numerics.hpp

#pragma once
 
#include "plg/config.hpp"
 
namespace plg {
    PLUGIFY_WARN_PUSH()
 
#if PLUGIFY_COMPILER_CLANG
    PLUGIFY_WARN_IGNORE("-Wgnu-anonymous-struct")
    PLUGIFY_WARN_IGNORE("-Wnested-anon-types")
#elif PLUGIFY_COMPILER_GCC
    PLUGIFY_WARN_IGNORE("-Wpedantic")
#elif PLUGIFY_COMPILER_MSVC
    PLUGIFY_WARN_IGNORE(4201)
#endif
 
    extern "C" {
        struct vec2 {
            union {
                struct {
                    float x;
                    float y;
                };
                float data[2];
            };
        };
 
        struct vec3 {
            union {
                struct {
                    float x;
                    float y;
                    float z;
                };
                float data[3];
            };
        };
 
        struct vec4 {
            union {
                struct {
                    float x;
                    float y;
                    float z;
                    float w;
                };
                float data[4];
            };
        };
 
        struct mat4x4 {
            union {
                struct {
                    float m00, m01, m02, m03;
                    float m10, m11, m12, m13;
                    float m20, m21, m22, m23;
                    float m30, m31, m32, m33;
                };
                float m[4][4];
                float data[16];
            };
        };
    }
 
    PLUGIFY_WARN_POP()
 
    constexpr float epsilon = 1e-5f;
 
    // TODO: Replace by std::fabs in C++23
    constexpr float fabs(float x) noexcept {
        return x < 0 ? -x : x;
    }
 
    constexpr bool operator==(vec2 lhs, vec2 rhs) {
        return fabs(lhs.x - rhs.x) < epsilon && fabs(lhs.y - rhs.y) < epsilon;
    }
 
    constexpr bool operator==(vec3 lhs, vec3 rhs) {
        return fabs(lhs.x - rhs.x) < epsilon && fabs(lhs.y - rhs.y) < epsilon && fabs(lhs.z - rhs.z) < epsilon;
    }
 
    constexpr bool operator==(vec4 lhs, vec4 rhs) {
        return fabs(lhs.x - rhs.x) < epsilon && fabs(lhs.y - rhs.y) < epsilon && fabs(lhs.z - rhs.z) < epsilon && fabs(lhs.w - rhs.w) < epsilon;
    }
 
    constexpr bool operator==(const mat4x4& lhs, const mat4x4& rhs) {
        for (int i = 0; i < 16; ++i) {
            if (fabs(lhs.data[i] - rhs.data[i]) > epsilon)
                return false;
        }
        return true;
    }
} // namespace plg