1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/scantmpl.h	Mon Nov 21 06:14:01 2011 +0200
     1.3 @@ -0,0 +1,158 @@
     1.4 +/*
     1.5 +256-color 3D graphics hack for real-mode DOS.
     1.6 +Copyright (C) 2011  John Tsiombikas <nuclear@member.fsf.org>
     1.7 +
     1.8 +This program is free software: you can redistribute it and/or modify
     1.9 +it under the terms of the GNU General Public License as published by
    1.10 +the Free Software Foundation, either version 3 of the License, or
    1.11 +(at your option) any later version.
    1.12 +
    1.13 +This program is distributed in the hope that it will be useful,
    1.14 +but WITHOUT ANY WARRANTY; without even the implied warranty of
    1.15 +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    1.16 +GNU General Public License for more details.
    1.17 +
    1.18 +You should have received a copy of the GNU General Public License
    1.19 +along with this program.  If not, see <http://www.gnu.org/licenses/>.
    1.20 +*/
    1.21 +static void SCAN_EDGE(struct vertex *v0, struct vertex *v1)
    1.22 +{
    1.23 +	int i, start, end;
    1.24 +	float dx, dy, dfdx;
    1.25 +#ifdef INTERP_DEPTH
    1.26 +	float z, dz, dfdz;
    1.27 +#endif
    1.28 +#ifdef INTERP_ENERGY
    1.29 +	float e, de, dfde;
    1.30 +#endif
    1.31 +	float x, y;
    1.32 +	struct vertex *edge;
    1.33 +
    1.34 +	dy = v1->pos.y - v0->pos.y;
    1.35 +	if(dy < 1e-6 && dy > -1e-6) {
    1.36 +		return;
    1.37 +	}
    1.38 +
    1.39 +	dx = v1->pos.x - v0->pos.x;
    1.40 +	dfdx = dx / dy;
    1.41 +
    1.42 +#ifdef INTERP_DEPTH
    1.43 +	assert(fb->zbuf);
    1.44 +	dz = v1->pos.z - v0->pos.z;
    1.45 +	dfdz = dz / dy;
    1.46 +#endif
    1.47 +#ifdef INTERP_ENERGY
    1.48 +	de = v1->energy - v0->energy;
    1.49 +	dfde = de / dy;
    1.50 +#endif
    1.51 +
    1.52 +	if(dy < 0.0) {
    1.53 +		struct vertex *tmp = v0;
    1.54 +		v0 = v1;
    1.55 +		v1 = tmp;
    1.56 +		edge = (st->ord == MGL_CCW) ? vright : vleft;
    1.57 +	} else {
    1.58 +		edge = (st->ord == MGL_CCW) ? vleft : vright;
    1.59 +	}
    1.60 +
    1.61 +	start = (int)ROUND(v0->pos.y);
    1.62 +	end = (int)ROUND(v1->pos.y);
    1.63 +
    1.64 +	x = v0->pos.x;
    1.65 +#ifdef INTERP_DEPTH
    1.66 +	z = v0->pos.z;
    1.67 +#endif
    1.68 +#ifdef INTERP_ENERGY
    1.69 +	e = v0->energy;
    1.70 +#endif
    1.71 +	for(i=start; i<end; i++) {
    1.72 +		edge[i].pos.x = x;
    1.73 +		x += dfdx;
    1.74 +
    1.75 +		edge[i].cidx = v0->cidx;
    1.76 +#ifdef INTERP_DEPTH
    1.77 +		edge[i].pos.z = z;
    1.78 +		z += dfdz;
    1.79 +#endif
    1.80 +
    1.81 +#ifdef INTERP_ENERGY
    1.82 +		edge[i].energy = e;
    1.83 +		e += dfde;
    1.84 +#else
    1.85 +		edge[i].energy = v0->energy;
    1.86 +#endif
    1.87 +	}
    1.88 +}
    1.89 +
    1.90 +static void SCAN_LINE(int y, unsigned char *sline)
    1.91 +{
    1.92 +	int i, x0, x1, len, tmp, cidx;
    1.93 +#if defined(INTERP_DEPTH) || defined(INTERP_ENERGY)
    1.94 +	float x, dx;
    1.95 +#endif
    1.96 +#ifdef INTERP_DEPTH
    1.97 +	float z, dz, dfdz;
    1.98 +#endif
    1.99 +#ifdef INTERP_ENERGY
   1.100 +	float e, de, dfde;
   1.101 +#endif
   1.102 +	struct vertex *left, *right;
   1.103 +
   1.104 +	x0 = (int)ROUND(vleft[y].pos.x);
   1.105 +	x1 = (int)ROUND(vright[y].pos.x);
   1.106 +	len = x1 - x0;
   1.107 +
   1.108 +	if(x1 < x0) {
   1.109 +		if(st->flags & MGL_CULL_FACE) {
   1.110 +			return;
   1.111 +		}
   1.112 +		tmp = x0;
   1.113 +		x0 = x1;
   1.114 +		x1 = tmp;
   1.115 +		len = -len;
   1.116 +
   1.117 +		left = vright;
   1.118 +		right = vleft;
   1.119 +	} else {
   1.120 +		left = vleft;
   1.121 +		right = vright;
   1.122 +	}
   1.123 +
   1.124 +	if(x0 < 0) x0 = 0;
   1.125 +	if(x1 >= fb->width) x1 = fb->width - 1;
   1.126 +
   1.127 +	assert(len >= 0);
   1.128 +
   1.129 +	cidx = left[y].cidx;
   1.130 +#if !defined(INTERP_DEPTH) && !defined(INTERP_ENERGY)
   1.131 +	/* no interpolation at all, just memset the whole scanline */
   1.132 +	memset(sline + x0, cidx + left[y].energy * st->col_range, len);
   1.133 +#else
   1.134 +	/* otherwise do a loop and interpolate whatever needs interpolating */
   1.135 +	x = left[y].pos.x;
   1.136 +	dx = right[y].pos.x - x;
   1.137 +
   1.138 +	if(dx < 0.5 && dx > -0.5) {
   1.139 +		return;
   1.140 +	}
   1.141 +
   1.142 +#ifdef INTERP_DEPTH
   1.143 +	z = left[y].pos.z;
   1.144 +	dz = right[y].pos.z - z;
   1.145 +	dfdz = dz / dx;
   1.146 +#endif
   1.147 +#ifdef INTERP_ENERGY
   1.148 +	e = left[y].energy;
   1.149 +	de = right[y].energy - e;
   1.150 +	dfde = de / dx;
   1.151 +#endif
   1.152 +
   1.153 +	for(i=0; i<len; i++) {
   1.154 +#ifdef INTERP_ENERGY
   1.155 +		cidx = left[y].cidx + e * st->col_range;
   1.156 +		e += dfde;
   1.157 +#endif
   1.158 +		sline[x0 + i] = cidx;
   1.159 +	}
   1.160 +#endif	/* flat */
   1.161 +}