fragmentshader.qml Example File

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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;
              }"

      }
  }