diff options
Diffstat (limited to 'OpenAL32/Include')
| -rw-r--r-- | OpenAL32/Include/alu.h | 40 |
1 files changed, 30 insertions, 10 deletions
diff --git a/OpenAL32/Include/alu.h b/OpenAL32/Include/alu.h index b977613c..c09caa65 100644 --- a/OpenAL32/Include/alu.h +++ b/OpenAL32/Include/alu.h @@ -431,13 +431,34 @@ void aluInitEffectPanning(struct ALeffectslot *slot); void aluSelectPostProcess(ALCdevice *device); /** + * Calculates ambisonic encoder coefficients using the X, Y, and Z direction + * components, which must represent a normalized (unit length) vector, and the + * spread is the angular width of the sound (0...tau). + * + * NOTE: The components use ambisonic coordinates. As a result: + * + * Ambisonic Y = OpenAL -X + * Ambisonic Z = OpenAL Y + * Ambisonic X = OpenAL -Z + * + * The components are ordered such that OpenAL's X, Y, and Z are the first, + * second, and third parameters respectively -- simply negate X and Z. + */ +void CalcAmbiCoeffs(const ALfloat y, const ALfloat z, const ALfloat x, const ALfloat spread, + ALfloat coeffs[MAX_AMBI_COEFFS]); + +/** * CalcDirectionCoeffs * - * Calculates ambisonic coefficients based on a direction vector. The vector - * must be normalized (unit length), and the spread is the angular width of the - * sound (0...tau). + * Calculates ambisonic coefficients based on an OpenAL direction vector. The + * vector must be normalized (unit length), and the spread is the angular width + * of the sound (0...tau). */ -void CalcDirectionCoeffs(const ALfloat dir[3], ALfloat spread, ALfloat coeffs[MAX_AMBI_COEFFS]); +inline void CalcDirectionCoeffs(const ALfloat dir[3], ALfloat spread, ALfloat coeffs[MAX_AMBI_COEFFS]) +{ + /* Convert from OpenAL coords to Ambisonics. */ + CalcAmbiCoeffs(-dir[0], dir[1], -dir[2], spread, coeffs); +} /** * CalcAngleCoeffs @@ -448,12 +469,11 @@ void CalcDirectionCoeffs(const ALfloat dir[3], ALfloat spread, ALfloat coeffs[MA */ inline 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, spread, coeffs); + ALfloat x = -sinf(azimuth) * cosf(elevation); + ALfloat y = sinf(elevation); + ALfloat z = cosf(azimuth) * cosf(elevation); + + CalcAmbiCoeffs(x, y, z, spread, coeffs); } /** |