fragmentshader.qml Example File

particles/customparticle/content/fragmentshader.qml
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 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;
             }"

     }
 }