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Diffstat (limited to 'src/runtimerender/Qt3DSRenderClippingFrustum.h')
| -rw-r--r-- | src/runtimerender/Qt3DSRenderClippingFrustum.h | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/src/runtimerender/Qt3DSRenderClippingFrustum.h b/src/runtimerender/Qt3DSRenderClippingFrustum.h new file mode 100644 index 0000000..b788ad2 --- /dev/null +++ b/src/runtimerender/Qt3DSRenderClippingFrustum.h @@ -0,0 +1,161 @@ +/**************************************************************************** +** +** Copyright (C) 2008-2012 NVIDIA Corporation. +** Copyright (C) 2017 The Qt Company Ltd. +** Contact: https://www.qt.io/licensing/ +** +** This file is part of Qt 3D Studio. +** +** $QT_BEGIN_LICENSE:GPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and The Qt Company. For licensing terms +** and conditions see https://www.qt.io/terms-conditions. For further +** information use the contact form at https://www.qt.io/contact-us. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3 or (at your option) any later version +** approved by the KDE Free Qt Foundation. The licenses are as published by +** the Free Software Foundation and appearing in the file LICENSE.GPL3 +** included in the packaging of this file. Please review the following +** information to ensure the GNU General Public License requirements will +** be met: https://www.gnu.org/licenses/gpl-3.0.html. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ +#pragma once +#ifndef QT3DS_RENDER_CLIPPING_PLANE_H +#define QT3DS_RENDER_CLIPPING_PLANE_H +#include "Qt3DSRender.h" +#include "foundation/Qt3DSPlane.h" +#include "foundation/Qt3DSFlags.h" +#include "foundation/Qt3DSBounds3.h" + +namespace qt3ds { +namespace render { + + struct BoxEdgeFlagValues + { + enum Enum { + xMax = 1, + yMax = 1 << 1, + zMax = 1 << 2, + }; + }; + + typedef NVFlags<BoxEdgeFlagValues::Enum, QT3DSU8> TRenderBoxEdge; + + // For an intesection test, we only need two points of the bounding box. + // There will be a point nearest to the plane, and a point furthest from the plane. + // We can derive these points from the plane normal equation. + struct SPlaneBoxEdge + { + TRenderBoxEdge lowerEdge; + TRenderBoxEdge upperEdge; + }; + + struct SClipPlane + { + QT3DSVec3 normal; + QT3DSF32 d; + SPlaneBoxEdge mEdges; + + // For intersection tests, we only need to know if the numerator is greater than, equal to, + // or less than zero. + inline QT3DSF32 distance(const QT3DSVec3 &pt) const { return normal.dot(pt) + d; } + + // Only works if p0 is above the line and p1 is below the plane. + inline QT3DSVec3 intersectWithLine(const QT3DSVec3 &p0, const QT3DSVec3 &p1) const + { + QT3DSVec3 dir = p1 - p0; + QT3DSVec3 pointOnPlane = normal * (-d); +#ifdef _DEBUG + QT3DSF32 distanceOfPoint = distance(pointOnPlane); + QT3DS_ASSERT(NVAbs(distanceOfPoint) < 0.0001f); +#endif + QT3DSF32 numerator = (pointOnPlane - p0).dot(normal); + QT3DSF32 denominator = dir.dot(normal); + + QT3DS_ASSERT(NVAbs(denominator) > .0001f); + QT3DSF32 t = (numerator / denominator); + QT3DSVec3 retval = p0 + dir * t; +#ifdef _DEBUG + QT3DSF32 retvalDistance = distance(retval); + QT3DS_ASSERT(NVAbs(retvalDistance) < .0001f); +#endif + return retval; + } + + static inline QT3DSVec3 corner(const NVBounds3 &bounds, TRenderBoxEdge edge) + { + return QT3DSVec3((edge & BoxEdgeFlagValues::xMax) ? bounds.maximum[0] : bounds.minimum[0], + (edge & BoxEdgeFlagValues::yMax) ? bounds.maximum[1] : bounds.minimum[1], + (edge & BoxEdgeFlagValues::zMax) ? bounds.maximum[2] : bounds.minimum[2]); + } + + // dividing the distance numerator + + // I got this code from osg, but it is in graphics gems + // as well. + /** intersection test between plane and bounding sphere. + return 1 if the bs is completely above plane, + return 0 if the bs intersects the plane, + return -1 if the bs is completely below the plane.*/ + inline int intersect(const NVBounds3 &bounds) const + { + // if lowest point above plane than all above. + if (distance(corner(bounds, mEdges.lowerEdge)) > 0.0f) + return 1; + + // if highest point is below plane then all below. + if (distance(corner(bounds, mEdges.upperEdge)) < 0.0f) + return -1; + + // d_lower<=0.0f && d_upper>=0.0f + // therefore must be crossing plane. + return 0; + } + + inline void calculateBBoxEdges() + { + mEdges.upperEdge = TRenderBoxEdge( + static_cast<QT3DSU8>((normal[0] >= 0.0f ? BoxEdgeFlagValues::xMax : 0) + | (normal[1] >= 0.0f ? BoxEdgeFlagValues::yMax : 0) + | (normal[2] >= 0.0f ? BoxEdgeFlagValues::zMax : 0))); + + mEdges.lowerEdge = TRenderBoxEdge((~((QT3DSU8)mEdges.upperEdge)) & 7); + } + }; + + struct SClippingFrustum + { + SClipPlane mPlanes[6]; + + SClippingFrustum() {} + + SClippingFrustum(const QT3DSMat44 &modelviewprojection, SClipPlane nearPlane); + + bool intersectsWith(const NVBounds3 &bounds) const + { + for (QT3DSU32 idx = 0; idx < 6; ++idx) + if (mPlanes[idx].intersect(bounds) < 0) + return false; + return true; + } + + bool intersectsWith(const QT3DSVec3 &point, QT3DSF32 radius = 0.0f) const + { + for (QT3DSU32 idx = 0; idx < 6; ++idx) + if (mPlanes[idx].distance(point) < radius) + return false; + return true; + } + }; +} +} + +#endif
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