text: /**********************************************************************************************
  *
  *   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) 2015-2021 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;
  
      // Vector4 type
      typedef struct Vector4 {
          float x;
          float y;
          float z;
          float w;
      } Vector4;
  
      // Quaternion type
      typedef Vector4 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);
  }
  
  // Normalize input value within input range
  RMDEF float Normalize(float value, float start, float end)
  {
      return (value - start) / (end - start);
  }
  
  // Remap input value within input range to output range
  RMDEF float Remap(float value, float inputStart, float inputEnd, float outputStart, float outputEnd)
  {
      return (value - inputStart) / (inputEnd - inputStart) * (outputEnd - outputStart) + outputStart;
  }
  
  //----------------------------------------------------------------------------------
  // 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;
  }
  
  // Add vector and float value
  RMDEF Vector2 Vector2AddValue(Vector2 v, float add)
  {
      Vector2 result = { v.x + add, v.y + add };
      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;
  }
  
  // Subtract vector by float value
  RMDEF Vector2 Vector2SubtractValue(Vector2 v, float sub)
  {
      Vector2 result = { v.x - sub, v.y - sub };
      return result;
  }
  
  // Calculate vector length
  RMDEF float Vector2Length(Vector2 v)
  {
      float result = sqrtf((v.x*v.x) + (v.y*v.y));
      return result;
  }
  
  // Calculate vector square length
  RMDEF float Vector2LengthSqr(Vector2 v)
  {
      float result = (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 Vector2Multiply(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 vector
  RMDEF Vector2 Vector2Divide(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 = Vector2Scale(v, 1/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;
  }
  
  // Calculate reflected vector to normal
  RMDEF Vector2 Vector2Reflect(Vector2 v, Vector2 normal)
  {
      Vector2 result = { 0 };
  
      float dotProduct = Vector2DotProduct(v, normal);
  
      result.x = v.x - (2.0f*normal.x)*dotProduct;
      result.y = v.y - (2.0f*normal.y)*dotProduct;
  
      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;
  }
  
  // Move Vector towards target
  RMDEF Vector2 Vector2MoveTowards(Vector2 v, Vector2 target, float maxDistance)
  {
      Vector2 result = { 0 };
      float dx = target.x - v.x;
      float dy = target.y - v.y;
      float value = (dx*dx) + (dy*dy);
  
      if ((value == 0) || ((maxDistance >= 0) && (value <= maxDistance*maxDistance))) result = target;
  
      float dist = sqrtf(value);
  
      result.x = v.x + dx/dist*maxDistance;
      result.y = v.y + dy/dist*maxDistance;
  
      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;
  }
  
  // Add vector and float value
  RMDEF Vector3 Vector3AddValue(Vector3 v, float add)
  {
      Vector3 result = { v.x + add, v.y + add, v.z + add };
      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;
  }
  
  // Subtract vector by float value
  RMDEF Vector3 Vector3SubtractValue(Vector3 v, float sub)
  {
      Vector3 result = { v.x - sub, v.y - sub, v.z - sub };
      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 vector square length
  RMDEF float Vector3LengthSqr(const Vector3 v)
  {
      float result = 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 vector
  RMDEF Vector3 Vector3Divide(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 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 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 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 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 zyx-rotation matrix (angles in radians)
  // TODO: This solution is suboptimal, it should be possible to create this matrix in one go
  // instead of using a 3 matrix multiplication
  RMDEF Matrix MatrixRotateZYX(Vector3 ang)
  {
      Matrix result = MatrixRotateZ(ang.z);
      result = MatrixMultiply(result, MatrixRotateY(ang.y));
      result = MatrixMultiply(result, MatrixRotateX(ang.x));
  
      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 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);
  
      result.m0 = x.x;
      result.m1 = y.x;
      result.m2 = z.x;
      result.m3 = 0.0f;
      result.m4 = x.y;
      result.m5 = y.y;
      result.m6 = z.y;
      result.m7 = 0.0f;
      result.m8 = x.z;
      result.m9 = y.z;
      result.m10 = z.z;
      result.m11 = 0.0f;
      result.m12 = -Vector3DotProduct(x, eye);
      result.m13 = -Vector3DotProduct(y, eye);
      result.m14 = -Vector3DotProduct(z, eye);
      result.m15 = 1.0f;
  
      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
  //----------------------------------------------------------------------------------
  
  // Add two quaternions
  RMDEF Quaternion QuaternionAdd(Quaternion q1, Quaternion q2)
  {
      Quaternion result = {q1.x + q2.x, q1.y + q2.y, q1.z + q2.z, q1.w + q2.w};
      return result;
  }
  
  // Add quaternion and float value
  RMDEF Quaternion QuaternionAddValue(Quaternion q, float add)
  {
      Quaternion result = {q.x + add, q.y + add, q.z + add, q.w + add};
      return result;
  }
  
  // Subtract two quaternions
  RMDEF Quaternion QuaternionSubtract(Quaternion q1, Quaternion q2)
  {
      Quaternion result = {q1.x - q2.x, q1.y - q2.y, q1.z - q2.z, q1.w - q2.w};
      return result;
  }
  
  // Subtract quaternion and float value
  RMDEF Quaternion QuaternionSubtractValue(Quaternion q, float sub)
  {
      Quaternion result = {q.x - sub, q.y - sub, q.z - sub, q.w - sub};
      return result;
  }
  
  // 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;
  }
  
  // Scale quaternion by float value
  RMDEF Quaternion QuaternionScale(Quaternion q, float mul)
  {
      Quaternion result = { 0 };
  
      float qax = q.x, qay = q.y, qaz = q.z, qaw = q.w;
  
      result.x = qax * mul + qaw * mul + qay * mul - qaz * mul;
      result.y = qay * mul + qaw * mul + qaz * mul - qax * mul;
      result.z = qaz * mul + qaw * mul + qax * mul - qay * mul;
      result.w = qaw * mul - qax * mul - qay * mul - qaz * mul;
  
      return result;
  }
  
  // Divide two quaternions
  RMDEF Quaternion QuaternionDivide(Quaternion q1, Quaternion q2)
  {
      Quaternion result = {q1.x / q2.x, q1.y / q2.y, q1.z / q2.z, q1.w / q2.w};
      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.z;
      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 };
  
      if ((mat.m0 > mat.m5) && (mat.m0 > mat.m10))
      {
          float s = sqrtf(1.0f + mat.m0 - mat.m5 - mat.m10)*2;
  
          result.x = 0.25f*s;
          result.y = (mat.m4 + mat.m1)/s;
          result.z = (mat.m2 + mat.m8)/s;
          result.w = (mat.m9 - mat.m6)/s;
      }
      else if (mat.m5 > mat.m10)
      {
          float s = sqrtf(1.0f + mat.m5 - mat.m0 - mat.m10)*2;
          result.x = (mat.m4 + mat.m1)/s;
          result.y = 0.25f*s;
          result.z = (mat.m9 + mat.m6)/s;
          result.w = (mat.m2 - mat.m8)/s;
      }
      else
      {
          float s  = sqrtf(1.0f + mat.m10 - mat.m0 - mat.m5)*2;
          result.x = (mat.m2 + mat.m8)/s;
          result.y = (mat.m9 + mat.m6)/s;
          result.z = 0.25f*s;
          result.w = (mat.m4 - mat.m1)/s;
      }
  
      return result;
  }
  
  // Returns a matrix for a given quaternion
  RMDEF Matrix QuaternionToMatrix(Quaternion q)
  {
      Matrix result = MatrixIdentity();
  
      float a2 = 2*(q.x*q.x), b2=2*(q.y*q.y), c2=2*(q.z*q.z); //, d2=2*(q.w*q.w);
  
      float ab = 2*(q.x*q.y), ac=2*(q.x*q.z), bc=2*(q.y*q.z);
      float ad = 2*(q.x*q.w), bd=2*(q.y*q.w), cd=2*(q.z*q.w);
  
      result.m0 = 1 - b2 - c2;
      result.m1 = ab - cd;
      result.m2 = ac + bd;
  
      result.m4 = ab + cd;
      result.m5 = 1 - a2 - c2;
      result.m6 = bc - ad;
  
      result.m8 = ac - bd;
      result.m9 = bc + ad;
      result.m10 = 1 - a2 - b2;
  
      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;
  }
  
  // Projects a Vector3 from screen space into object space
  RMDEF Vector3 Vector3Unproject(Vector3 source, Matrix projection, Matrix view)
  {
      Vector3 result = { 0.0f, 0.0f, 0.0f };
  
      // Calculate unproject matrix (multiply view patrix by projection matrix) and invert it
      Matrix matViewProj = MatrixMultiply(view, projection);
      matViewProj = MatrixInvert(matViewProj);
  
      // Create quaternion from source point
      Quaternion quat = { source.x, source.y, source.z, 1.0f };
  
      // Multiply quat point by unproject matrix
      quat = QuaternionTransform(quat, matViewProj);
  
      // Normalized world points in vectors
      result.x = quat.x/quat.w;
      result.y = quat.y/quat.w;
      result.z = quat.z/quat.w;
  
      return result;
  }
  
  #endif  // RAYMATH_H
  