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 <math.h>
nuclear@0: #include <assert.h>
nuclear@0: #include "mingl.h"
nuclear@0: 
nuclear@0: 
nuclear@0: void mgl_cube(float sz)
nuclear@0: {
nuclear@0: 	float hsz = sz * 0.5;
nuclear@0: 
nuclear@0: 	mgl_begin(MGL_QUADS);
nuclear@0: 	/* front */
nuclear@0: 	mgl_normal(0, 0, 1);
nuclear@0: 	mgl_vertex3f(-hsz, hsz, hsz);
nuclear@0: 	mgl_vertex3f(-hsz, -hsz, hsz);
nuclear@0: 	mgl_vertex3f(hsz, -hsz, hsz);
nuclear@0: 	mgl_vertex3f(hsz, hsz, hsz);
nuclear@0: 	/* back */
nuclear@0: 	mgl_normal(0, 0, -1);
nuclear@0: 	mgl_vertex3f(hsz, hsz, -hsz);
nuclear@0: 	mgl_vertex3f(hsz, -hsz, -hsz);
nuclear@0: 	mgl_vertex3f(-hsz, -hsz, -hsz);
nuclear@0: 	mgl_vertex3f(-hsz, hsz, -hsz);
nuclear@0: 	/* right */
nuclear@0: 	mgl_normal(1, 0, 0);
nuclear@0: 	mgl_vertex3f(hsz, hsz, hsz);
nuclear@0: 	mgl_vertex3f(hsz, -hsz, hsz);
nuclear@0: 	mgl_vertex3f(hsz, -hsz, -hsz);
nuclear@0: 	mgl_vertex3f(hsz, hsz, -hsz);
nuclear@0: 	/* left */
nuclear@0: 	mgl_normal(-1, 0, 0);
nuclear@0: 	mgl_vertex3f(-hsz, hsz, -hsz);
nuclear@0: 	mgl_vertex3f(-hsz, -hsz, -hsz);
nuclear@0: 	mgl_vertex3f(-hsz, -hsz, hsz);
nuclear@0: 	mgl_vertex3f(-hsz, hsz, hsz);
nuclear@0: 	/* top */
nuclear@0: 	mgl_normal(0, 1, 0);
nuclear@0: 	mgl_vertex3f(-hsz, hsz, -hsz);
nuclear@0: 	mgl_vertex3f(-hsz, hsz, hsz);
nuclear@0: 	mgl_vertex3f(hsz, hsz, hsz);
nuclear@0: 	mgl_vertex3f(hsz, hsz, -hsz);
nuclear@0: 	/* bottom */
nuclear@0: 	mgl_normal(0, -1, 0);
nuclear@0: 	mgl_vertex3f(hsz, -hsz, -hsz);
nuclear@0: 	mgl_vertex3f(hsz, -hsz, hsz);
nuclear@0: 	mgl_vertex3f(-hsz, -hsz, hsz);
nuclear@0: 	mgl_vertex3f(-hsz, -hsz, -hsz);
nuclear@0: 	mgl_end();
nuclear@0: }
nuclear@0: 
nuclear@0: void mgl_sphere(float rad, int usub, int vsub)
nuclear@0: {
nuclear@0: 	mgl_sphere_part(rad, usub, vsub, 1.0, 1.0);
nuclear@0: }
nuclear@0: 
nuclear@0: #define sphere_vertex(u, v) \
nuclear@0: 	do { \
nuclear@0: 		float x, y, z, theta, phi; \
nuclear@0: 		float costheta, sinphi; \
nuclear@0: 		theta = (u) * 2.0 * M_PI; \
nuclear@0: 		phi = (v) * M_PI; \
nuclear@0: 		costheta = cos(theta); \
nuclear@0: 		sinphi = sin(phi); \
nuclear@0: 		x = costheta * sinphi; \
nuclear@0: 		y = cos(phi); \
nuclear@0: 		z = sin(theta) * sinphi; \
nuclear@0: 		mgl_normal(x, y, z); \
nuclear@0: 		mgl_texcoord2f(u, v); \
nuclear@0: 		mgl_vertex3f(rad * x, rad * y, rad * z); \
nuclear@0: 	} while(0)
nuclear@0: 
nuclear@0: void mgl_sphere_part(float rad, int usub, int vsub, float umax, float vmax)
nuclear@0: {
nuclear@0: 	int i, j;
nuclear@0: 	float u, v, du, dv;
nuclear@0: 
nuclear@0: 	assert(usub > 2);
nuclear@0: 	assert(vsub > 2);
nuclear@0: 
nuclear@0: 	du = umax / (float)usub;
nuclear@0: 	dv = vmax / (float)vsub;
nuclear@0: 
nuclear@0: 	mgl_begin(MGL_QUADS);
nuclear@0: 
nuclear@0: 	u = 0.0;
nuclear@0: 	for(i=0; i<usub; i++) {
nuclear@0: 		v = 0.0;
nuclear@0: 		for(j=0; j<vsub; j++) {
nuclear@0: 			sphere_vertex(u, v);
nuclear@0: 			sphere_vertex(u + du, v);
nuclear@0: 			sphere_vertex(u + du, v + dv);
nuclear@0: 			sphere_vertex(u, v + dv);
nuclear@0: 			v += dv;
nuclear@0: 		}
nuclear@0: 		u += du;
nuclear@0: 	}
nuclear@0: 	mgl_end();
nuclear@0: }
nuclear@0: 
nuclear@0: void mgl_torus(float inner, float outer, int usub, int vsub)
nuclear@0: {
nuclear@0: 	mgl_torus_part(inner, outer, usub, vsub, 1.0, 0.0, 1.0);
nuclear@0: }
nuclear@0: 
nuclear@0: #define torus_vertex(u, v) \
nuclear@0: 	do { \
nuclear@0: 		float rx, ry, rz, cx, cy, cz, theta, phi; \
nuclear@0: 		float costheta, sintheta, sinphi; \
nuclear@0: 		theta = (u) * 2.0 * M_PI; \
nuclear@0: 		phi = (v) * 2.0 * M_PI; \
nuclear@0: 		costheta = cos(theta); \
nuclear@0: 		sintheta = sin(theta); \
nuclear@0: 		sinphi = sin(phi); \
nuclear@0: 		cx = costheta * inner; \
nuclear@0: 		cy = 0.0f; \
nuclear@0: 		cz = sintheta * inner; \
nuclear@0: 		rx = costheta * sinphi; \
nuclear@0: 		ry = cos(phi); \
nuclear@0: 		rz = sintheta * sinphi; \
nuclear@0: 		mgl_normal(rx, ry, rz); \
nuclear@0: 		mgl_texcoord2f(u, v); \
nuclear@0: 		mgl_vertex3f(outer * rx + cx, outer * ry + cy, outer * rz + cz); \
nuclear@0: 	} while(0)
nuclear@0: 
nuclear@0: void mgl_torus_part(float inner, float outer, int usub, int vsub, float umax, float vmin, float vmax)
nuclear@0: {
nuclear@0: 	int i, j;
nuclear@0: 	float u, v, du, dv;
nuclear@0: 
nuclear@0: 	assert(usub > 2);
nuclear@0: 	assert(vsub > 2);
nuclear@0: 
nuclear@0: 	du = umax / (float)usub;
nuclear@0: 	dv = (vmax - vmin) / (float)vsub;
nuclear@0: 
nuclear@0: 	mgl_begin(MGL_QUADS);
nuclear@0: 
nuclear@0: 	u = 0.0;
nuclear@0: 	for(i=0; i<usub; i++) {
nuclear@0: 		v = vmin;
nuclear@0: 		for(j=0; j<vsub; j++) {
nuclear@0: 			torus_vertex(u, v);
nuclear@0: 			torus_vertex(u + du, v);
nuclear@0: 			torus_vertex(u + du, v + dv);
nuclear@0: 			torus_vertex(u, v + dv);
nuclear@0: 			v += dv;
nuclear@0: 		}
nuclear@0: 		u += du;
nuclear@0: 	}
nuclear@0: 	mgl_end();
nuclear@0: }