cube.h

#ifndef OE_SCENE_PRIMITIVE_CUBE_H
#define OE_SCENE_PRIMITIVE_CUBE_H
 
#include "../mesh.h"
 
namespace oe::scene::primitive
{
    template <typename VertexType = Vertex>
    struct Cube : public Mesh<VertexType>
    {
        Cube(const bool mirror_textures = false)
        {
            auto generateTexCoords = [mirror_textures](const glm::vec2& input) -> glm::vec2
            {
                return glm::vec2((mirror_textures ? (1.f-input.x) : input.x), input.y);
            };
 
            auto& vertices = Mesh<VertexType>::vertices;
            auto& indices = Mesh<VertexType>::indices;
            auto& primitives = Mesh<VertexType>::primitives;
 
            vertices =
            {
                {.position = glm::vec3( 0.5f,  0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 0.0f))},
                {.position = glm::vec3( 0.5f, -0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 1.0f))},
                {.position = glm::vec3(-0.5f, -0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 1.0f))},
                {.position = glm::vec3(-0.5f, -0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 1.0f))},
                {.position = glm::vec3(-0.5f,  0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 0.0f))},
                {.position = glm::vec3( 0.5f,  0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 0.0f))},
 
                {.position = glm::vec3(-0.5f, -0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 1.0f))},
                {.position = glm::vec3( 0.5f, -0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 1.0f))},
                {.position = glm::vec3( 0.5f,  0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 0.0f))},
                {.position = glm::vec3( 0.5f,  0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 0.0f))},
                {.position = glm::vec3(-0.5f,  0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 0.0f))},
                {.position = glm::vec3(-0.5f, -0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 1.0f))},
 
                {.position = glm::vec3(-0.5f,  0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 0.0f))},
                {.position = glm::vec3(-0.5f,  0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 0.0f))},
                {.position = glm::vec3(-0.5f, -0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 1.0f))},
                {.position = glm::vec3(-0.5f, -0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 1.0f))},
                {.position = glm::vec3(-0.5f, -0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 1.0f))},
                {.position = glm::vec3(-0.5f,  0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 0.0f))},
 
                {.position = glm::vec3( 0.5f, -0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 1.0f))},
                {.position = glm::vec3( 0.5f,  0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 0.0f))},
                {.position = glm::vec3( 0.5f,  0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 0.0f))},
                {.position = glm::vec3( 0.5f,  0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 0.0f))},
                {.position = glm::vec3( 0.5f, -0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 1.0f))},
                {.position = glm::vec3( 0.5f, -0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 1.0f))},
 
                {.position = glm::vec3(-0.5f, -0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 1.0f))},
                {.position = glm::vec3( 0.5f, -0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 0.0f))},
                {.position = glm::vec3( 0.5f, -0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 0.0f))},
                {.position = glm::vec3( 0.5f, -0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 0.0f))},
                {.position = glm::vec3(-0.5f, -0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 1.0f))},
                {.position = glm::vec3(-0.5f, -0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 1.0f))},
 
                {.position = glm::vec3( 0.5f,  0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 1.0f))},
                {.position = glm::vec3( 0.5f,  0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 1.0f))},
                {.position = glm::vec3(-0.5f,  0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 0.0f))},
                {.position = glm::vec3(-0.5f,  0.5f, -0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(1.0f, 0.0f))},
                {.position = glm::vec3(-0.5f,  0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 0.0f))},
                {.position = glm::vec3( 0.5f,  0.5f,  0.5f), .tex_coords_0 = generateTexCoords(glm::vec2(0.0f, 1.0f))}
            };
 
            indices.reserve(vertices.size());
 
            for (auto i = 0u; i<vertices.size(); ++i)
            {
                indices.push_back(i);
            }
 
            primitives = {{0, vertices.size()}};
 
            if constexpr (IsVertexWithTangents<Vertex>)
            {
                Mesh<VertexType>::generateNormals();
                Mesh<VertexType>::generateTangents();
            }
        }
    };
}
 
#endif