aabb.hpp

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#pragma once
 
#include <glm/glm.hpp>
#include <glm/gtc/quaternion.hpp>
 
namespace Engine::Physics {
    struct AABB {
        glm::vec2 center;
        glm::vec2 halfSize;

        AABB(glm::vec2 pos, glm::vec2 size, glm::quat rot = glm::quat()) {
            glm::vec2 half = size * 0.5f;
 
            // Définir les 4 coins dans l'espace local
            glm::vec3 corners[4] = {
                glm::vec3(-half.x, -half.y, 0),
                glm::vec3( half.x, -half.y, 0),
                glm::vec3( half.x,  half.y, 0),
                glm::vec3(-half.x,  half.y, 0)
            };
 
            // Appliquer la rotation 3D (autour de Z), puis projection 2D
            glm::vec2 min(FLT_MAX), max(-FLT_MAX);
            for (int i = 0; i < 4; ++i) {
                glm::vec3 rotated = rot * corners[i]; // rotation quaternion
                glm::vec2 p = glm::vec2(rotated.x, rotated.y) + pos;
 
                min = glm::min(min, p);
                max = glm::max(max, p);
            }
 
            center = (min + max) * 0.5f;
            halfSize = (max - min) * 0.5f;
        }

        glm::vec2 Min() const {
            return center - halfSize;
        }

        glm::vec2 Max() const {
            return center + halfSize;
        }

        bool Intersects(const AABB& other, float margin = 0.0f) const {
            return (
                (Max().x + margin) > other.Min().x && (Min().x - margin) < other.Max().x &&
                (Max().y + margin) > other.Min().y && (Min().y - margin) < other.Max().y
            );
        }
    };
}