/* * ppmtpspu.c - Read a raw PPM file on stdin and write an uncompressed * Spectrum file on stdout. * * Copyright (C) 1990, Steve Belczyk */ #include #include #include #include "pm_c_util.h" #include "mallocvar.h" #include "shhopt.h" #include "pam.h" #define SPU_WIDTH 320 #define SPU_HEIGHT 200 struct CmdlineInfo { /* All the information the user supplied in the command line, in a form easy for the program to use. */ const char * inputFileName; /* Name of input file */ unsigned int dithflag; /* dithering flag */ }; static void parseCommandLine(int argc, const char ** argv, struct CmdlineInfo * const cmdlineP) { /*---------------------------------------------------------------------------- Parse the program arguments (given by argc and argv) into a form the program can deal with more easily -- a cmdline_info structure. If the syntax is invalid, issue a message and exit the program via pm_error(). Note that the file spec array we return is stored in the storage that was passed to us as the argv array. -----------------------------------------------------------------------------*/ optEntry * option_def; /* malloc'ed */ optStruct3 opt; /* set by OPTENT3 */ unsigned int option_def_index; unsigned int d0Spec, d2Spec, d4Spec; MALLOCARRAY_NOFAIL(option_def, 100); option_def_index = 0; /* incremented by OPTENT3 */ OPTENT3(0, "d0", OPT_FLAG, NULL, &d0Spec, 0); OPTENT3(0, "d2", OPT_FLAG, NULL, &d2Spec, 0); OPTENT3(0, "d4", OPT_FLAG, NULL, &d4Spec, 0); opt.opt_table = option_def; opt.short_allowed = false; /* We have no short (old-fashioned) options */ opt.allowNegNum = false; /* We have no parms that are negative numbers */ pm_optParseOptions4(&argc, argv, opt, sizeof(opt), 0); /* Uses and sets argc, argv, and some of *cmdlineP and others. */ if (d4Spec) cmdlineP->dithflag = 4; else if (d2Spec) cmdlineP->dithflag = 2; else if (d0Spec) cmdlineP->dithflag = 0; else cmdlineP->dithflag = 2; if (argc-1 < 1) cmdlineP->inputFileName = "-"; else { cmdlineP->inputFileName = argv[1]; if (argc-1 > 1) pm_error("Program takes zero or one argument (filename). You " "specified %u", argc-1); } } /* This is the stuff to remember about each pixel */ struct PixelType { unsigned int index4; /* 4-bit color, used in bitmap */ unsigned int x; /* Pixel's original x-position */ unsigned int popularity; /* Popularity of this pixel's color */ unsigned int color9; /* 9-bit color this pixel actually got */ }; typedef struct { int index[SPU_WIDTH][16]; /* Indices into the 48 color entries */ } Index48; typedef struct { /* These are the palettes, 3 16-color palettes per each of 200 scan lines */ int pal[SPU_HEIGHT][48]; /* -1 means free */ } Pal; static void initializePalette(Pal * const palP) { /*---------------------------------------------------------------------------- Set palettes to zero -----------------------------------------------------------------------------*/ unsigned int row; for (row = 0; row < SPU_HEIGHT; ++row) { unsigned int j; for (j = 0; j < 48; ++j) palP->pal[row][j] = 0; } } static int findIndex(unsigned int const col, unsigned int const index) { /*---------------------------------------------------------------------------- Given an x-coordinate and a color index, return the corresponding Spectrum palette index. -----------------------------------------------------------------------------*/ int r, x1; x1 = 10 * index; /* initial value */ if (index & 0x1) x1 -= 5; else ++x1; r = index; /* initial value */ if ((col >= x1) && (col < (x1+160))) r += 16; if (col >= (x1+160)) r += 32; return r; } static void setup48(Index48 * const index48P) { /*---------------------------------------------------------------------------- For each pixel position, set up the indices into the 48-color palette -----------------------------------------------------------------------------*/ unsigned int col; for (col = 0; col < SPU_WIDTH; ++col) { unsigned int i; for (i = 0; i < 16; ++i) index48P->index[col][i] = findIndex(col, i); } } static void dither(unsigned int const row, tuple * const tuplerow, unsigned int const dithflag, struct PixelType * const pixelType) { static int const dith4[4][4] = { { 0, 8, 2, 10 }, { 12, 4, 14, 6 }, { 3, 11, 1, 9 }, { 15, 7, 13, 5 } }; static int const dith2[2][2] = { { 0, 2 }, { 3, 1 } }; unsigned int c[3]; /* An element for each plane */ unsigned int col; for (col = 0; col < SPU_WIDTH; ++col) { unsigned int plane; for (plane = 0; plane < 3; ++plane) { unsigned int t; c[plane] = ((tuplerow[col][plane] & 0xe0) >> 5) & 0x7; /* initial value */ switch (dithflag) { case 0: break; case 2: t = (tuplerow[col][plane] & 0x18 ) >> 3; if (t > dith2[col%2][row%2]) ++c[plane]; break; case 4: t = (tuplerow[col][plane] & 0x1e) >> 1; if (t > dith4[col%4][row%4]) ++c[plane]; break; } c[plane] = MIN(7, c[plane]); } pixelType[col].color9 = (c[0] << 6) | (c[1] << 3) | c[2]; pixelType[col].x = col; } } static void swapPixelType(struct PixelType * const pixelType, unsigned int const i, unsigned int const j) { struct PixelType const w = pixelType[i]; pixelType[i] = pixelType[j]; pixelType[j] = w; } static void sort(struct PixelType * const pixelType, unsigned int const left, unsigned int const right) { /*---------------------------------------------------------------------------- Sort pixelType[] from element 'left' to (not including) element 'right' in increasing popularity. Good ol' Quicksort. -----------------------------------------------------------------------------*/ unsigned int const pivot = pixelType[(left+right-1)/2].popularity; unsigned int i, j; /* Rearrange so that everything less than 'pivot' is on the left side of the subject array slice and everything greater than is on the right side and elements equal could be on either side (we won't know until we're done where the dividing line between the sides is), then sort those two sides. */ assert(left < right); for (i = left, j = right; i < j; ) { while (pixelType[i].popularity < pivot) ++i; while (pixelType[j-1].popularity > pivot) --j; if (i < j) { /* An element not less popular than pivot is to the left of a pixel not more popular than pivot, so swap them. Note that we could be swapping equal (pivot-valued) elements. Though the swap isn't necessary, moving 'i' and 'j' is. */ swapPixelType(pixelType, i, j-1); ++i; --j; } } if (j - left > 1) sort(pixelType, left, j); if (right - i > 1) sort(pixelType, i, right); } static void computePalette(struct PixelType * const pixelType) { unsigned int hist[512]; /* Count for each color */ unsigned int col; unsigned int i; /* Uses popularity algorithm */ /* Count the occurrences of each color */ for (i = 0; i < 512; ++i) hist[i] = 0; for (col = 0; col < SPU_WIDTH; ++col) ++hist[pixelType[col].color9]; /* Set the popularity of each pixel's color */ for (col = 0; col < SPU_WIDTH; ++col) pixelType[col].popularity = hist[pixelType[col].color9]; /* Sort to find the most popular colors */ sort(pixelType, 0, SPU_WIDTH); } static int dist9(unsigned int const x, unsigned int const y) { /*---------------------------------------------------------------------------- Return the distance between two 9-bit colors. -----------------------------------------------------------------------------*/ unsigned int i; unsigned int d; int x0[3], y0[3]; x0[0] = (x & 0x007); x0[1] = (x & 0x038) >> 3; x0[2] = (x & 0x1c0) >> 6; y0[0] = (y & 0x007); y0[1] = (y & 0x038) >> 3; y0[2] = (y & 0x1c0) >> 6; for (i = 0, d = 0; i < 3; ++i) { unsigned int const t = x0[i] - y0[i]; d += t * t; } return d; } static void convertPixel(unsigned int const col, unsigned int const row, struct PixelType * const pixelType, Pal * const palP, const Index48 * const index48P) { int ifree; unsigned int const x = pixelType[col].x; unsigned int const c = pixelType[col].color9; ifree = -1; /* Set if free slot found */ /* Handle each possible case, from easiest to hardest, in the hopes the easy ones are more frequent. */ /* If it wants black, it gets it */ if (c == 0) pixelType[col].index4 = 0; else { /* If another pixel is using this color, it gets it */ unsigned int i; for (i = 1; i < 15; ++i) { /* Check for free slots while we're here */ if ((ifree < 0) && (palP->pal[row][index48P->index[x][i]] == -1)) ifree = i; else if (c == palP->pal[row][index48P->index[x][i]]) { pixelType[col].index4 = i; return; } } /* If there are no free slots, we must use the closest entry in use so far */ if (ifree < 0) { unsigned int i; unsigned int d; unsigned int b; for (i = 1, d = 1000; i < 15; ++i) { unsigned int const t = dist9(c, palP->pal[row][index48P->index[x][i]]); if (t < d) { d = t; b = i; } } /* See if it would be better off with black */ if (d > dist9(c, 0)) b = 0; pixelType[col].index4 = b; } else { /* Use up a slot and give it what it wants */ palP->pal[row][index48P->index[x][ifree]] = c; pixelType[col].index4 = ifree; } } } static void setPixel(unsigned int const col, unsigned int const row, unsigned int const c, short * const screen) { unsigned int index, bit, plane; /* In the next few statements, the bit operations are a little quicker, but the arithmetic versions are easier to read and maybe more portable. Please try swapping them if you have trouble on your machine. */ /* index = (80 * row) + 4 * (col / 16); */ index = (row << 6) + (row << 4) + ((col >> 4) << 2); /* bit = 0x8000 >> (col % 16); */ bit = 0x8000 >> (col & 0x0f); for (plane=0; plane<4; ++plane) { if (c & (1 << plane)) screen[index + plane] |= bit; } } static void convertRow(unsigned int const row, struct PixelType * const pixelType, Pal * const palP, const Index48 * const index48P, short * const screen) { unsigned int i; /* Mark palette entries as all free */ for (i = 0; i < 48; ++i) palP->pal[row][i] = -1; /* Mark reserved palette entries */ palP->pal[row][0] = palP->pal[row][15] = palP->pal[row][16] = 0; palP->pal[row][31] = palP->pal[row][32] = palP->pal[row][47] = 0; /* Convert each pixel */ { /* Process the pixels in order of the popularity of the desired color */ int col; for (col = SPU_WIDTH-1; col >= 0; --col) { convertPixel(col, row, pixelType, palP, index48P); setPixel(pixelType[col].x, row, pixelType[col].index4, screen); } } } static void doRow(unsigned int const row, tuple * const tuplerow, unsigned int const dithflag, const Index48 * const index48P, Pal * const palP, short * const screen) { struct PixelType pixelType[SPU_WIDTH]; /* Dither and reduce to 9 bits */ dither(row, tuplerow, dithflag, pixelType); /* Compute the best colors for this row */ computePalette(pixelType); /* Convert this row */ convertRow(row, pixelType, palP, index48P, screen); } static void writeScreen(const short * const screen) { /* Write the bitmap */ unsigned int i; for (i = 0; i < 16000; ++i) { char const c0 = 0xff & (screen[i] >> 8); char const c1 = 0xff & screen[i]; putchar(c0); putchar(c1); } } static void writePalettes(const Pal * const palP) { unsigned int row; for (row = 1; row < SPU_HEIGHT; ++row) { unsigned int i; for (i = 0; i < 48; ++i) { int const p = palP->pal[row][i]; unsigned int const q = ((p & 0x1c0) << 2) + ((p & 0x038) << 1) + ((p & 0x007) << 0); putchar((q >> 8) & 0xff); putchar((q >> 0) & 0xff); } } } static void writeSpu(const short * const screen, const Pal * const palP ) { writeScreen(screen); writePalettes(palP); } int main (int argc, const char ** argv) { struct pam pam; struct CmdlineInfo cmdline; FILE * ifP; tuple ** tuples; Pal pal; Index48 index48; short screen[16000]; /* This is the ST's video RAM */ pm_proginit(&argc, argv); parseCommandLine(argc, argv, &cmdline); ifP = pm_openr(cmdline.inputFileName); tuples = pnm_readpam(ifP, &pam, PAM_STRUCT_SIZE(tuple_type)); if (pam.depth < 3) pm_error("Image must be RGB, so at least 3 deep. This image is " "only %u deep", pam.depth); if ((pam.width != SPU_WIDTH) || (pam.height != SPU_HEIGHT)) pm_error("Image size must be %ux%u. This one is %u x %u", SPU_WIDTH, SPU_HEIGHT, pam.width, pam.height); { unsigned int i; for (i = 0; i < 16000; screen[i++] = 0); } setup48(&index48); initializePalette(&pal); { /* Set first row of screen data to black */ unsigned int i; for (i = 0; i < 80; ++i) screen[i] = 0; } { unsigned int row; for (row = 0; row < SPU_HEIGHT; ++row) doRow(row, tuples[row], cmdline.dithflag, &index48, &pal, screen); } writeSpu(screen, &pal); return 0; }