219 lines
2.9 KiB
C
219 lines
2.9 KiB
C
#include <c64/vic.h>
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#include <c64/memmap.h>
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#include <string.h>
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#include <stdlib.h>
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#define screen ((byte *)0x0400)
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#define color ((byte *)0xd800)
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#define sline(x, y) (screen + 40 * (y) + (x))
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char rbuff[25];
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void expand(char x)
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{
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#assign y 0
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#repeat
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sline(0, y)[x] = rbuff[y];
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#assign y y + 1
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#until y == 25
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}
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void scrollLeft(void)
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{
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for(char x=0; x<39; x++)
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{
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#assign y 0
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#repeat
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sline(0, y)[x] = sline(1, y)[x];
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#assign y y + 1
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#until y == 12
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}
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#assign y 0
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#repeat
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sline(0, y)[39] = rbuff[y];
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#assign y y + 1
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#until y == 12
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for(char x=0; x<39; x++)
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{
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#assign y 12
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#repeat
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sline(0, y)[x] = sline(1, y)[x];
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#assign y y + 1
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#until y == 25
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}
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#assign y 12
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#repeat
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sline(0, y)[39] = rbuff[y];
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#assign y y + 1
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#until y == 25
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}
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void scrollRight(void)
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{
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for(char x=39; x>0; x--)
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{
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#assign y 0
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#repeat
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sline(0, y)[x] = sline(-1, y)[x];
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#assign y y + 1
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#until y == 12
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}
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#assign y 0
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#repeat
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sline(0, y)[0] = rbuff[y];
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#assign y y + 1
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#until y == 12
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for(char x=39; x>0; x--)
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{
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#assign y 12
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#repeat
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sline(0, y)[x] = sline(-1, y)[x];
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#assign y y + 1
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#until y == 25
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}
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#assign y 12
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#repeat
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sline(0, y)[0] = rbuff[y];
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#assign y y + 1
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#until y == 25
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}
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inline void waitBottom(void)
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{
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while (!(vic.ctrl1 & VIC_CTRL1_RST8))
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;
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}
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inline void waitTop(void)
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{
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while ((vic.ctrl1 & VIC_CTRL1_RST8))
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;
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}
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char ytop[256], ybottom[256];
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void prepcol(char xi)
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{
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char yt, yb;
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signed char dyt, dyb;
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yt = ytop[(char)(xi + 0)];
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yb = ybottom[(char)(xi + 0)];
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dyt = yt - ytop[(char)(xi - 1)];
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dyb = yb - ybottom[(char)(xi - 1)];
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for(char i=0; i<yt; i++)
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rbuff[i] = 160;
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for(char i=yt; i<yb; i++)
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rbuff[i] = 32;
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for(char i=yb; i<25; i++)
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rbuff[i] = 160;
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if (dyt < 0)
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rbuff[yt] = 105;
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else if (dyt > 0)
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rbuff[yt - 1] = 95;
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if (dyb < 0)
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rbuff[yb] = 233;
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else if (dyb > 0)
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rbuff[yb - 1] = 223;
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}
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void buildTunnel(void)
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{
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signed char yt = 1, yb = 24, dyt = 1, dyb = -1;
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for(int i=0; i<256; i++)
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{
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unsigned r = rand();
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if (!(r & 0x00e0))
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dyt = -dyt;
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if (!(r & 0xe000))
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dyb = -dyb;
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yt += dyt;
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yb += dyb;
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if (yt < 0)
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{
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yt = 0;
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dyt = 1;
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}
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if (yb > 25)
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{
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yb = 25;
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dyb = -1;
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}
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ytop[i] = yt;
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ybottom[i] = yb;
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if (yt + 5 > yb)
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{
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dyt = -1;
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dyb = 1;
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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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memset(screen, 0x20, 1000);
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memset(color, 7, 1000);
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vic.color_back = VCOL_BLACK;
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vic.color_border = VCOL_BLACK;
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buildTunnel();
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for(char i=0; i<40; i++)
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{
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prepcol(i);
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expand(i);
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}
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int xpos = 0, dx = 0, ax = 1;
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int xi = 0, pxi = 0;
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for(;;)
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{
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unsigned r = rand();
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if ((r & 127) == 0)
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ax = -ax;
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dx += ax;
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if (dx > 32)
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dx = 32;
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else if (dx < -32)
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dx = -32;
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xpos += dx;
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pxi = xi;
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xi = xpos >> 5;
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if (pxi < xi)
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prepcol(xi + 39);
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else if (pxi > xi)
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prepcol(xi + 0);
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waitTop();
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waitBottom();
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vic.ctrl2 = (7 - (xpos >> 2)) & 7;
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if (pxi < xi)
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scrollLeft();
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else if (pxi > xi)
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scrollRight();
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}
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return 0;
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}
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