Stas Cymbalov : dsound: Fix angle to sound source calculation.
Alexandre Julliard
julliard at wine.codeweavers.com
Mon Apr 6 10:34:19 CDT 2015
Module: wine
Branch: master
Commit: c1c108f58ce84a2aeefdc93de26287198acc6348
URL: http://source.winehq.org/git/wine.git/?a=commit;h=c1c108f58ce84a2aeefdc93de26287198acc6348
Author: Stas Cymbalov <dummyunit at gmail.com>
Date: Sun Mar 22 18:22:49 2015 +0300
dsound: Fix angle to sound source calculation.
---
dlls/dsound/sound3d.c | 25 ++++++++++++++-----------
1 file changed, 14 insertions(+), 11 deletions(-)
diff --git a/dlls/dsound/sound3d.c b/dlls/dsound/sound3d.c
index 9a0226a..ffd4d45 100644
--- a/dlls/dsound/sound3d.c
+++ b/dlls/dsound/sound3d.c
@@ -112,7 +112,6 @@ static inline D3DVALUE AngleBetweenVectorsRad (const D3DVECTOR *a, const D3DVECT
cos = product/(la*lb);
angle = acos(cos);
- if (cos < 0.0f) { angle -= M_PI; }
TRACE("angle between (%f,%f,%f) and (%f,%f,%f) = %f radians (%f degrees)\n", a->x, a->y, a->z, b->x,
b->y, b->z, angle, RadToDeg(angle));
return angle;
@@ -264,16 +263,20 @@ void DSOUND_Calc3DBuffer(IDirectSoundBufferImpl *dsb)
else
{
vLeft = VectorProduct(&dsb->device->ds3dl.vOrientFront, &dsb->device->ds3dl.vOrientTop);
- flAngle = AngleBetweenVectorsRad(&dsb->device->ds3dl.vOrientFront, &vDistance);
- flAngle2 = AngleBetweenVectorsRad(&vLeft, &vDistance);
-
- /* AngleBetweenVectorsRad performs a dot product, which gives us the cosine of the angle
- * between two vectors. Unfortunately, because cos(theta) = cos(-theta), we've no idea from
- * this whether the sound is to our left or to our right. We have to perform another dot
- * product, with a vector at right angles to the initial one, to get the correct angle.
- * The angle should be between -180 degrees and 180 degrees. */
- if (flAngle < 0.0f) { flAngle += M_PI; }
- if (flAngle2 > 0.0f) { flAngle = -flAngle; }
+ /* To calculate angle to sound source we need to:
+ * 1) Get angle between vDistance and a plane on which angle to sound source should be 0.
+ * Such a plane is given by vectors vOrientFront and vOrientTop, and angle between vector
+ * and a plane equals to M_PI_2 - angle between vector and normal to this plane (vLeft in this case).
+ * 2) Determine if the source is behind or in front of us by calculating angle between vDistance
+ * and vOrientFront.
+ */
+ flAngle = AngleBetweenVectorsRad(&vLeft, &vDistance);
+ flAngle2 = AngleBetweenVectorsRad(&dsb->device->ds3dl.vOrientFront, &vDistance);
+ if (flAngle2 > M_PI_2)
+ flAngle = -flAngle;
+ flAngle -= M_PI_2;
+ if (flAngle < -M_PI)
+ flAngle += 2*M_PI;
}
TRACE("panning: Angle = %f rad, lPan = %d\n", flAngle, dsb->volpan.lPan);
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