From: paramat <mat.gregory@virginmedia.com>
Date: Tue, 24 Jan 2017 10:16:56 +0000 (+0000)
Subject: OpenAL sound: Use a simpler distance model
X-Git-Tag: 0.4.16~450
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=a5ee7139a591eeffce5171e0df7a76f3c7a1d57e;p=oweals%2Fminetest.git

OpenAL sound: Use a simpler distance model

In createPlayingSoundAt(), AL_ROLLOFF_FACTOR is not set, so it has
the default value of 1.0, this makes the equation of the currently
used AL_EXPONENT_DISTANCE distance model identical to the equation
of the simpler AL_INVERSE_DISTANCE distance model.

Using AL_INVERSE_DISTANCE means an exponent is not processed,
exponents are quite intensive to process.
There is no change in sound attenuation behaviour.

The commented-out AL_ROLLOFF_FACTOR value is removed as it would
now have a different effect if used.
---

diff --git a/src/sound_openal.cpp b/src/sound_openal.cpp
index 317667f52..b9af9e3a9 100644
--- a/src/sound_openal.cpp
+++ b/src/sound_openal.cpp
@@ -317,7 +317,7 @@ public:
 			return;
 		}
 
-		alDistanceModel(AL_EXPONENT_DISTANCE);
+		alDistanceModel(AL_INVERSE_DISTANCE);
 
 		infostream<<"Audio: Initialized: OpenAL "<<alGetString(AL_VERSION)
 				<<", using "<<alcGetString(m_device, ALC_DEVICE_SPECIFIER)
@@ -409,7 +409,6 @@ public:
 		alSourcei(sound->source_id, AL_SOURCE_RELATIVE, false);
 		alSource3f(sound->source_id, AL_POSITION, pos.X, pos.Y, pos.Z);
 		alSource3f(sound->source_id, AL_VELOCITY, 0, 0, 0);
-		//alSourcef(sound->source_id, AL_ROLLOFF_FACTOR, 0.7);
 		alSourcef(sound->source_id, AL_REFERENCE_DISTANCE, 30.0);
 		alSourcei(sound->source_id, AL_LOOPING, loop ? AL_TRUE : AL_FALSE);
 		volume = MYMAX(0.0, volume);