contents/ui/ColorShower.qml

0001 /*
0002     SPDX-FileCopyrightText: 2013 Digia Plc and /or its subsidiary(-ies) <http://www.qt-project.org/legal>
0003
0004     This file is part of the examples of the Qt Toolkit.
0005
0006     SPDX-License-Identifier: BSD-3-Clause
0007 */
0008
0009 import QtQuick
0010 import QtQuick.Particles
0011
0012 ShaderExample {
0013
0014     pageName: "Particles"
0015     pageDescription: "Fun rainbow colors using a fragment shader"
0016
0017     Item {
0018         anchors.fill: parent
0019         clip: true
0020         anchors.margins: -_s
0021         ParticleSystem {
0022             id: psItem
0023             //anchors.fill: parent
0024             x: parent.width / 2
0025             y: parent.height / 2
0026             width: parent.width
0027             height: parent.height
0028 //             clip: true
0029             anchors.topMargin: 48
0030             //anchors.leftMargin: 42
0031
0032             Emitter {
0033                 emitRate: 400
0034                 lifeSpan: 8000
0035                 size: 24
0036                 sizeVariation: 16
0037                 velocity: PointDirection {x: psItem.width/20; y: psItem.height/20;}
0038                 acceleration: PointDirection {x: -psItem.width/40; y: -psItem.height/40; xVariation: -psItem.width/20; yVariation: -psItem.width/20}
0039             }
0040
0041             CustomParticle {
0042                 vertexShader:"
0043                     uniform lowp float qt_Opacity;
0044                     varying lowp float fFade;
0045                     varying highp vec2 fPos;
0046
0047                     void main() {
0048                         qt_TexCoord0 = qt_ParticleTex;
0049                         highp float size = qt_ParticleData.z;
0050                         highp float endSize = qt_ParticleData.w;
0051
0052                         highp float t = (qt_Timestamp - qt_ParticleData.x) / qt_ParticleData.y;
0053
0054                         highp float currentSize = mix(size, endSize, t * t);
0055
0056                         if (t < 0. || t > 1.)
0057                         currentSize = 0.;
0058
0059                         highp vec2 pos = qt_ParticlePos
0060                         - currentSize / 2. + currentSize * qt_ParticleTex          // adjust size
0061                         + qt_ParticleVec.xy * t * qt_ParticleData.y         // apply velocity vector..
0062                         + 0.5 * qt_ParticleVec.zw * pow(t * qt_ParticleData.y, 2.);
0063
0064                         gl_Position = qt_Matrix * vec4(pos.x, pos.y, 0, 1);
0065
0066                         highp float fadeIn = min(t * 20., 1.);
0067                         highp float fadeOut = 1. - max(0., min((t - 0.75) * 4., 1.));
0068
0069                         fFade = fadeIn * fadeOut * qt_Opacity;
0070                         fPos = vec2(pos.x/320., pos.y/480.);
0071                     }
0072                 "
0073                 //! [0]
0074                 fragmentShader: "
0075                     varying highp vec2 fPos;
0076                     varying lowp float fFade;
0077                     varying highp vec2 qt_TexCoord0;
0078                     void main() {//*2 because this generates dark colors mostly
0079                         highp vec2 circlePos = qt_TexCoord0*2.0 - vec2(1.0,1.0);
0080                         highp float dist = length(circlePos);
0081                         highp float circleFactor = max(min(1.0 - dist, 1.0), 0.0);
0082                         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;
0083                     }"
0084                 //! [0]
0085
0086             }
0087         }
0088     }
0089 }