1 /* 2 Copyright (c) 2005-2021 Intel Corporation 3 4 Licensed under the Apache License, Version 2.0 (the "License"); 5 you may not use this file except in compliance with the License. 6 You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10 Unless required by applicable law or agreed to in writing, software 11 distributed under the License is distributed on an "AS IS" BASIS, 12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 See the License for the specific language governing permissions and 14 limitations under the License. 15 */ 16 17 /* 18 The original source for this example is 19 Copyright (c) 1994-2008 John E. Stone 20 All rights reserved. 21 22 Redistribution and use in source and binary forms, with or without 23 modification, are permitted provided that the following conditions 24 are met: 25 1. Redistributions of source code must retain the above copyright 26 notice, this list of conditions and the following disclaimer. 27 2. Redistributions in binary form must reproduce the above copyright 28 notice, this list of conditions and the following disclaimer in the 29 documentation and/or other materials provided with the distribution. 30 3. The name of the author may not be used to endorse or promote products 31 derived from this software without specific prior written permission. 32 33 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 34 OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 35 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 36 ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 37 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 38 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 39 OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 40 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 41 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 42 OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 43 SUCH DAMAGE. 44 */ 45 46 /* 47 * cylinder.cpp - This file contains the functions for dealing with cylinders. 48 */ 49 50 #include "machine.hpp" 51 #include "types.hpp" 52 #include "macros.hpp" 53 #include "vector.hpp" 54 #include "intersect.hpp" 55 #include "util.hpp" 56 57 #define CYLINDER_PRIVATE 58 #include "cylinder.hpp" 59 60 static object_methods cylinder_methods = { (void (*)(void *, void *))(cylinder_intersect), 61 (void (*)(void *, void *, void *, void *))( 62 cylinder_normal), 63 cylinder_bbox, 64 free }; 65 66 static object_methods fcylinder_methods = { (void (*)(void *, void *))(fcylinder_intersect), 67 (void (*)(void *, void *, void *, void *))( 68 cylinder_normal), 69 fcylinder_bbox, 70 free }; 71 72 object *newcylinder(void *tex, vector ctr, vector axis, flt rad) { 73 cylinder *c; 74 75 c = (cylinder *)rt_getmem(sizeof(cylinder)); 76 memset(c, 0, sizeof(cylinder)); 77 c->methods = &cylinder_methods; 78 79 c->tex = (texture *)tex; 80 c->ctr = ctr; 81 c->axis = axis; 82 c->rad = rad; 83 return (object *)c; 84 } 85 86 static int cylinder_bbox(void *obj, vector *min, vector *max) { 87 return 0; /* infinite / unbounded object */ 88 } 89 90 static void cylinder_intersect(cylinder *cyl, ray *ry) { 91 vector rc, n, D, O; 92 flt t, s, tin, tout, ln, d; 93 94 rc.x = ry->o.x - cyl->ctr.x; 95 rc.y = ry->o.y - cyl->ctr.y; 96 rc.z = ry->o.z - cyl->ctr.z; 97 98 VCross(&ry->d, &cyl->axis, &n); 99 100 VDOT(ln, n, n); 101 ln = sqrt(ln); /* finish length calculation */ 102 103 if (ln == 0.0) { /* ray is parallel to the cylinder.. */ 104 VDOT(d, rc, cyl->axis); 105 D.x = rc.x - d * cyl->axis.x; 106 D.y = rc.y - d * cyl->axis.y; 107 D.z = rc.z - d * cyl->axis.z; 108 VDOT(d, D, D); 109 d = sqrt(d); 110 tin = -FHUGE; 111 tout = FHUGE; 112 /* if (d <= cyl->rad) then ray is inside cylinder.. else outside */ 113 } 114 115 VNorm(&n); 116 VDOT(d, rc, n); 117 d = fabs(d); 118 119 if (d <= cyl->rad) { /* ray intersects cylinder.. */ 120 VCross(&rc, &cyl->axis, &O); 121 VDOT(t, O, n); 122 t = -t / ln; 123 VCross(&n, &cyl->axis, &O); 124 VNorm(&O); 125 VDOT(s, ry->d, O); 126 s = fabs(sqrt(cyl->rad * cyl->rad - d * d) / s); 127 tin = t - s; 128 add_intersection(tin, (object *)cyl, ry); 129 tout = t + s; 130 add_intersection(tout, (object *)cyl, ry); 131 } 132 } 133 134 static void cylinder_normal(cylinder *cyl, vector *pnt, ray *incident, vector *N) { 135 vector a, b, c; 136 flt t; 137 138 VSub((vector *)pnt, &(cyl->ctr), &a); 139 140 c = cyl->axis; 141 142 VNorm(&c); 143 144 VDOT(t, a, c); 145 146 b.x = c.x * t + cyl->ctr.x; 147 b.y = c.y * t + cyl->ctr.y; 148 b.z = c.z * t + cyl->ctr.z; 149 150 VSub(pnt, &b, N); 151 VNorm(N); 152 153 if (VDot(N, &(incident->d)) > 0.0) { /* make cylinder double sided */ 154 N->x = -N->x; 155 N->y = -N->y; 156 N->z = -N->z; 157 } 158 } 159 160 object *newfcylinder(void *tex, vector ctr, vector axis, flt rad) { 161 cylinder *c; 162 163 c = (cylinder *)rt_getmem(sizeof(cylinder)); 164 memset(c, 0, sizeof(cylinder)); 165 c->methods = &fcylinder_methods; 166 167 c->tex = (texture *)tex; 168 c->ctr = ctr; 169 c->axis = axis; 170 c->rad = rad; 171 172 return (object *)c; 173 } 174 175 static int fcylinder_bbox(void *obj, vector *min, vector *max) { 176 cylinder *c = (cylinder *)obj; 177 vector mintmp, maxtmp; 178 179 mintmp.x = c->ctr.x; 180 mintmp.y = c->ctr.y; 181 mintmp.z = c->ctr.z; 182 maxtmp.x = c->ctr.x + c->axis.x; 183 maxtmp.y = c->ctr.y + c->axis.y; 184 maxtmp.z = c->ctr.z + c->axis.z; 185 186 min->x = MYMIN(mintmp.x, maxtmp.x); 187 min->y = MYMIN(mintmp.y, maxtmp.y); 188 min->z = MYMIN(mintmp.z, maxtmp.z); 189 min->x -= c->rad; 190 min->y -= c->rad; 191 min->z -= c->rad; 192 193 max->x = MYMAX(mintmp.x, maxtmp.x); 194 max->y = MYMAX(mintmp.y, maxtmp.y); 195 max->z = MYMAX(mintmp.z, maxtmp.z); 196 max->x += c->rad; 197 max->y += c->rad; 198 max->z += c->rad; 199 200 return 1; 201 } 202 203 static void fcylinder_intersect(cylinder *cyl, ray *ry) { 204 vector rc, n, O, hit, tmp2, ctmp4; 205 flt t, s, tin, tout, ln, d, tmp, tmp3; 206 207 rc.x = ry->o.x - cyl->ctr.x; 208 rc.y = ry->o.y - cyl->ctr.y; 209 rc.z = ry->o.z - cyl->ctr.z; 210 211 VCross(&ry->d, &cyl->axis, &n); 212 213 VDOT(ln, n, n); 214 ln = sqrt(ln); /* finish length calculation */ 215 216 if (ln == 0.0) { /* ray is parallel to the cylinder.. */ 217 return; /* in this case, we want to miss or go through the "hole" */ 218 } 219 220 VNorm(&n); 221 VDOT(d, rc, n); 222 d = fabs(d); 223 224 if (d <= cyl->rad) { /* ray intersects cylinder.. */ 225 VCross(&rc, &cyl->axis, &O); 226 VDOT(t, O, n); 227 t = -t / ln; 228 VCross(&n, &cyl->axis, &O); 229 VNorm(&O); 230 VDOT(s, ry->d, O); 231 s = fabs(sqrt(cyl->rad * cyl->rad - d * d) / s); 232 tin = t - s; 233 234 RAYPNT(hit, (*ry), tin); 235 236 ctmp4 = cyl->axis; 237 VNorm(&ctmp4); 238 239 tmp2.x = hit.x - cyl->ctr.x; 240 tmp2.y = hit.y - cyl->ctr.y; 241 tmp2.z = hit.z - cyl->ctr.z; 242 243 VDOT(tmp, tmp2, ctmp4); 244 VDOT(tmp3, cyl->axis, cyl->axis); 245 246 if ((tmp > 0.0) && (tmp < sqrt(tmp3))) 247 add_intersection(tin, (object *)cyl, ry); 248 tout = t + s; 249 250 RAYPNT(hit, (*ry), tout); 251 252 tmp2.x = hit.x - cyl->ctr.x; 253 tmp2.y = hit.y - cyl->ctr.y; 254 tmp2.z = hit.z - cyl->ctr.z; 255 256 VDOT(tmp, tmp2, ctmp4); 257 VDOT(tmp3, cyl->axis, cyl->axis); 258 259 if ((tmp > 0.0) && (tmp < sqrt(tmp3))) 260 add_intersection(tout, (object *)cyl, ry); 261 } 262 } 263