diff options
| -rw-r--r-- | Alc/hrtf.cpp | 63 |
1 files changed, 26 insertions, 37 deletions
diff --git a/Alc/hrtf.cpp b/Alc/hrtf.cpp index 655aff1f..0165ed23 100644 --- a/Alc/hrtf.cpp +++ b/Alc/hrtf.cpp @@ -173,28 +173,27 @@ public: }; +struct IdxBlend { ALsizei idx; ALfloat blend; }; /* Calculate the elevation index given the polar elevation in radians. This * will return an index between 0 and (evcount - 1). */ -ALsizei CalcEvIndex(ALsizei evcount, ALfloat ev, ALfloat *mu) +IdxBlend CalcEvIndex(ALsizei evcount, ALfloat ev) { ev = (al::MathDefs<float>::Pi()*0.5f + ev) * (evcount-1) / al::MathDefs<float>::Pi(); ALsizei idx{float2int(ev)}; - *mu = ev - idx; - return mini(idx, evcount-1); + return IdxBlend{mini(idx, evcount-1), ev-idx}; } /* Calculate the azimuth index given the polar azimuth in radians. This will * return an index between 0 and (azcount - 1). */ -ALsizei CalcAzIndex(ALsizei azcount, ALfloat az, ALfloat *mu) +IdxBlend CalcAzIndex(ALsizei azcount, ALfloat az) { az = (al::MathDefs<float>::Tau()+az) * azcount / al::MathDefs<float>::Tau(); ALsizei idx{float2int(az)}; - *mu = az - idx; - return idx % azcount; + return IdxBlend{idx%azcount, az-idx}; } } // namespace @@ -209,50 +208,40 @@ void GetHrtfCoeffs(const HrtfEntry *Hrtf, ALfloat elevation, ALfloat azimuth, AL const ALfloat dirfact{1.0f - (spread / al::MathDefs<float>::Tau())}; /* Claculate the lower elevation index. */ - ALfloat emu; - ALsizei evidx{CalcEvIndex(Hrtf->evCount, elevation, &emu)}; - ALsizei evoffset{Hrtf->evOffset[evidx]}; + const auto elev = CalcEvIndex(Hrtf->evCount, elevation); + ALsizei ev0offset{Hrtf->evOffset[elev.idx]}; + ALsizei ev1offset{ev0offset}; /* Calculate lower azimuth index. */ - ALfloat amu[2]; - ALsizei azidx{CalcAzIndex(Hrtf->azCount[evidx], azimuth, &amu[0])}; + const auto az0 = CalcAzIndex(Hrtf->azCount[elev.idx], azimuth); + auto az1 = az0; - /* Calculate the lower HRIR indices. */ - ALsizei idx[4]{ - evoffset + azidx, - evoffset + ((azidx+1) % Hrtf->azCount[evidx]) - }; - if(evidx < Hrtf->evCount-1) + if(LIKELY(elev.idx < Hrtf->evCount-1)) { /* Increment elevation to the next (upper) index. */ - evidx++; - evoffset = Hrtf->evOffset[evidx]; + ALsizei evidx{elev.idx+1}; + ev1offset = Hrtf->evOffset[evidx]; /* Calculate upper azimuth index. */ - azidx = CalcAzIndex(Hrtf->azCount[evidx], azimuth, &amu[1]); - - /* Calculate the upper HRIR indices. */ - idx[2] = evoffset + azidx; - idx[3] = evoffset + ((azidx+1) % Hrtf->azCount[evidx]); - } - else - { - /* If the lower elevation is the top index, the upper elevation is the - * same as the lower. - */ - amu[1] = amu[0]; - idx[2] = idx[0]; - idx[3] = idx[1]; + az1 = CalcAzIndex(Hrtf->azCount[evidx], azimuth); } + /* Calculate the HRIR indices to blend. */ + ALsizei idx[4]{ + ev0offset + az0.idx, + ev0offset + ((az0.idx+1) % Hrtf->azCount[elev.idx]), + ev1offset + az1.idx, + ev1offset + ((az1.idx+1) % Hrtf->azCount[elev.idx]) + }; + /* Calculate bilinear blending weights, attenuated according to the * directional panning factor. */ const ALfloat blend[4]{ - (1.0f-emu) * (1.0f-amu[0]) * dirfact, - (1.0f-emu) * ( amu[0]) * dirfact, - ( emu) * (1.0f-amu[1]) * dirfact, - ( emu) * ( amu[1]) * dirfact + (1.0f-elev.blend) * (1.0f-az0.blend) * dirfact, + (1.0f-elev.blend) * ( az0.blend) * dirfact, + ( elev.blend) * (1.0f-az1.blend) * dirfact, + ( elev.blend) * ( az1.blend) * dirfact }; /* Calculate the blended HRIR delays. */ |