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Differential D748 Diff 2453 source/blender/blenlib/intern/math_interp.c

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source/blender/blenlib/intern/math_interp.c

Show First 20 Lines • Show All 360 Lines • ▼ Show 20 Linesvoid BLI_bilinear_interpolation_fl(const float *buffer, float *output, int width, int height,
bilinear_interpolation(NULL, buffer, NULL, output, width, height, components, u, v); bilinear_interpolation(NULL, buffer, NULL, output, width, height, components, u, v);
} }
void BLI_bilinear_interpolation_char(const unsigned char *buffer, unsigned char *output, int width, int height, void BLI_bilinear_interpolation_char(const unsigned char *buffer, unsigned char *output, int width, int height,
int components, float u, float v) int components, float u, float v)
{ {
bilinear_interpolation(buffer, NULL, output, NULL, width, height, components, u, v); bilinear_interpolation(buffer, NULL, output, NULL, width, height, components, u, v);
} }
/**************************************************************************
* Filtering method based on
* "Creating raster omnimax images from multiple perspective views using the elliptical weighted average filter"
* by Ned Greene and Paul S. Heckbert (1986)
***************************************************************************/
/* table of (exp(ar) - exp(a)) / (1 - exp(a)) for r in range [0, 1] and a = -2
* used instead of actual gaussian, otherwise at high texture magnifications circular artifacts are visible */
#define EWA_MAXIDX 255
const float EWA_WTS[EWA_MAXIDX + 1] = {
1.f, 0.990965f, 0.982f, 0.973105f, 0.96428f, 0.955524f, 0.946836f, 0.938216f, 0.929664f,
0.921178f, 0.912759f, 0.904405f, 0.896117f, 0.887893f, 0.879734f, 0.871638f, 0.863605f,
0.855636f, 0.847728f, 0.839883f, 0.832098f, 0.824375f, 0.816712f, 0.809108f, 0.801564f,
0.794079f, 0.786653f, 0.779284f, 0.771974f, 0.76472f, 0.757523f, 0.750382f, 0.743297f,
0.736267f, 0.729292f, 0.722372f, 0.715505f, 0.708693f, 0.701933f, 0.695227f, 0.688572f,
0.68197f, 0.67542f, 0.66892f, 0.662471f, 0.656073f, 0.649725f, 0.643426f, 0.637176f,
0.630976f, 0.624824f, 0.618719f, 0.612663f, 0.606654f, 0.600691f, 0.594776f, 0.588906f,
0.583083f, 0.577305f, 0.571572f, 0.565883f, 0.56024f, 0.55464f, 0.549084f, 0.543572f,
0.538102f, 0.532676f, 0.527291f, 0.521949f, 0.516649f, 0.511389f, 0.506171f, 0.500994f,
0.495857f, 0.490761f, 0.485704f, 0.480687f, 0.475709f, 0.470769f, 0.465869f, 0.461006f,
0.456182f, 0.451395f, 0.446646f, 0.441934f, 0.437258f, 0.432619f, 0.428017f, 0.42345f,
0.418919f, 0.414424f, 0.409963f, 0.405538f, 0.401147f, 0.39679f, 0.392467f, 0.388178f,
0.383923f, 0.379701f, 0.375511f, 0.371355f, 0.367231f, 0.363139f, 0.359079f, 0.355051f,
0.351055f, 0.347089f, 0.343155f, 0.339251f, 0.335378f, 0.331535f, 0.327722f, 0.323939f,
0.320186f, 0.316461f, 0.312766f, 0.3091f, 0.305462f, 0.301853f, 0.298272f, 0.294719f,
0.291194f, 0.287696f, 0.284226f, 0.280782f, 0.277366f, 0.273976f, 0.270613f, 0.267276f,
0.263965f, 0.26068f, 0.257421f, 0.254187f, 0.250979f, 0.247795f, 0.244636f, 0.241502f,
0.238393f, 0.235308f, 0.232246f, 0.229209f, 0.226196f, 0.223206f, 0.220239f, 0.217296f,
0.214375f, 0.211478f, 0.208603f, 0.20575f, 0.20292f, 0.200112f, 0.197326f, 0.194562f,
0.191819f, 0.189097f, 0.186397f, 0.183718f, 0.18106f, 0.178423f, 0.175806f, 0.17321f,
0.170634f, 0.168078f, 0.165542f, 0.163026f, 0.16053f, 0.158053f, 0.155595f, 0.153157f,
0.150738f, 0.148337f, 0.145955f, 0.143592f, 0.141248f, 0.138921f, 0.136613f, 0.134323f,
0.132051f, 0.129797f, 0.12756f, 0.125341f, 0.123139f, 0.120954f, 0.118786f, 0.116635f,
0.114501f, 0.112384f, 0.110283f, 0.108199f, 0.106131f, 0.104079f, 0.102043f, 0.100023f,
0.0980186f, 0.09603f, 0.094057f, 0.0920994f, 0.0901571f, 0.08823f, 0.0863179f, 0.0844208f,
0.0825384f, 0.0806708f, 0.0788178f, 0.0769792f, 0.0751551f, 0.0733451f, 0.0715493f, 0.0697676f,
0.0679997f, 0.0662457f, 0.0645054f, 0.0627786f, 0.0610654f, 0.0593655f, 0.0576789f, 0.0560055f,
0.0543452f, 0.0526979f, 0.0510634f, 0.0494416f, 0.0478326f, 0.0462361f, 0.0446521f, 0.0430805f,
0.0415211f, 0.039974f, 0.0384389f, 0.0369158f, 0.0354046f, 0.0339052f, 0.0324175f, 0.0309415f,
0.029477f, 0.0280239f, 0.0265822f, 0.0251517f, 0.0237324f, 0.0223242f, 0.020927f, 0.0195408f,
0.0181653f, 0.0168006f, 0.0154466f, 0.0141031f, 0.0127701f, 0.0114476f, 0.0101354f, 0.00883339f,
0.00754159f, 0.00625989f, 0.00498819f, 0.00372644f, 0.00247454f, 0.00123242f, 0.f
};
static void radangle2imp(float a2, float b2, float th, float *A, float *B, float *C, float *F)
{
float ct2 = cosf(th);
const float st2 = 1.0f - ct2 * ct2; /* <- sin(th)^2 */
ct2 *= ct2;
*A = a2*st2 + b2*ct2;
*B = (b2 - a2)*sinf(2.f*th);
*C = a2*ct2 + b2*st2;
*F = a2*b2;
}
/* all tests here are done to make sure possible overflows are hopefully minimized */
void BLI_ewa_imp2radangle(float A, float B, float C, float F, float *a, float *b, float *th, float *ecc)
{
if (F <= 1e-5f) { /* use arbitrary major radius, zero minor, infinite eccentricity */
*a = sqrtf(A > C ? A : C);
*b = 0.f;
*ecc = 1e10f;
*th = 0.5f * (atan2f(B, A - C) + (float)M_PI);
}
else {
const float AmC = A - C, ApC = A + C, F2 = F*2.f;
const float r = sqrtf(AmC * AmC + B * B);
float d = ApC - r;
*a = (d <= 0.f) ? sqrtf(A > C ? A : C) : sqrtf(F2 / d);
d = ApC + r;
if (d <= 0.f) {
*b = 0.f;
*ecc = 1e10f;
}
else {
*b = sqrtf(F2 / d);
*ecc = *a / *b;
}
/* incr theta by 0.5*pi (angle of major axis) */
*th = 0.5f * (atan2f(B, AmC) + (float)M_PI);
}
}
void BLI_ewa_filter(const int width, const int height,
const bool intpol,
const bool use_alpha,
const float uv[2],
const float du[2],
const float dv[2],
ewa_filter_read_pixel_cb read_pixel_cb,
void *userdata,
float result[4])
{
/* scaling dxt/dyt by full resolution can cause overflow because of huge A/B/C and esp. F values,
* scaling by aspect ratio alone does the opposite, so try something in between instead... */
const float ff2 = (float)width, ff = sqrtf(ff2), q = (float)height / ff;
const float Ux = du[0] * ff, Vx = dv[0] * q, Uy = du[1] * ff, Vy = dv[1] * q;
float A = Vx * Vx + Vy * Vy;
float B = -2.0f * (Ux * Vx + Uy * Vy);
float C = Ux * Ux + Uy * Uy;
float F = A * C - B * B * 0.25f;
float a, b, th, ecc, a2, b2, ue, ve, U0, V0, DDQ, U, ac1, ac2, BU, d;
int u, v, u1, u2, v1, v2;
/* The so-called 'high' quality ewa method simply adds a constant of 1 to both A & C,
* so the ellipse always covers at least some texels. But since the filter is now always larger,
* it also means that everywhere else it's also more blurry then ideally should be the case.
* So instead here the ellipse radii are modified instead whenever either is too low.
* Use a different radius based on interpolation switch, just enough to anti-alias when interpolation is off,
* and slightly larger to make result a bit smoother than bilinear interpolation when interpolation is on
* (minimum values: const float rmin = intpol ? 1.f : 0.5f;) */
const float rmin = (intpol ? 1.5625f : 0.765625f)/ff2;
BLI_ewa_imp2radangle(A, B, C, F, &a, &b, &th, &ecc);
if ((b2 = b * b) < rmin) {
if ((a2 = a*a) < rmin) {
B = 0.0f;
A = C = rmin;
F = A * C;
}
else {
b2 = rmin;
radangle2imp(a2, b2, th, &A, &B, &C, &F);
}
}
ue = ff * sqrtf(C);
ve = ff * sqrtf(A);
d = (float)(EWA_MAXIDX + 1) / (F * ff2);
A *= d;
B *= d;
C *= d;
U0 = uv[0] * (float)width;
V0 = uv[1] * (float)height;
u1 = (int)(floorf(U0 - ue));
u2 = (int)(ceilf(U0 + ue));
v1 = (int)(floorf(V0 - ve));
v2 = (int)(ceilf(V0 + ve));
/* sane clamping to avoid unnecessarily huge loops */
/* note: if eccentricity gets clamped (see above),
* the ue/ve limits can also be lowered accordingly
*/
if (U0 - (float)u1 > EWA_MAXIDX) u1 = (int)U0 - EWA_MAXIDX;
if ((float)u2 - U0 > EWA_MAXIDX) u2 = (int)U0 + EWA_MAXIDX;
if (V0 - (float)v1 > EWA_MAXIDX) v1 = (int)V0 - EWA_MAXIDX;
if ((float)v2 - V0 > EWA_MAXIDX) v2 = (int)V0 + EWA_MAXIDX;
/* Early output check for cases the whole region is outside of the buffer. */
if ((u2 < 0 || u1 >= width) || (v2 < 0 || v1 >= height)) {
zero_v4(result);
return;
}
U0 -= 0.5f;
V0 -= 0.5f;
DDQ = 2.0f * A;
U = (float)u1 - U0;
ac1 = A * (2.0f * U + 1.0f);
ac2 = A * U * U;
BU = B * U;
d = 0.0f;
zero_v4(result);
for (v = v1; v <= v2; ++v) {
const float V = (float)v - V0;
float DQ = ac1 + B*V;
float Q = (C * V + BU) * V + ac2;
for (u = u1; u <= u2; ++u) {
if (Q < (float)(EWA_MAXIDX + 1)) {
float tc[4];
const float wt = EWA_WTS[(Q < 0.0f) ? 0 : (unsigned int)Q];
read_pixel_cb(userdata, u, v, tc);
madd_v3_v3fl(result, tc, wt);
result[3] += use_alpha ? tc[3] * wt : 0.0f;
d += wt;
}
Q += DQ;
DQ += DDQ;
}
}
/* d should hopefully never be zero anymore */
d = 1.0f / d;
mul_v3_fl(result, d);
/* clipping can be ignored if alpha used, texr->ta already includes filtered edge */
result[3] = use_alpha ? result[3] * d : 1.0f;
}