I was trying to add an attribute for material index to each vertex:
...
glVertexAttribPointer(3, 1, GL_INT, GL_FALSE, sizeof(VertexMaterial), (void*)offsetof(VertexMaterial, material_id));
...
But the material_id read in the vertex shader was totally wrong:
layout(location = 3) in int aMaterial;
Then I replaced glVertexAttribPointer with glVertexAttribIPointer:
glVertexAttribIPointer(3, 1, GL_INT, sizeof(VertexMaterial), (void*)offsetof(VertexMaterial, material_id));
I modified nowhere else, but the vertex shader successfully got the right value for material_id this time.
But the OpenGL doc says that both glVertexAttribPointer and glVertexAttribIPointer can accept GL_INT (https://docs.gl/gl4/glVertexAttribPointer):
doc
So what's wrong in my code ?
