131 lines
2.7 KiB
C
131 lines
2.7 KiB
C
#include <stdio.h>
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#include <math.h>
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#include <conio.h>
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#include <stdarg.h>
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int horizony=70;
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int bail=192;
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int bailhalve=64;
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int group=150;
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int zwave[1024];
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FILE *f1;
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void P(char *str,...)
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{
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char out[256];
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va_list argp;
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va_start(argp,str);
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vsprintf(out,str,argp);
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fprintf(f1,"%s\n",out);
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va_end(argp);
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}
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long wflip(unsigned long l)
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{
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long m,lo,hi;
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lo=l&0xffff;
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hi=l>>16;
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m=(lo<<16)+hi;
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return(m);
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}
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main()
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{
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int i,j,k,jm,y,a;
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int sina=1;
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long l,firstraydir;
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f1=fopen("theloop.inc","wt");
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for(i=0;i<bail;i++)
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{
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zwave[i]=(int)(16.0*sin((double)i*3.1415926535*2.0*3.0/(double)bail));
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}
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P(";Register usage: ");
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P(";eax low... ray heigth ");
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P(";ebx - ! ");
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P(";ecx low... ray direction (always negative)");
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P(";edx bail scenary heigth ");
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P(";esi - xsin ");
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P(";edi - ysin ");
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P(";ebp - p->screen ");
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P(";ds ->codesegment");
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P(";es ->screenbuffer");
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P(";fs ->wavetablex");
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P(";gs ->wavetabley");
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P("");
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P("ALIGN 16 ;following should stay in cache");
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P("theloop_waveseg dw 0");
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P("theloop_xsina1 dw 0");
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P("theloop_ysina1 dw 0");
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P("theloop_xsina2 dw 0");
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P("theloop_ysina2 dw 0");
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P("theloop_heigth dw 0");
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firstraydir=-(200-horizony)*2560L;
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P("");
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P(";entry: es=videbuf");
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P("; bp=pointer to bottom of current column in videbuf");
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P("; fs=waveXsegment");
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P("; gs=waveYsegment");
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P("; si=waveXpos");
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P("; di=waveYpos");
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P("; cx=waveXadd");
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P("; dx=waveYadd");
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P("; ax=camera heigth adder");
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P("theloop PROC FAR");
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P("mov cs:theloop_xsina1,cx");
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P("mov cs:theloop_ysina1,dx");
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P("add cx,cx");
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P("mov cs:theloop_xsina2,cx");
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P("add dx,dx");
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P("mov cs:theloop_ysina2,dx");
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P("mov cs:theloop_heigth,ax");
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P("mov bx,cs:theloop_xsina1");
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//P("mov bp,OFFSET theloop_raydir");
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P("mov ax,cs");
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P("mov ds,ax");
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P("mov edx,10000h*(%i/3)",-bail);
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P("xor eax,eax");
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P("xor ecx,ecx");
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for(i=199;i>=horizony;i--)
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{
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j=i;
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printf("%i \r",j);
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// seek until scene hits row i
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P("_@seek%i:",j);
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for(k=0;k<3;k++)
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{
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P("add si,ds:theloop_xsina1");
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P("mov dx,fs:[si]");
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P("add di,ds:theloop_ysina1");
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P("add dx,gs:[di]");
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P("add dx,%i",-100);
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l=(i-horizony)*2560L;
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P("add ecx,0%08lXh",wflip(2560L));
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P("adc cx,0");
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P("sub eax,0%08lXh",wflip(l));
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P("sbb ax,0");
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P("cmp ax,dx");
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P("jl short _@seek%im",j);
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}
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P("add edx,00010000h");
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P("jnc _@seek%i",j);
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P("ret");
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// hit, draw pixel & advance rays
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P("_@seek%im:",j);
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P("mov es:[bp+%i],dl",-(199-j)*160);
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P("add eax,ecx");
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P("adc ax,0");
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P("cmp ax,dx");
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P("jl short _@seek%im",j-1);
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}
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P("_@seek%im:",j-1);
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P("ret");
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P("theloop ENDP");
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printf(" \r",i);
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fclose(f1);
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}
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