* Add support for u8 bone indicies when loading glTF

* Fix segfault for glTF animations not keyframed at 0

When loading glTF animations we lerp between keyframes, and previously
assume that if the frame we are considering has a later keyframe, there
must be a previous keyframe. This is not true if the animation's first
keyframe is some time into the animation. In this case we now
effectively clamp to that first keyframe for any time prior to it.

* Respect parent bones tranform when loading glTF animations

We previously assumed that when loading glTF animations, the bones were
ordered with those higher up the skeleton tree (i.e. closer to the root)
came first in the list of nodes. This may not be true, so now we
repeatedly loop, preparing each level of the skeleton tree one after the
other, starting at the root level. This ensures that any parent
transforms are applied before transforming any child bones.

We also ensure that we have forced the loading of animation data before
attempting to interpolate to generate the animation frames for use
later, without this no animations are applied.

Finally we remove the check that assumed the first node in the nodes
list is the root, and use an invalid index value as the sentinal value
for when a node has no parent. Previously this was 0, which made
distinguishing between root nodes and children of the first node
impossible.

Actually, it seems more logical that rlgl takes care of OpenGL data than the models module...

Also, models module loaded vertex data is unloaded by models module.

Co-authored-by: Jeffery Myers <JefMyers@blizzard.com>

Current implementation is probably wrong and it should be reimplemented from scratch, in the meantime, I prefer to remove the function.

This is to account for GLTF info being more like instructions on how to build your animation instead of verbose description of each pose.

* Added example for gltf animation and split some functions for loading model animations into IQM and GLTF similar to how models are being loaded.

* Removed wrongly duplicated function

* Bone loading for gltf model (not working at this point)

* Loading info about vertex to joint connection but animation is still not working

* Skeleton and pose is correctly loaded. Need to communicate about interpolation in GLTF

* The model almost looks like a real person on animation.

* Fixed model loading with bones.

Also updated license info on the model.

* Cleaned up some code and updated examples.

* Fix identation issues

* Fix identation issues

* Fix identation issues

Upload mesh data to GPU and get VAO/VBO identifiers

Resolves #1495
This line allocated some memory that was already allocated in the beginning of the function and was essentially creating a leak.

Pefixing/Suffixing some data type identifier in the variables is not a convention used in raylib, just reviewed it for consistency...

Still, I kept the *Rec suffix in some functions.

Make model collision function call the mesh function.

WARNING: OBJ loading is broken at this point...

* allow for multiple materials in obj files also fix obj_loader hash map issues

* minor fix for warning

Co-authored-by: codifies <nospam@antispam.com>

This redesign allows more flexibility when creating RenderTexture and a simplification (and hopefully removal) of `GenTexture*()` functions, that should not belong to this model but the user code, due to the use of custom shaders.

Also, this new API opens the door for a possible GBuffers type and advance rendering possibilities...

Some functions of the API have been also simplified or even removed.

rlgl module can be used as an standalone library, so, a version for the library has been added: v3.1.0, matching current raylib version.

* MeshSmoothNormals() by average

* wrong comment

* spelling

* use correct function naming convention

Co-authored-by: frithrah <simon@frithrah.com>

This change could introduce an issue on dataSize precalculation...

Just flipped the signs of `n5` and `n6` at lines `2021` and `2022`.

Those functions could be very useful for custom triangle data drawing, using internal batch system.

Most warning were related to types conversion (casting required) and unsigned/signed types comparisons.

Added preprocessor directives (_CRT_SECURE_NO_DEPRECATE; _CRT_NONSTDC_NO_DEPRECATE) to avoid warnings about unsafe functions, those functions are safe while used properly and recommended alternatives are MS only.

Some external libraries still generate warnings.

There are multiple #define values around raylib, usually not exposed for redefinition, just reviewed all of them to allow users redefining them on compile time if required.

Also, multiple #define have been renamed and commented.