void rt_tri_fcylinder(void * tex, vector ctr, vector axis, apiflt rad) {
vector x, y, z, tmp;
double u, v, u2, v2;
int j;
vector p1, p2, p3, p4;
vector n1, n2;
z = axis;
MyVNorm(&z);
tmp.x = z.y - 2.1111111;
tmp.y = -z.z + 3.14159267;
tmp.z = z.x - 3.915292342341;
MyVNorm(&z);
MyVNorm(&tmp);
MyVCross(&z, &tmp, &x);
MyVNorm(&x);
MyVCross(&x, &z, &y);
MyVNorm(&y);
for (j=0; j<CYLFACETS; j++) {
u = rad * sin((6.28 * j) / (CYLFACETS - 1.0));
v = rad * cos((6.28 * j) / (CYLFACETS - 1.0));
u2 = rad * sin((6.28 * (j + 1.0)) / (CYLFACETS - 1.0));
v2 = rad * cos((6.28 * (j + 1.0)) / (CYLFACETS - 1.0));
p1.x = p1.y = p1.z = 0.0;
p4 = p3 = p2 = p1;
MyVAddS(u, &x, &p1, &p1);
MyVAddS(v, &y, &p1, &p1);
n1 = p1;
MyVNorm(&n1);
MyVAddS(1.0, &ctr, &p1, &p1);
MyVAddS(u2, &x, &p2, &p2);
MyVAddS(v2, &y, &p2, &p2);
n2 = p2;
MyVNorm(&n2);
MyVAddS(1.0, &ctr, &p2, &p2);
MyVAddS(1.0, &axis, &p1, &p3);
MyVAddS(1.0, &axis, &p2, &p4);
rt_stri(tex, p1, p2, p3, n1, n2, n1);
rt_stri(tex, p3, p2, p4, n1, n2, n2);
}
}
void rt_tri_ring(void * tex, vector ctr, vector norm, apiflt a, apiflt b) {
vector x, y, z, tmp;
double u, v, u2, v2;
int j;
vector p1, p2, p3, p4;
vector n1, n2;
z = norm;
MyVNorm(&z);
tmp.x = z.y - 2.1111111;
tmp.y = -z.z + 3.14159267;
tmp.z = z.x - 3.915292342341;
MyVNorm(&z);
MyVNorm(&tmp);
MyVCross(&z, &tmp, &x);
MyVNorm(&x);
MyVCross(&x, &z, &y);
MyVNorm(&y);
for (j=0; j<RINGFACETS; j++) {
u = sin((6.28 * j) / (RINGFACETS - 1.0));
v = cos((6.28 * j) / (RINGFACETS - 1.0));
u2 = sin((6.28 * (j + 1.0)) / (RINGFACETS - 1.0));
v2 = cos((6.28 * (j + 1.0)) / (RINGFACETS - 1.0));
p1.x = p1.y = p1.z = 0.0;
p4 = p3 = p2 = p1;
MyVAddS(u, &x, &p1, &p1);
MyVAddS(v, &y, &p1, &p1);
n1 = p1;
MyVNorm(&n1);
MyVAddS(a, &n1, &ctr, &p1);
MyVAddS(b, &n1, &ctr, &p3);
MyVAddS(u2, &x, &p2, &p2);
MyVAddS(v2, &y, &p2, &p2);
n2 = p2;
MyVNorm(&n2);
MyVAddS(a, &n2, &ctr, &p2);
MyVAddS(b, &n2, &ctr, &p4);
rt_stri(tex, p1, p2, p3, norm, norm, norm);
rt_stri(tex, p3, p2, p4, norm, norm, norm);
}
}
static void rt_sheightfield(void * tex, vector ctr, int m, int n,
apiflt * field, apiflt wx, apiflt wy) {
vector * vertices;
vector * normals;
vector offset;
apiflt xinc, yinc;
int x, y, addr;
vertices = (vector *) malloc(m*n*sizeof(vector));
normals = (vector *) malloc(m*n*sizeof(vector));
offset.x = ctr.x - (wx / 2.0);
offset.y = ctr.z - (wy / 2.0);
offset.z = ctr.y;
xinc = wx / ((apiflt) m);
yinc = wy / ((apiflt) n);
/* build vertex list */
for (y=0; y<n; y++) {
for (x=0; x<m; x++) {
addr = y*m + x;
vertices[addr] = rt_vector(
x * xinc + offset.x,
field[addr] + offset.z,
y * yinc + offset.y);
}
}
/* build normals from vertex list */
for (x=1; x<m; x++) {
normals[x] = normals[(n - 1)*m + x] = rt_vector(0.0, 1.0, 0.0);
}
for (y=1; y<n; y++) {
normals[y*m] = normals[y*m + (m-1)] = rt_vector(0.0, 1.0, 0.0);
}
for (y=1; y<(n-1); y++) {
for (x=1; x<(m-1); x++) {
addr = y*m + x;
normals[addr] = rt_vector(
-(field[addr + 1] - field[addr - 1]) / (2.0 * xinc),
1.0,
-(field[addr + m] - field[addr - m]) / (2.0 * yinc));
MyVNorm(&normals[addr]);
}
}
/* generate actual triangles */
for (y=0; y<(n-1); y++) {
for (x=0; x<(m-1); x++) {
addr = y*m + x;
rt_stri(tex, vertices[addr], vertices[addr + 1 + m], vertices[addr + 1],
normals[addr], normals[addr + 1 + m], normals[addr + 1]);
rt_stri(tex, vertices[addr], vertices[addr + m], vertices[addr + 1 + m],
normals[addr], normals[addr + m], normals[addr + 1 + m]);
}
}
free(normals);
free(vertices);
} /* end of smoothed heightfield */