C++ header array initialization in constructor - c++

Question

I am working with OpenGL and I am trying to make a simple ground class that draws a rectangle.
I have a class called Vertex:
class Vertex
{
public:
Vertex(
glm::vec3 _position,
glm::vec3 _color = glm::vec3(0.0, 0.0, 0.0),
glm::vec3 _normal = glm::vec3(0.0, 1.0, 0.0),
glm::vec3 _texture = glm::vec3(0.0, 0.0, 0.0));
void setNormal(glm::vec3 _normal);
void setTexture(glm::vec3 _texture);
virtual ~Vertex();
protected:
private:
glm::vec3 position;
glm::vec3 color;
glm::vec3 normal;
glm::vec3 texture;
};
And this is my Ground class:
class Ground
{
private:
double widht;
double length;
double y;
int* indexes;
Vertex* vertices;
public:
Ground(double _width, double_length, double y);
}
And here is what I want to do in the Ground constructor:
this->indexes = {0, 3, 1, 1, 3, 2};
this->vertices = {
Vertex(glm::vec3(0 - width/2, y, 0-length/2)),
Vertex(glm::vec3(0 - width/2, y, 0+length/2)),
Vertex(glm::vec3(0 + width/2, y, 0+length/2)),
Vertex(glm::vec3(0 + width/2, y, 0-length/2))
}
I am getting this error when compiling:
error: cannot convert ‘<brace-enclosed initializer list>’ to ‘Vertex*’
Now I know I could hard-code initialize all of this, but I want a solution for a general ClassX* array header definition and constructor initialization.

Answer 1

vertices is a Vertex pointer, rather than an array. You can either make the member variable an array of fixed size or create an array of type Vertex on the heap.
for the first way something like this:
const int NUM_VERTS = 4;
class Ground{
.
.
.
Vertex vertices[NUM_VERTS]
.
.
.
};
Or if you want several different Ground objects with varying number of vertices you can use templates, but this will cause a big code bloat and executable size. Not a good idea, but it is possible
template<size n>
class Ground{
.
.
.
Vertex vertices[n];
.
.
.
}
otherwise, of course
vertices = new Vertex[4];
vertices[0] = Vertex(glm::vec3(0 - width/2, y, 0-length/2));
//etc
.
.
.

Answer 2

Change indexes (indices) and vertices to be std::vector<int> and std::vector<Vertex> respectively. Then you can write:
Ground::Ground(double _width, double _length, double y)
: indexes{0, 3, 1, 1, 3, 2}
, vertices{
Vertex(glm::vec3(0 - width/2, y, 0-length/2)),
Vertex(glm::vec3(0 - width/2, y, 0+length/2)),
Vertex(glm::vec3(0 + width/2, y, 0+length/2)),
Vertex(glm::vec3(0 + width/2, y, 0-length/2))
}
{
}