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/*
* texture.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 "texture.h"
/*
* Transformation structures used to map from texture space to
* model/primitive/world space.
*/
Trans prim2model, model2text, prim2text, world2text;
#define ApplyMapping(m,o,p,n,c,u,v) (*m->method)(m, o, p, n, c, u, v)
Texture *
TextCreate(data, meth)
TextRef data;
void (*meth)();
{
Texture *res;
res = (Texture *)share_calloc(1, sizeof(Texture));
res->data = data;
res->method = meth;
res->trans = (Trans *)NULL;
res->next = (Texture *)NULL;
return res;
}
/*
* Apply appropriate textures to a surface.
*/
void
TextApply(tlist, prim, ray, pos, norm, gnorm, surf, p2model, world2model)
Texture *tlist; /* Textures */
Object *prim;
Ray *ray;
Vector *pos, *norm, *gnorm; /* pos, shading norm, geo. norm */
Surface *surf;
Trans *p2model, *world2model;
{
Vector ptmp;
Texture *ttmp;
prim2model = *p2model;
/*
* Walk down texture list, applying each in turn.
*/
for (ttmp = tlist; ttmp; ttmp = ttmp->next) {
/*
* Make copies of pos & ray to pass to the texturing function.
*/
ptmp = *pos;
if (ttmp->trans) {
/*
* We compose ttmp->trans, which maps from model to
* texture space, with prim2model and world2model
* to get prim2text and world2text.
*/
model2text = *ttmp->trans;
TransCompose(&model2text, &prim2model, &prim2text);
TransCompose(&model2text, world2model, &world2text);
/*
* Transform intersection point to texture space.
* Ray and normal are passed in model space.
*/
ModelPointToText(&ptmp);
} else {
/*
* By default, texture and model space are identical.
*/
TransInit(&model2text);
TransCopy(&prim2model, &prim2text);
TransCopy(world2model, &world2text);
}
/*
* Call texture function.
*/
(*ttmp->method) (ttmp->data,prim,ray,&ptmp,norm,gnorm,surf);
}
}
/*
* Compute UV at 'pos' on given primitive.
*/
TextToUV(mapping, prim, pos, norm, u, v, dpdu, dpdv)
Mapping *mapping;
Object *prim;
Vector *pos, *norm, *dpdu, *dpdv;
Float *u, *v;
{
Vec2d uv;
Vector ptmp;
Matrix *t;
ptmp = *pos;
if (mapping->flags & PRIMSPACE) {
/*
* Convert point and normal to primitive space.
*/
TextPointToPrim(&ptmp);
} else {
/*
* Convert point and normal to object space.
*/
TextPointToModel(&ptmp);
}
ApplyMapping(mapping, prim, &ptmp, norm, &uv, dpdu, dpdv);
/*
* Transform UV by model2text. We set X = u and Y = v,
* while Z = 0.
* Although the UV coordinates may be in prim space,
* we treat them as if they are model-space coords.
* This is due to the fact that we want the texture
* to be applied in model space.
*/
ptmp.x = uv.u;
ptmp.y = uv.v;
ptmp.z = 0.;
PointTransform(&ptmp, &model2text.trans);
*u = ptmp.x;
*v = ptmp.y;
if (dpdu == (Vector *)NULL || dpdv == (Vector *)NULL)
return;
/*
* Here's the ugly part.
* Build initial UVN-->XYZ matrix...
*/
t = ArbitraryMatrix(dpdu->x, dpdu->y, dpdu->z,
dpdv->x, dpdv->y, dpdv->z,
norm->x, norm->y, norm->z, 0., 0., 0.);
/*
* ...transform to model space...
*/
MatrixMult(t, &prim2model.trans, t);
/*
* ... apply model2text in UVN space.
*/
MatrixMult(&model2text.itrans, t, t);
dpdu->x = t->matrix[0][0];
dpdu->y = t->matrix[0][1];
dpdu->z = t->matrix[0][2];
dpdv->x = t->matrix[1][0];
dpdv->y = t->matrix[1][1];
dpdv->z = t->matrix[1][2];
(void)VecNormalize(dpdu);
(void)VecNormalize(dpdv);
free((voidstar)t);
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.