1 files changed, 95 insertions, 0 deletions
diff --git a/gfx/thebes/gfxQuaternion.h b/gfx/thebes/gfxQuaternion.h
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+++ b/gfx/thebes/gfxQuaternion.h
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GFX_QUATERNION_H
+#define GFX_QUATERNION_H
+
+#include "mozilla/gfx/BasePoint4D.h"
+#include "mozilla/gfx/Matrix.h"
+#include "nsAlgorithm.h"
+#include <algorithm>
+
+struct gfxQuaternion
+    : public mozilla::gfx::BasePoint4D<gfxFloat, gfxQuaternion> {
+  typedef mozilla::gfx::BasePoint4D<gfxFloat, gfxQuaternion> Super;
+
+  gfxQuaternion() : Super() {}
+  gfxQuaternion(gfxFloat aX, gfxFloat aY, gfxFloat aZ, gfxFloat aW)
+      : Super(aX, aY, aZ, aW) {}
+
+  explicit gfxQuaternion(const mozilla::gfx::Matrix4x4& aMatrix) {
+    w = 0.5 *
+        sqrt(std::max(1 + aMatrix[0][0] + aMatrix[1][1] + aMatrix[2][2], 0.0f));
+    x = 0.5 *
+        sqrt(std::max(1 + aMatrix[0][0] - aMatrix[1][1] - aMatrix[2][2], 0.0f));
+    y = 0.5 *
+        sqrt(std::max(1 - aMatrix[0][0] + aMatrix[1][1] - aMatrix[2][2], 0.0f));
+    z = 0.5 *
+        sqrt(std::max(1 - aMatrix[0][0] - aMatrix[1][1] + aMatrix[2][2], 0.0f));
+
+    if (aMatrix[2][1] > aMatrix[1][2]) x = -x;
+    if (aMatrix[0][2] > aMatrix[2][0]) y = -y;
+    if (aMatrix[1][0] > aMatrix[0][1]) z = -z;
+  }
+
+  gfxQuaternion Slerp(const gfxQuaternion& aOther, gfxFloat aCoeff) const {
+    gfxFloat dot = mozilla::clamped(DotProduct(aOther), -1.0, 1.0);
+    if (dot == 1.0) {
+      return *this;
+    }
+
+    gfxFloat theta = acos(dot);
+    gfxFloat rsintheta = 1 / sqrt(1 - dot * dot);
+    gfxFloat rightWeight = sin(aCoeff * theta) * rsintheta;
+
+    gfxQuaternion left = *this;
+    gfxQuaternion right = aOther;
+
+    left *= cos(aCoeff * theta) - dot * rightWeight;
+    right *= rightWeight;
+
+    return left + right;
+  }
+
+  using Super::operator*=;
+
+  // Quaternion multiplication
+  // Reference:
+  // https://en.wikipedia.org/wiki/Quaternion#Ordered_list_form
+  //
+  // (w1, x1, y1, z1)(w2, x2, y2, z2) = (w1w2 - x1x2 - y1y2 - z1z2,
+  //                                     w1x2 + x1w2 + y1z2 - z1y2,
+  //                                     w1y2 - x1z2 + y1w2 + z1x2,
+  //                                     w1z2 + x1y2 - y1x2 + z1w2)
+  gfxQuaternion operator*(const gfxQuaternion& aOther) const {
+    return gfxQuaternion(
+        w * aOther.x + x * aOther.w + y * aOther.z - z * aOther.y,
+        w * aOther.y - x * aOther.z + y * aOther.w + z * aOther.x,
+        w * aOther.z + x * aOther.y - y * aOther.x + z * aOther.w,
+        w * aOther.w - x * aOther.x - y * aOther.y - z * aOther.z);
+  }
+  gfxQuaternion& operator*=(const gfxQuaternion& aOther) {
+    *this = *this * aOther;
+    return *this;
+  }
+
+  mozilla::gfx::Matrix4x4 ToMatrix() const {
+    mozilla::gfx::Matrix4x4 temp;
+
+    temp[0][0] = 1 - 2 * (y * y + z * z);
+    temp[0][1] = 2 * (x * y + w * z);
+    temp[0][2] = 2 * (x * z - w * y);
+    temp[1][0] = 2 * (x * y - w * z);
+    temp[1][1] = 1 - 2 * (x * x + z * z);
+    temp[1][2] = 2 * (y * z + w * x);
+    temp[2][0] = 2 * (x * z + w * y);
+    temp[2][1] = 2 * (y * z - w * x);
+    temp[2][2] = 1 - 2 * (x * x + y * y);
+
+    return temp;
+  }
+};
+
+#endif /* GFX_QUATERNION_H */