Improve bad hash functions

[Nazarwadim]

Working on #90082. When using the collision checker, I found that hash maps/sets with these hash functions do not work well and create a large number of collisions (max number of collisions is more than 13). So I improved the algorithm for their work. In most cases, I changed the hashing algorithm from djb2 to murmur3. The maximum number of collisions after these changes decreased by 1.5 - 2 times.

[AThousandShips]

How did you check for these collisions?

[Nazarwadim]

Used code from this closed pr #72561. Only the check was for the constant 8 and I also used __PRETTY_FUNCTION__ to find the function itself. So, if there were more than 8 collisions, then the console displayed something like this:

WARNING: Excessive collision count (11), is the right hash function being used? Class Name:void HashMap<TKey, TValue, Hasher, Comparator, Allocator>::_insert_with_hash_and_element(uint32_t, HashMapElement<TKey, TValue>*) [with TKey = gd::EdgeKey; TValue = Vector<gd::Edge::Connection>; Hasher = gd::EdgeKey; Comparator = HashMapComparatorDefault<gd::EdgeKey>; Allocator = DefaultTypedAllocator<HashMapElement<gd::EdgeKey, Vector<gd::Edge::Connection> > >; uint32_t = unsigned int]

I used projects such as https://github.com/godotengine/godot-demo-projects and also several of mine.

[fire]

Since these methods are used in the import pipeline any change to hash functions would need to be an upward upgrade to the import formats.

[Nazarwadim]

How is it used? I didn't find any hash calls in the import and io directories related to my changes. Also in most cases, I changed hashers that are used only by hash structures.

[fire]

See https://github.com/godotengine/godot/blob/master/scene/resources/surface_tool.cpp#L136C1-L151C2

[Nazarwadim]

See https://github.com/godotengine/godot/blob/master/scene/resources/surface_tool.cpp#L136C1-L151C2

?

[Calinou]

In most cases, I changed the hashing algorithm from djb2 to murmur3

Didn't reduz do the opposite while rewriting HashMap for Godot 4?

Edit: Nevermind, I was thinking about #62176 which doesn't swap the algorithms together; it just cleans them up.