//clips an edge against one plane.
vertex *clip_edge(int plane_flag,vertex *on_pnt,vertex *off_pnt, uint flags)
{
float ratio;
vertex *tmp;
tmp = get_temp_point();
if ( plane_flag & CC_OFF_USER ) {
// Clip with user-defined plane
vector w, ray_direction;
float num,den;
vm_vec_sub(&ray_direction,(vector *)&off_pnt->x,(vector *)&on_pnt->x);
vm_vec_sub(&w,(vector *)&on_pnt->x,&G3_user_clip_point);
den = -vm_vec_dot(&G3_user_clip_normal,&ray_direction);
if ( den == 0.0f ) { // Ray & plane are parallel, so there is no intersection
Int3(); // Get John
ratio = 1.0f;
} else {
num = vm_vec_dot(&G3_user_clip_normal,&w);
ratio = num / den;
}
tmp->x = on_pnt->x + (off_pnt->x-on_pnt->x) * ratio;
tmp->y = on_pnt->y + (off_pnt->y-on_pnt->y) * ratio;
tmp->z = on_pnt->z + (off_pnt->z-on_pnt->z) * ratio;
} else {
float a,b,kn,kd;
//compute clipping value k = (xs-zs) / (xs-xe-zs+ze)
//use x or y as appropriate, and negate x/y value as appropriate
if (plane_flag & (CC_OFF_RIGHT | CC_OFF_LEFT)) {
a = on_pnt->x;
b = off_pnt->x;
}
else {
a = on_pnt->y;
b = off_pnt->y;
}
if (plane_flag & (CC_OFF_LEFT | CC_OFF_BOT)) {
a = -a;
b = -b;
}
kn = a - on_pnt->z; //xs-zs
kd = kn - b + off_pnt->z; //xs-zs-xe+ze
ratio = kn / kd;
tmp->x = on_pnt->x + (off_pnt->x-on_pnt->x) * ratio;
tmp->y = on_pnt->y + (off_pnt->y-on_pnt->y) * ratio;
if (plane_flag & (CC_OFF_TOP|CC_OFF_BOT)) {
tmp->z = tmp->y;
} else {
tmp->z = tmp->x;
}
if (plane_flag & (CC_OFF_LEFT|CC_OFF_BOT))
tmp->z = -tmp->z;
}
if (flags & TMAP_FLAG_TEXTURED) {
tmp->u = on_pnt->u + (off_pnt->u-on_pnt->u) * ratio;
tmp->v = on_pnt->v + (off_pnt->v-on_pnt->v) * ratio;
tmp->env_u = on_pnt->env_u + (off_pnt->env_u-on_pnt->env_u) * ratio;
tmp->env_v = on_pnt->env_v + (off_pnt->env_v-on_pnt->env_v) * ratio;
}
if (flags & TMAP_FLAG_GOURAUD ) {
if (flags & TMAP_FLAG_RAMP) {
float on_b, off_b;
on_b = i2fl(on_pnt->b);
off_b = i2fl(off_pnt->b);
tmp->b = ubyte(fl2i(on_b + (off_b-on_b) * ratio));
}
if (flags & TMAP_FLAG_RGB) {
float on_r, on_b, on_g, onspec_r, onspec_g, onspec_b;
float off_r, off_b, off_g, offspec_r, offspec_g, offspec_b;
on_r = i2fl(on_pnt->r);
off_r = i2fl(off_pnt->r);
on_g = i2fl(on_pnt->g);
off_g = i2fl(off_pnt->g);
on_b = i2fl(on_pnt->b);
off_b = i2fl(off_pnt->b);
onspec_r = i2fl(on_pnt->spec_r);
offspec_r = i2fl(off_pnt->spec_r);
onspec_g = i2fl(on_pnt->spec_g);
offspec_g = i2fl(off_pnt->spec_g);
onspec_b = i2fl(on_pnt->spec_b);
offspec_b = i2fl(off_pnt->spec_b);
tmp->r = ubyte(fl2i(on_r + (off_r-on_r) * ratio));
tmp->g = ubyte(fl2i(on_g + (off_g-on_g) * ratio));
tmp->b = ubyte(fl2i(on_b + (off_b-on_b) * ratio));
tmp->spec_r = ubyte(fl2i(onspec_r + (offspec_r-onspec_r) * ratio));
tmp->spec_g = ubyte(fl2i(onspec_g + (offspec_g-onspec_g) * ratio));
tmp->spec_b = ubyte(fl2i(onspec_b + (offspec_b-onspec_b) * ratio));
}
}
else
{
tmp->spec_r=tmp->spec_g=tmp->spec_b=0;
}
if (flags & TMAP_FLAG_ALPHA) {
float on_a, off_a;
on_a = i2fl(on_pnt->a);
off_a = i2fl(off_pnt->a);
tmp->a = ubyte(fl2i(on_a + (off_a-on_a) * ratio));
}
g3_code_vertex(tmp);
return tmp;
}
//clips an edge against one plane.
g3s_point *clip_edge(int plane_flag,g3s_point *on_pnt,g3s_point *off_pnt)
{
fix psx_ratio;
fix a,b,kn,kd;
g3s_point *tmp;
//compute clipping value k = (xs-zs) / (xs-xe-zs+ze)
//use x or y as appropriate, and negate x/y value as appropriate
if (plane_flag & (CC_OFF_RIGHT | CC_OFF_LEFT)) {
a = on_pnt->p3_x;
b = off_pnt->p3_x;
}
else {
a = on_pnt->p3_y;
b = off_pnt->p3_y;
}
if (plane_flag & (CC_OFF_LEFT | CC_OFF_BOT)) {
a = -a;
b = -b;
}
kn = a - on_pnt->p3_z; //xs-zs
kd = kn - b + off_pnt->p3_z; //xs-zs-xe+ze
tmp = get_temp_point();
psx_ratio = fixdiv( kn, kd );
// PSX_HACK!!!!
// tmp->p3_x = on_pnt->p3_x + fixmuldiv(off_pnt->p3_x-on_pnt->p3_x,kn,kd);
// tmp->p3_y = on_pnt->p3_y + fixmuldiv(off_pnt->p3_y-on_pnt->p3_y,kn,kd);
tmp->p3_x = on_pnt->p3_x + fixmul( (off_pnt->p3_x-on_pnt->p3_x), psx_ratio);
tmp->p3_y = on_pnt->p3_y + fixmul( (off_pnt->p3_y-on_pnt->p3_y), psx_ratio);
if (plane_flag & (CC_OFF_TOP|CC_OFF_BOT))
tmp->p3_z = tmp->p3_y;
else
tmp->p3_z = tmp->p3_x;
if (plane_flag & (CC_OFF_LEFT|CC_OFF_BOT))
tmp->p3_z = -tmp->p3_z;
if (on_pnt->p3_flags & PF_UVS) {
// PSX_HACK!!!!
// tmp->p3_u = on_pnt->p3_u + fixmuldiv(off_pnt->p3_u-on_pnt->p3_u,kn,kd);
// tmp->p3_v = on_pnt->p3_v + fixmuldiv(off_pnt->p3_v-on_pnt->p3_v,kn,kd);
tmp->p3_u = on_pnt->p3_u + fixmul((off_pnt->p3_u-on_pnt->p3_u), psx_ratio);
tmp->p3_v = on_pnt->p3_v + fixmul((off_pnt->p3_v-on_pnt->p3_v), psx_ratio);
tmp->p3_flags |= PF_UVS;
}
if (on_pnt->p3_flags & PF_LS) {
// PSX_HACK
// tmp->p3_r = on_pnt->p3_r + fixmuldiv(off_pnt->p3_r-on_pnt->p3_r,kn,kd);
// tmp->p3_g = on_pnt->p3_g + fixmuldiv(off_pnt->p3_g-on_pnt->p3_g,kn,kd);
// tmp->p3_b = on_pnt->p3_b + fixmuldiv(off_pnt->p3_b-on_pnt->p3_b,kn,kd);
tmp->p3_l = on_pnt->p3_l + fixmul((off_pnt->p3_l-on_pnt->p3_l), psx_ratio);
tmp->p3_flags |= PF_LS;
}
G3EncodePoint(tmp);
return tmp;
}
