diff options
Diffstat (limited to 'converter/ppm/ppmtospu.c')
| -rw-r--r-- | converter/ppm/ppmtospu.c | 593 |
1 files changed, 593 insertions, 0 deletions
diff --git a/converter/ppm/ppmtospu.c b/converter/ppm/ppmtospu.c new file mode 100644 index 00000000..b558c1fe --- /dev/null +++ b/converter/ppm/ppmtospu.c @@ -0,0 +1,593 @@ +/* + * ppmtpspu.c - Read a raw PPM file on stdin and write an uncompressed + * Spectrum file on stdout. + * + * Copyright (C) 1990, Steve Belczyk + */ + +#include <assert.h> +#include <stdio.h> + +#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_optParseOptions3(&argc, (char **)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 occurences 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; +} + + + |