Wrap rlgl

[planetis-m]

• rl Prefix needs to go from every function/struct/enum definition.
• MaxShaderLocations constant taken from rlgl.h needs be imported from raylib.
• rest of the constants wrapped manually?
• rlTraceLogLevel, rlPixelFormat, rlTextureFilter, rlBlendMode, rlShaderLocationIndex, rlShaderUniformDataType, ShaderAttributeDataType need to be hidden and the respective enums from raylib imported and re-exported.
• Wrap rlSetUniform, rlSetVertexAttributeDefault the same way as SetShaderValue.
• rlLoadExtensions, rlGetShaderLocsDefault, glMultMatrixf, rlLoadVertexBuffer, rlLoadVertexBufferElement, rlUpdateVertexBuffer, rlUpdateVertexBufferElements, rlSetVertexAttribute, rlSetVertexAttributeDefault, rlDrawVertexArrayElements, rlDrawVertexArrayElementsInstanced, rlLoadTexture, rlLoadTextureCubemap, rlUpdateTexture, rlGetGlTextureFormats, rlGenTextureMipmaps, rlReadShaderBufferElements, rlUpdateShaderBufferElements, rlLoadShaderBuffer, rlGenTextureMipmaps, rlReadScreenPixels etc all need manual wrapping
• returning void pointer rlReadTexturePixels need multiple overloads?
• rlGetGlTextureFormats, others need out parameters.
• loader of type rlglLoadProc void *(*rlglLoadProc)(const char *name)
• rlGetShaderLocsDefault same type as rlSetShader and Shader.locs
• RenderBatch.draws type is ptr array[RL_DEFAULT_BATCH_DRAWCALLS, DrawCall]
• RenderBatch.vertexBuffer bounds need to be checked at runtime.
• VertexBuffer.vertices cast to array[4, Vector3] * bufferElements
• VertexBuffer.texcoords cast to array[4, Vector2] * bufferElements
• VertexBuffer.colors cast to array[4, Color] * bufferElements
• RenderBatch needs a destructor.
• VertexBuffer needs .error =sink, =copy hooks

[planetis-m]

rlGetPixelFormatName can be rewritten in Nim to avoid allocations when converting to string. But imo looks worthless and for debug. $PixelFormat value does the same thing. Maybe remove it.

Removed for now, but one can make a PR with an overload $ for PixelFormat in raylib.nim.

[planetis-m]

loadShaderBuffer needs StreamCopy as default parameter

[planetis-m]

rlUpdateShaderBuffer, rlUpdateVertexBuffer, rlUpdateVertexBufferElements, rlReadShaderBuffer can be wrapped since it always calls glBindBuffer before. But for the rest, data is nil can be valid. Not sure how to approach this.

So is rlLoadVertexBuffer, rlLoadVertexBufferElement but not rlLoadShadderBuffer?