1// Copyright (C) 2008-2012 NVIDIA Corporation.
2// Copyright (C) 2019 The Qt Company Ltd.
3// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
4
5#include "qssgrenderclippingfrustum_p.h"
6
7#include <QtQuick3DUtils/private/qssgutils_p.h>
8
9QT_BEGIN_NAMESPACE
10
11QSSGClippingFrustum::QSSGClippingFrustum(const QMatrix4x4 &modelviewprojection, const QSSGClipPlane &nearPlane)
12{
13 const float *modelviewProjection = modelviewprojection.data();
14
15 // update planes (http://read.pudn.com/downloads128/doc/542641/Frustum.pdf)
16 // Google for Gribb plane extraction if that link doesn't work.
17 // http://www.google.com/search?q=ravensoft+plane+extraction
18#define M(_x, _y) modelviewProjection[(4 * (_y)) + (_x)]
19 // left plane
20 mPlanes[0].normal = { M(3, 0) + M(0, 0), M(3, 1) + M(0, 1), M(3, 2) + M(0, 2) };
21 mPlanes[0].d = (M(3, 3) + M(0, 3)) / QSSGUtils::vec3::normalize(v&: mPlanes[0].normal);
22
23 // right plane
24 mPlanes[1].normal = { M(3, 0) - M(0, 0), M(3, 1) - M(0, 1), M(3, 2) - M(0, 2) };
25 mPlanes[1].d = (M(3, 3) - M(0, 3)) / QSSGUtils::vec3::normalize(v&: mPlanes[1].normal);
26
27 // far plane
28 mPlanes[2].normal = { (M(3, 0) - M(2, 0)), M(3, 1) - M(2, 1), M(3, 2) - M(2, 2) };
29 mPlanes[2].d = (M(3, 3) - M(2, 3)) / QSSGUtils::vec3::normalize(v&: mPlanes[2].normal);
30
31 // bottom plane
32 mPlanes[3].normal = { M(3, 0) + M(1, 0), M(3, 1) + M(1, 1), M(3, 2) + M(1, 2) };
33 mPlanes[3].d = (M(3, 3) + M(1, 3)) / QSSGUtils::vec3::normalize(v&: mPlanes[3].normal);
34
35 // top plane
36 mPlanes[4].normal = { M(3, 0) - M(1, 0), M(3, 1) - M(1, 1), M(3, 2) - M(1, 2) };
37 mPlanes[4].d = (M(3, 3) - M(1, 3)) / QSSGUtils::vec3::normalize(v&: mPlanes[4].normal);
38#undef M
39 mPlanes[5] = nearPlane;
40 // http://www.openscenegraph.org/projects/osg/browser/OpenSceneGraph/trunk/include/osg/Plane?rev=5328
41 // setup the edges of the plane that we will clip against an axis-aligned bounding box.
42 for (quint32 idx = 0; idx < 6; ++idx)
43 mPlanes[idx].calculateBBoxEdges();
44}
45
46QT_END_NAMESPACE
47

source code of qtquick3d/src/runtimerender/qssgrenderclippingfrustum.cpp