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/*
* File: sipp_cone.c
*
* Create a, possibly truncated, cone. Cylinder is a special case
* of a truncated cone with the same top and bottom radius.
*
* Author: David Jones
* djones@awesome.berkeley.edu
*
* Adapted for inclusion into the SIPP package by Jonas Yngvesson
*/
#include <stdio.h>
#include <math.h>
#include <sipp.h>
#include <primitives.h>
#include <xalloca.h>
Object *
sipp_cone(radius_bot, radius_top, length, res, surface, shader, texture)
double radius_bot;
double radius_top;
double length;
int res;
void * surface;
Shader * shader;
int texture;
{
Object * cone;
double * xb;
double * yb;
double * ub;
double * vb;
double * xt;
double * yt;
double * ut;
double * vt;
double frac;
double half_length;
int bot_exists;
int top_exists;
int i;
bool old_user_refs;
/*
* If both top and bottom radii is zero it's a line
* and can't be rendered.
*/
if (radius_bot == 0.0 && radius_top == 0.0) {
return NULL;
}
if (radius_bot > 0.0) {
xb = (double *) alloca((res + 1) * sizeof(double));
yb = (double *) alloca((res + 1) * sizeof(double));
ub = (double *) alloca((res + 1) * sizeof(double));
vb = (double *) alloca((res + 1) * sizeof(double));
bot_exists = 1;
} else if (radius_bot == 0.0 ){
bot_exists = 0;
} else {
return NULL;
}
if (radius_top > 0.0) {
xt = (double *) alloca((res + 1) * sizeof(double));
yt = (double *) alloca((res + 1) * sizeof(double));
ut = (double *) alloca((res + 1) * sizeof(double));
vt = (double *) alloca((res + 1) * sizeof(double));
top_exists = 1;
} else if (radius_top == 0.0) {
top_exists = 0;
} else {
return NULL;
}
half_length = length * 0.5;
/* list of coordinates */
for (i = 0; i <= res ; ++i) {
frac = ((double) i) / ((double) res);
if (bot_exists) {
xb[i] = radius_bot * cos(frac * 2.0 * M_PI);
yb[i] = radius_bot * sin(frac * 2.0 * M_PI);
switch (texture) {
case NATURAL:
case CYLINDRICAL:
ub[i] = frac;
vb[i] = 0.0;
break;
case SPHERICAL:
ub[i] = frac;
vb[i] = atan(-half_length / radius_bot) / M_PI + 0.5;
break;
case WORLD:
default:
ub[i] = xb[i];
vb[i] = yb[i];
break;
}
}
if (top_exists) {
xt[i] = radius_top * cos(frac * 2.0 * M_PI);
yt[i] = radius_top * sin(frac * 2.0 * M_PI);
switch (texture) {
case NATURAL:
case CYLINDRICAL:
ut[i] = frac;
vt[i] = 1.0;
break;
case SPHERICAL:
ut[i] = frac;
vt[i] = atan(half_length / radius_top) / M_PI + 0.5;
break;
case WORLD:
default:
ut[i] = xt[i];
vt[i] = yt[i];
break;
}
}
}
/* empty object */
cone = object_create();
old_user_refs = sipp_user_refcount (FALSE);
/* The bottom surface */
if (bot_exists) {
for (i = res; i > 0 ; --i) {
vertex_tx_push(xb[i], yb[i], -half_length,
ub[i], vb[i], -half_length);
vertex_tx_push(xb[i - 1], yb[i - 1], -half_length,
ub[i - 1], vb[i - 1], -half_length);
switch (texture) {
case NATURAL:
case CYLINDRICAL:
vertex_tx_push(0.0, 0.0, -half_length,
ub[i - 1], vb[i - 1], -half_length);
vertex_tx_push(0.0, 0.0, -half_length,
ub[i], vb[1], -half_length);
break;
case SPHERICAL:
vertex_tx_push(0.0, 0.0, -half_length,
ub[i - 1], 0.0, -half_length);
vertex_tx_push(0.0, 0.0, -half_length,
ub[i], 0.0, -half_length);
break;
case WORLD:
default:
vertex_tx_push(0.0, 0.0, -half_length,
0.0, 0.0, -half_length);
break;
}
polygon_push();
}
object_add_surface(cone, surface_create(surface, shader));
}
/* The top surface */
if (top_exists) {
for (i = 0; i < res ; ++i) {
vertex_tx_push(xt[i], yt[i], half_length,
ut[i], vt[i], half_length);
vertex_tx_push(xt[i + 1], yt[i + 1], half_length,
ut[i + 1], vt[i + 1], half_length);
switch (texture) {
case NATURAL:
case CYLINDRICAL:
vertex_tx_push(0.0, 0.0, half_length,
ut[i + 1], vt[i + 1], half_length);
vertex_tx_push(0.0, 0.0, half_length,
ut[i], vt[i], half_length);
break;
case SPHERICAL:
vertex_tx_push(0.0, 0.0, half_length,
ut[i + 1], 1.0, half_length);
vertex_tx_push(0.0, 0.0, half_length,
ut[i], 1.0, half_length);
break;
case WORLD:
default:
vertex_tx_push(0.0, 0.0, half_length,
0.0, 0.0, half_length);
break;
}
polygon_push();
}
object_add_surface(cone, surface_create(surface, shader));
}
/* The side surface */
for (i = 0; i < res ; ++i) {
if (top_exists && bot_exists) {
vertex_tx_push(xb[i], yb[i], -half_length,
ub[i], vb[i], -half_length);
vertex_tx_push(xb[i+1], yb[i+1], -half_length,
ub[i+1], vb[i+1], -half_length);
vertex_tx_push(xt[i+1], yt[i+1], half_length,
ut[i+1], vt[i+1], half_length);
vertex_tx_push(xt[i], yt[i], half_length,
ut[i], vt[i], half_length);
} else if (top_exists) {
vertex_tx_push(0.0, 0.0, -half_length,
0.0, 0.0, -half_length);
vertex_tx_push(xt[i+1], yt[i+1], half_length,
ut[i+1], vt[i+1], half_length);
vertex_tx_push(xt[i], yt[i], half_length,
ut[i], vt[i], half_length);
} else {
vertex_tx_push(xb[i], yb[i], -half_length,
ub[i], vb[i], -half_length);
vertex_tx_push(xb[i+1], yb[i+1], -half_length,
ub[i+1], vb[i+1], -half_length);
switch (texture) {
case NATURAL:
case CYLINDRICAL:
case SPHERICAL:
vertex_tx_push(0.0, 0.0, half_length,
0.0, 1.0, half_length);
break;
case WORLD:
default:
vertex_tx_push(0.0, 0.0, half_length,
0.0, 0.0, half_length);
break;
}
}
polygon_push();
}
object_add_surface(cone, surface_create(surface, shader));
sipp_user_refcount (old_user_refs);
return cone;
}
Object *
sipp_cylinder(radius, length, res, surface, shader, texture)
double radius;
double length;
int res;
void *surface;
Shader *shader;
int texture;
{
Object *cylinder;
cylinder = sipp_cone(radius, radius, length, res, surface, shader,
texture);
return cylinder;
}
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