Certain entity animations stop after they've existed in world for too long

Confirmed for 1.18.

Code analysis: the issue is exactly as stated, some entity renderers use the entity's tick count for calculation, resulting in an eventual integer overflow as they use Mth.cos(). This is using Mojang mappings.

In LivingEntityRenderer#render(...), the animation is set up with this line: ((EntityModel)this.model).setupAnim($$0, $$16, $$15, $$14, $$8, $$11);

In the case of bees, the relevant value is $$14 (which I will call entityBob here), as it is the value called to set up the wings’ Z rotation. Said rotation is a float set to Mth.cos(entityBob * 120.32113f * ((float)Math.PI / 180)) * (float)Math.PI * 0.15f, as can be found in BeeModel#setupAnim(...). entityBob is LivingEntityRenderer#getBob(Entity, $$2), which returns (float)((LivingEntity)Entity).tickCount + $$2.

The problem is that Mth.cos() uses a float to int conversion:

public static float cos(float $$0) {
        return SIN[(int)($$0 * 10430.378f + 16384.0f) & 0xFFFF];
    }

And this results in an overflow when entityBob * 120.32113 * (pi / 180) * 10430.378 + 16384 > 2147483647, which is the int limit. This happens when entityBob exceeds approximately 98040.88, which happens around 82 minutes after the entity is spawned in.

The issue is the same for bats. The wings' Y rotation is set to Mth.cos(entityBob * 74.48451f * ((float)Math.PI / 180)) * (float)Math.PI * 0.25f in BatModel#setupAnim(...), which overflows when entityBob exceeds approximately 158373.73, which happens around 132 minutes after the entity is spawned in.

Edit: fixed some values, but they might still be off by around 100.

Relates to MC-1279 and MC-63720

Couldn't this be solved by using

return SIN[(int)((($$0 * 10430.378f + 16384.0f) & 0xFFFF) % Integer.MAX_VALUE)]

basically just wrapping the value back to zero if it reaches the limit

@unknown Yes, I think that in theory that would work.

Mth.sin() would also need to be fixed.

There are no instances where this would affect anything and would simply just be an extra division calculation

It is used in the guardian renderer. But I suppose that it would become irrelevant if MC-165595 were fixed.

After more testing, I came up with this...

In sin and cos methods, modulo by TAU (2PI)

public static float cos(float value) {
   value %= TAU; // TAU = 2PI
   return SINE_TABLE[(int)(value * 10430.378F + 16384.0F) & 65535];
} 

public static float sin(float value) {
   value %= TAU; // TAU = 2PI
   return SINE_TABLE[(int)(value * 10430.378F) & 65535];
}

Can confirm in 1.19.3.