#include <noise1.h>
Inheritance diagram for NoiseGen1:
Public Member Functions | |
| NoiseGen1 () | |
| virtual | ~NoiseGen1 () |
| virtual BOOL | Initialise () |
| Initialise all the data tables we need to get this noise generator going. This particular table holds random float values in the range [0..1]. | |
| virtual double | VNoise1D (const Vector3D &v, double s) |
| virtual Vector3D | VNoise3D (const Vector3D &v) |
| Vector-valued version of "Noise". | |
| virtual void | SeedTable (UINT32 seed) |
| Seed the random number table we use. | |
Private Attributes | |
| float * | RTable |
Definition at line 118 of file noise1.h.
|
|
Definition at line 122 of file noise1.cpp.
|
|
|
Definition at line 131 of file noise1.cpp. 00132 { 00133 if (RTable!=NULL) 00134 { 00135 free((void*)RTable); 00136 RTable=NULL; 00137 } 00138 }
|
|
|
Initialise all the data tables we need to get this noise generator going. This particular table holds random float values in the range [0..1]. Aurthor: Mike
Implements NoiseBase. Definition at line 152 of file noise1.cpp. 00153 { 00154 // allocate some space big enough 00155 RTable = (float*)malloc(MAXPTS * sizeof(float)); 00156 if (RTable==NULL) 00157 return FALSE; 00158 00159 // create the table 00160 SeedTable(0); 00161 return TRUE; 00162 }
|
|
|
Seed the random number table we use. Aurthor: Mike
Implements NoiseBase. Definition at line 176 of file noise1.cpp. 00177 { 00178 if (RTable!=NULL) 00179 { 00180 // seed the random number generator for consitency 00181 srand(seed); 00182 // now create those random impulses! 00183 // ok I'm assuming rand() will be compiled in and not a opsys level call. 00184 for (INT32 i=0; i<MAXPTS; i++) 00185 RTable[i] = (float)rand() / ((float)RAND_MAX); 00186 } 00187 }
|
|
||||||||||||
|
1d quadratic bsplines are defined as... C0 = 1 - 2u + u^2 C1 = 1 + 2u - 2u^2 C2 = u^2 v = (C0*p0 + C1*p1 + C2*p2)/2 0<=u<=1 Note, this spline is a none-interpolating spline, i.e. it tends towards the points but never passes through any! This doesn't matter to us as we're interpolating random impulses. To make our tile cyclic, wrap coordinates at the edges. Also note, give points { p0,p1,p2 } the curve lives in the region [p0,p1] i.e. it is does not cover all p0..p2. To get segment [p1,p2] you'll need { p1,p2,p3 } Calculating the cyclic curve through p0,p1,p2,p3 fit... [p0,p1] = CF{ p0,p1,p2 } [p1,p2] = CF{ p1,p2,p3 } [p2,p3] = CF{ p2,p3,p0 } [P3,P0] = CF{ p3,p0,p1 } i.e. 4 input points = 4 curves = 4 intervals Implements NoiseBase. Definition at line 227 of file noise1.cpp. 00228 { 00229 float x2, x1, x0, y2, y1, y0, xf, yf; 00230 float p00, p01, p02; 00231 INT32 ax, bx, cx; 00232 INT32 ay, by, cy; 00233 INT32 samplerange; 00234 00235 // multiplying by TABLEWIDTH rather than (TABLEWIDTH-1) 00236 // forces a wrapping as our range is 0..TABLEWIDTH-1 00237 samplerange = (INT32)(scale); // *TABLEWIDTH); 00238 00239 if (samplerange<1) 00240 return 0.0; 00241 00242 // essentially ignore p.z (the calling routine sets it to 0) 00243 xf = ((float)p.x) * samplerange; 00244 yf = ((float)p.y) * samplerange; 00245 00246 // index the 9 random impulses we'll used for (xf,yf) 00247 ax = (INT32)floor(xf); 00248 ay = (INT32)floor(yf); 00249 00250 // calculate the 2d bspline blending coefs 00251 xf = xf - ax; // u (i.e. fract(p.x) 0..1) 00252 yf = yf - ay; // v (i.e. fract(p.y) 0..1) 00253 x1 = xf * xf; // u^2 00254 y1 = yf * yf; // v^2 00255 x2 = 0.5f * x1; // u^2/2 00256 y2 = 0.5f * y1; // v^2/2 00257 x1 = 0.5f + xf - x1; // 0.5 + u - u^2 00258 y1 = 0.5f + yf - y1; // 0.5 + v - v^2 00259 x0 = 0.5f - xf + x2; // 0.5 - u + u^2/2 00260 y0 = 0.5f - yf + y2; // 0.5 - v + v^2/2 00261 00262 // get the next neighbours 00263 bx = ax + 1; 00264 by = ay + 1; 00265 cx = bx + 1; 00266 cy = by + 1; 00267 00268 // do a potential double modulus as follows... 00269 // 00270 // 0 1 2 3 4 5 6 7 8 9 a b c d e f index into impulse table 00271 // 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 ... samplerange == 8 00272 // 0 1 2 3 4 0 1 2 0 1 2 3 4 0 1 2 ... tablewidth == 5 00273 // ^ ^ 00274 // notice the important symmetry of the values at either end of sample range 00275 // this gives tileable noise. 00276 00277 ax = ax % samplerange; // all 0 if samplerange == 1 00278 ay = ay % samplerange; 00279 bx = bx % samplerange; 00280 by = by % samplerange; 00281 cx = cx % samplerange; 00282 cy = cy % samplerange; 00283 00284 if (samplerange==1) // do something at zero if poss 00285 cx=cy=1; 00286 00287 if (TABLEWIDTH<samplerange) 00288 { 00289 // if our random impulse table is smaller than samplerange 00290 // then we need to mod into it. 00291 ax = ax % TABLEWIDTH; 00292 ay = ay % TABLEWIDTH; 00293 bx = bx % TABLEWIDTH; 00294 by = by % TABLEWIDTH; 00295 cx = cx % TABLEWIDTH; 00296 cy = cy % TABLEWIDTH; 00297 } 00298 00299 ay*=TABLEWIDTH; 00300 by*=TABLEWIDTH; 00301 cy*=TABLEWIDTH; 00302 00303 // read and interpolate the impulse values 00304 p00 = RTable[ax+ay]; 00305 p01 = RTable[bx+ay]; 00306 p02 = RTable[cx+ay]; 00307 00308 xf = y0 * (x0*p00 + x1*p01 + x2*p02); 00309 00310 p00 = RTable[ax+by]; 00311 p01 = RTable[bx+by]; 00312 p02 = RTable[cx+by]; 00313 00314 xf += y1 * (x0*p00 + x1*p01 + x2*p02); 00315 00316 p00 = RTable[ax+cy]; 00317 p01 = RTable[bx+cy]; 00318 p02 = RTable[cx+cy]; 00319 00320 xf += y2 * (x0*p00 + x1*p01 + x2*p02); 00321 00322 return (double)xf; 00323 }
|
|
|
Vector-valued version of "Noise".
Implements NoiseBase. Definition at line 420 of file noise1.cpp. 00421 { 00422 return Vector3D(0,0,0); 00423 }
|
|
|
|
1.4.4