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/*
* mapping.c
*
* Copyright (C) 1989, 1991, Craig E. Kolb
* All rights reserved.
*
* This software may be freely copied, modified, and redistributed
* provided that this copyright notice is preserved on all copies.
*
* You may not distribute this software, in whole or in part, as part of
* any commercial product without the express consent of the authors.
*
* There is no warranty or other guarantee of fitness of this software
* for any purpose. It is provided solely "as is".
*
* $Id$
*
* $Log$
*/
#include "libobj/object.h"
#include "mapping.h"
void UVMapping(), SphereMapping(), CylinderMapping(), LinearMapping();
Mapping *
UVMappingCreate()
{
Mapping *res;
res = (Mapping *)Malloc(sizeof(Mapping));
res->flags = PRIMSPACE;
res->method = UVMapping;
return res;
}
Mapping *
SphereMappingCreate(center, norm, uaxis)
Vector *center, *norm, *uaxis;
{
Mapping *res;
res = (Mapping *)Malloc(sizeof(Mapping));
res->flags = OBJSPACE;
res->method = SphereMapping;
if (center)
res->center = *center;
else
res->center.x = res->center.y = res->center.z = 0.;
if (norm && uaxis) {
res->norm = *norm;
if (VecNormalize(&res->norm) == 0.) {
RLerror(RL_ABORT, "Degenerate mapping vector.\n");
return (Mapping *)NULL;
}
if (VecNormCross(norm, uaxis, &res->vaxis) == 0.) {
RLerror(RL_ABORT, "Degenerate mapping vector.\n");
return (Mapping *)NULL;
}
(void)VecNormCross(&res->vaxis, norm, &res->uaxis);
} else {
res->norm.x = res->norm.y = res->uaxis.y = res->uaxis.z =
res->vaxis.x = res->vaxis.z = 0.;
res->norm.z = res->uaxis.x = res->vaxis.y = 1.;
}
return res;
}
Mapping *
CylMappingCreate(center, norm, uaxis)
Vector *center, *norm, *uaxis;
{
Mapping *res;
res = (Mapping *)Malloc(sizeof(Mapping));
res->flags = OBJSPACE;
res->method = CylinderMapping;
if (center)
res->center = *center;
else
res->center.x = res->center.y = res->center.z = 0.;
if (norm && uaxis) {
res->norm = *norm;
if (VecNormalize(&res->norm) == 0.) {
RLerror(RL_ABORT, "Degenerate mapping vector.\n");
return (Mapping *)NULL;
}
/*
* Here, uaxis indicates where theta (u) = 0.
*/
if (VecNormCross(norm, uaxis, &res->vaxis) == 0.) {
RLerror(RL_ABORT, "Degenerate mapping vector.\n");
return (Mapping *)NULL;
}
(void)VecNormCross(&res->vaxis, norm, &res->uaxis);
} else {
res->norm.x = res->norm.y = res->uaxis.y = res->uaxis.z =
res->vaxis.x = res->vaxis.z = 0.;
res->norm.z = res->uaxis.x = res->vaxis.y = 1.;
}
return res;
}
Mapping *
LinearMappingCreate(center, vaxis, uaxis)
Vector *center, *vaxis, *uaxis;
{
Mapping *res;
Matrix *m;
Vector n;
res = (Mapping *)Malloc(sizeof(Mapping));
res->flags = OBJSPACE;
res->method= LinearMapping;
if (center)
res->center = *center;
else
res->center.x = res->center.y = res->center.z = 0.;
if (uaxis && vaxis) {
VecCross(uaxis, vaxis, &n);
/* this is wrong, since uaxis and vaxis
* give U and V in world space, and we
* need the inverse.
*/
m = ArbitraryMatrix(
uaxis->x, uaxis->y, uaxis->z,
vaxis->x, vaxis->y, vaxis->z,
n.x, n.y, n.z,
res->center.x, res->center.y, res->center.z);
res->m = MatrixCreate();
MatrixInvert(m, res->m);
res->uaxis = *uaxis;
res->vaxis = *vaxis;
VecNormalize(&res->uaxis);
VecNormalize(&res->vaxis);
free((voidstar)m);
} else {
VecScale(-1., res->center, &n);
res->m = TranslationMatrix(&n);
res->uaxis.x = res->vaxis.y = 1.;
res->uaxis.y = res->uaxis.z = res->vaxis.x =
res->vaxis.z = 0.;
}
return res;
}
void
UVMapping(map, obj, pos, norm, uv, dpdu, dpdv)
Mapping *map;
Object *obj;
Vec2d *uv;
Vector *pos, *norm, *dpdu, *dpdv;
{
PrimUV(obj, pos, norm, uv, dpdu, dpdv);
}
void
SphereMapping(map, obj, pos, norm, uv, dpdu, dpdv)
Mapping *map;
Object *obj;
Vec2d *uv;
Vector *pos, *norm, *dpdu, *dpdv;
{
Vector vtmp;
Float nx, ny, nz, phi, theta;
VecSub(*pos, map->center, &vtmp);
if (VecNormalize(&vtmp) == 0.) {
/*
* Point is coincident with origin of sphere. Punt.
*/
uv->u = uv->v = 0.;
return;
}
/*
* Find location of point projected onto unit sphere
* in the sphere's coordinate system.
*/
nx = dotp(&map->uaxis, &vtmp);
ny = dotp(&map->vaxis, &vtmp);
nz = dotp(&map->norm, &vtmp);
if (nz > 1.) /* roundoff */
phi = PI;
else if (nz < -1.)
phi = 0;
else
phi = acos(-nz);
uv->v = phi / PI;
if (fabs(uv->v) < EPSILON || equal(uv->v, 1.))
uv->u = 0.;
else {
theta = nx / sin(phi);
if (theta > 1.)
theta = 0.;
else if (theta < -1.)
theta = 0.5;
else
theta = acos(theta) / TWOPI;
if (ny > 0)
uv->u = theta;
else
uv->u = 1 - theta;
}
}
void
CylinderMapping(map, obj, pos, norm, uv, dpdu, dpdv)
Mapping *map;
Object *obj;
Vec2d *uv;
Vector *pos, *norm, *dpdu, *dpdv;
{
Vector vtmp;
Float nx, ny, r;
VecSub(*pos, map->center, &vtmp);
nx = dotp(&map->uaxis, &vtmp);
ny = dotp(&map->vaxis, &vtmp);
uv->v = dotp(&map->norm, &vtmp);
r = sqrt(nx*nx + ny*ny);
if (r < EPSILON) {
uv->u = 0.;
return;
}
nx /= r;
ny /= r;
if (fabs(nx) > 1.)
uv->u = 0.5;
else
uv->u = acos(nx) / TWOPI;
if (ny < 0.)
uv->u = 1. - uv->u;
if (dpdv)
*dpdv = map->norm;
if (dpdu)
(void)VecNormCross(&map->norm, pos, dpdu);
}
void
LinearMapping(map, obj, pos, norm, uv, dpdu, dpdv)
Mapping *map;
Object *obj;
Vec2d *uv;
Vector *pos, *norm, *dpdu, *dpdv;
{
Vector vtmp;
vtmp = *pos;
VecTransform(&vtmp, map->m);
uv->u = vtmp.x; uv->v = vtmp.y;
if (dpdu) {
*dpdu = map->uaxis;
}
if (dpdv) {
*dpdv = map->vaxis;
}
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.