Issue with passing integer vertex attributes with "in" keyword - c++

Question

I'm working on bone animation. I have a vertex struct that basically looks like
struct MeshVertex
{
glm::vec3 pos;
glm::vec3 normal;
glm::vec2 tex;
glm::vec3 tangent;
glm::vec3 bitangent;
uint32_t ids[4] = {};
float weights[4] = {};
void print() const;
};
The mesh is a basic cube with one bone. Therefore ids = {0,0,0,0} and weights = {1.0f,0.0f,0.0f,0.0f} for every single vertex. In my mesh class I have a static function Mesh::genFormat() that handles attributes. vao is a static int in the mesh class and for_i is just a convenient macro I use to do for loops. Note that I correctly use glVertexArrayAttribIFormat.
Mesh::Mesh(const std::vector<MeshVertex>& vertices, const std::vector<uint>& indices, const std::vector<Texture>& textures)
{
m_textures = textures;
m_num_indices = indices.size();
// create vertex and index buffers
glCreateBuffers(1, &m_vbo);
glCreateBuffers(1, &m_ibo);
glNamedBufferData(m_vbo, sizeof(MeshVertex) * vertices.size(), &vertices[0], GL_STATIC_DRAW);
glNamedBufferData(m_ibo, sizeof(uint) * indices.size(), &indices[0], GL_STATIC_DRAW);
}
void Mesh::genFormat()
{
glCreateVertexArrays(1, &vao);
for_i(7) { glEnableVertexArrayAttrib(vao, i); }
glVertexArrayAttribFormat(vao, 0, 3, GL_FLOAT, false, offsetof(MeshVertex, pos)));
glVertexArrayAttribFormat(vao, 1, 3, GL_FLOAT, false, offsetof(MeshVertex, normal));
glVertexArrayAttribFormat(vao, 2, 2, GL_FLOAT, false, offsetof(MeshVertex, tex));
glVertexArrayAttribFormat(vao, 3, 3, GL_FLOAT, false, offsetof(MeshVertex, tangent));
glVertexArrayAttribFormat(vao, 4, 3, GL_FLOAT, false, offsetof(MeshVertex, bitangent));
glVertexArrayAttribIFormat(vao, 5, 4, GL_UNSIGNED_INT, offsetof(MeshVertex, ids)));
glVertexArrayAttribFormat(vao, 6, 4, GL_FLOAT, false, offsetof(MeshVertex, weights)));
for_i(7) { glVertexArrayAttribBinding(vao, i, 0); }
glBindVertexArray(0);
}
The following GLSL won't render anything.
#version 460 core
layout(location = 0) in vec3 Pos;
layout(location = 1) in vec3 Normal;
layout(location = 2) in vec2 Tex;
layout(location = 3) in vec3 Tan;
layout(location = 4) in vec3 BiTan;
layout(location = 5) in uvec4 BoneIds;
layout(location = 6) in vec4 Weights;
out vec3 normal;
out vec2 tex;
layout(binding = 2, std140) uniform Camera
{
mat4 VP;
vec4 cpos;
};
uniform mat4 node;
uniform mat4 bones_inverse_bind_mesh_parent[50];
void main()
{
tex = Tex;
mat4 W = mat4(0.0f);
if (Weights[0] != 0.0f)
{
for (uint i = 0; i < 4; i++)
W = W + (Weights[i] * bones_inverse_bind_mesh_parent[BoneIds[i]]);
W = node * W;
}
else
W = node;
gl_Position = VP * W * vec4(Pos, 1.0);
}
Since BoneIds[i] is always zero, if I replace
W = W + (Weights[i] * bones_inverse_bind_mesh_parent[BoneIds[i]]);
with
W = W + (Weights[i] * bones_inverse_bind_mesh_parent[0]);
the result should be unchanged. My matrix transforms are currently a bit off (something to fix later), but now the cube renders fine. So there is something wrong with BoneIds. After bashing my head against the wall on this for a while, I instead replaced
layout(location = 5) in uvec4 BoneIds;
with
layout(location = 5) varying uvec4 BoneIds;
after seeing some old GLSL online, and now everything works. What I don't understand is why. I've seen plenty of GLSL code on the internet work with integer attributes using the in keyword.
UPDATE :
If I replace glVertexArrayAttribIFormat in Mesh::genFormat() with
glVertexArrayAttribFormat(vao, 5, 4, GL_UNSIGNED_INT, false, offsetof(MeshVertex, ids));
in C++ and
layout(location = 5) in vec4 BoneIds;
in GLSL and cast bone ids from float to int in the glsl code, the code also works.

Answer 1

Okay I solved the issue, even though I don't quite understand how this fixes the problem. My preferred graphics processor was on auto but when I forced it to use the NVIDIA processor over my integrated graphics, everything works out fine. image of solution
Update :
I think it is as simple as my Intel processor graphics supporting OpenGL 4.4 and glVertexArrayAttribIFormat came about in OpenGL 4.5.