OpenGL Project - objects not keeping filling color on movement
Solution 1:
OpenGL is a state engine. Once a state has been set, it is retained until it is changed again, even beyond frames. Therefore, you need to set the polygon mode GL_FILL before rendering the solid geometry:
void CALLBACK display (void)
{
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
// render solid geometry
// [...]
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
// render wireframe geometry
// [...]
}