[rmodels] Inconsistent MAX_MESH_VERTEX_BUFFERS causes crash when unloading mesh

[deDug]

Issue description

config.h defines MAX_MESH_VERTEX_BUFFERS as 7, rmodels.c does this:

#ifndef MAX_MESH_VERTEX_BUFFERS
    #define MAX_MESH_VERTEX_BUFFERS  9    // Maximum vertex buffers (VBO) per mesh
#endif

I noticed this when I was trying to run the heightmap rendering example code and got a memory error when the mesh was unloaded. It looks it will use 9 spots even if 7 are allocated:

In UploadMesh:

    mesh->vboId = (unsigned int *)RL_CALLOC(MAX_MESH_VERTEX_BUFFERS, sizeof(unsigned int));

    mesh->vaoId = 0;        // Vertex Array Object
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_POSITION] = 0;     // Vertex buffer: positions
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD] = 0;     // Vertex buffer: texcoords
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_NORMAL] = 0;       // Vertex buffer: normals
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_COLOR] = 0;        // Vertex buffer: colors
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_TANGENT] = 0;      // Vertex buffer: tangents
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD2] = 0;    // Vertex buffer: texcoords2
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_BONEIDS] = 0;      // Vertex buffer: boneIds
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_BONEWEIGHTS] = 0;  // Vertex buffer: boneWeights
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_INDICES] = 0;      // Vertex buffer: indices

Then when the mesh is unloaded and it frees vboId, it can crash.

Environment

Lenovo Ideapad 5 2-in-1 14IRU9
Windows 11
OpenGl 3.3

Code Example

This causes a crash on my system:

#include "raylib.h"

//------------------------------------------------------------------------------------
// Program main entry point
//------------------------------------------------------------------------------------
int main(void)
{
    // Initialization
    //--------------------------------------------------------------------------------------
    const int screenWidth = 800;
    const int screenHeight = 450;

    InitWindow(screenWidth, screenHeight, "raylib [models] example - heightmap loading and drawing");
    Image image = LoadImage("resources/heightmap.png");     // Load heightmap image (RAM)
    Mesh mesh = GenMeshHeightmap(image, (Vector3) { 16, 8, 16 }); // Generate heightmap mesh (RAM and VRAM)
    UnloadImage(image);             // Unload heightmap image from RAM, already uploaded to VRAM
    UnloadMesh(mesh);
    return 0;
}

In rmodels.c, UploadMesh:

    mesh->vaoId = 0;        // Vertex Array Object
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_POSITION] = 0;     // Vertex buffer: positions
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD] = 0;     // Vertex buffer: texcoords
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_NORMAL] = 0;       // Vertex buffer: normals
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_COLOR] = 0;        // Vertex buffer: colors
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_TANGENT] = 0;      // Vertex buffer: tangents
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD2] = 0;    // Vertex buffer: texcoords2
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_BONEIDS] = 0;      // Vertex buffer: boneIds
    
    // This free will not crash
    RL_FREE(mesh->vboId);
    mesh->vboId = (unsigned int*)RL_CALLOC(MAX_MESH_VERTEX_BUFFERS, sizeof(unsigned int));

    // This writes out of bounds when MAX_MESH_VERTEX_BUFFERS is 7
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_BONEWEIGHTS] = 0;  // Vertex buffer: boneWeights
    mesh->vboId[RL_DEFAULT_SHADER_ATTRIB_LOCATION_INDICES] = 0;      // Vertex buffer: indices

    // This causes a crash:
    RL_FREE(mesh->vboId);
    mesh->vboId = (unsigned int*)RL_CALLOC(MAX_MESH_VERTEX_BUFFERS, sizeof(unsigned int));