plane.h

#ifndef OE_SCENE_PRIMITIVE_PLANE_H
#define OE_SCENE_PRIMITIVE_PLANE_H
 
#include "../mesh.h"
 
namespace oe::scene::primitive
{
    template <typename VertexType = Vertex>
    struct Plane : public Mesh<VertexType>
    {
        Plane()
        {
            /*
                Vertices are layed like this :
                (view from above)
 
                ^
                X
                0 1
                2 3
                O    Z >
 
                We will draw the plane as 2 triangles 021 and 123
            */
 
            auto& vertices = Mesh<VertexType>::vertices;
            auto& indices = Mesh<VertexType>::indices;
            auto& primitives = Mesh<VertexType>::primitives;
 
            vertices =
            {
                {.position = glm::vec3( 0.5f, 0.f, -0.5f), .tex_coords_0 = glm::vec2(0.f, 0.f), .normal = glm::vec3( 0.f, 1.f, 0.f)},
                {.position = glm::vec3( 0.5f, 0.f,  0.5f), .tex_coords_0 = glm::vec2(1.f, 0.f), .normal = glm::vec3( 0.f, 1.f, 0.f)},
                {.position = glm::vec3(-0.5f, 0.f, -0.5f), .tex_coords_0 = glm::vec2(0.f, 1.f), .normal = glm::vec3( 0.f, 1.f, 0.f)},
                {.position = glm::vec3(-0.5f, 0.f,  0.5f), .tex_coords_0 = glm::vec2(1.f, 1.f), .normal = glm::vec3( 0.f, 1.f, 0.f)},
            };
 
            indices = {{
                0, 2, 1, // Up-left triangle
                1, 2, 3  // lower-right triangle
            }};
 
            primitives = {{0, indices.size()}};
 
            if constexpr (IsVertexWithTangents<Vertex>)
            {
                Mesh<VertexType>::generateTangents();
            }
        }
    };
}
 
#endif