Make gui/math3d classes use float rather than qreal

This corrects the mismatch between using floats for internal storage
and qreal in the API of QVector*D which leads to lots of implicit
casts between double and float.

This change also stops users from being surprised by the loss of
precision when using these classes on desktop platforms and removes
the need for the private constructors taking a dummy int as the final
argument.

The QMatrix4x4 and QQuaternion classes have been changed to use float
for their internal storage since these are meant to be used in
conjunction with the QVector*D classes. This is to prevent unexpected
loss of precision and to improve performance.

The on-disk format has also been changed from double to float thereby
reducing the storage required when streaming vectors and matrices. This
is potentially a large saving when working with complex 3D meshes etc.

This also has a significant performance improvement when passing
matrices to QOpenGLShaderProgram (and QGLShaderProgram) as we no
longer have to iterate and convert the data to floats. This is
an operation that could easily be needed many times per frame.

This change also opens the door for further optimisations of these
classes to be implemented by using SIMD intrinsics.

This needs to be applied in conjunction with

https://codereview.qt-project.org/#change,33548

Task-number: QTBUG-21035
Task-number: QTBUG-20661
Change-Id: I9321b06040ffb93ae1cbd72fd2013267ac901b2e
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>

1 files changed, 48 insertions, 48 deletions

diff --git a/src/gui/math3d/qquaternion.h b/src/gui/math3d/qquaternion.h
index 0a1552f045..2188a08fc9 100644
--- a/src/gui/math3d/qquaternion.h
+++ b/src/gui/math3d/qquaternion.h
@@ -59,9 +59,9 @@ class Q_GUI_EXPORT QQuaternion
 {
 public:
     QQuaternion();
-    QQuaternion(qreal scalar, qreal xpos, qreal ypos, qreal zpos);
+    QQuaternion(float scalar, float xpos, float ypos, float zpos);
 #ifndef QT_NO_VECTOR3D
-    QQuaternion(qreal scalar, const QVector3D& vector);
+    QQuaternion(float scalar, const QVector3D& vector);
 #endif
 #ifndef QT_NO_VECTOR4D
     explicit QQuaternion(const QVector4D& vector);
@@ -74,20 +74,20 @@ public:
     QVector3D vector() const;
     void setVector(const QVector3D& vector);
 #endif
-    void setVector(qreal x, qreal y, qreal z);
+    void setVector(float x, float y, float z);
 
-    qreal x() const;
-    qreal y() const;
-    qreal z() const;
-    qreal scalar() const;
+    float x() const;
+    float y() const;
+    float z() const;
+    float scalar() const;
 
-    void setX(qreal x);
-    void setY(qreal y);
-    void setZ(qreal z);
-    void setScalar(qreal scalar);
+    void setX(float x);
+    void setY(float y);
+    void setZ(float z);
+    void setScalar(float scalar);
 
-    qreal length() const;
-    qreal lengthSquared() const;
+    float length() const;
+    float lengthSquared() const;
 
     QQuaternion normalized() const;
     void normalize();
@@ -98,19 +98,19 @@ public:
 
     QQuaternion &operator+=(const QQuaternion &quaternion);
     QQuaternion &operator-=(const QQuaternion &quaternion);
-    QQuaternion &operator*=(qreal factor);
+    QQuaternion &operator*=(float factor);
     QQuaternion &operator*=(const QQuaternion &quaternion);
-    QQuaternion &operator/=(qreal divisor);
+    QQuaternion &operator/=(float divisor);
 
     friend inline bool operator==(const QQuaternion &q1, const QQuaternion &q2);
     friend inline bool operator!=(const QQuaternion &q1, const QQuaternion &q2);
     friend inline const QQuaternion operator+(const QQuaternion &q1, const QQuaternion &q2);
     friend inline const QQuaternion operator-(const QQuaternion &q1, const QQuaternion &q2);
-    friend inline const QQuaternion operator*(qreal factor, const QQuaternion &quaternion);
-    friend inline const QQuaternion operator*(const QQuaternion &quaternion, qreal factor);
+    friend inline const QQuaternion operator*(float factor, const QQuaternion &quaternion);
+    friend inline const QQuaternion operator*(const QQuaternion &quaternion, float factor);
     friend inline const QQuaternion operator*(const QQuaternion &q1, const QQuaternion& q2);
     friend inline const QQuaternion operator-(const QQuaternion &quaternion);
-    friend inline const QQuaternion operator/(const QQuaternion &quaternion, qreal divisor);
+    friend inline const QQuaternion operator/(const QQuaternion &quaternion, float divisor);
 
     friend inline bool qFuzzyCompare(const QQuaternion& q1, const QQuaternion& q2);
 
@@ -121,25 +121,25 @@ public:
     operator QVariant() const;
 
 #ifndef QT_NO_VECTOR3D
-    static QQuaternion fromAxisAndAngle(const QVector3D& axis, qreal angle);
+    static QQuaternion fromAxisAndAngle(const QVector3D& axis, float angle);
 #endif
     static QQuaternion fromAxisAndAngle
-            (qreal x, qreal y, qreal z, qreal angle);
+            (float x, float y, float z, float angle);
 
     static QQuaternion slerp
-        (const QQuaternion& q1, const QQuaternion& q2, qreal t);
+        (const QQuaternion& q1, const QQuaternion& q2, float t);
     static QQuaternion nlerp
-        (const QQuaternion& q1, const QQuaternion& q2, qreal t);
+        (const QQuaternion& q1, const QQuaternion& q2, float t);
 
 private:
-    qreal wp, xp, yp, zp;
+    float wp, xp, yp, zp;
 };
 
 Q_DECLARE_TYPEINFO(QQuaternion, Q_MOVABLE_TYPE);
 
 inline QQuaternion::QQuaternion() : wp(1.0f), xp(0.0f), yp(0.0f), zp(0.0f) {}
 
-inline QQuaternion::QQuaternion(qreal aScalar, qreal xpos, qreal ypos, qreal zpos) : wp(aScalar), xp(xpos), yp(ypos), zp(zpos) {}
+inline QQuaternion::QQuaternion(float aScalar, float xpos, float ypos, float zpos) : wp(aScalar), xp(xpos), yp(ypos), zp(zpos) {}
 
 
 inline bool QQuaternion::isNull() const
@@ -152,15 +152,15 @@ inline bool QQuaternion::isIdentity() const
     return qIsNull(xp) && qIsNull(yp) && qIsNull(zp) && wp == 1.0f;
 }
 
-inline qreal QQuaternion::x() const { return qreal(xp); }
-inline qreal QQuaternion::y() const { return qreal(yp); }
-inline qreal QQuaternion::z() const { return qreal(zp); }
-inline qreal QQuaternion::scalar() const { return qreal(wp); }
+inline float QQuaternion::x() const { return xp; }
+inline float QQuaternion::y() const { return yp; }
+inline float QQuaternion::z() const { return zp; }
+inline float QQuaternion::scalar() const { return wp; }
 
-inline void QQuaternion::setX(qreal aX) { xp = aX; }
-inline void QQuaternion::setY(qreal aY) { yp = aY; }
-inline void QQuaternion::setZ(qreal aZ) { zp = aZ; }
-inline void QQuaternion::setScalar(qreal aScalar) { wp = aScalar; }
+inline void QQuaternion::setX(float aX) { xp = aX; }
+inline void QQuaternion::setY(float aY) { yp = aY; }
+inline void QQuaternion::setZ(float aZ) { zp = aZ; }
+inline void QQuaternion::setScalar(float aScalar) { wp = aScalar; }
 
 inline QQuaternion QQuaternion::conjugate() const
 {
@@ -185,7 +185,7 @@ inline QQuaternion &QQuaternion::operator-=(const QQuaternion &quaternion)
     return *this;
 }
 
-inline QQuaternion &QQuaternion::operator*=(qreal factor)
+inline QQuaternion &QQuaternion::operator*=(float factor)
 {
     xp *= factor;
     yp *= factor;
@@ -196,16 +196,16 @@ inline QQuaternion &QQuaternion::operator*=(qreal factor)
 
 inline const QQuaternion operator*(const QQuaternion &q1, const QQuaternion& q2)
 {
-    qreal ww = (q1.zp + q1.xp) * (q2.xp + q2.yp);
-    qreal yy = (q1.wp - q1.yp) * (q2.wp + q2.zp);
-    qreal zz = (q1.wp + q1.yp) * (q2.wp - q2.zp);
-    qreal xx = ww + yy + zz;
-    qreal qq = 0.5 * (xx + (q1.zp - q1.xp) * (q2.xp - q2.yp));
+    float ww = (q1.zp + q1.xp) * (q2.xp + q2.yp);
+    float yy = (q1.wp - q1.yp) * (q2.wp + q2.zp);
+    float zz = (q1.wp + q1.yp) * (q2.wp - q2.zp);
+    float xx = ww + yy + zz;
+    float qq = 0.5 * (xx + (q1.zp - q1.xp) * (q2.xp - q2.yp));
 
-    qreal w = qq - ww + (q1.zp - q1.yp) * (q2.yp - q2.zp);
-    qreal x = qq - xx + (q1.xp + q1.wp) * (q2.xp + q2.wp);
-    qreal y = qq - yy + (q1.wp - q1.xp) * (q2.yp + q2.zp);
-    qreal z = qq - zz + (q1.zp + q1.yp) * (q2.wp - q2.xp);
+    float w = qq - ww + (q1.zp - q1.yp) * (q2.yp - q2.zp);
+    float x = qq - xx + (q1.xp + q1.wp) * (q2.xp + q2.wp);
+    float y = qq - yy + (q1.wp - q1.xp) * (q2.yp + q2.zp);
+    float z = qq - zz + (q1.zp + q1.yp) * (q2.wp - q2.xp);
 
     return QQuaternion(w, x, y, z);
 }
@@ -216,7 +216,7 @@ inline QQuaternion &QQuaternion::operator*=(const QQuaternion &quaternion)
     return *this;
 }
 
-inline QQuaternion &QQuaternion::operator/=(qreal divisor)
+inline QQuaternion &QQuaternion::operator/=(float divisor)
 {
     xp /= divisor;
     yp /= divisor;
@@ -245,12 +245,12 @@ inline const QQuaternion operator-(const QQuaternion &q1, const QQuaternion &q2)
     return QQuaternion(q1.wp - q2.wp, q1.xp - q2.xp, q1.yp - q2.yp, q1.zp - q2.zp);
 }
 
-inline const QQuaternion operator*(qreal factor, const QQuaternion &quaternion)
+inline const QQuaternion operator*(float factor, const QQuaternion &quaternion)
 {
     return QQuaternion(quaternion.wp * factor, quaternion.xp * factor, quaternion.yp * factor, quaternion.zp * factor);
 }
 
-inline const QQuaternion operator*(const QQuaternion &quaternion, qreal factor)
+inline const QQuaternion operator*(const QQuaternion &quaternion, float factor)
 {
     return QQuaternion(quaternion.wp * factor, quaternion.xp * factor, quaternion.yp * factor, quaternion.zp * factor);
 }
@@ -260,7 +260,7 @@ inline const QQuaternion operator-(const QQuaternion &quaternion)
     return QQuaternion(-quaternion.wp, -quaternion.xp, -quaternion.yp, -quaternion.zp);
 }
 
-inline const QQuaternion operator/(const QQuaternion &quaternion, qreal divisor)
+inline const QQuaternion operator/(const QQuaternion &quaternion, float divisor)
 {
     return QQuaternion(quaternion.wp / divisor, quaternion.xp / divisor, quaternion.yp / divisor, quaternion.zp / divisor);
 }
@@ -275,7 +275,7 @@ inline bool qFuzzyCompare(const QQuaternion& q1, const QQuaternion& q2)
 
 #ifndef QT_NO_VECTOR3D
 
-inline QQuaternion::QQuaternion(qreal aScalar, const QVector3D& aVector)
+inline QQuaternion::QQuaternion(float aScalar, const QVector3D& aVector)
     : wp(aScalar), xp(aVector.x()), yp(aVector.y()), zp(aVector.z()) {}
 
 inline void QQuaternion::setVector(const QVector3D& aVector)
@@ -292,7 +292,7 @@ inline QVector3D QQuaternion::vector() const
 
 #endif
 
-inline void QQuaternion::setVector(qreal aX, qreal aY, qreal aZ)
+inline void QQuaternion::setVector(float aX, float aY, float aZ)
 {
     xp = aX;
     yp = aY;