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| -rw-r--r-- | gfx/thebes/gfxQuaternion.h | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/gfx/thebes/gfxQuaternion.h b/gfx/thebes/gfxQuaternion.h new file mode 100644 index 0000000000..4180f7a7b4 --- /dev/null +++ b/gfx/thebes/gfxQuaternion.h @@ -0,0 +1,117 @@ +/* -*- 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; + } + + // Convert from |direction axis, angle| pair to gfxQuaternion. + // + // Reference: + // https://en.wikipedia.org/wiki/Quaternions_and_spatial_rotation + // + // if the direction axis is (x, y, z) = xi + yj + zk, + // and the angle is |theta|, this formula can be done using + // an extension of Euler's formula: + // q = cos(theta/2) + (xi + yj + zk)(sin(theta/2)) + // = cos(theta/2) + + // x*sin(theta/2)i + y*sin(theta/2)j + z*sin(theta/2)k + // Note: aDirection should be an unit vector and + // the unit of aAngle should be Radian. + gfxQuaternion(const mozilla::gfx::Point3D& aDirection, gfxFloat aAngle) { + MOZ_ASSERT(mozilla::gfx::FuzzyEqual(aDirection.Length(), 1.0f), + "aDirection should be an unit vector"); + x = aDirection.x * sin(aAngle / 2.0); + y = aDirection.y * sin(aAngle / 2.0); + z = aDirection.z * sin(aAngle / 2.0); + w = cos(aAngle / 2.0); + } + + 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 */ |