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/*
* texgen.c
*
* FUNCTION:
* texture mapping hack
*
* HISTORY:
* Created by Linas Vepstas April 1994
* general cleanup December 1995
*/
#include <stdlib.h>
#include <math.h>
#include <GL/tube.h>
#include "port.h"
#include "tube_gc.h"
/* ======================================================= */
gleGC *_gle_gc = 0x0;
gleGC * gleCreateGC (void) {
gleGC * retval = (gleGC *) malloc (sizeof (gleGC));
retval -> bgn_gen_texture = 0x0;
retval -> n3f_gen_texture = 0x0;
retval -> n3d_gen_texture = 0x0;
retval -> v3f_gen_texture = 0x0;
retval -> v3d_gen_texture = 0x0;
retval -> end_gen_texture = 0x0;
retval -> save_bgn_gen_texture = 0x0;
retval -> save_n3f_gen_texture = 0x0;
retval -> save_n3d_gen_texture = 0x0;
retval -> save_v3f_gen_texture = 0x0;
retval -> save_v3d_gen_texture = 0x0;
retval -> save_end_gen_texture = 0x0;
retval -> join_style = TUBE_JN_ANGLE | TUBE_JN_CAP | TUBE_NORM_FACET;
retval -> ncp = 0;
retval -> npoints = 0;
retval -> num_vert = 0;
retval -> segment_number = 0;
retval -> segment_length = 0.0;
retval -> accum_seg_len = 0.0;
retval -> prev_x = 0.0;
retval -> prev_y = 0.0;
return retval;
}
/* ======================================================= */
#define segment_number (_gle_gc -> segment_number)
#define segment_length (_gle_gc -> segment_length)
#define accum_seg_len (_gle_gc -> accum_seg_len)
#define num_vert (_gle_gc -> num_vert)
#define prev_x (_gle_gc -> prev_x)
#define prev_y (_gle_gc -> prev_y)
/* ======================================================= */
static double save_nx = 0.0;
static double save_ny = 0.0;
static double save_nz = 0.0;
static void save_normal (double *v) {
save_nx = v[0];
save_ny = v[1];
save_nz = v[2];
}
/* ======================================================= */
static void bgn_sphere_texgen (int inext, double len) {
segment_number = inext - 1;
segment_length = len;
num_vert = 0;
}
/* ======================================================= */
/*
* this routine assumes that the vertex passed in has been normalized
* (i.e. is of unit length)
*/
/* ARGSUSED3 */
static void sphere_texgen (double x, double y, double z,
int jcnt, int which_end)
{
double theta, phi;
/* let phi and theta range fro 0 to 1 */
phi = 0.5 * atan2 (x, y) / M_PI;
phi += 0.5;
theta = 1.0 - acos (z) / M_PI;
/* if first vertex, merely record the texture coords */
if (num_vert == 0) {
prev_x = phi;
prev_y = theta;
num_vert ++;
} else {
/* if texture coordinates changed radically, wrap them */
if ((prev_y - theta) > 0.6) {
theta +=1.0;
} else if ((prev_y - theta) < -0.6) {
theta -=1.0;
} /* else no-op */
prev_y = theta;
/* if texture coordinates changed radically, wrap them */
if ((prev_x - phi) > 0.6) {
phi +=1.0;
} else if ((prev_x - phi) < -0.6) {
phi -=1.0;
} /* else no-op */
prev_x = phi;
}
T2F_D (phi, theta);
}
/* ======================================================= */
/* mappers */
static void vertex_sphere_texgen_v (double *v, int jcnt, int which_end) {
double x = v[0]; double y = v[1]; double z = v[2];
double r;
r = 1.0 / sqrt (x*x + y*y + z*z);
x *= r;
y *= r;
z *= r;
sphere_texgen (x, y, z, jcnt, which_end);
}
/* ARGSUSED */
static void normal_sphere_texgen_v (double *v, int jcnt, int which_end) {
sphere_texgen (save_nx, save_ny, save_nz, jcnt, which_end);
}
static void vertex_sphere_model_v (double *v, int jcnt, int which_end) {
double x = _gle_gc->contour[jcnt][0];
double y = _gle_gc->contour[jcnt][1];
double z = v[2];
double r;
r = 1.0 / sqrt (x*x + y*y + z*z);
x *= r;
y *= r;
z *= r;
sphere_texgen (x, y, z, jcnt, which_end);
}
/* ARGSUSED */
static void normal_sphere_model_v (double *v, int jcnt, int which_end) {
if (!(_gle_gc -> cont_normal)) return;
sphere_texgen (_gle_gc->cont_normal[jcnt][0],
_gle_gc->cont_normal[jcnt][1], 0.0, jcnt, which_end);
}
/* ======================================================= */
static void bgn_z_texgen (int inext, double len) {
/* accumulate the previous length */
accum_seg_len += segment_length;
/* save current values */
segment_number = inext - 1;
segment_length = len;
/* reset counter on first segment */
if (1 >= segment_number) accum_seg_len = 0.0;
num_vert = 0;
}
/* ======================================================= */
/* ARGSUSED2 */
static void cylinder_texgen (double x, double y, double z,
int jcnt, int which_end)
{
double phi;
/* let phi and theta range fro 0 to 1 */
phi = 0.5 * atan2 (x, y) / M_PI;
phi += 0.5;
/* if first vertex, merely record the texture coords */
if (num_vert == 0) {
prev_x = phi;
num_vert ++;
} else {
/* if texture coordinates changed radically, wrap them */
if ((prev_x - phi) > 0.6) {
phi +=1.0;
} else if ((prev_x - phi) < -0.6) {
phi -=1.0;
} /* else no-op */
prev_x = phi;
}
if (FRONT == which_end) {
T2F_D (phi, accum_seg_len);
}
if (BACK == which_end) {
T2F_D (phi, accum_seg_len + segment_length);
}
}
/* ======================================================= */
/* mappers */
static void vertex_cylinder_texgen_v (double *v, int jcnt, int which_end) {
double x = v[0]; double y = v[1]; double z = v[2];
double r;
r = 1.0 / sqrt (x*x + y*y);
x *= r;
y *= r;
cylinder_texgen (x, y, z, jcnt, which_end);
}
/* ARGSUSED */
static void normal_cylinder_texgen_v (double *v, int jcnt, int which_end) {
cylinder_texgen (save_nx, save_ny, save_nz, jcnt, which_end);
}
static void vertex_cylinder_model_v (double *v, int jcnt, int which_end) {
double x = _gle_gc->contour[jcnt][0];
double y = _gle_gc->contour[jcnt][1];
double z = v[2];
double r;
r = 1.0 / sqrt (x*x + y*y);
x *= r;
y *= r;
cylinder_texgen (x, y, z, jcnt, which_end);
}
/* ARGSUSED */
static void normal_cylinder_model_v (double *v, int jcnt, int which_end) {
if (!(_gle_gc -> cont_normal)) return;
cylinder_texgen (_gle_gc->cont_normal[jcnt][0],
_gle_gc->cont_normal[jcnt][1], 0.0, jcnt, which_end);
}
/* ======================================================= */
/* ARGSUSED1 */
static void flat_texgen (double x, double y, double z,
int jcnt, int which_end)
{
if (FRONT == which_end) {
T2F_D (x, accum_seg_len);
}
if (BACK == which_end) {
T2F_D (x, accum_seg_len + segment_length);
}
}
/* ======================================================= */
static void vertex_flat_texgen_v (double *v, int jcnt, int which_end) {
flat_texgen (v[0], v[1], v[2], jcnt, which_end);
}
/* ARGSUSED */
static void normal_flat_texgen_v (double *v, int jcnt, int which_end) {
flat_texgen (save_nx, save_ny, save_nz, jcnt, which_end);
}
static void vertex_flat_model_v (double *v, int jcnt, int which_end) {
flat_texgen (_gle_gc->contour[jcnt][0],
_gle_gc->contour[jcnt][1], v[2], jcnt, which_end);
}
/* ARGSUSED */
static void normal_flat_model_v (double *v, int jcnt, int which_end) {
if (!(_gle_gc -> cont_normal)) return;
flat_texgen (_gle_gc->cont_normal[jcnt][0],
_gle_gc->cont_normal[jcnt][1], 0.0, jcnt, which_end);
}
/* ======================================================= */
void gleTextureMode (int mode) {
INIT_GC();
/* enable textureing by restoring the mode */
_gle_gc -> bgn_gen_texture = _gle_gc -> save_bgn_gen_texture;
_gle_gc -> n3f_gen_texture = _gle_gc -> save_n3f_gen_texture;
_gle_gc -> n3d_gen_texture = _gle_gc -> save_n3d_gen_texture;
_gle_gc -> v3f_gen_texture = _gle_gc -> save_v3f_gen_texture;
_gle_gc -> v3d_gen_texture = _gle_gc -> save_v3d_gen_texture;
_gle_gc -> end_gen_texture = _gle_gc -> save_end_gen_texture;
switch (mode&GLE_TEXTURE_STYLE_MASK) {
case GLE_TEXTURE_VERTEX_FLAT:
_gle_gc -> bgn_gen_texture = bgn_z_texgen;
_gle_gc -> v3d_gen_texture = vertex_flat_texgen_v;
_gle_gc -> n3d_gen_texture = 0x0;
break;
case GLE_TEXTURE_NORMAL_FLAT:
_gle_gc -> bgn_gen_texture = bgn_z_texgen;
_gle_gc -> v3d_gen_texture = normal_flat_texgen_v;
_gle_gc -> n3d_gen_texture = save_normal;
break;
case GLE_TEXTURE_VERTEX_MODEL_FLAT:
_gle_gc -> bgn_gen_texture = bgn_z_texgen;
_gle_gc -> v3d_gen_texture = vertex_flat_model_v;
_gle_gc -> n3d_gen_texture = 0x0;
break;
case GLE_TEXTURE_NORMAL_MODEL_FLAT:
_gle_gc -> bgn_gen_texture = bgn_z_texgen;
_gle_gc -> v3d_gen_texture = normal_flat_model_v;
_gle_gc -> n3d_gen_texture = 0x0;
break;
case GLE_TEXTURE_VERTEX_CYL:
_gle_gc -> bgn_gen_texture = bgn_z_texgen;
_gle_gc -> v3d_gen_texture = vertex_cylinder_texgen_v;
_gle_gc -> n3d_gen_texture = 0x0;
break;
case GLE_TEXTURE_NORMAL_CYL:
_gle_gc -> bgn_gen_texture = bgn_z_texgen;
_gle_gc -> v3d_gen_texture = normal_cylinder_texgen_v;
_gle_gc -> n3d_gen_texture = save_normal;
break;
case GLE_TEXTURE_VERTEX_MODEL_CYL:
_gle_gc -> bgn_gen_texture = bgn_z_texgen;
_gle_gc -> v3d_gen_texture = vertex_cylinder_model_v;
_gle_gc -> n3d_gen_texture = 0x0;
break;
case GLE_TEXTURE_NORMAL_MODEL_CYL:
_gle_gc -> bgn_gen_texture = bgn_z_texgen;
_gle_gc -> v3d_gen_texture = normal_cylinder_model_v;
_gle_gc -> n3d_gen_texture = 0x0;
break;
case GLE_TEXTURE_VERTEX_SPH:
_gle_gc -> bgn_gen_texture = bgn_sphere_texgen;
_gle_gc -> v3d_gen_texture = vertex_sphere_texgen_v;
_gle_gc -> n3d_gen_texture = 0x0;
break;
case GLE_TEXTURE_NORMAL_SPH:
_gle_gc -> bgn_gen_texture = bgn_sphere_texgen;
_gle_gc -> v3d_gen_texture = normal_sphere_texgen_v;
_gle_gc -> n3d_gen_texture = save_normal;
break;
case GLE_TEXTURE_VERTEX_MODEL_SPH:
_gle_gc -> bgn_gen_texture = bgn_sphere_texgen;
_gle_gc -> v3d_gen_texture = vertex_sphere_model_v;
_gle_gc -> n3d_gen_texture = 0x0;
break;
case GLE_TEXTURE_NORMAL_MODEL_SPH:
_gle_gc -> bgn_gen_texture = bgn_sphere_texgen;
_gle_gc -> v3d_gen_texture = normal_sphere_model_v;
_gle_gc -> n3d_gen_texture = 0x0;
break;
default:
break;
}
/* disable texturing, and save the mode */
if (!(mode & GLE_TEXTURE_ENABLE)) {
_gle_gc -> save_bgn_gen_texture = _gle_gc -> bgn_gen_texture;
_gle_gc -> save_n3f_gen_texture = _gle_gc -> n3f_gen_texture;
_gle_gc -> save_n3d_gen_texture = _gle_gc -> n3d_gen_texture;
_gle_gc -> save_v3f_gen_texture = _gle_gc -> v3f_gen_texture;
_gle_gc -> save_v3d_gen_texture = _gle_gc -> v3d_gen_texture;
_gle_gc -> save_end_gen_texture = _gle_gc -> end_gen_texture;
_gle_gc -> bgn_gen_texture = 0x0;
_gle_gc -> n3f_gen_texture = 0x0;
_gle_gc -> n3d_gen_texture = 0x0;
_gle_gc -> v3f_gen_texture = 0x0;
_gle_gc -> v3d_gen_texture = 0x0;
_gle_gc -> end_gen_texture = 0x0;
}
}
/* ================== END OF FILE ========================= */
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