voxlap.c

#include <sys/nearptr.h>
#include <sys/farptr.h>
#include <go32.h>
#include <pc.h>
#include <math.h>
#include <conio.h>

int main(int argc, char **argv)
{
	asm(
		"movb $0,%ah    \n\t"
		"movb $0x13,%al \n\t"
		"int $0x10      \n\t"
	);
	
	
	unsigned long seg = 0xA000;
	_farsetsel(_go32_info_block.selector_for_linear_memory);
	
	//Generate palette
	outportb(0x3c8, 0);
	for(int z = 0; z < 64; z++){
		outportb(0x3c9, z);
		outportb(0x3c9, z);
		outportb(0x3c9, z / 2);
	}
	for(int z = 0; z < 64; z++){
		outportb(0x3c9, z / 2);
		outportb(0x3c9, z);
		outportb(0x3c9, z);
	}
	
	#define POKE(arg1, arg2) _farnspokeb(seg*16 + arg1, arg2)
	
	short hei[4096], col[4096];
	
	//Generate interesting height & color maps
	int p = 0;
	for(int y = 0; y < 64; y++){
		for(int x = 0; x < 64; x++){
			int d = 15 * 15 - pow(((x & 31) - 16), 2) - pow(((y & 31) - 16), 2);
			if(d > 0 && ((x ^ y) & 32)){
				hei[p] = 64 - sqrt(d);
				col[p] = (x + y) * 0.5;
			}
			else{
				hei[p] = 64;
				col[p] = (cos(x * 0.2) + sin(y * 0.3)) * 3 + 88;
			}
			p++;
		}
	}
	
	//Initialize starting position
	int posx = 0, posy = 0, posz = 40 * 65536, horiz = -50;
	double ang = 0;
	
	const double r160 = 1.0 / 160.0;
	int dd = 65536 * r160; //Increment size
	int de = dd * 128;	 //Scan out 128 units
	int sdz = (100 - horiz) * 65536 * r160;
	
	do{
		int cosang = cos(ang) * 65536, sinang = sin(ang) * 65536;
		int dx = sinang + cosang, dxi = -sinang * r160;
		int dy = sinang - cosang, dyi = cosang * r160;

		//For each column in 320*200 mode...
		for(int sx = 0; sx < 320; sx++){

			//Fast ray trace! No *'s or /'s in here (\ 65536 is a shift)
			int x = posx;
			int y = posy;
			int z = posz;
			int dz = sdz;
			int p = sx + 199 * 320;
			
			for(int d = 0; d < de; d += dd){
				x += dx;
				y += dy;
				z += dz;
				
				int i = (((x * 64) & (63 * 64 * 0x10000)) + (y & (63 * 0x10000))) / 65536;
				int h = hei[i] * 65536;
				while(h < z){
					POKE(p, col[i]);
					p -= 320;
					z -= d;
					dz -= dd;
				}
			}
			dx += dxi;
			dy += dyi;
			
			//Finish off rest of line
			while(p >= 0){
				POKE(p, 0);
				p -= 320;
			}
		}

		//Move position & angle
		posx = posx + cosang * 4;
		posy = posy + sinang * 4;
		ang = ang + 0.02;
	} while(!_conio_kbhit());
	
	return 0;
}