AuroraMiddleware/AuroraOpenALSoft
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Scale the source volume by +3dB for a full spread

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This effectively turns a full spread source into an ambient response,
preventing such sources from being unexpectedly quiet.
This commit is contained in:
Chris Robinson 2017-07-18 22:15:32 -07:00
parent 5f7268c0cc
commit 0135ddc2e5
1 changed files with 7 additions and 6 deletions
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13
Alc/panning.c
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@ -152,8 +152,7 @@ void CalcDirectionCoeffs(const ALfloat dir[3], ALfloat spread, ALfloat coeffs[MA
* ZH5 = -0.0625*sqrt(pi) * (-1+ca)*(ca+1)*(21*ca*ca*ca*ca - 14*ca*ca + 1);
*
* The gain of the source is compensated for size, so that the
* loundness doesn't depend on the spread. That is, the factors are
* scaled so that ZH0 remains 1 regardless of the spread. Thus:
* loundness doesn't depend on the spread. Thus:
*
* ZH0 = 1.0f;
* ZH1 = 0.5f * (ca+1.0f);
@ -163,11 +162,13 @@ void CalcDirectionCoeffs(const ALfloat dir[3], ALfloat spread, ALfloat coeffs[MA
* ZH5 = 0.0625f * (ca+1.0f)*(21.0f*ca*ca*ca*ca - 14.0f*ca*ca + 1.0f);
*/
ALfloat ca = cosf(spread * 0.5f);
/* Increase the source volume by up to +3dB for a full spread. */
ALfloat scale = sqrtf(1.0f + spread/F_TAU);
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);
ALfloat ZH0_norm = scale;
ALfloat ZH1_norm = 0.5f * (ca+1.f) * scale;
ALfloat ZH2_norm = 0.5f * (ca+1.f)*ca * scale;
ALfloat ZH3_norm = 0.125f * (ca+1.f)*(5.f*ca*ca-1.f) * scale;
/* Zeroth-order */
coeffs[0] *= ZH0_norm;