nuclear@0: /*
nuclear@0: 256-color 3D graphics hack for real-mode DOS.
nuclear@0: Copyright (C) 2011  John Tsiombikas <nuclear@member.fsf.org>
nuclear@0: 
nuclear@0: This program is free software: you can redistribute it and/or modify
nuclear@0: it under the terms of the GNU General Public License as published by
nuclear@0: the Free Software Foundation, either version 3 of the License, or
nuclear@0: (at your option) any later version.
nuclear@0: 
nuclear@0: This program is distributed in the hope that it will be useful,
nuclear@0: but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@0: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
nuclear@0: GNU General Public License for more details.
nuclear@0: 
nuclear@0: You should have received a copy of the GNU General Public License
nuclear@0: along with this program.  If not, see <http://www.gnu.org/licenses/>.
nuclear@0: */
nuclear@0: #include <stdio.h>
nuclear@0: #include <stdlib.h>
nuclear@0: #include <string.h>
nuclear@0: #include <assert.h>
nuclear@0: #include "mingl.h"
nuclear@0: #include "mglimpl.h"
nuclear@0: 
nuclear@0: 
nuclear@0: static struct vertex *vleft, *vright;
nuclear@0: static struct framebuffer *fb;
nuclear@0: static struct state *st;
nuclear@0: 
nuclear@0: 
nuclear@0: #define SCAN_EDGE scan_edge_flat
nuclear@0: #define SCAN_LINE scan_line_flat
nuclear@0: #undef INTERP_DEPTH
nuclear@0: #undef INTERP_ENERGY
nuclear@0: #include "scantmpl.h"
nuclear@0: #undef SCAN_EDGE
nuclear@0: #undef SCAN_LINE
nuclear@0: 
nuclear@0: #define SCAN_EDGE scan_edge_z
nuclear@0: #define SCAN_LINE scan_line_z
nuclear@0: #define INTERP_DEPTH
nuclear@0: #undef INTERP_ENERGY
nuclear@0: #include "scantmpl.h"
nuclear@0: #undef SCAN_EDGE
nuclear@0: #undef SCAN_LINE
nuclear@0: 
nuclear@0: #define SCAN_EDGE scan_edge_e
nuclear@0: #define SCAN_LINE scan_line_e
nuclear@0: #undef INTERP_DEPTH
nuclear@0: #define INTERP_ENERGY
nuclear@0: #include "scantmpl.h"
nuclear@0: #undef SCAN_EDGE
nuclear@0: #undef SCAN_LINE
nuclear@0: 
nuclear@0: #define SCAN_EDGE scan_edge_ze
nuclear@0: #define SCAN_LINE scan_line_ze
nuclear@0: #define INTERP_DEPTH
nuclear@0: #define INTERP_ENERGY
nuclear@0: #include "scantmpl.h"
nuclear@0: #undef SCAN_EDGE
nuclear@0: #undef SCAN_LINE
nuclear@0: 
nuclear@0: static void (*scan_edge)(struct vertex*, struct vertex*);
nuclear@0: static void (*scan_line)(int, unsigned char*);
nuclear@0: 
nuclear@0: int mgl_rast_init(struct state *state, struct framebuffer *fbuf)
nuclear@0: {
nuclear@0: 	fb = fbuf;
nuclear@0: 	st = state;
nuclear@0: 
nuclear@0: 	if(!(vleft = malloc(fb->height * sizeof *vleft))) {
nuclear@0: 		return -1;
nuclear@0: 	}
nuclear@0: 	if(!(vright = malloc(fb->height * sizeof *vright))) {
nuclear@0: 		free(vleft);
nuclear@0: 		return -1;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	scan_edge = scan_edge_flat;
nuclear@0: 	scan_line = scan_line_flat;
nuclear@0: 
nuclear@0: 	return 0;
nuclear@0: }
nuclear@0: 
nuclear@0: void mgl_rast_cleanup(void)
nuclear@0: {
nuclear@0: 	free(vleft);
nuclear@0: 	free(vright);
nuclear@0: }
nuclear@0: 
nuclear@0: void mgl_rast_prepare(void)
nuclear@0: {
nuclear@0: 	static void (*sedge[])(struct vertex*, struct vertex*) = {
nuclear@0: 		scan_edge_flat,		/* 00 */
nuclear@0: 		scan_edge_z,		/* 01 */
nuclear@0: 		scan_edge_e,		/* 10 */
nuclear@0: 		scan_edge_ze		/* 11 */
nuclear@0: 	};
nuclear@0: 	static void (*sline[])(int, unsigned char*) = {
nuclear@0: 		scan_line_flat,		/* 00 */
nuclear@0: 		scan_line_z,		/* 01 */
nuclear@0: 		scan_line_e,		/* 10 */
nuclear@0: 		scan_line_ze		/* 11 */
nuclear@0: 	};
nuclear@0: 	int bits = 0;
nuclear@0: 
nuclear@0: 	if(st->flags & MGL_SMOOTH) {
nuclear@0: 		bits |= 2;
nuclear@0: 	}
nuclear@0: 	if((st->flags & MGL_DEPTH_TEST) && fb->zbuf) {
nuclear@0: 		bits |= 1;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	scan_edge = sedge[bits];
nuclear@0: 	scan_line = sline[bits];
nuclear@0: }
nuclear@0: 
nuclear@0: void mgl_draw_point(struct vertex *v)
nuclear@0: {
nuclear@0: 	int x = (int)ROUND(v->pos.x);
nuclear@0: 	int y = (int)ROUND(v->pos.y);
nuclear@0: 
nuclear@0: 	if(x >= 0 && x < fb->width && y >= 0 && y < fb->height) {
nuclear@0: 		int cidx = v->cidx + v->energy * st->col_range;
nuclear@0: 		fb->pixels[y * fb->width + x] = cidx;
nuclear@0: 	}
nuclear@0: }
nuclear@0: 
nuclear@0: void mgl_draw_line(struct vertex *v0, struct vertex *v1)
nuclear@0: {
nuclear@0: 	/* TODO */
nuclear@0: 	fprintf(stderr, "draw_line unimplemented\n");
nuclear@0: 	abort();
nuclear@0: }
nuclear@0: 
nuclear@0: void mgl_draw_poly(struct vertex *v, int numv)
nuclear@0: {
nuclear@0: 	int ybeg, yend, i;
nuclear@0: 	unsigned char *sline;
nuclear@0: 
nuclear@0: 	ybeg = fb->height;
nuclear@0: 	yend = 0;
nuclear@0: 
nuclear@0: 	for(i=0; i<numv; i++) {
nuclear@0: 		struct vertex *v0 = v + i;
nuclear@0: 		struct vertex *v1 = v + (i + 1) % numv;
nuclear@0: 		int y = (int)ROUND(v0->pos.y);
nuclear@0: 
nuclear@0: 		scan_edge(v0, v1);
nuclear@0: 
nuclear@0: 		if(y > yend) yend = y;
nuclear@0: 		if(y < ybeg) ybeg = y;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	if(ybeg < 0) ybeg = 0;
nuclear@0: 	if(yend >= fb->height) yend = fb->height - 1;
nuclear@0: 
nuclear@0: 	sline = fb->pixels + ybeg * fb->width;
nuclear@0: 	for(i=ybeg; i<yend; i++) {
nuclear@0: 		scan_line(i, sline);
nuclear@0: 		sline += fb->width;
nuclear@0: 	}
nuclear@0: }