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https://github.com/sehugg/8bitworkshop.git
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96 lines
2.5 KiB
C
96 lines
2.5 KiB
C
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/*****************************************************************************\
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** mandelbrot sample program for cc65. **
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** **
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** (w) 2002 by groepaz/hitmen, TGI support by Stefan Haubenthal **
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\*****************************************************************************/
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#include <stdlib.h>
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#include <time.h>
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#include <conio.h>
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#include <c64.h>
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#include <cc65.h>
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#include "common.h"
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//#link "multilines.c"
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void setup_bitmap_multi();
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void set_pixel(byte x, byte y, byte color);
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/* Graphics definitions */
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#define SCREEN_X 160
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#define SCREEN_Y 192
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#define MAXCOL 16
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#define maxiterations 16
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#define fpshift (10)
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#define tofp(_x) ((_x)<<fpshift)
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#define fromfp(_x) ((_x)>>fpshift)
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#define fpabs(_x) (abs(_x))
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#define mulfp(_a,_b) ((((signed long)_a)*(_b))>>fpshift)
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#define divfp(_a,_b) ((((signed long)_a)<<fpshift)/(_b))
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const byte COLORS[MAXCOL] = {
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0, 11, 12, 15, 1,
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2, 9, 4, 8, 10, 7,
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6, 14, 3,
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5, 13,
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};
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void mandelbrot (signed short x1, signed short y1, signed short x2,
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signed short y2)
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{
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unsigned char count;
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signed short r, r1, i;
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signed short xs, ys, xx, yy;
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signed short x, y;
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byte color;
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/* Calc stepwidth */
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xs = ((x2 - x1) / (SCREEN_X));
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ys = ((y2 - y1) / (SCREEN_Y));
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yy = y1;
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for (y = 3; y < (SCREEN_Y); y++) {
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yy += ys;
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xx = x1;
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for (x = 0; x < (SCREEN_X); x++) {
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xx += xs;
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/* Do iterations */
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r = 0;
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i = 0;
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for (count = 0; (count < maxiterations) &&
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(fpabs (r) < tofp (2)) && (fpabs (i) < tofp (2));
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++count) {
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r1 = (mulfp (r, r) - mulfp (i, i)) + xx;
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/* i = (mulfp(mulfp(r,i),tofp(2)))+yy; */
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i = (((signed long) r * i) >> (fpshift - 1)) + yy;
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r = r1;
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}
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if (count == maxiterations) {
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color = (0);
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} else {
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color = COLORS[count % MAXCOL];
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}
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/* Set pixel */
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set_pixel(x, y, color);
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}
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}
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}
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int main (void)
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{
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setup_bitmap_multi();
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VIC.bgcolor0 = 0x00;
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/* Calc mandelbrot set */
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mandelbrot (tofp (-2), tofp (-2), tofp (2), tofp (2));
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/* Fetch the character from the keyboard buffer and discard it */
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cgetc ();
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/* Done */
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return EXIT_SUCCESS;
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}
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