367 lines
8.2 KiB
C
367 lines
8.2 KiB
C
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/*
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3DKIT version 1.3
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High speed 3D graphics and rendering library for Linux.
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Copyright (C) 1996, 1997 Paul Sheer psheer@icon.co.za
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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MA 02111-1307, USA
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*/
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#include <stdlib.h>
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#ifdef WRAP
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#ifdef INTERP
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void gl_wtriangle (int x0, int y0, int xd0, int yd0, int z0,
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int x1, int y1, int xd1, int yd1, int z1,
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int x2, int y2, int xd2, int yd2, int z2,
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TD_tridata * tri)
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#else
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void gl_swtriangle (int x0, int y0, int xd0, int yd0,
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int x1, int y1, int xd1, int yd1,
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int x2, int y2, int xd2, int yd2, int z0,
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TD_tridata * tri)
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#endif
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#else
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#ifdef INTERP
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void gl_triangle (int x0, int y0, int z0,
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int x1, int y1, int z1,
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int x2, int y2, int z2, int bf)
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#else
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void gl_striangle (int x0, int y0,
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int x1, int y1,
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int x2, int y2, int z0, int bf)
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#endif
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#endif
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{
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void (*colhline_pos) (void);
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void (*colhline_neg) (void);
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int dir;
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int X;
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int nz;
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int g0, g1h = 0, g1l = 0;
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#ifdef INTERP
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int c0;
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int c_y;
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#endif
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#ifdef WRAP
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int X0, Y0;
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int bf = tri->bf;
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int xd_y, yd_y;
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#endif
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dir = 1;
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/*Max triangle size in the order of (2^31) >> SHLB)^(.5) : */
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if ((nz = (x0 - x1) * (y0 - y2) - (y0 - y1) * (x0 - x2)) == 0)
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return; /*the points are collinear. */
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#ifdef INTERP
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c_x = -(((y0 - y1) * (z0 - z2) - (z0 - z1) * (y0 - y2)) << SHLB) / nz;
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c_y = -(((z0 - z1) * (x0 - x2) - (x0 - x1) * (z0 - z2)) << SHLB) / nz;
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#endif
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#ifdef WRAP
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xd_x = -(((y0 - y1) * (xd0 - xd2) - (xd0 - xd1) * (y0 - y2)) << SHLB) / nz;
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xd_y = -(((xd0 - xd1) * (x0 - x2) - (x0 - x1) * (xd0 - xd2)) << SHLB) / nz;
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yd_x = -(((y0 - y1) * (yd0 - yd2) - (yd0 - yd1) * (y0 - y2)) << SHLB) / nz;
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yd_y = -(((yd0 - yd1) * (x0 - x2) - (x0 - x1) * (yd0 - yd2)) << SHLB) / nz;
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#endif
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#ifdef INTERP
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if ((abs (c_x) > (6 << SHLB)) || (abs (c_y) > (6 << SHLB))) {
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int tz0, tz1;
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/*so that high colour gradients don't screw up at the edges. */
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/*4 is the maximum gradient per pixel. */
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c_x >>= 2;
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c_y >>= 2;
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tz0 = ((2 * z0 + z1 + z2) << SHLB) / 4;
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tz1 = ((z0 + 2 * z1 + z2) << SHLB) / 4;
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z2 = ((z0 + z1 + 2 * z2) << SHLB) / 4;
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z0 = tz0;
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z1 = tz1;
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} else {
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z0 <<= SHLB;
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z1 <<= SHLB;
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z2 <<= SHLB;
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}
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#endif
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/************** BOOLEAN LOGIC HERE ************/
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/* The following allows a triangle to have a different picture on either side */
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/* To print triangles that don't appear when viewed from behind use bf = 0|1 */
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/* To print triangles that appear with a different picture when viewed from */
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/* behind use bf = 2|3 */
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#ifdef WRAP
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dat = tri->bitmap1;
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if (nz > 0) { /* nz is the cross product of the vectors of the two sides
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it indicates whether the points were ordered clockwise
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or anti-clockwise (you can find out which way by testing) */
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if (bf == 1)
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return;
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if (bf == 3)
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dat = tri->bitmap1;
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dir++;
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} else {
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if (!bf)
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return;
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if (bf == 2)
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dat = tri->bitmap2;
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}
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#else
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if (nz > 0) {
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if (bf == 1)
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return;
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dir++;
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} else {
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if (!bf)
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return;
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}
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#endif
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#define Xchg(a,b) {X=(a);(a)=(b);(b)=X;}
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if (y1 < y0) {
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Xchg (y0, y1);
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Xchg (x0, x1);
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#ifdef INTERP
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Xchg (z0, z1);
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#endif
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#ifdef WRAP
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Xchg (xd0, xd1);
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Xchg (yd0, yd1);
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#endif
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dir++;
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}
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if (y2 < y1) {
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Xchg (y2, y1);
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Xchg (x2, x1);
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#ifdef INTERP
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Xchg (z2, z1);
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#endif
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#ifdef WRAP
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Xchg (xd2, xd1);
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Xchg (yd2, yd1);
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#endif
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dir++;
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}
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if (y1 < y0) {
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Xchg (y0, y1);
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Xchg (x0, x1);
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#ifdef INTERP
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Xchg (z0, z1);
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#endif
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#ifdef WRAP
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Xchg (xd0, xd1);
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Xchg (yd0, yd1);
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#endif
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dir++;
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}
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_color_lookup = color_lookup;
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#ifdef INTERP
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c0 = z0;
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#else
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if(BYTESPERPIXEL == 1) {
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c = z0;
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} else {
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c = _color_lookup[z0];
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}
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#endif
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#ifdef WRAP
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X0 = xd0 << SHLB;
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Y0 = yd0 << SHLB;
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#endif
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if (y2 == y0)
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return;
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g0 = ((int) (x2 - x0) << SHLB) / (y2 - y0);
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if (y1 != y0)
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g1h = ((int) (x1 - x0) << SHLB) / (y1 - y0);
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if (y2 != y1)
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g1l = ((int) (x2 - x1) << SHLB) / (y2 - y1);
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dir = dir & 1;
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/* Very large triangles (larger than the screen) sometimes become a problem,
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if so: */
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if (__clip) {
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if (((abs (x0 - x1) + abs (x1 - x2) + abs (x0 - x2)) >
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((__clipx2 - __clipx1) * 2)) || ((y2 - y0) > (__clipy2 - __clipy1)))
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return;
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if (y2 < __clipy1 || y0 > __clipy2 ||
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(x0 < __clipx1 && x1 < __clipx1 && x2 < __clipx1) ||
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(x0 > __clipx2 && x1 > __clipx2 && x2 > __clipx2))
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return;
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}
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dx0 = x0;
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dy0 = y0;
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if(tri_drawpoint) {
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_tri_drawpoint = tri_drawpoint;
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colhline_pos = linefuncs[(7 * 2) + (BYTESPERPIXEL - 1) * 16];
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colhline_neg = linefuncs[(7 * 2) + (BYTESPERPIXEL - 1) * 16 + 1];
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} else {
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_tri_drawpoint = gl_setpixel;
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colhline_pos = linefuncs[(MODETYPE * 2) + (BYTESPERPIXEL - 1) * 16];
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colhline_neg = linefuncs[(MODETYPE * 2) + (BYTESPERPIXEL - 1) * 16 + 1];
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}
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#ifdef tri_set_color
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#undef tri_set_color
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#endif
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#ifdef WRAP
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#ifdef INTERP
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#define tri_set_color \
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xd = X0 + xd_x * px1 + xd_y * py; \
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yd = Y0 + yd_x * px1 + yd_y * py; \
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c = c0 + c_x * px1 + c_y * py;
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#else
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#define tri_set_color \
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xd = X0 + xd_x * px1 + xd_y * py; \
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yd = Y0 + yd_x * px1 + yd_y * py;
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#endif
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#else
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#ifdef INTERP
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#define tri_set_color \
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c = c0 + c_x * px1 + c_y * py;
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#else
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#define tri_set_color
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#endif
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#endif
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if (dir == 1) {
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if (y1 != y0) {
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py = 0;
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if (x1 < x0) {
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px1 = 0;
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px2 = -((abs (g1h) >> 1)) >> SHLB;
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} else {
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px1 = ((abs (g0) >> 1)) >> SHLB;
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px2 = 0;
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}
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tri_set_color;
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colhline_neg ();
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if ((py = 1) < y1 - y0)
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for (; py < y1 - y0; py++) {
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px1 = ((g0 * py) + (abs (g0) >> 1)) >> SHLB;
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px2 = ((g1h * py) - (abs (g1h) >> 1)) >> SHLB;
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tri_set_color;
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colhline_neg ();
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}
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px1 = min (((g0 * py) + (abs (g0) >> 1)) >> SHLB, max (x2, x0) - x0);
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px2 = x1 - x0;
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tri_set_color;
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colhline_neg ();
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} else {
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py = 0;
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px1 = 0;
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px2 = x1 - x0;
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tri_set_color;
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colhline_neg ();
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}
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if (y1 != y2) {
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if ((py = y1 - y0 + 1) < y2 - y0)
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for (; py < y2 - y0; py++) {
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px1 = ((g0 * py) + (abs (g0) >> 1)) >> SHLB;
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px2 = (((g1l * (py - y1 + y0)) - (abs (g1l) >> 1)) >> SHLB) + x1 - x0;
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tri_set_color;
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colhline_neg ();
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}
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if (x1 < x2) {
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px1 = x2 - x0;
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px2 = x2 - x0 - ((abs (g1l) >> 1) >> SHLB);
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} else {
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px1 = x2 - x0 + ((abs (g0) >> 1) >> SHLB);
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px2 = x2 - x0;
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}
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tri_set_color;
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colhline_neg ();
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}
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} else {
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if (y1 != y0) {
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py = 0;
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if (x1 > x0) {
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px1 = 0;
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px2 = ((abs (g1h) >> 1)) >> SHLB;
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} else {
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px1 = -((abs (g0) >> 1)) >> SHLB;
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px2 = 0;
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}
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tri_set_color;
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colhline_pos ();
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if ((py = 1) < y1 - y0)
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for (; py < y1 - y0; py++) {
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px1 = ((g0 * py) - (abs (g0) >> 1)) >> SHLB;
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px2 = ((g1h * py) + (abs (g1h) >> 1)) >> SHLB;
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tri_set_color;
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colhline_pos ();
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}
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px1 = max (((g0 * py) - (abs (g0) >> 1)) >> SHLB, min (x2, x0) - x0);
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px2 = x1 - x0;
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tri_set_color;
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colhline_pos ();
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} else {
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py = 0;
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px1 = 0;
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px2 = x1 - x0;
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tri_set_color;
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colhline_pos ();
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}
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if (y1 != y2) {
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if ((py = y1 - y0 + 1) < y2 - y0)
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for (; py < y2 - y0; py++) {
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px1 = ((g0 * py) - (abs (g0) >> 1)) >> SHLB;
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px2 = (((g1l * (py - y1 + y0)) + (abs (g1l) >> 1)) >> SHLB) + x1 - x0;
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tri_set_color;
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colhline_pos ();
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}
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if (x1 > x2) {
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px1 = x2 - x0;
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px2 = x2 - x0 + ((abs (g1l) >> 1) >> SHLB);
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} else {
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px1 = x2 - x0 - ((abs (g0) >> 1) >> SHLB);
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px2 = x2 - x0;
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}
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tri_set_color;
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colhline_pos ();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|