fragmentshader.qml Example File | Qt Quick 5.12.12

- Qt 5.12
- Qt Quick
- Qt Quick Particles Examples - CustomParticle
- fragmentshader.qml Example File
- Qt 5.12.12 Reference Documentation

# fragmentshader.qml Example File

particles/customparticle/content/fragmentshader.qml

     /****************************************************************************
     **
     ** Copyright (C) 2017 The Qt Company Ltd.
     ** Contact: https://www.qt.io/licensing/
     **
     ** This file is part of the examples 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."
     **
     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     import QtQuick 2.0
     import QtQuick.Particles 2.0

     ParticleSystem {
         id: root
         width: 320
         height: 480
         Rectangle {
             z: -1
             anchors.fill: parent
             color: "black"
             Text {
                 anchors.bottom: parent.bottom
                 anchors.horizontalCenter: parent.horizontalCenter
                 font.pixelSize: 14
                 color: "white"
                 text: "It's all in the fragment shader."
             }
         }

         Emitter {
             emitRate: 400
             lifeSpan: 8000
             size: 24
             sizeVariation: 16
             velocity: PointDirection {x: root.width/10; y: root.height/10;}
             acceleration: PointDirection {x: -root.width/40; y: -root.height/40; xVariation: -root.width/20; yVariation: -root.width/20}
         }

         CustomParticle {
             vertexShader:"
                 uniform lowp float qt_Opacity;
                 varying lowp float fFade;
                 varying highp vec2 fPos;

                 void main() {
                     qt_TexCoord0 = qt_ParticleTex;
                     highp float size = qt_ParticleData.z;
                     highp float endSize = qt_ParticleData.w;

                     highp float t = (qt_Timestamp - qt_ParticleData.x) / qt_ParticleData.y;

                     highp float currentSize = mix(size, endSize, t * t);

                     if (t < 0. || t > 1.)
                     currentSize = 0.;

                     highp vec2 pos = qt_ParticlePos
                     - currentSize / 2. + currentSize * qt_ParticleTex          // adjust size
                     + qt_ParticleVec.xy * t * qt_ParticleData.y         // apply velocity vector..
                     + 0.5 * qt_ParticleVec.zw * pow(t * qt_ParticleData.y, 2.);

                     gl_Position = qt_Matrix * vec4(pos.x, pos.y, 0, 1);

                     highp float fadeIn = min(t * 20., 1.);
                     highp float fadeOut = 1. - max(0., min((t - 0.75) * 4., 1.));

                     fFade = fadeIn * fadeOut * qt_Opacity;
                     fPos = vec2(pos.x/320., pos.y/480.);
                 }
             "
             fragmentShader: "
                 varying highp vec2 fPos;
                 varying lowp float fFade;
                 varying highp vec2 qt_TexCoord0;
                 void main() {//*2 because this generates dark colors mostly
                     highp vec2 circlePos = qt_TexCoord0*2.0 - vec2(1.0,1.0);
                     highp float dist = length(circlePos);
                     highp float circleFactor = max(min(1.0 - dist, 1.0), 0.0);
                     gl_FragColor = vec4(fPos.x*2.0 - fPos.y, fPos.y*2.0 - fPos.x, fPos.x*fPos.y*2.0, 0.0) * circleFactor * fFade;
                 }"

         }
     }