16-bit heightfield (respectively) [the Blue byte can be left to zero] Byte ordering is blue-green-red, or 0-low-high */ fflush(fptr); return 0; } /* j is the elevation to write. Values written in 0-lowbyte-highbyte order */ int fwritec24(int j, FILE *fptr) { fputc(0, fptr); fputc((char)(j & 0x00ff), fptr); fputc((char)((j & 0xff00) >> 8), fptr); return 0; } int fgetcb(FILE *fptr) { if (feof(fptr)) return 0; else return fgetc(fptr); } int nextint(FILE * fptr) { char ch; int i; char in[64]; while(isspace(ch = fgetcb(fptr))) { } i=0; in[0] = ch; while(!isspace(ch = fgetcb(fptr))) { i++; in[i] = ch; } in[i+1] = '\0'; return(atoi(in)); } double nextfloat(FILE * fptr) { char ch; int i; char in[64]; while(isspace(ch = fgetcb(fptr))) { } i=0; in[0] = ch; while(!isspace(ch = fgetcb(fptr))) { i++; if(ch == 'D') { ch = 'E'; } in[i] = ch; } in[i+1] = '\0'; atof(in); } /* int argc, char **argv */ int main(int argc, char **argv) { FILE *demfile; FILE *outfile; int i, j, l; long int x; float k; int maxelev, minelev; int rows, columns; int irows, icols; int elevrange; float colormap_scale; int r, c, omode; int cur_r, cur_c; char ch; char name[144]; fprintf(stdout, "dem2tga v1.0 (c) 1997 Jon Larimer\n"); fprintf(stdout, " enhanced 1997 by Greg Billock\n"); fprintf(stdout, "This program is public domain.\n\n"); if (argc < 2) { fprintf(stdout, "usage: dem2tga input_file output_file mode\n"); fprintf(stdout, " input_file is the DEM you want to convert\n"); fprintf(stdout, " output_file is the name you want to save the image under.\n"); fprintf(stdout, " You should supply a .tga at the end of the file.\n"); fprintf(stdout, " mode is the 8 or 16 bit mode: the numbers 8 (default) or 16\n"); exit(1); } omode = 1; /* default to 8-bit */ if (argc>=3) { if ( strncmp(argv[3], "16", 2) == 0 ) omode = 2; /* 16-bit mode */ } if((demfile = fopen(argv[1], "r")) == NULL) { fprintf(stderr, "%s: fopen: %s", argv[0], strerror(errno)); exit(1); } /****** DEM TYPE A RECORDS ******/ /* get the name field (144 characters) */ for(i=0; i < 144; i++) { name[i] = fgetc(demfile); } name[i+1] = '\0'; /* clean off the whitespace at the end */ for(i=strlen(name)-2; i > 0; i--) { if(!isspace(name[i])) { i=0; } else { name[i] = '\0'; } } fprintf(stdout, "Quad name field: %s\n", name); /* don't need the next 19 items for anything */ for(i=0; i < 19; i++) { (void)nextint(demfile); } fprintf(stdout, "Units code (ground planametric coordinates): %i\n", nextint(demfile)); fprintf(stdout, "Units code (elevation coordinates): %i\n", nextint(demfile)); (void)nextint(demfile); printf("Ground coordinates of 4 corners of DEM: (in arc-seconds) \n"); for(i=1; i<=4; i++) fprintf(stdout, " %.4f %.4f\n", nextfloat(demfile), nextfloat(demfile)); minelev = (int)nextfloat(demfile); maxelev = (int)nextfloat(demfile); fprintf(stdout, "\nMinimum elevation: %i\n", minelev); fprintf(stdout, "Maximum elevation: %i\n", maxelev); elevrange = maxelev-minelev; fprintf(stdout, "Elevation range: %i\n", elevrange); /* this is the value to multiply elevations by to get a number between 0 and 255 to determine the color of the pixel */ colormap_scale = (float)255 / (float)elevrange; fprintf(stdout, "Colormap scaling value: %.5f\n", colormap_scale); /* don't need the next 3 items */ for(i=1; i<3; i++) { (void)nextint(demfile); } cur_r = nextint(demfile); columns = nextint(demfile); /* DEM TYPE B RECORDS */ /* Format: current_row, current_column, num_rows, num_cols + 5 */ /* numbers: el. of local datum, profile max, profile min, etc. */ cur_c = 1; fprintf(stdout, "Writing image...\n"); fflush(stdout); outfile = fopen(argv[2], "wb+"); l = 1; /* we need to see how many rows of data before we write the header */ cur_r = nextint(demfile); cur_c = nextint(demfile); rows = nextint(demfile); x = 0L; if (omode==1) writetgaheader(outfile, rows, columns); else writetgaheader24(outfile,rows,columns); irows = rows; icols = columns; #ifdef VERBOSE fprintf(stdout, "FILE SIZE: %d COLUMNS, %d ROWS\n", icols, irows); fprintf(stdout, "Writing col %d\n", cur_c); #endif /* now ready to write the image data */ while (cur_c <= columns) { (void)nextint(demfile); (void)nextint(demfile); (void)nextint(demfile); (void)nextint(demfile); (void)nextint(demfile); (void)nextint(demfile); for (i=1; i<=rows; i++) { j = nextint(demfile) - minelev; k = (float)j * colormap_scale; if (omode==1) fputc((int)k, outfile); else fwritec24(j+minelev, outfile); x++; } /* try to trap overflow */ if (cur_c == columns) break; if (cur_c < columns) { cur_r = nextint(demfile); cur_c = nextint(demfile); rows = nextint(demfile); } #ifdef VERBOSE fprintf(stdout, "Writing col %d\n", cur_c); #endif /* try to trap underflow */ if (cur_r==0 && cur_c==0 && rows==0) break; } /* pad file if too short */ if (x < ((long)irows * (long)icols)) { while (x < ((long)irows * (long)icols)) { fprintf(stdout,"%ld bytes read | padding file...", x); if (omode==1) fputc((int)0, outfile); else fwritec24(0, outfile); x++; } } fprintf(stdout, "done.\n"); fprintf(stdout, "Wrote %d rows, %d columns, %ld pixels\n\n", irows, icols, x); fprintf(stdout, "Image must be rotated 90 degrees counter-clockwise and flipped\n"); fprintf(stdout, "horizontally to align the top of the image with north and the left with west.\n\n"); fclose(outfile); fclose(demfile); return 0; }