ViewVC Help
View File | Revision Log | Show Annotations | Download File | Root Listing
root/radiance/ray/src/cv/mgflib/vect.c
Revision: 1.2
Committed: Fri Jan 16 10:47:27 1998 UTC (26 years, 3 months ago) by gregl
Content type: text/plain
Branch: MAIN
Changes since 1.1: +13 -12 lines
Log Message:
changed M_PI definition to ward off long double problems

File Contents

# User Rev Content
1 greg 1.1 #ifndef lint
2     static char SCCSid[] = "$SunId$ LBL";
3     #endif
4    
5     #include <math.h>
6     #include <string.h>
7     #include "vect.h"
8    
9     #ifndef M_PI
10     #define M_PI 3.14159265358979323846
11     #endif
12 gregl 1.2 #define PI ((double)M_PI)
13 greg 1.1
14     #define EPSILON 1e-6
15    
16     void adjoint (Matrix mat);
17     double det4x4 (Matrix mat);
18     double det3x3 (double a1, double a2, double a3, double b1, double b2,
19     double b3, double c1, double c2, double c3);
20     double det2x2 (double a, double b, double c, double d);
21    
22    
23     void vect_init (Vector v, float x, float y, float z)
24     {
25     v[X] = x;
26     v[Y] = y;
27     v[Z] = z;
28     }
29    
30    
31     void vect_copy (Vector v1, Vector v2)
32     {
33     v1[X] = v2[X];
34     v1[Y] = v2[Y];
35     v1[Z] = v2[Z];
36     }
37    
38    
39     int vect_equal (Vector v1, Vector v2)
40     {
41     if (v1[X] == v2[X] && v1[Y] == v2[Y] && v1[Z] == v2[Z])
42     return 1;
43     else
44     return 0;
45     }
46    
47    
48     void vect_add (Vector v1, Vector v2, Vector v3)
49     {
50     v1[X] = v2[X] + v3[X];
51     v1[Y] = v2[Y] + v3[Y];
52     v1[Z] = v2[Z] + v3[Z];
53     }
54    
55    
56     void vect_sub (Vector v1, Vector v2, Vector v3)
57     {
58     v1[X] = v2[X] - v3[X];
59     v1[Y] = v2[Y] - v3[Y];
60     v1[Z] = v2[Z] - v3[Z];
61     }
62    
63    
64     void vect_scale (Vector v1, Vector v2, float k)
65     {
66     v1[X] = k * v2[X];
67     v1[Y] = k * v2[Y];
68     v1[Z] = k * v2[Z];
69     }
70    
71    
72     float vect_mag (Vector v)
73     {
74     float mag = sqrt(v[X]*v[X] + v[Y]*v[Y] + v[Z]*v[Z]);
75    
76     return mag;
77     }
78    
79    
80     void vect_normalize (Vector v)
81     {
82     float mag = vect_mag (v);
83    
84     if (mag > 0.0)
85     vect_scale (v, v, 1.0/mag);
86     }
87    
88    
89     float vect_dot (Vector v1, Vector v2)
90     {
91     return (v1[X]*v2[X] + v1[Y]*v2[Y] + v1[Z]*v2[Z]);
92     }
93    
94    
95     void vect_cross (Vector v1, Vector v2, Vector v3)
96     {
97     v1[X] = (v2[Y] * v3[Z]) - (v2[Z] * v3[Y]);
98     v1[Y] = (v2[Z] * v3[X]) - (v2[X] * v3[Z]);
99     v1[Z] = (v2[X] * v3[Y]) - (v2[Y] * v3[X]);
100     }
101    
102     void vect_min (Vector v1, Vector v2, Vector v3)
103     {
104     v1[X] = (v2[X] < v3[X]) ? v2[X] : v3[X];
105     v1[Y] = (v2[Y] < v3[Y]) ? v2[Y] : v3[Y];
106     v1[Z] = (v2[Z] < v3[Z]) ? v2[Z] : v3[Z];
107     }
108    
109    
110     void vect_max (Vector v1, Vector v2, Vector v3)
111     {
112     v1[X] = (v2[X] > v3[X]) ? v2[X] : v3[X];
113     v1[Y] = (v2[Y] > v3[Y]) ? v2[Y] : v3[Y];
114     v1[Z] = (v2[Z] > v3[Z]) ? v2[Z] : v3[Z];
115     }
116    
117    
118     /* Return the angle between two vectors */
119     float vect_angle (Vector v1, Vector v2)
120     {
121     float mag1, mag2, angle, cos_theta;
122    
123     mag1 = vect_mag(v1);
124     mag2 = vect_mag(v2);
125    
126     if (mag1 * mag2 == 0.0)
127     angle = 0.0;
128     else {
129     cos_theta = vect_dot(v1,v2) / (mag1 * mag2);
130    
131     if (cos_theta <= -1.0)
132     angle = 180.0;
133     else if (cos_theta >= +1.0)
134     angle = 0.0;
135     else
136 gregl 1.2 angle = (180.0/PI) * acos(cos_theta);
137 greg 1.1 }
138    
139     return angle;
140     }
141    
142    
143     void vect_print (FILE *f, Vector v, int dec, char sep)
144     {
145     char fstr[] = "%.4f, %.4f, %.4f";
146    
147     if (dec < 0) dec = 0;
148     if (dec > 9) dec = 9;
149    
150     fstr[2] = '0' + dec;
151     fstr[8] = '0' + dec;
152     fstr[14] = '0' + dec;
153    
154     fstr[4] = sep;
155     fstr[10] = sep;
156    
157     fprintf (f, fstr, v[X], v[Y], v[Z]);
158     }
159    
160    
161     /* Rotate a vector about the X, Y or Z axis */
162     void vect_rotate (Vector v1, Vector v2, int axis, float angle)
163     {
164     float cosa, sina;
165    
166 gregl 1.2 cosa = cos ((PI/180.0) * angle);
167     sina = sin ((PI/180.0) * angle);
168 greg 1.1
169     switch (axis) {
170     case X:
171     v1[X] = v2[X];
172     v1[Y] = v2[Y] * cosa + v2[Z] * sina;
173     v1[Z] = v2[Z] * cosa - v2[Y] * sina;
174     break;
175    
176     case Y:
177     v1[X] = v2[X] * cosa - v2[Z] * sina;
178     v1[Y] = v2[Y];
179     v1[Z] = v2[Z] * cosa + v2[X] * sina;
180     break;
181    
182     case Z:
183     v1[X] = v2[X] * cosa + v2[Y] * sina;
184     v1[Y] = v2[Y] * cosa - v2[X] * sina;
185     v1[Z] = v2[Z];
186     break;
187     }
188     }
189    
190    
191     /* Rotate a vector about a specific axis */
192     void vect_axis_rotate (Vector v1, Vector v2, Vector axis, float angle)
193     {
194     float cosa, sina;
195     Matrix mat;
196    
197 gregl 1.2 cosa = cos ((PI/180.0) * angle);
198     sina = sin ((PI/180.0) * angle);
199 greg 1.1
200     mat[0][0] = (axis[X] * axis[X]) + ((1.0 - (axis[X] * axis[X]))*cosa);
201     mat[0][1] = (axis[X] * axis[Y] * (1.0 - cosa)) - (axis[Z] * sina);
202     mat[0][2] = (axis[X] * axis[Z] * (1.0 - cosa)) + (axis[Y] * sina);
203     mat[0][3] = 0.0;
204    
205     mat[1][0] = (axis[X] * axis[Y] * (1.0 - cosa)) + (axis[Z] * sina);
206     mat[1][1] = (axis[Y] * axis[Y]) + ((1.0 - (axis[Y] * axis[Y])) * cosa);
207     mat[1][2] = (axis[Y] * axis[Z] * (1.0 - cosa)) - (axis[X] * sina);
208     mat[1][3] = 0.0;
209    
210     mat[2][0] = (axis[X] * axis[Z] * (1.0 - cosa)) - (axis[Y] * sina);
211     mat[2][1] = (axis[Y] * axis[Z] * (1.0 - cosa)) + (axis[X] * sina);
212     mat[2][2] = (axis[Z] * axis[Z]) + ((1.0 - (axis[Z] * axis[Z])) * cosa);
213     mat[2][3] = 0.0;
214    
215     mat[3][0] = mat[3][1] = mat[3][2] = mat[3][3] = 0.0;
216    
217     vect_transform (v1, v2, mat);
218     }
219    
220    
221     /* Transform the given vector */
222     void vect_transform (Vector v1, Vector v2, Matrix mat)
223     {
224     Vector tmp;
225    
226     tmp[X] = (v2[X] * mat[0][0]) + (v2[Y] * mat[1][0]) + (v2[Z] * mat[2][0]) + mat[3][0];
227     tmp[Y] = (v2[X] * mat[0][1]) + (v2[Y] * mat[1][1]) + (v2[Z] * mat[2][1]) + mat[3][1];
228     tmp[Z] = (v2[X] * mat[0][2]) + (v2[Y] * mat[1][2]) + (v2[Z] * mat[2][2]) + mat[3][2];
229    
230     vect_copy (v1, tmp);
231     }
232    
233    
234     /* Create an identity matrix */
235     void mat_identity (Matrix mat)
236     {
237     int i, j;
238    
239     for (i = 0; i < 4; i++)
240     for (j = 0; j < 4; j++)
241     mat[i][j] = 0.0;
242    
243     for (i = 0; i < 4; i++)
244     mat[i][i] = 1.0;
245     }
246    
247    
248     void mat_copy (Matrix mat1, Matrix mat2)
249     {
250     int i, j;
251    
252     for (i = 0; i < 4; i++)
253     for (j = 0; j < 4; j++)
254     mat1[i][j] = mat2[i][j];
255     }
256    
257    
258     /* Rotate a matrix about the X, Y or Z axis */
259     void mat_rotate (Matrix mat1, Matrix mat2, int axis, float angle)
260     {
261     Matrix mat;
262     float cosa, sina;
263    
264 gregl 1.2 cosa = cos ((PI/180.0) * angle);
265     sina = sin ((PI/180.0) * angle);
266 greg 1.1
267     mat_identity (mat);
268    
269     switch (axis) {
270     case X:
271     mat[1][1] = cosa;
272     mat[1][2] = sina;
273     mat[2][1] = -sina;
274     mat[2][2] = cosa;
275     break;
276    
277     case Y:
278     mat[0][0] = cosa;
279     mat[0][2] = -sina;
280     mat[2][0] = sina;
281     mat[2][2] = cosa;
282     break;
283    
284     case Z:
285     mat[0][0] = cosa;
286     mat[0][1] = sina;
287     mat[1][0] = -sina;
288     mat[1][1] = cosa;
289     break;
290     }
291    
292     mat_mult (mat1, mat2, mat);
293     }
294    
295    
296     void mat_axis_rotate (Matrix mat1, Matrix mat2, Vector axis, float angle)
297     {
298     float cosa, sina;
299     Matrix mat;
300    
301 gregl 1.2 cosa = cos ((PI/180.0) * angle);
302     sina = sin ((PI/180.0) * angle);
303 greg 1.1
304     mat[0][0] = (axis[X] * axis[X]) + ((1.0 - (axis[X] * axis[X]))*cosa);
305     mat[0][1] = (axis[X] * axis[Y] * (1.0 - cosa)) - (axis[Z] * sina);
306     mat[0][2] = (axis[X] * axis[Z] * (1.0 - cosa)) + (axis[Y] * sina);
307     mat[0][3] = 0.0;
308    
309     mat[1][0] = (axis[X] * axis[Y] * (1.0 - cosa)) + (axis[Z] * sina);
310     mat[1][1] = (axis[Y] * axis[Y]) + ((1.0 - (axis[Y] * axis[Y])) * cosa);
311     mat[1][2] = (axis[Y] * axis[Z] * (1.0 - cosa)) - (axis[X] * sina);
312     mat[1][3] = 0.0;
313    
314     mat[2][0] = (axis[X] * axis[Z] * (1.0 - cosa)) - (axis[Y] * sina);
315     mat[2][1] = (axis[Y] * axis[Z] * (1.0 - cosa)) + (axis[X] * sina);
316     mat[2][2] = (axis[Z] * axis[Z]) + ((1.0 - (axis[Z] * axis[Z])) * cosa);
317     mat[2][3] = 0.0;
318    
319     mat[3][0] = mat[3][1] = mat[3][2] = mat[3][3] = 0.0;
320    
321     mat_mult (mat1, mat2, mat);
322     }
323    
324    
325     /* mat1 <-- mat2 * mat3 */
326     void mat_mult (Matrix mat1, Matrix mat2, Matrix mat3)
327     {
328     float sum;
329     int i, j, k;
330     Matrix result;
331    
332     for (i = 0; i < 4; i++) {
333     for (j = 0; j < 4; j++) {
334     sum = 0.0;
335    
336     for (k = 0; k < 4; k++)
337     sum = sum + mat2[i][k] * mat3[k][j];
338    
339     result[i][j] = sum;
340     }
341     }
342    
343     for (i = 0; i < 4; i++)
344     for (j = 0; j < 4; j++)
345     mat1[i][j] = result[i][j];
346     }
347    
348    
349     /*
350     Decodes a 3x4 transformation matrix into separate scale, rotation,
351     translation, and shear vectors. Based on a program by Spencer W.
352     Thomas (Graphics Gems II)
353     */
354     void mat_decode (Matrix mat, Vector scale, Vector shear, Vector rotate,
355     Vector transl)
356     {
357     int i;
358     Vector row[3], temp;
359    
360     for (i = 0; i < 3; i++)
361     transl[i] = mat[3][i];
362    
363     for (i = 0; i < 3; i++) {
364     row[i][X] = mat[i][0];
365     row[i][Y] = mat[i][1];
366     row[i][Z] = mat[i][2];
367     }
368    
369     scale[X] = vect_mag (row[0]);
370     vect_normalize (row[0]);
371    
372     shear[X] = vect_dot (row[0], row[1]);
373     row[1][X] = row[1][X] - shear[X]*row[0][X];
374     row[1][Y] = row[1][Y] - shear[X]*row[0][Y];
375     row[1][Z] = row[1][Z] - shear[X]*row[0][Z];
376    
377     scale[Y] = vect_mag (row[1]);
378     vect_normalize (row[1]);
379    
380     if (scale[Y] != 0.0)
381     shear[X] /= scale[Y];
382    
383     shear[Y] = vect_dot (row[0], row[2]);
384     row[2][X] = row[2][X] - shear[Y]*row[0][X];
385     row[2][Y] = row[2][Y] - shear[Y]*row[0][Y];
386     row[2][Z] = row[2][Z] - shear[Y]*row[0][Z];
387    
388     shear[Z] = vect_dot (row[1], row[2]);
389     row[2][X] = row[2][X] - shear[Z]*row[1][X];
390     row[2][Y] = row[2][Y] - shear[Z]*row[1][Y];
391     row[2][Z] = row[2][Z] - shear[Z]*row[1][Z];
392    
393     scale[Z] = vect_mag (row[2]);
394     vect_normalize (row[2]);
395    
396     if (scale[Z] != 0.0) {
397     shear[Y] /= scale[Z];
398     shear[Z] /= scale[Z];
399     }
400    
401     vect_cross (temp, row[1], row[2]);
402     if (vect_dot (row[0], temp) < 0.0) {
403     for (i = 0; i < 3; i++) {
404     scale[i] *= -1.0;
405     row[i][X] *= -1.0;
406     row[i][Y] *= -1.0;
407     row[i][Z] *= -1.0;
408     }
409     }
410    
411     if (row[0][Z] < -1.0) row[0][Z] = -1.0;
412     if (row[0][Z] > +1.0) row[0][Z] = +1.0;
413    
414     rotate[Y] = asin(-row[0][Z]);
415    
416     if (fabs(cos(rotate[Y])) > EPSILON) {
417     rotate[X] = atan2 (row[1][Z], row[2][Z]);
418     rotate[Z] = atan2 (row[0][Y], row[0][X]);
419     }
420     else {
421     rotate[X] = atan2 (row[1][X], row[1][Y]);
422     rotate[Z] = 0.0;
423     }
424    
425     /* Convert the rotations to degrees */
426 gregl 1.2 rotate[X] = (180.0/PI)*rotate[X];
427     rotate[Y] = (180.0/PI)*rotate[Y];
428     rotate[Z] = (180.0/PI)*rotate[Z];
429 greg 1.1 }
430    
431    
432     /* Matrix inversion code from Graphics Gems */
433    
434     /* mat1 <-- mat2^-1 */
435     float mat_inv (Matrix mat1, Matrix mat2)
436     {
437     int i, j;
438     float det;
439    
440     if (mat1 != mat2) {
441     for (i = 0; i < 4; i++)
442     for (j = 0; j < 4; j++)
443     mat1[i][j] = mat2[i][j];
444     }
445    
446     det = det4x4 (mat1);
447    
448     if (fabs (det) < EPSILON)
449     return 0.0;
450    
451     adjoint (mat1);
452    
453     for (i = 0; i < 4; i++)
454     for(j = 0; j < 4; j++)
455     mat1[i][j] = mat1[i][j] / det;
456    
457     return det;
458     }
459    
460    
461     void adjoint (Matrix mat)
462     {
463     double a1, a2, a3, a4, b1, b2, b3, b4;
464     double c1, c2, c3, c4, d1, d2, d3, d4;
465    
466     a1 = mat[0][0]; b1 = mat[0][1];
467     c1 = mat[0][2]; d1 = mat[0][3];
468    
469     a2 = mat[1][0]; b2 = mat[1][1];
470     c2 = mat[1][2]; d2 = mat[1][3];
471    
472     a3 = mat[2][0]; b3 = mat[2][1];
473     c3 = mat[2][2]; d3 = mat[2][3];
474    
475     a4 = mat[3][0]; b4 = mat[3][1];
476     c4 = mat[3][2]; d4 = mat[3][3];
477    
478     /* row column labeling reversed since we transpose rows & columns */
479     mat[0][0] = det3x3 (b2, b3, b4, c2, c3, c4, d2, d3, d4);
480     mat[1][0] = -det3x3 (a2, a3, a4, c2, c3, c4, d2, d3, d4);
481     mat[2][0] = det3x3 (a2, a3, a4, b2, b3, b4, d2, d3, d4);
482     mat[3][0] = -det3x3 (a2, a3, a4, b2, b3, b4, c2, c3, c4);
483    
484     mat[0][1] = -det3x3 (b1, b3, b4, c1, c3, c4, d1, d3, d4);
485     mat[1][1] = det3x3 (a1, a3, a4, c1, c3, c4, d1, d3, d4);
486     mat[2][1] = -det3x3 (a1, a3, a4, b1, b3, b4, d1, d3, d4);
487     mat[3][1] = det3x3 (a1, a3, a4, b1, b3, b4, c1, c3, c4);
488    
489     mat[0][2] = det3x3 (b1, b2, b4, c1, c2, c4, d1, d2, d4);
490     mat[1][2] = -det3x3 (a1, a2, a4, c1, c2, c4, d1, d2, d4);
491     mat[2][2] = det3x3 (a1, a2, a4, b1, b2, b4, d1, d2, d4);
492     mat[3][2] = -det3x3 (a1, a2, a4, b1, b2, b4, c1, c2, c4);
493    
494     mat[0][3] = -det3x3 (b1, b2, b3, c1, c2, c3, d1, d2, d3);
495     mat[1][3] = det3x3 (a1, a2, a3, c1, c2, c3, d1, d2, d3);
496     mat[2][3] = -det3x3 (a1, a2, a3, b1, b2, b3, d1, d2, d3);
497     mat[3][3] = det3x3 (a1, a2, a3, b1, b2, b3, c1, c2, c3);
498     }
499    
500    
501     double det4x4 (Matrix mat)
502     {
503     double ans;
504     double a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, c4, d1, d2, d3, d4;
505    
506     a1 = mat[0][0]; b1 = mat[0][1];
507     c1 = mat[0][2]; d1 = mat[0][3];
508    
509     a2 = mat[1][0]; b2 = mat[1][1];
510     c2 = mat[1][2]; d2 = mat[1][3];
511    
512     a3 = mat[2][0]; b3 = mat[2][1];
513     c3 = mat[2][2]; d3 = mat[2][3];
514    
515     a4 = mat[3][0]; b4 = mat[3][1];
516     c4 = mat[3][2]; d4 = mat[3][3];
517    
518     ans = a1 * det3x3 (b2, b3, b4, c2, c3, c4, d2, d3, d4) -
519     b1 * det3x3 (a2, a3, a4, c2, c3, c4, d2, d3, d4) +
520     c1 * det3x3 (a2, a3, a4, b2, b3, b4, d2, d3, d4) -
521     d1 * det3x3 (a2, a3, a4, b2, b3, b4, c2, c3, c4);
522    
523     return ans;
524     }
525    
526    
527     double det3x3 (double a1, double a2, double a3, double b1, double b2,
528     double b3, double c1, double c2, double c3)
529     {
530     double ans;
531    
532     ans = a1 * det2x2 (b2, b3, c2, c3)
533     - b1 * det2x2 (a2, a3, c2, c3)
534     + c1 * det2x2 (a2, a3, b2, b3);
535    
536     return ans;
537     }
538    
539    
540     double det2x2 (double a, double b, double c, double d)
541     {
542     double ans;
543     ans = a * d - b * c;
544     return ans;
545     }
546