dos3d

annotate src/scantmpl.h @ 0:f04884489bad

find changesets by author, revision, files, or words in the commit message
dos3d initial import
author John Tsiombikas <nuclear@member.fsf.org>
date Mon, 21 Nov 2011 06:14:01 +0200
parents
children 0e781cc43178
rev   line source
nuclear@0 1 /*
nuclear@0 2 256-color 3D graphics hack for real-mode DOS.
nuclear@0 3 Copyright (C) 2011 John Tsiombikas <nuclear@member.fsf.org>
nuclear@0 4
nuclear@0 5 This program is free software: you can redistribute it and/or modify
nuclear@0 6 it under the terms of the GNU General Public License as published by
nuclear@0 7 the Free Software Foundation, either version 3 of the License, or
nuclear@0 8 (at your option) any later version.
nuclear@0 9
nuclear@0 10 This program is distributed in the hope that it will be useful,
nuclear@0 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@0 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
nuclear@0 13 GNU General Public License for more details.
nuclear@0 14
nuclear@0 15 You should have received a copy of the GNU General Public License
nuclear@0 16 along with this program. If not, see <http://www.gnu.org/licenses/>.
nuclear@0 17 */
nuclear@0 18 static void SCAN_EDGE(struct vertex *v0, struct vertex *v1)
nuclear@0 19 {
nuclear@0 20 int i, start, end;
nuclear@0 21 float dx, dy, dfdx;
nuclear@0 22 #ifdef INTERP_DEPTH
nuclear@0 23 float z, dz, dfdz;
nuclear@0 24 #endif
nuclear@0 25 #ifdef INTERP_ENERGY
nuclear@0 26 float e, de, dfde;
nuclear@0 27 #endif
nuclear@0 28 float x, y;
nuclear@0 29 struct vertex *edge;
nuclear@0 30
nuclear@0 31 dy = v1->pos.y - v0->pos.y;
nuclear@0 32 if(dy < 1e-6 && dy > -1e-6) {
nuclear@0 33 return;
nuclear@0 34 }
nuclear@0 35
nuclear@0 36 dx = v1->pos.x - v0->pos.x;
nuclear@0 37 dfdx = dx / dy;
nuclear@0 38
nuclear@0 39 #ifdef INTERP_DEPTH
nuclear@0 40 assert(fb->zbuf);
nuclear@0 41 dz = v1->pos.z - v0->pos.z;
nuclear@0 42 dfdz = dz / dy;
nuclear@0 43 #endif
nuclear@0 44 #ifdef INTERP_ENERGY
nuclear@0 45 de = v1->energy - v0->energy;
nuclear@0 46 dfde = de / dy;
nuclear@0 47 #endif
nuclear@0 48
nuclear@0 49 if(dy < 0.0) {
nuclear@0 50 struct vertex *tmp = v0;
nuclear@0 51 v0 = v1;
nuclear@0 52 v1 = tmp;
nuclear@0 53 edge = (st->ord == MGL_CCW) ? vright : vleft;
nuclear@0 54 } else {
nuclear@0 55 edge = (st->ord == MGL_CCW) ? vleft : vright;
nuclear@0 56 }
nuclear@0 57
nuclear@0 58 start = (int)ROUND(v0->pos.y);
nuclear@0 59 end = (int)ROUND(v1->pos.y);
nuclear@0 60
nuclear@0 61 x = v0->pos.x;
nuclear@0 62 #ifdef INTERP_DEPTH
nuclear@0 63 z = v0->pos.z;
nuclear@0 64 #endif
nuclear@0 65 #ifdef INTERP_ENERGY
nuclear@0 66 e = v0->energy;
nuclear@0 67 #endif
nuclear@0 68 for(i=start; i<end; i++) {
nuclear@0 69 edge[i].pos.x = x;
nuclear@0 70 x += dfdx;
nuclear@0 71
nuclear@0 72 edge[i].cidx = v0->cidx;
nuclear@0 73 #ifdef INTERP_DEPTH
nuclear@0 74 edge[i].pos.z = z;
nuclear@0 75 z += dfdz;
nuclear@0 76 #endif
nuclear@0 77
nuclear@0 78 #ifdef INTERP_ENERGY
nuclear@0 79 edge[i].energy = e;
nuclear@0 80 e += dfde;
nuclear@0 81 #else
nuclear@0 82 edge[i].energy = v0->energy;
nuclear@0 83 #endif
nuclear@0 84 }
nuclear@0 85 }
nuclear@0 86
nuclear@0 87 static void SCAN_LINE(int y, unsigned char *sline)
nuclear@0 88 {
nuclear@0 89 int i, x0, x1, len, tmp, cidx;
nuclear@0 90 #if defined(INTERP_DEPTH) || defined(INTERP_ENERGY)
nuclear@0 91 float x, dx;
nuclear@0 92 #endif
nuclear@0 93 #ifdef INTERP_DEPTH
nuclear@0 94 float z, dz, dfdz;
nuclear@0 95 #endif
nuclear@0 96 #ifdef INTERP_ENERGY
nuclear@0 97 float e, de, dfde;
nuclear@0 98 #endif
nuclear@0 99 struct vertex *left, *right;
nuclear@0 100
nuclear@0 101 x0 = (int)ROUND(vleft[y].pos.x);
nuclear@0 102 x1 = (int)ROUND(vright[y].pos.x);
nuclear@0 103 len = x1 - x0;
nuclear@0 104
nuclear@0 105 if(x1 < x0) {
nuclear@0 106 if(st->flags & MGL_CULL_FACE) {
nuclear@0 107 return;
nuclear@0 108 }
nuclear@0 109 tmp = x0;
nuclear@0 110 x0 = x1;
nuclear@0 111 x1 = tmp;
nuclear@0 112 len = -len;
nuclear@0 113
nuclear@0 114 left = vright;
nuclear@0 115 right = vleft;
nuclear@0 116 } else {
nuclear@0 117 left = vleft;
nuclear@0 118 right = vright;
nuclear@0 119 }
nuclear@0 120
nuclear@0 121 if(x0 < 0) x0 = 0;
nuclear@0 122 if(x1 >= fb->width) x1 = fb->width - 1;
nuclear@0 123
nuclear@0 124 assert(len >= 0);
nuclear@0 125
nuclear@0 126 cidx = left[y].cidx;
nuclear@0 127 #if !defined(INTERP_DEPTH) && !defined(INTERP_ENERGY)
nuclear@0 128 /* no interpolation at all, just memset the whole scanline */
nuclear@0 129 memset(sline + x0, cidx + left[y].energy * st->col_range, len);
nuclear@0 130 #else
nuclear@0 131 /* otherwise do a loop and interpolate whatever needs interpolating */
nuclear@0 132 x = left[y].pos.x;
nuclear@0 133 dx = right[y].pos.x - x;
nuclear@0 134
nuclear@0 135 if(dx < 0.5 && dx > -0.5) {
nuclear@0 136 return;
nuclear@0 137 }
nuclear@0 138
nuclear@0 139 #ifdef INTERP_DEPTH
nuclear@0 140 z = left[y].pos.z;
nuclear@0 141 dz = right[y].pos.z - z;
nuclear@0 142 dfdz = dz / dx;
nuclear@0 143 #endif
nuclear@0 144 #ifdef INTERP_ENERGY
nuclear@0 145 e = left[y].energy;
nuclear@0 146 de = right[y].energy - e;
nuclear@0 147 dfde = de / dx;
nuclear@0 148 #endif
nuclear@0 149
nuclear@0 150 for(i=0; i<len; i++) {
nuclear@0 151 #ifdef INTERP_ENERGY
nuclear@0 152 cidx = left[y].cidx + e * st->col_range;
nuclear@0 153 e += dfde;
nuclear@0 154 #endif
nuclear@0 155 sline[x0 + i] = cidx;
nuclear@0 156 }
nuclear@0 157 #endif /* flat */
nuclear@0 158 }