71 lines
1.9 KiB
QML
71 lines
1.9 KiB
QML
// Copyright (C) 2025 The Qt Company Ltd.
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// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
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import QtQuick
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import QtQuick3D
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// The rotation math is based on the paper
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// ARCBALL:
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// A User Interface for Specifying Three-Dimensional Orientation Using a Mouse
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// by Ken Shoemake, 1992
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Item {
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id: root
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visible: false
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required property Node controlledObject
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property vector3d lastPos: Qt.vector3d(0, 0, 0)
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property bool moving: false
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// From Shoemake 1992:
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// pt.x <- (screen.x - center.x)/radius;
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// pt.y <- (screen.y - center.y)/radius;
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// r <- pt.x*pt.x + pt.y*pt.y;
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// IF r > 1.0
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// THEN s <- 1.0/Sqrt[r];
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// pt.x <- s*pt.x;
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// pt.y <- s*pt.y;
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// pt.z <- 0.0;
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// ELSE pt.z <- Sqrt[1.0 - r] ;
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function pos2DToPos3D(posNDC) {
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var pt = Qt.vector3d(posNDC.x, posNDC.y, 0)
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let r = posNDC.x * posNDC.x + posNDC.y * posNDC.y
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if (r > 1.0) {
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let s = 1.0 / Math.sqrt(r)
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pt.x = s * pt.x
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pt.y = s * pt.y
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pt.z = 0.0
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} else {
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pt.z = Math.sqrt(1.0 - r)
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}
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return pt
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}
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function mousePressed(posNDC) {
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lastPos = pos2DToPos3D(posNDC)
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moving = true
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}
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function mouseReleased(posNDC) {
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moving = false
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}
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function mouseMoved(posNDC) {
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if (!moving)
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return
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let currentPos = pos2DToPos3D(posNDC)
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// From Shoemake 1992:
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// [q.x, q.y, q.z] <- V3_Cross[pO, p1];
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// q.w <- V3_Dot[pO, p1];
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// qnow <- QuatMul[q, qstart];
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let p0 = lastPos
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let p1 = currentPos
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let p0p1 = p0.crossProduct(p1)
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let q = Qt.quaternion(p0.dotProduct(p1), p0p1.x, p0p1.y, p0p1.z)
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let qnow = q.times(controlledObject.rotation)
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controlledObject.rotation = qnow
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lastPos = currentPos
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}
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}
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