raylib-sys 3.0.0

/**********************************************************************************************
*
*   raymath v1.2 - Math functions to work with Vector3, Matrix and Quaternions
*
*   CONFIGURATION:
*
*   #define RAYMATH_IMPLEMENTATION
*       Generates the implementation of the library into the included file.
*       If not defined, the library is in header only mode and can be included in other headers
*       or source files without problems. But only ONE file should hold the implementation.
*
*   #define RAYMATH_HEADER_ONLY
*       Define static inline functions code, so #include header suffices for use.
*       This may use up lots of memory.
*
*   #define RAYMATH_STANDALONE
*       Avoid raylib.h header inclusion in this file.
*       Vector3 and Matrix data types are defined internally in raymath module.
*
*
*   LICENSE: zlib/libpng
*
*   Copyright (c) 2015-2020 Ramon Santamaria (@raysan5)
*
*   This software is provided "as-is", without any express or implied warranty. In no event
*   will the authors be held liable for any damages arising from the use of this software.
*
*   Permission is granted to anyone to use this software for any purpose, including commercial
*   applications, and to alter it and redistribute it freely, subject to the following restrictions:
*
*     1. The origin of this software must not be misrepresented; you must not claim that you
*     wrote the original software. If you use this software in a product, an acknowledgment
*     in the product documentation would be appreciated but is not required.
*
*     2. Altered source versions must be plainly marked as such, and must not be misrepresented
*     as being the original software.
*
*     3. This notice may not be removed or altered from any source distribution.
*
**********************************************************************************************/

#ifndef RAYMATH_H
#define RAYMATH_H

//#define RAYMATH_STANDALONE      // NOTE: To use raymath as standalone lib, just uncomment this line
//#define RAYMATH_HEADER_ONLY     // NOTE: To compile functions as static inline, uncomment this line

#ifndef RAYMATH_STANDALONE
#include "raylib.h" // Required for structs: Vector3, Matrix
#endif

#if defined(RAYMATH_IMPLEMENTATION) && defined(RAYMATH_HEADER_ONLY)
#error "Specifying both RAYMATH_IMPLEMENTATION and RAYMATH_HEADER_ONLY is contradictory"
#endif

#if defined(RAYMATH_IMPLEMENTATION)
#if defined(_WIN32) && defined(BUILD_LIBTYPE_SHARED)
#define RMDEF __declspec(dllexport) extern inline // We are building raylib as a Win32 shared library (.dll).
#elif defined(_WIN32) && defined(USE_LIBTYPE_SHARED)
#define RMDEF __declspec(dllimport) // We are using raylib as a Win32 shared library (.dll)
#else
#define RMDEF extern inline // Provide external definition
#endif
#elif defined(RAYMATH_HEADER_ONLY)
#define RMDEF static inline // Functions may be inlined, no external out-of-line definition
#else
#if defined(__TINYC__)
#define RMDEF static inline // plain inline not supported by tinycc (See issue #435)
#else
#define RMDEF inline // Functions may be inlined or external definition used
#endif
#endif

//----------------------------------------------------------------------------------
// Defines and Macros
//----------------------------------------------------------------------------------
#ifndef PI
#define PI 3.14159265358979323846
#endif

#ifndef DEG2RAD
#define DEG2RAD (PI / 180.0f)
#endif

#ifndef RAD2DEG
#define RAD2DEG (180.0f / PI)
#endif

// Return float vector for Matrix
#ifndef MatrixToFloat
#define MatrixToFloat(mat) (MatrixToFloatV(mat).v)
#endif

// Return float vector for Vector3
#ifndef Vector3ToFloat
#define Vector3ToFloat(vec) (Vector3ToFloatV(vec).v)
#endif

//----------------------------------------------------------------------------------
// Types and Structures Definition
//----------------------------------------------------------------------------------

#if defined(RAYMATH_STANDALONE)
// Vector2 type
typedef struct Vector2
{
    float x;
    float y;
} Vector2;

// Vector3 type
typedef struct Vector3
{
    float x;
    float y;
    float z;
} Vector3;

// Quaternion type
typedef struct Quaternion
{
    float x;
    float y;
    float z;
    float w;
} Quaternion;

// Matrix type (OpenGL style 4x4 - right handed, column major)
typedef struct Matrix
{
    float m0, m4, m8, m12;
    float m1, m5, m9, m13;
    float m2, m6, m10, m14;
    float m3, m7, m11, m15;
} Matrix;
#endif

// NOTE: Helper types to be used instead of array return types for *ToFloat functions
typedef struct float3
{
    float v[3];
} float3;
typedef struct float16
{
    float v[16];
} float16;

#include <math.h> // Required for: sinf(), cosf(), sqrtf(), tan(), fabs()

//----------------------------------------------------------------------------------
// Module Functions Definition - Utils math
//----------------------------------------------------------------------------------

// Clamp float value
RMDEF float Clamp(float value, float min, float max)
{
    const float res = value < min ? min : value;
    return res > max ? max : res;
}

// Calculate linear interpolation between two floats
RMDEF float Lerp(float start, float end, float amount)
{
    return start + amount * (end - start);
}

//----------------------------------------------------------------------------------
// Module Functions Definition - Vector2 math
//----------------------------------------------------------------------------------

// Vector with components value 0.0f
RMDEF Vector2 Vector2Zero(void)
{
    Vector2 result = {0.0f, 0.0f};
    return result;
}

// Vector with components value 1.0f
RMDEF Vector2 Vector2One(void)
{
    Vector2 result = {1.0f, 1.0f};
    return result;
}

// Add two vectors (v1 + v2)
RMDEF Vector2 Vector2Add(Vector2 v1, Vector2 v2)
{
    Vector2 result = {v1.x + v2.x, v1.y + v2.y};
    return result;
}

// Subtract two vectors (v1 - v2)
RMDEF Vector2 Vector2Subtract(Vector2 v1, Vector2 v2)
{
    Vector2 result = {v1.x - v2.x, v1.y - v2.y};
    return result;
}

// Calculate vector length
RMDEF float Vector2Length(Vector2 v)
{
    float result = sqrtf((v.x * v.x) + (v.y * v.y));
    return result;
}

// Calculate two vectors dot product
RMDEF float Vector2DotProduct(Vector2 v1, Vector2 v2)
{
    float result = (v1.x * v2.x + v1.y * v2.y);
    return result;
}

// Calculate distance between two vectors
RMDEF float Vector2Distance(Vector2 v1, Vector2 v2)
{
    float result = sqrtf((v1.x - v2.x) * (v1.x - v2.x) + (v1.y - v2.y) * (v1.y - v2.y));
    return result;
}

// Calculate angle from two vectors in X-axis
RMDEF float Vector2Angle(Vector2 v1, Vector2 v2)
{
    float result = atan2f(v2.y - v1.y, v2.x - v1.x) * (180.0f / PI);
    if (result < 0)
        result += 360.0f;
    return result;
}

// Scale vector (multiply by value)
RMDEF Vector2 Vector2Scale(Vector2 v, float scale)
{
    Vector2 result = {v.x * scale, v.y * scale};
    return result;
}

// Multiply vector by vector
RMDEF Vector2 Vector2MultiplyV(Vector2 v1, Vector2 v2)
{
    Vector2 result = {v1.x * v2.x, v1.y * v2.y};
    return result;
}

// Negate vector
RMDEF Vector2 Vector2Negate(Vector2 v)
{
    Vector2 result = {-v.x, -v.y};
    return result;
}

// Divide vector by a float value
RMDEF Vector2 Vector2Divide(Vector2 v, float div)
{
    Vector2 result = {v.x / div, v.y / div};
    return result;
}

// Divide vector by vector
RMDEF Vector2 Vector2DivideV(Vector2 v1, Vector2 v2)
{
    Vector2 result = {v1.x / v2.x, v1.y / v2.y};
    return result;
}

// Normalize provided vector
RMDEF Vector2 Vector2Normalize(Vector2 v)
{
    Vector2 result = Vector2Divide(v, Vector2Length(v));
    return result;
}

// Calculate linear interpolation between two vectors
RMDEF Vector2 Vector2Lerp(Vector2 v1, Vector2 v2, float amount)
{
    Vector2 result = {0};

    result.x = v1.x + amount * (v2.x - v1.x);
    result.y = v1.y + amount * (v2.y - v1.y);

    return result;
}

// Rotate Vector by float in Degrees.
RMDEF Vector2 Vector2Rotate(Vector2 v, float degs)
{
    float rads = degs * DEG2RAD;
    Vector2 result = {v.x * cosf(rads) - v.y * sinf(rads), v.x * sinf(rads) + v.y * cosf(rads)};
    return result;
}

//----------------------------------------------------------------------------------
// Module Functions Definition - Vector3 math
//----------------------------------------------------------------------------------

// Vector with components value 0.0f
RMDEF Vector3 Vector3Zero(void)
{
    Vector3 result = {0.0f, 0.0f, 0.0f};
    return result;
}

// Vector with components value 1.0f
RMDEF Vector3 Vector3One(void)
{
    Vector3 result = {1.0f, 1.0f, 1.0f};
    return result;
}

// Add two vectors
RMDEF Vector3 Vector3Add(Vector3 v1, Vector3 v2)
{
    Vector3 result = {v1.x + v2.x, v1.y + v2.y, v1.z + v2.z};
    return result;
}

// Subtract two vectors
RMDEF Vector3 Vector3Subtract(Vector3 v1, Vector3 v2)
{
    Vector3 result = {v1.x - v2.x, v1.y - v2.y, v1.z - v2.z};
    return result;
}

// Multiply vector by scalar
RMDEF Vector3 Vector3Scale(Vector3 v, float scalar)
{
    Vector3 result = {v.x * scalar, v.y * scalar, v.z * scalar};
    return result;
}

// Multiply vector by vector
RMDEF Vector3 Vector3Multiply(Vector3 v1, Vector3 v2)
{
    Vector3 result = {v1.x * v2.x, v1.y * v2.y, v1.z * v2.z};
    return result;
}

// Calculate two vectors cross product
RMDEF Vector3 Vector3CrossProduct(Vector3 v1, Vector3 v2)
{
    Vector3 result = {v1.y * v2.z - v1.z * v2.y, v1.z * v2.x - v1.x * v2.z, v1.x * v2.y - v1.y * v2.x};
    return result;
}

// Calculate one vector perpendicular vector
RMDEF Vector3 Vector3Perpendicular(Vector3 v)
{
    Vector3 result = {0};

    float min = (float)fabs(v.x);
    Vector3 cardinalAxis = {1.0f, 0.0f, 0.0f};

    if (fabs(v.y) < min)
    {
        min = (float)fabs(v.y);
        Vector3 tmp = {0.0f, 1.0f, 0.0f};
        cardinalAxis = tmp;
    }

    if (fabs(v.z) < min)
    {
        Vector3 tmp = {0.0f, 0.0f, 1.0f};
        cardinalAxis = tmp;
    }

    result = Vector3CrossProduct(v, cardinalAxis);

    return result;
}

// Calculate vector length
RMDEF float Vector3Length(const Vector3 v)
{
    float result = sqrtf(v.x * v.x + v.y * v.y + v.z * v.z);
    return result;
}

// Calculate two vectors dot product
RMDEF float Vector3DotProduct(Vector3 v1, Vector3 v2)
{
    float result = (v1.x * v2.x + v1.y * v2.y + v1.z * v2.z);
    return result;
}

// Calculate distance between two vectors
RMDEF float Vector3Distance(Vector3 v1, Vector3 v2)
{
    float dx = v2.x - v1.x;
    float dy = v2.y - v1.y;
    float dz = v2.z - v1.z;
    float result = sqrtf(dx * dx + dy * dy + dz * dz);
    return result;
}

// Negate provided vector (invert direction)
RMDEF Vector3 Vector3Negate(Vector3 v)
{
    Vector3 result = {-v.x, -v.y, -v.z};
    return result;
}

// Divide vector by a float value
RMDEF Vector3 Vector3Divide(Vector3 v, float div)
{
    Vector3 result = {v.x / div, v.y / div, v.z / div};
    return result;
}

// Divide vector by vector
RMDEF Vector3 Vector3DivideV(Vector3 v1, Vector3 v2)
{
    Vector3 result = {v1.x / v2.x, v1.y / v2.y, v1.z / v2.z};
    return result;
}

// Normalize provided vector
RMDEF Vector3 Vector3Normalize(Vector3 v)
{
    Vector3 result = v;

    float length, ilength;
    length = Vector3Length(v);
    if (length == 0.0f)
        length = 1.0f;
    ilength = 1.0f / length;

    result.x *= ilength;
    result.y *= ilength;
    result.z *= ilength;

    return result;
}

// Orthonormalize provided vectors
// Makes vectors normalized and orthogonal to each other
// Gram-Schmidt function implementation
RMDEF void Vector3OrthoNormalize(Vector3 *v1, Vector3 *v2)
{
    *v1 = Vector3Normalize(*v1);
    Vector3 vn = Vector3CrossProduct(*v1, *v2);
    vn = Vector3Normalize(vn);
    *v2 = Vector3CrossProduct(vn, *v1);
}

// Transforms a Vector3 by a given Matrix
RMDEF Vector3 Vector3Transform(Vector3 v, Matrix mat)
{
    Vector3 result = {0};
    float x = v.x;
    float y = v.y;
    float z = v.z;

    result.x = mat.m0 * x + mat.m4 * y + mat.m8 * z + mat.m12;
    result.y = mat.m1 * x + mat.m5 * y + mat.m9 * z + mat.m13;
    result.z = mat.m2 * x + mat.m6 * y + mat.m10 * z + mat.m14;

    return result;
}

// Transform a vector by quaternion rotation
RMDEF Vector3 Vector3RotateByQuaternion(Vector3 v, Quaternion q)
{
    Vector3 result = {0};

    result.x = v.x * (q.x * q.x + q.w * q.w - q.y * q.y - q.z * q.z) + v.y * (2 * q.x * q.y - 2 * q.w * q.z) + v.z * (2 * q.x * q.z + 2 * q.w * q.y);
    result.y = v.x * (2 * q.w * q.z + 2 * q.x * q.y) + v.y * (q.w * q.w - q.x * q.x + q.y * q.y - q.z * q.z) + v.z * (-2 * q.w * q.x + 2 * q.y * q.z);
    result.z = v.x * (-2 * q.w * q.y + 2 * q.x * q.z) + v.y * (2 * q.w * q.x + 2 * q.y * q.z) + v.z * (q.w * q.w - q.x * q.x - q.y * q.y + q.z * q.z);

    return result;
}

// Calculate linear interpolation between two vectors
RMDEF Vector3 Vector3Lerp(Vector3 v1, Vector3 v2, float amount)
{
    Vector3 result = {0};

    result.x = v1.x + amount * (v2.x - v1.x);
    result.y = v1.y + amount * (v2.y - v1.y);
    result.z = v1.z + amount * (v2.z - v1.z);

    return result;
}

// Calculate reflected vector to normal
RMDEF Vector3 Vector3Reflect(Vector3 v, Vector3 normal)
{
    // I is the original vector
    // N is the normal of the incident plane
    // R = I - (2*N*( DotProduct[ I,N] ))

    Vector3 result = {0};

    float dotProduct = Vector3DotProduct(v, normal);

    result.x = v.x - (2.0f * normal.x) * dotProduct;
    result.y = v.y - (2.0f * normal.y) * dotProduct;
    result.z = v.z - (2.0f * normal.z) * dotProduct;

    return result;
}

// Return min value for each pair of components
RMDEF Vector3 Vector3Min(Vector3 v1, Vector3 v2)
{
    Vector3 result = {0};

    result.x = fminf(v1.x, v2.x);
    result.y = fminf(v1.y, v2.y);
    result.z = fminf(v1.z, v2.z);

    return result;
}

// Return max value for each pair of components
RMDEF Vector3 Vector3Max(Vector3 v1, Vector3 v2)
{
    Vector3 result = {0};

    result.x = fmaxf(v1.x, v2.x);
    result.y = fmaxf(v1.y, v2.y);
    result.z = fmaxf(v1.z, v2.z);

    return result;
}

// Compute barycenter coordinates (u, v, w) for point p with respect to triangle (a, b, c)
// NOTE: Assumes P is on the plane of the triangle
RMDEF Vector3 Vector3Barycenter(Vector3 p, Vector3 a, Vector3 b, Vector3 c)
{
    //Vector v0 = b - a, v1 = c - a, v2 = p - a;

    Vector3 v0 = Vector3Subtract(b, a);
    Vector3 v1 = Vector3Subtract(c, a);
    Vector3 v2 = Vector3Subtract(p, a);
    float d00 = Vector3DotProduct(v0, v0);
    float d01 = Vector3DotProduct(v0, v1);
    float d11 = Vector3DotProduct(v1, v1);
    float d20 = Vector3DotProduct(v2, v0);
    float d21 = Vector3DotProduct(v2, v1);

    float denom = d00 * d11 - d01 * d01;

    Vector3 result = {0};

    result.y = (d11 * d20 - d01 * d21) / denom;
    result.z = (d00 * d21 - d01 * d20) / denom;
    result.x = 1.0f - (result.z + result.y);

    return result;
}

// Returns Vector3 as float array
RMDEF float3 Vector3ToFloatV(Vector3 v)
{
    float3 buffer = {0};

    buffer.v[0] = v.x;
    buffer.v[1] = v.y;
    buffer.v[2] = v.z;

    return buffer;
}

//----------------------------------------------------------------------------------
// Module Functions Definition - Matrix math
//----------------------------------------------------------------------------------

// Compute matrix determinant
RMDEF float MatrixDeterminant(Matrix mat)
{
    // Cache the matrix values (speed optimization)
    float a00 = mat.m0, a01 = mat.m1, a02 = mat.m2, a03 = mat.m3;
    float a10 = mat.m4, a11 = mat.m5, a12 = mat.m6, a13 = mat.m7;
    float a20 = mat.m8, a21 = mat.m9, a22 = mat.m10, a23 = mat.m11;
    float a30 = mat.m12, a31 = mat.m13, a32 = mat.m14, a33 = mat.m15;

    float result = a30 * a21 * a12 * a03 - a20 * a31 * a12 * a03 - a30 * a11 * a22 * a03 + a10 * a31 * a22 * a03 +
                   a20 * a11 * a32 * a03 - a10 * a21 * a32 * a03 - a30 * a21 * a02 * a13 + a20 * a31 * a02 * a13 +
                   a30 * a01 * a22 * a13 - a00 * a31 * a22 * a13 - a20 * a01 * a32 * a13 + a00 * a21 * a32 * a13 +
                   a30 * a11 * a02 * a23 - a10 * a31 * a02 * a23 - a30 * a01 * a12 * a23 + a00 * a31 * a12 * a23 +
                   a10 * a01 * a32 * a23 - a00 * a11 * a32 * a23 - a20 * a11 * a02 * a33 + a10 * a21 * a02 * a33 +
                   a20 * a01 * a12 * a33 - a00 * a21 * a12 * a33 - a10 * a01 * a22 * a33 + a00 * a11 * a22 * a33;

    return result;
}

// Returns the trace of the matrix (sum of the values along the diagonal)
RMDEF float MatrixTrace(Matrix mat)
{
    float result = (mat.m0 + mat.m5 + mat.m10 + mat.m15);
    return result;
}

// Transposes provided matrix
RMDEF Matrix MatrixTranspose(Matrix mat)
{
    Matrix result = {0};

    result.m0 = mat.m0;
    result.m1 = mat.m4;
    result.m2 = mat.m8;
    result.m3 = mat.m12;
    result.m4 = mat.m1;
    result.m5 = mat.m5;
    result.m6 = mat.m9;
    result.m7 = mat.m13;
    result.m8 = mat.m2;
    result.m9 = mat.m6;
    result.m10 = mat.m10;
    result.m11 = mat.m14;
    result.m12 = mat.m3;
    result.m13 = mat.m7;
    result.m14 = mat.m11;
    result.m15 = mat.m15;

    return result;
}

// Invert provided matrix
RMDEF Matrix MatrixInvert(Matrix mat)
{
    Matrix result = {0};

    // Cache the matrix values (speed optimization)
    float a00 = mat.m0, a01 = mat.m1, a02 = mat.m2, a03 = mat.m3;
    float a10 = mat.m4, a11 = mat.m5, a12 = mat.m6, a13 = mat.m7;
    float a20 = mat.m8, a21 = mat.m9, a22 = mat.m10, a23 = mat.m11;
    float a30 = mat.m12, a31 = mat.m13, a32 = mat.m14, a33 = mat.m15;

    float b00 = a00 * a11 - a01 * a10;
    float b01 = a00 * a12 - a02 * a10;
    float b02 = a00 * a13 - a03 * a10;
    float b03 = a01 * a12 - a02 * a11;
    float b04 = a01 * a13 - a03 * a11;
    float b05 = a02 * a13 - a03 * a12;
    float b06 = a20 * a31 - a21 * a30;
    float b07 = a20 * a32 - a22 * a30;
    float b08 = a20 * a33 - a23 * a30;
    float b09 = a21 * a32 - a22 * a31;
    float b10 = a21 * a33 - a23 * a31;
    float b11 = a22 * a33 - a23 * a32;

    // Calculate the invert determinant (inlined to avoid double-caching)
    float invDet = 1.0f / (b00 * b11 - b01 * b10 + b02 * b09 + b03 * b08 - b04 * b07 + b05 * b06);

    result.m0 = (a11 * b11 - a12 * b10 + a13 * b09) * invDet;
    result.m1 = (-a01 * b11 + a02 * b10 - a03 * b09) * invDet;
    result.m2 = (a31 * b05 - a32 * b04 + a33 * b03) * invDet;
    result.m3 = (-a21 * b05 + a22 * b04 - a23 * b03) * invDet;
    result.m4 = (-a10 * b11 + a12 * b08 - a13 * b07) * invDet;
    result.m5 = (a00 * b11 - a02 * b08 + a03 * b07) * invDet;
    result.m6 = (-a30 * b05 + a32 * b02 - a33 * b01) * invDet;
    result.m7 = (a20 * b05 - a22 * b02 + a23 * b01) * invDet;
    result.m8 = (a10 * b10 - a11 * b08 + a13 * b06) * invDet;
    result.m9 = (-a00 * b10 + a01 * b08 - a03 * b06) * invDet;
    result.m10 = (a30 * b04 - a31 * b02 + a33 * b00) * invDet;
    result.m11 = (-a20 * b04 + a21 * b02 - a23 * b00) * invDet;
    result.m12 = (-a10 * b09 + a11 * b07 - a12 * b06) * invDet;
    result.m13 = (a00 * b09 - a01 * b07 + a02 * b06) * invDet;
    result.m14 = (-a30 * b03 + a31 * b01 - a32 * b00) * invDet;
    result.m15 = (a20 * b03 - a21 * b01 + a22 * b00) * invDet;

    return result;
}

// Normalize provided matrix
RMDEF Matrix MatrixNormalize(Matrix mat)
{
    Matrix result = {0};

    float det = MatrixDeterminant(mat);

    result.m0 = mat.m0 / det;
    result.m1 = mat.m1 / det;
    result.m2 = mat.m2 / det;
    result.m3 = mat.m3 / det;
    result.m4 = mat.m4 / det;
    result.m5 = mat.m5 / det;
    result.m6 = mat.m6 / det;
    result.m7 = mat.m7 / det;
    result.m8 = mat.m8 / det;
    result.m9 = mat.m9 / det;
    result.m10 = mat.m10 / det;
    result.m11 = mat.m11 / det;
    result.m12 = mat.m12 / det;
    result.m13 = mat.m13 / det;
    result.m14 = mat.m14 / det;
    result.m15 = mat.m15 / det;

    return result;
}

// Returns identity matrix
RMDEF Matrix MatrixIdentity(void)
{
    Matrix result = {1.0f, 0.0f, 0.0f, 0.0f,
                     0.0f, 1.0f, 0.0f, 0.0f,
                     0.0f, 0.0f, 1.0f, 0.0f,
                     0.0f, 0.0f, 0.0f, 1.0f};

    return result;
}

// Add two matrices
RMDEF Matrix MatrixAdd(Matrix left, Matrix right)
{
    Matrix result = MatrixIdentity();

    result.m0 = left.m0 + right.m0;
    result.m1 = left.m1 + right.m1;
    result.m2 = left.m2 + right.m2;
    result.m3 = left.m3 + right.m3;
    result.m4 = left.m4 + right.m4;
    result.m5 = left.m5 + right.m5;
    result.m6 = left.m6 + right.m6;
    result.m7 = left.m7 + right.m7;
    result.m8 = left.m8 + right.m8;
    result.m9 = left.m9 + right.m9;
    result.m10 = left.m10 + right.m10;
    result.m11 = left.m11 + right.m11;
    result.m12 = left.m12 + right.m12;
    result.m13 = left.m13 + right.m13;
    result.m14 = left.m14 + right.m14;
    result.m15 = left.m15 + right.m15;

    return result;
}

// Subtract two matrices (left - right)
RMDEF Matrix MatrixSubtract(Matrix left, Matrix right)
{
    Matrix result = MatrixIdentity();

    result.m0 = left.m0 - right.m0;
    result.m1 = left.m1 - right.m1;
    result.m2 = left.m2 - right.m2;
    result.m3 = left.m3 - right.m3;
    result.m4 = left.m4 - right.m4;
    result.m5 = left.m5 - right.m5;
    result.m6 = left.m6 - right.m6;
    result.m7 = left.m7 - right.m7;
    result.m8 = left.m8 - right.m8;
    result.m9 = left.m9 - right.m9;
    result.m10 = left.m10 - right.m10;
    result.m11 = left.m11 - right.m11;
    result.m12 = left.m12 - right.m12;
    result.m13 = left.m13 - right.m13;
    result.m14 = left.m14 - right.m14;
    result.m15 = left.m15 - right.m15;

    return result;
}

// Returns translation matrix
RMDEF Matrix MatrixTranslate(float x, float y, float z)
{
    Matrix result = {1.0f, 0.0f, 0.0f, x,
                     0.0f, 1.0f, 0.0f, y,
                     0.0f, 0.0f, 1.0f, z,
                     0.0f, 0.0f, 0.0f, 1.0f};

    return result;
}

// Create rotation matrix from axis and angle
// NOTE: Angle should be provided in radians
RMDEF Matrix MatrixRotate(Vector3 axis, float angle)
{
    Matrix result = {0};

    float x = axis.x, y = axis.y, z = axis.z;

    float length = sqrtf(x * x + y * y + z * z);

    if ((length != 1.0f) && (length != 0.0f))
    {
        length = 1.0f / length;
        x *= length;
        y *= length;
        z *= length;
    }

    float sinres = sinf(angle);
    float cosres = cosf(angle);
    float t = 1.0f - cosres;

    result.m0 = x * x * t + cosres;
    result.m1 = y * x * t + z * sinres;
    result.m2 = z * x * t - y * sinres;
    result.m3 = 0.0f;

    result.m4 = x * y * t - z * sinres;
    result.m5 = y * y * t + cosres;
    result.m6 = z * y * t + x * sinres;
    result.m7 = 0.0f;

    result.m8 = x * z * t + y * sinres;
    result.m9 = y * z * t - x * sinres;
    result.m10 = z * z * t + cosres;
    result.m11 = 0.0f;

    result.m12 = 0.0f;
    result.m13 = 0.0f;
    result.m14 = 0.0f;
    result.m15 = 1.0f;

    return result;
}

// Returns xyz-rotation matrix (angles in radians)
RMDEF Matrix MatrixRotateXYZ(Vector3 ang)
{
    Matrix result = MatrixIdentity();

    float cosz = cosf(-ang.z);
    float sinz = sinf(-ang.z);
    float cosy = cosf(-ang.y);
    float siny = sinf(-ang.y);
    float cosx = cosf(-ang.x);
    float sinx = sinf(-ang.x);

    result.m0 = cosz * cosy;
    result.m4 = (cosz * siny * sinx) - (sinz * cosx);
    result.m8 = (cosz * siny * cosx) + (sinz * sinx);

    result.m1 = sinz * cosy;
    result.m5 = (sinz * siny * sinx) + (cosz * cosx);
    result.m9 = (sinz * siny * cosx) - (cosz * sinx);

    result.m2 = -siny;
    result.m6 = cosy * sinx;
    result.m10 = cosy * cosx;

    return result;
}

// Returns x-rotation matrix (angle in radians)
RMDEF Matrix MatrixRotateX(float angle)
{
    Matrix result = MatrixIdentity();

    float cosres = cosf(angle);
    float sinres = sinf(angle);

    result.m5 = cosres;
    result.m6 = -sinres;
    result.m9 = sinres;
    result.m10 = cosres;

    return result;
}

// Returns y-rotation matrix (angle in radians)
RMDEF Matrix MatrixRotateY(float angle)
{
    Matrix result = MatrixIdentity();

    float cosres = cosf(angle);
    float sinres = sinf(angle);

    result.m0 = cosres;
    result.m2 = sinres;
    result.m8 = -sinres;
    result.m10 = cosres;

    return result;
}

// Returns z-rotation matrix (angle in radians)
RMDEF Matrix MatrixRotateZ(float angle)
{
    Matrix result = MatrixIdentity();

    float cosres = cosf(angle);
    float sinres = sinf(angle);

    result.m0 = cosres;
    result.m1 = -sinres;
    result.m4 = sinres;
    result.m5 = cosres;

    return result;
}

// Returns scaling matrix
RMDEF Matrix MatrixScale(float x, float y, float z)
{
    Matrix result = {x, 0.0f, 0.0f, 0.0f,
                     0.0f, y, 0.0f, 0.0f,
                     0.0f, 0.0f, z, 0.0f,
                     0.0f, 0.0f, 0.0f, 1.0f};

    return result;
}

// Returns two matrix multiplication
// NOTE: When multiplying matrices... the order matters!
RMDEF Matrix MatrixMultiply(Matrix left, Matrix right)
{
    Matrix result = {0};

    result.m0 = left.m0 * right.m0 + left.m1 * right.m4 + left.m2 * right.m8 + left.m3 * right.m12;
    result.m1 = left.m0 * right.m1 + left.m1 * right.m5 + left.m2 * right.m9 + left.m3 * right.m13;
    result.m2 = left.m0 * right.m2 + left.m1 * right.m6 + left.m2 * right.m10 + left.m3 * right.m14;
    result.m3 = left.m0 * right.m3 + left.m1 * right.m7 + left.m2 * right.m11 + left.m3 * right.m15;
    result.m4 = left.m4 * right.m0 + left.m5 * right.m4 + left.m6 * right.m8 + left.m7 * right.m12;
    result.m5 = left.m4 * right.m1 + left.m5 * right.m5 + left.m6 * right.m9 + left.m7 * right.m13;
    result.m6 = left.m4 * right.m2 + left.m5 * right.m6 + left.m6 * right.m10 + left.m7 * right.m14;
    result.m7 = left.m4 * right.m3 + left.m5 * right.m7 + left.m6 * right.m11 + left.m7 * right.m15;
    result.m8 = left.m8 * right.m0 + left.m9 * right.m4 + left.m10 * right.m8 + left.m11 * right.m12;
    result.m9 = left.m8 * right.m1 + left.m9 * right.m5 + left.m10 * right.m9 + left.m11 * right.m13;
    result.m10 = left.m8 * right.m2 + left.m9 * right.m6 + left.m10 * right.m10 + left.m11 * right.m14;
    result.m11 = left.m8 * right.m3 + left.m9 * right.m7 + left.m10 * right.m11 + left.m11 * right.m15;
    result.m12 = left.m12 * right.m0 + left.m13 * right.m4 + left.m14 * right.m8 + left.m15 * right.m12;
    result.m13 = left.m12 * right.m1 + left.m13 * right.m5 + left.m14 * right.m9 + left.m15 * right.m13;
    result.m14 = left.m12 * right.m2 + left.m13 * right.m6 + left.m14 * right.m10 + left.m15 * right.m14;
    result.m15 = left.m12 * right.m3 + left.m13 * right.m7 + left.m14 * right.m11 + left.m15 * right.m15;

    return result;
}

// Returns perspective projection matrix
RMDEF Matrix MatrixFrustum(double left, double right, double bottom, double top, double near, double far)
{
    Matrix result = {0};

    float rl = (float)(right - left);
    float tb = (float)(top - bottom);
    float fn = (float)(far - near);

    result.m0 = ((float)near * 2.0f) / rl;
    result.m1 = 0.0f;
    result.m2 = 0.0f;
    result.m3 = 0.0f;

    result.m4 = 0.0f;
    result.m5 = ((float)near * 2.0f) / tb;
    result.m6 = 0.0f;
    result.m7 = 0.0f;

    result.m8 = ((float)right + (float)left) / rl;
    result.m9 = ((float)top + (float)bottom) / tb;
    result.m10 = -((float)far + (float)near) / fn;
    result.m11 = -1.0f;

    result.m12 = 0.0f;
    result.m13 = 0.0f;
    result.m14 = -((float)far * (float)near * 2.0f) / fn;
    result.m15 = 0.0f;

    return result;
}

// Returns perspective projection matrix
// NOTE: Angle should be provided in radians
RMDEF Matrix MatrixPerspective(double fovy, double aspect, double near, double far)
{
    double top = near * tan(fovy * 0.5);
    double right = top * aspect;
    Matrix result = MatrixFrustum(-right, right, -top, top, near, far);

    return result;
}

// Returns orthographic projection matrix
RMDEF Matrix MatrixOrtho(double left, double right, double bottom, double top, double near, double far)
{
    Matrix result = {0};

    float rl = (float)(right - left);
    float tb = (float)(top - bottom);
    float fn = (float)(far - near);

    result.m0 = 2.0f / rl;
    result.m1 = 0.0f;
    result.m2 = 0.0f;
    result.m3 = 0.0f;
    result.m4 = 0.0f;
    result.m5 = 2.0f / tb;
    result.m6 = 0.0f;
    result.m7 = 0.0f;
    result.m8 = 0.0f;
    result.m9 = 0.0f;
    result.m10 = -2.0f / fn;
    result.m11 = 0.0f;
    result.m12 = -((float)left + (float)right) / rl;
    result.m13 = -((float)top + (float)bottom) / tb;
    result.m14 = -((float)far + (float)near) / fn;
    result.m15 = 1.0f;

    return result;
}

// Returns camera look-at matrix (view matrix)
RMDEF Matrix MatrixLookAt(Vector3 eye, Vector3 target, Vector3 up)
{
    Matrix result = {0};

    Vector3 z = Vector3Subtract(eye, target);
    z = Vector3Normalize(z);
    Vector3 x = Vector3CrossProduct(up, z);
    x = Vector3Normalize(x);
    Vector3 y = Vector3CrossProduct(z, x);
    y = Vector3Normalize(y);

    result.m0 = x.x;
    result.m1 = x.y;
    result.m2 = x.z;
    result.m3 = 0.0f;
    result.m4 = y.x;
    result.m5 = y.y;
    result.m6 = y.z;
    result.m7 = 0.0f;
    result.m8 = z.x;
    result.m9 = z.y;
    result.m10 = z.z;
    result.m11 = 0.0f;
    result.m12 = eye.x;
    result.m13 = eye.y;
    result.m14 = eye.z;
    result.m15 = 1.0f;

    result = MatrixInvert(result);

    return result;
}

// Returns float array of matrix data
RMDEF float16 MatrixToFloatV(Matrix mat)
{
    float16 buffer = {0};

    buffer.v[0] = mat.m0;
    buffer.v[1] = mat.m1;
    buffer.v[2] = mat.m2;
    buffer.v[3] = mat.m3;
    buffer.v[4] = mat.m4;
    buffer.v[5] = mat.m5;
    buffer.v[6] = mat.m6;
    buffer.v[7] = mat.m7;
    buffer.v[8] = mat.m8;
    buffer.v[9] = mat.m9;
    buffer.v[10] = mat.m10;
    buffer.v[11] = mat.m11;
    buffer.v[12] = mat.m12;
    buffer.v[13] = mat.m13;
    buffer.v[14] = mat.m14;
    buffer.v[15] = mat.m15;

    return buffer;
}

//----------------------------------------------------------------------------------
// Module Functions Definition - Quaternion math
//----------------------------------------------------------------------------------

// Returns identity quaternion
RMDEF Quaternion QuaternionIdentity(void)
{
    Quaternion result = {0.0f, 0.0f, 0.0f, 1.0f};
    return result;
}

// Computes the length of a quaternion
RMDEF float QuaternionLength(Quaternion q)
{
    float result = (float)sqrt(q.x * q.x + q.y * q.y + q.z * q.z + q.w * q.w);
    return result;
}

// Normalize provided quaternion
RMDEF Quaternion QuaternionNormalize(Quaternion q)
{
    Quaternion result = {0};

    float length, ilength;
    length = QuaternionLength(q);
    if (length == 0.0f)
        length = 1.0f;
    ilength = 1.0f / length;

    result.x = q.x * ilength;
    result.y = q.y * ilength;
    result.z = q.z * ilength;
    result.w = q.w * ilength;

    return result;
}

// Invert provided quaternion
RMDEF Quaternion QuaternionInvert(Quaternion q)
{
    Quaternion result = q;
    float length = QuaternionLength(q);
    float lengthSq = length * length;

    if (lengthSq != 0.0)
    {
        float i = 1.0f / lengthSq;

        result.x *= -i;
        result.y *= -i;
        result.z *= -i;
        result.w *= i;
    }

    return result;
}

// Calculate two quaternion multiplication
RMDEF Quaternion QuaternionMultiply(Quaternion q1, Quaternion q2)
{
    Quaternion result = {0};

    float qax = q1.x, qay = q1.y, qaz = q1.z, qaw = q1.w;
    float qbx = q2.x, qby = q2.y, qbz = q2.z, qbw = q2.w;

    result.x = qax * qbw + qaw * qbx + qay * qbz - qaz * qby;
    result.y = qay * qbw + qaw * qby + qaz * qbx - qax * qbz;
    result.z = qaz * qbw + qaw * qbz + qax * qby - qay * qbx;
    result.w = qaw * qbw - qax * qbx - qay * qby - qaz * qbz;

    return result;
}

// Calculate linear interpolation between two quaternions
RMDEF Quaternion QuaternionLerp(Quaternion q1, Quaternion q2, float amount)
{
    Quaternion result = {0};

    result.x = q1.x + amount * (q2.x - q1.x);
    result.y = q1.y + amount * (q2.y - q1.y);
    result.z = q1.z + amount * (q2.z - q1.z);
    result.w = q1.w + amount * (q2.w - q1.w);

    return result;
}

// Calculate slerp-optimized interpolation between two quaternions
RMDEF Quaternion QuaternionNlerp(Quaternion q1, Quaternion q2, float amount)
{
    Quaternion result = QuaternionLerp(q1, q2, amount);
    result = QuaternionNormalize(result);

    return result;
}

// Calculates spherical linear interpolation between two quaternions
RMDEF Quaternion QuaternionSlerp(Quaternion q1, Quaternion q2, float amount)
{
    Quaternion result = {0};

    float cosHalfTheta = q1.x * q2.x + q1.y * q2.y + q1.z * q2.z + q1.w * q2.w;

    if (fabs(cosHalfTheta) >= 1.0f)
        result = q1;
    else if (cosHalfTheta > 0.95f)
        result = QuaternionNlerp(q1, q2, amount);
    else
    {
        float halfTheta = acosf(cosHalfTheta);
        float sinHalfTheta = sqrtf(1.0f - cosHalfTheta * cosHalfTheta);

        if (fabs(sinHalfTheta) < 0.001f)
        {
            result.x = (q1.x * 0.5f + q2.x * 0.5f);
            result.y = (q1.y * 0.5f + q2.y * 0.5f);
            result.z = (q1.z * 0.5f + q2.z * 0.5f);
            result.w = (q1.w * 0.5f + q2.w * 0.5f);
        }
        else
        {
            float ratioA = sinf((1 - amount) * halfTheta) / sinHalfTheta;
            float ratioB = sinf(amount * halfTheta) / sinHalfTheta;

            result.x = (q1.x * ratioA + q2.x * ratioB);
            result.y = (q1.y * ratioA + q2.y * ratioB);
            result.z = (q1.z * ratioA + q2.z * ratioB);
            result.w = (q1.w * ratioA + q2.w * ratioB);
        }
    }

    return result;
}

// Calculate quaternion based on the rotation from one vector to another
RMDEF Quaternion QuaternionFromVector3ToVector3(Vector3 from, Vector3 to)
{
    Quaternion result = {0};

    float cos2Theta = Vector3DotProduct(from, to);
    Vector3 cross = Vector3CrossProduct(from, to);

    result.x = cross.x;
    result.y = cross.y;
    result.z = cross.y;
    result.w = 1.0f + cos2Theta; // NOTE: Added QuaternioIdentity()

    // Normalize to essentially nlerp the original and identity to 0.5
    result = QuaternionNormalize(result);

    // Above lines are equivalent to:
    //Quaternion result = QuaternionNlerp(q, QuaternionIdentity(), 0.5f);

    return result;
}

// Returns a quaternion for a given rotation matrix
RMDEF Quaternion QuaternionFromMatrix(Matrix mat)
{
    Quaternion result = {0};

    float trace = MatrixTrace(mat);

    if (trace > 0.0f)
    {
        float s = sqrtf(trace + 1) * 2.0f;
        float invS = 1.0f / s;

        result.w = s * 0.25f;
        result.x = (mat.m6 - mat.m9) * invS;
        result.y = (mat.m8 - mat.m2) * invS;
        result.z = (mat.m1 - mat.m4) * invS;
    }
    else
    {
        float m00 = mat.m0, m11 = mat.m5, m22 = mat.m10;

        if (m00 > m11 && m00 > m22)
        {
            float s = (float)sqrt(1.0f + m00 - m11 - m22) * 2.0f;
            float invS = 1.0f / s;

            result.w = (mat.m6 - mat.m9) * invS;
            result.x = s * 0.25f;
            result.y = (mat.m4 + mat.m1) * invS;
            result.z = (mat.m8 + mat.m2) * invS;
        }
        else if (m11 > m22)
        {
            float s = sqrtf(1.0f + m11 - m00 - m22) * 2.0f;
            float invS = 1.0f / s;

            result.w = (mat.m8 - mat.m2) * invS;
            result.x = (mat.m4 + mat.m1) * invS;
            result.y = s * 0.25f;
            result.z = (mat.m9 + mat.m6) * invS;
        }
        else
        {
            float s = sqrtf(1.0f + m22 - m00 - m11) * 2.0f;
            float invS = 1.0f / s;

            result.w = (mat.m1 - mat.m4) * invS;
            result.x = (mat.m8 + mat.m2) * invS;
            result.y = (mat.m9 + mat.m6) * invS;
            result.z = s * 0.25f;
        }
    }

    return result;
}

// Returns a matrix for a given quaternion
RMDEF Matrix QuaternionToMatrix(Quaternion q)
{
    Matrix result = {0};

    float x = q.x, y = q.y, z = q.z, w = q.w;

    float x2 = x + x;
    float y2 = y + y;
    float z2 = z + z;

    float length = QuaternionLength(q);
    float lengthSquared = length * length;

    float xx = x * x2 / lengthSquared;
    float xy = x * y2 / lengthSquared;
    float xz = x * z2 / lengthSquared;

    float yy = y * y2 / lengthSquared;
    float yz = y * z2 / lengthSquared;
    float zz = z * z2 / lengthSquared;

    float wx = w * x2 / lengthSquared;
    float wy = w * y2 / lengthSquared;
    float wz = w * z2 / lengthSquared;

    result.m0 = 1.0f - (yy + zz);
    result.m1 = xy - wz;
    result.m2 = xz + wy;
    result.m3 = 0.0f;
    result.m4 = xy + wz;
    result.m5 = 1.0f - (xx + zz);
    result.m6 = yz - wx;
    result.m7 = 0.0f;
    result.m8 = xz - wy;
    result.m9 = yz + wx;
    result.m10 = 1.0f - (xx + yy);
    result.m11 = 0.0f;
    result.m12 = 0.0f;
    result.m13 = 0.0f;
    result.m14 = 0.0f;
    result.m15 = 1.0f;

    return result;
}

// Returns rotation quaternion for an angle and axis
// NOTE: angle must be provided in radians
RMDEF Quaternion QuaternionFromAxisAngle(Vector3 axis, float angle)
{
    Quaternion result = {0.0f, 0.0f, 0.0f, 1.0f};

    if (Vector3Length(axis) != 0.0f)

        angle *= 0.5f;

    axis = Vector3Normalize(axis);

    float sinres = sinf(angle);
    float cosres = cosf(angle);

    result.x = axis.x * sinres;
    result.y = axis.y * sinres;
    result.z = axis.z * sinres;
    result.w = cosres;

    result = QuaternionNormalize(result);

    return result;
}

// Returns the rotation angle and axis for a given quaternion
RMDEF void QuaternionToAxisAngle(Quaternion q, Vector3 *outAxis, float *outAngle)
{
    if (fabs(q.w) > 1.0f)
        q = QuaternionNormalize(q);

    Vector3 resAxis = {0.0f, 0.0f, 0.0f};
    float resAngle = 2.0f * acosf(q.w);
    float den = sqrtf(1.0f - q.w * q.w);

    if (den > 0.0001f)
    {
        resAxis.x = q.x / den;
        resAxis.y = q.y / den;
        resAxis.z = q.z / den;
    }
    else
    {
        // This occurs when the angle is zero.
        // Not a problem: just set an arbitrary normalized axis.
        resAxis.x = 1.0f;
    }

    *outAxis = resAxis;
    *outAngle = resAngle;
}

// Returns he quaternion equivalent to Euler angles
RMDEF Quaternion QuaternionFromEuler(float roll, float pitch, float yaw)
{
    Quaternion q = {0};

    float x0 = cosf(roll * 0.5f);
    float x1 = sinf(roll * 0.5f);
    float y0 = cosf(pitch * 0.5f);
    float y1 = sinf(pitch * 0.5f);
    float z0 = cosf(yaw * 0.5f);
    float z1 = sinf(yaw * 0.5f);

    q.x = x1 * y0 * z0 - x0 * y1 * z1;
    q.y = x0 * y1 * z0 + x1 * y0 * z1;
    q.z = x0 * y0 * z1 - x1 * y1 * z0;
    q.w = x0 * y0 * z0 + x1 * y1 * z1;

    return q;
}

// Return the Euler angles equivalent to quaternion (roll, pitch, yaw)
// NOTE: Angles are returned in a Vector3 struct in degrees
RMDEF Vector3 QuaternionToEuler(Quaternion q)
{
    Vector3 result = {0};

    // roll (x-axis rotation)
    float x0 = 2.0f * (q.w * q.x + q.y * q.z);
    float x1 = 1.0f - 2.0f * (q.x * q.x + q.y * q.y);
    result.x = atan2f(x0, x1) * RAD2DEG;

    // pitch (y-axis rotation)
    float y0 = 2.0f * (q.w * q.y - q.z * q.x);
    y0 = y0 > 1.0f ? 1.0f : y0;
    y0 = y0 < -1.0f ? -1.0f : y0;
    result.y = asinf(y0) * RAD2DEG;

    // yaw (z-axis rotation)
    float z0 = 2.0f * (q.w * q.z + q.x * q.y);
    float z1 = 1.0f - 2.0f * (q.y * q.y + q.z * q.z);
    result.z = atan2f(z0, z1) * RAD2DEG;

    return result;
}

// Transform a quaternion given a transformation matrix
RMDEF Quaternion QuaternionTransform(Quaternion q, Matrix mat)
{
    Quaternion result = {0};

    result.x = mat.m0 * q.x + mat.m4 * q.y + mat.m8 * q.z + mat.m12 * q.w;
    result.y = mat.m1 * q.x + mat.m5 * q.y + mat.m9 * q.z + mat.m13 * q.w;
    result.z = mat.m2 * q.x + mat.m6 * q.y + mat.m10 * q.z + mat.m14 * q.w;
    result.w = mat.m3 * q.x + mat.m7 * q.y + mat.m11 * q.z + mat.m15 * q.w;

    return result;
}

#endif // RAYMATH_H