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Diffstat (limited to 'basicsuite/advancedcustommaterial/shaders/gl3/coordinatesystems.inc')
-rw-r--r-- | basicsuite/advancedcustommaterial/shaders/gl3/coordinatesystems.inc | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/basicsuite/advancedcustommaterial/shaders/gl3/coordinatesystems.inc b/basicsuite/advancedcustommaterial/shaders/gl3/coordinatesystems.inc new file mode 100644 index 0000000..ed3d2cb --- /dev/null +++ b/basicsuite/advancedcustommaterial/shaders/gl3/coordinatesystems.inc @@ -0,0 +1,70 @@ +/**************************************************************************** +** +** Copyright (C) 2017 Klaralvdalens Datakonsult AB (KDAB). +** Contact: https://www.qt.io/licensing/ +** +** This file is part of the Qt3D module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** 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. +** +** BSD License Usage +** Alternatively, you may use this file under the terms of the BSD license +** as follows: +** +** "Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are +** met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** * Neither the name of The Qt Company Ltd nor the names of its +** contributors may be used to endorse or promote products derived +** from this software without specific prior written permission. +** +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +mat3 calcWorldSpaceToTangentSpaceMatrix(const in vec3 wNormal, const in vec4 wTangent) +{ + // Make the tangent truly orthogonal to the normal by using Gram-Schmidt. + // This allows to build the tangentMatrix below by simply transposing the + // tangent -> eyespace matrix (which would now be orthogonal) + vec3 wFixedTangent = normalize(wTangent.xyz - dot(wTangent.xyz, wNormal) * wNormal); + + // Calculate binormal vector. No "real" need to renormalize it, + // as built by crossing two normal vectors. + // To orient the binormal correctly, use the fourth coordinate of the tangent, + // which is +1 for a right hand system, and -1 for a left hand system. + vec3 wBinormal = cross(wNormal, wFixedTangent.xyz) * wTangent.w; + + // Construct matrix to transform from world space to tangent space + // This is the transpose of the tangentToWorld transformation matrix + mat3 tangentToWorldMatrix = mat3(wFixedTangent, wBinormal, wNormal); + mat3 worldToTangentMatrix = transpose(tangentToWorldMatrix); + return worldToTangentMatrix; +} + |