gfx/thebes/gfxQuaternion.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef GFX_QUATERNION_H
   7 #define GFX_QUATERNION_H
   8
   9 #include "mozilla/gfx/BasePoint4D.h"
  10 #include "mozilla/gfx/Matrix.h"
  11 #include "nsAlgorithm.h"
  12 #include <algorithm>
  13
  14 struct gfxQuaternion : public mozilla::gfx::BasePoint4D<gfxFloat, gfxQuaternion> {
  15     typedef mozilla::gfx::BasePoint4D<gfxFloat, gfxQuaternion> Super;
  16
  17     gfxQuaternion() : Super() {}
  18     gfxQuaternion(gfxFloat aX, gfxFloat aY, gfxFloat aZ, gfxFloat aW) : Super(aX, aY, aZ, aW) {}
  19
  20     explicit gfxQuaternion(const mozilla::gfx::Matrix4x4& aMatrix) {
  21         w = 0.5 * sqrt(std::max(1 + aMatrix[0][0] + aMatrix[1][1] + aMatrix[2][2], 0.0f));
  22         x = 0.5 * sqrt(std::max(1 + aMatrix[0][0] - aMatrix[1][1] - aMatrix[2][2], 0.0f));
  23         y = 0.5 * sqrt(std::max(1 - aMatrix[0][0] + aMatrix[1][1] - aMatrix[2][2], 0.0f));
  24         z = 0.5 * sqrt(std::max(1 - aMatrix[0][0] - aMatrix[1][1] + aMatrix[2][2], 0.0f));
  25
  26         if(aMatrix[2][1] > aMatrix[1][2])
  27             x = -x;
  28         if(aMatrix[0][2] > aMatrix[2][0])
  29             y = -y;
  30         if(aMatrix[1][0] > aMatrix[0][1])
  31             z = -z;
  32     }
  33
  34     gfxQuaternion Slerp(const gfxQuaternion &aOther, gfxFloat aCoeff) {
  35         gfxFloat dot = mozilla::clamped(DotProduct(aOther), -1.0, 1.0);
  36         if (dot == 1.0) {
  37             return *this;
  38         }
  39
  40         gfxFloat theta = acos(dot);
  41         gfxFloat rsintheta = 1/sqrt(1 - dot*dot);
  42         gfxFloat rightWeight = sin(aCoeff*theta)*rsintheta;
  43
  44         gfxQuaternion left = *this;
  45         gfxQuaternion right = aOther;
  46
  47         left *= cos(aCoeff*theta) - dot*rightWeight;
  48         right *= rightWeight;
  49
  50         return left + right;
  51     }
  52
  53     mozilla::gfx::Matrix4x4 ToMatrix() {
  54       mozilla::gfx::Matrix4x4 temp;
  55
  56         temp[0][0] = 1 - 2 * (y * y + z * z);
  57         temp[0][1] = 2 * (x * y + w * z);
  58         temp[0][2] = 2 * (x * z - w * y);
  59         temp[1][0] = 2 * (x * y - w * z);
  60         temp[1][1] = 1 - 2 * (x * x + z * z);
  61         temp[1][2] = 2 * (y * z + w * x);
  62         temp[2][0] = 2 * (x * z + w * y);
  63         temp[2][1] = 2 * (y * z - w * x);
  64         temp[2][2] = 1 - 2 * (x * x + y * y);
  65
  66         return temp;
  67     }
  68
  69 };
  70
  71 #endif /* GFX_QUATERNION_H */