diff options
Diffstat (limited to 'Alc/panning.c')
| -rw-r--r-- | Alc/panning.c | 57 |
1 files changed, 52 insertions, 5 deletions
diff --git a/Alc/panning.c b/Alc/panning.c index 51b8e5cc..9ff97477 100644 --- a/Alc/panning.c +++ b/Alc/panning.c @@ -36,7 +36,7 @@ #include "bs2b.h" -extern inline void CalcXYZCoeffs(ALfloat x, ALfloat y, ALfloat z, ALfloat coeffs[MAX_AMBI_COEFFS]); +extern inline void CalcXYZCoeffs(ALfloat x, ALfloat y, ALfloat z, ALfloat spread, ALfloat coeffs[MAX_AMBI_COEFFS]); #define ZERO_ORDER_SCALE 0.0f @@ -109,7 +109,7 @@ static const ALfloat FuMa2N3DScale[MAX_AMBI_COEFFS] = { }; -void CalcDirectionCoeffs(const ALfloat dir[3], ALfloat coeffs[MAX_AMBI_COEFFS]) +void CalcDirectionCoeffs(const ALfloat dir[3], ALfloat spread, ALfloat coeffs[MAX_AMBI_COEFFS]) { /* Convert from OpenAL coords to Ambisonics. */ ALfloat x = -dir[2]; @@ -136,16 +136,63 @@ void CalcDirectionCoeffs(const ALfloat dir[3], ALfloat coeffs[MAX_AMBI_COEFFS]) coeffs[13] = 1.620185175f * x * (5.0f*z*z - 1.0f); /* ACN 13 = sqrt(21/8) * X * (5*Z*Z - 1) */ coeffs[14] = 5.123475383f * z * (x*x - y*y); /* ACN 14 = sqrt(105)/2 * Z * (X*X - Y*Y) */ coeffs[15] = 2.091650066f * x * (x*x - 3.0f*y*y); /* ACN 15 = sqrt(35/8) * X * (X*X - 3*Y*Y) */ + + if(spread > 0.0f) + { + /* Implement the spread by using a spherical source that subtends the + * angle spread. See: + * http://www.ppsloan.org/publications/StupidSH36.pdf - Appendix A3 + * + * The gain of the source is compensated for size, so that the + * loundness doesn't depend on the spread. + * + * ZH0 = (-sqrt_pi * (-1.f + ca)); + * ZH1 = ( 0.5f*sqrtf(3.f)*sqrt_pi * sa*sa); + * ZH2 = (-0.5f*sqrtf(5.f)*sqrt_pi * ca*(-1.f+ca)*(ca+1.f)); + * ZH3 = (-0.125f*sqrtf(7.f)*sqrt_pi * (-1.f+ca)*(ca+1.f)*(5.f*ca*ca-1.f)); + * solidangle = 2.f*F_PI*(1.f-ca) + * size_normalisation_coef = 1.f/ZH0; + * + * This is then adjusted for N3D normalization over SN3D. + */ + ALfloat ca = cosf(spread * 0.5f); + + ALfloat ZH0_norm = 1.0f; + ALfloat ZH1_norm = 0.5f * (ca+1.f); + ALfloat ZH2_norm = 0.5f * (ca+1.f)*ca; + ALfloat ZH3_norm = 0.125f * (ca+1.f)*(5.f*ca*ca-1.f); + + /* Zeroth-order */ + coeffs[0] *= ZH0_norm; + /* First-order */ + coeffs[1] *= ZH1_norm; + coeffs[2] *= ZH1_norm; + coeffs[3] *= ZH1_norm; + /* Second-order */ + coeffs[4] *= ZH2_norm; + coeffs[5] *= ZH2_norm; + coeffs[6] *= ZH2_norm; + coeffs[7] *= ZH2_norm; + coeffs[8] *= ZH2_norm; + /* Third-order */ + coeffs[9] *= ZH3_norm; + coeffs[10] *= ZH3_norm; + coeffs[11] *= ZH3_norm; + coeffs[12] *= ZH3_norm; + coeffs[13] *= ZH3_norm; + coeffs[14] *= ZH3_norm; + coeffs[15] *= ZH3_norm; + } } -void CalcAngleCoeffs(ALfloat azimuth, ALfloat elevation, ALfloat coeffs[MAX_AMBI_COEFFS]) +void CalcAngleCoeffs(ALfloat azimuth, ALfloat elevation, ALfloat spread, ALfloat coeffs[MAX_AMBI_COEFFS]) { ALfloat dir[3] = { sinf(azimuth) * cosf(elevation), sinf(elevation), -cosf(azimuth) * cosf(elevation) }; - CalcDirectionCoeffs(dir, coeffs); + CalcDirectionCoeffs(dir, spread, coeffs); } @@ -714,7 +761,7 @@ static void InitHrtfPanning(ALCdevice *device) for(i = 0;i < device->Dry.NumChannels;i++) { int chan = GetChannelIndex(CubeChannels, CubeInfo[i].Channel); - GetLerpedHrtfCoeffs(device->Hrtf, CubeInfo[i].Elevation, CubeInfo[i].Angle, 1.0f, 1.0f, + GetLerpedHrtfCoeffs(device->Hrtf, CubeInfo[i].Elevation, CubeInfo[i].Angle, 1.0f, 0.0f, device->Hrtf_Params[chan].Coeffs, device->Hrtf_Params[chan].Delay); } } |