[MC-91803] Cave / ambiance music can play far away from the player and is not audible

The bug

Ambiance / cave music can play far away from the player. This way the player might hear it less often than it should appear.

Report history

This report used to include in-game and title music as well. These were fixed in previous versions.

Code analysis

Based on 1.11 decompiled using MCP 9.35 rc1

The problem is that the method net.minecraft.client.multiplayer.WorldClient.playMoodSoundAndCheckLight(int, int, Chunk), which plays the ambient cave sound, is called with chunk coordinates of all visible chunks and only tests if the position tested is at least 2 meters away. This means the position can be hundreds of blocks away.

Example fix (1.11)

protected void playMoodSoundAndCheckLight(int p_147467_1_, int p_147467_2_, Chunk chunkIn)
{
    super.playMoodSoundAndCheckLight(p_147467_1_, p_147467_2_, chunkIn);

    if (this.ambienceTicks == 0)
    {
        this.updateLCG = this.updateLCG * 3 + 1013904223;
        int i = this.updateLCG >> 2;
        int j = i & 15;
        int k = i >> 8 & 15;
        int l = i >> 16 & 255;
        BlockPos blockpos = new BlockPos(j + p_147467_1_, l, k + p_147467_2_);
        IBlockState iblockstate = chunkIn.getBlockState(blockpos);
        j = j + p_147467_1_;
        k = k + p_147467_2_;

        // Old code
        //if (iblockstate.getMaterial() == Material.AIR && this.getLight(blockpos) <= this.rand.nextInt(8) && this.getLightFor(EnumSkyBlock.SKY, blockpos) <= 0 && this.mc.player != null && this.mc.player.getDistanceSq((double)j + 0.5D, (double)l + 0.5D, (double)k + 0.5D) > 4.0D)
        //{
        //    this.playSound((double)j + 0.5D, (double)l + 0.5D, (double)k + 0.5D, SoundEvents.AMBIENT_CAVE, SoundCategory.AMBIENT, 0.7F, 0.8F + this.rand.nextFloat() * 0.2F, false);
        //    this.ambienceTicks = this.rand.nextInt(12000) + 6000;
        //}
        
        if (this.mc.player != null) {
            double distanceToPlayerSquared = this.mc.player.getDistanceSq((double)j + 0.5D, (double)l + 0.5D, (double)k + 0.5D);
            
            // The player cannot hear the sound if it is played more than 15 (sqrt(255)) blocks away
            if (distanceToPlayerSquared > 4.0 && distanceToPlayerSquared <= 255.0 && iblockstate.getMaterial() == Material.AIR && this.getLight(blockpos) <= this.rand.nextInt(8) && this.getLightFor(EnumSkyBlock.SKY, blockpos) <= 0)
            {
                this.playSound((double)j + 0.5D, (double)l + 0.5D, (double)k + 0.5D, SoundEvents.AMBIENT_CAVE, SoundCategory.AMBIENT, 0.7F, 0.8F + this.rand.nextFloat() * 0.2F, false);
                this.ambienceTicks = this.rand.nextInt(12000) + 6000;
            }
        }
    }
}