Qt Quick 3D - Custom Shaders Example

This example demonstrates using a material with completely custom vertex and fragment shader code.

This example is the counterpart to the custommaterials example, which demonstrates the other group of custom materials: shaded materials where the shader code snippet augments a PrincipledMaterial, rather than replacing it.

Implementing a custom material

In this example, a mesh is deformed by the vertex shader according to a sine function. The end result is controlled by two sliders corresponding to the time and amplitude values of the sine function.

The fragment shader is used to color the mesh according to the position values of the vertices. There are two fragment shaders included: one with and without texturing. The textured version samples a texture that is source from either an image file, or from a live Qt Quick layer.

The material does not participate in the default lighting or shadowing system, and therefore has its shadingMode property set to CustomMaterial.Unshaded.

See CustomMaterial for a detailed description of custom material capabilities.

 CustomMaterial {
     id: root
     property real time: 0.0
     property real amplitude: 5.0
     property real alpha: 1.0

     property bool texturing: false
     property bool textureFromItem: false
     property Item texSrc
     Texture {
         id: texFromFile
         source: "qt_logo.png"
     }
     Texture {
         id: texFromItem
         sourceItem: root.texSrc
     }
     property TextureInput tex: TextureInput {
         enabled: root.texturing
         texture: root.textureFromItem ? texFromItem : texFromFile
     }

     shadingMode: CustomMaterial.Unshaded
     sourceBlend: root.alpha < 1.0 ? CustomMaterial.SrcAlpha : CustomMaterial.NoBlend
     destinationBlend: root.alpha < 1.0 ? CustomMaterial.OneMinusSrcAlpha : CustomMaterial.NoBlend
     cullMode: CustomMaterial.BackFaceCulling

     vertexShader: "example.vert"
     fragmentShader: root.texturing ? "example_tex.frag" : "example.frag"
 }

Using a custom material

A custom material using custom shaders is used the same way as any other material. The uniforms in the shader can be easily updated through QML property bindings.

 Model {
     position: Qt.vector3d(0, 0, 0)
     NumberAnimation on eulerRotation.y {
         from: 0
         to: 360
         duration: 3000
         loops: -1
         running: control.animateRotation
     }
     scale: Qt.vector3d(2, 2, 2)
     source: "#Sphere"
     materials: [
         ExampleMaterial {
             id: exampleMaterial
             time: control.time
             amplitude: control.amplitude
             alpha: control.alpha
             texturing: control.texturing
             textureFromItem: control.textureFromItem
             texSrc: Rectangle {
                 layer.enabled: true
                 layer.textureMirroring: ShaderEffectSource.NoMirroring
                 visible: false
                 SequentialAnimation on color {
                     ColorAnimation { from: "black"; to: "yellow"; duration: 2000 }
                     ColorAnimation { from: "yellow"; to: "cyan"; duration: 1000 }
                     ColorAnimation { from: "cyan"; to: "black"; duration: 500 }
                     loops: -1
                 }
                 width: 512
                 height: 512
                 Image {
                     source: "qt_logo.png"
                     anchors.centerIn: parent
                 }
             }
         }
     ]
 }

Example project @ code.qt.io