Qt Quick 3D - Lights Example

Demonstrates the use of different light types.

This example demonstrates using three different light types in an application.

Setting the Scene Lights

Directional Light

The directional light emits light in one direction from an unidentifiable source located infinitely far away. This is similar to the way sunlight works in real life. A directional light has infinite range and does not diminish.

We setup directional light to emit red color and animate its rotation around x-axis.


  DirectionalLight {
      id: light1
      color: Qt.rgba(1.0, 0.1, 0.1, 1.0)
      ambientColor: Qt.rgba(0.1, 0.1, 0.1, 1.0)
      position: Qt.vector3d(0, 200, 0)
      rotation: Qt.vector3d(135, 90, 0)
      shadowMapQuality: Light.ShadowMapQualityHigh
      visible: checkBox1.checked
      castsShadow: checkBoxShadows.checked
      brightness: slider1.sliderValue
      SequentialAnimation on rotation {
          loops: Animation.Infinite
          PropertyAnimation {
              to: Qt.vector3d(45, 90, 0)
              duration: 2000
              easing.type: Easing.InOutQuad
          }
          PropertyAnimation {
              to: Qt.vector3d(135, 90, 0)
              duration: 2000
              easing.type: Easing.InOutQuad
          }
      }
  }

Point Light

The point light can be described as a sphere, emitting light with equal strength in all directions from the center of the light. This is similar to the way a light bulb emits light.

We setup point light to emit green color and animate its position in x-coordinate.


  PointLight {
      id: light2
      color: Qt.rgba(0.1, 1.0, 0.1, 1.0)
      ambientColor: Qt.rgba(0.1, 0.1, 0.1, 1.0)
      position: Qt.vector3d(0, 300, 0)
      shadowMapFar: 2000
      shadowMapQuality: Light.ShadowMapQualityHigh
      visible: checkBox2.checked
      castsShadow: checkBoxShadows.checked
      brightness: slider2.sliderValue
      SequentialAnimation on x {
          loops: Animation.Infinite
          NumberAnimation {
              to: 400
              duration: 2000
              easing.type: Easing.InOutQuad
          }
          NumberAnimation {
              to: 0
              duration: 2000
              easing.type: Easing.InOutQuad
          }
      }
  }

Area Light

The area light is similar to the directional light, but instead of emitting equally bright light across the whole scene, the area light emits directional light from a rectangle shaped object. Aside from the size, an area light has the same characteristics and properties as the directional light.

We setup area light to emit blue color and animate its position in z-coordinate.


  AreaLight {
      id: light3
      color: Qt.rgba(0.1, 0.1, 1.0, 1.0)
      ambientColor: Qt.rgba(0.1, 0.1, 0.1, 1.0)
      position: Qt.vector3d(-50, 250, -150)
      rotation: Qt.vector3d(90, 0, 0)
      width: 1000
      height: 200
      shadowMapFar: 2000
      shadowMapQuality: Light.ShadowMapQualityHigh
      visible: checkBox3.checked
      castsShadow: checkBoxShadows.checked
      brightness: slider3.sliderValue
      SequentialAnimation on z {
          loops: Animation.Infinite
          NumberAnimation {
              to: 150
              duration: 2000
              easing.type: Easing.InOutQuad
          }
          NumberAnimation {
              to: -150
              duration: 2000
              easing.type: Easing.InOutQuad
          }
      }
  }

Setting the Scene Models

First we add two rectangle models to act as the floor and the back wall for our scene. These are useful for seeing light shadows.


  Model {
      source: "#Rectangle"
      y: -200
      scale: Qt.vector3d(15, 15, 15)
      rotation: Qt.vector3d(90, 0, 0)
      materials: [
          DefaultMaterial {
              diffuseColor: Qt.rgba(0.8, 0.6, 0.4, 1.0)
          }
      ]
  }
  Model {
      source: "#Rectangle"
      z: 400
      scale: Qt.vector3d(15, 15, 15)
      materials: [
          DefaultMaterial {
              diffuseColor: Qt.rgba(0.8, 0.8, 0.9, 1.0)
          }
      ]
  }

Then we add our main teapot model which is rotated around y-axis.


  Model {
      source: "teapot.mesh"
      y: -100
      scale: Qt.vector3d(75, 75, 75)
      materials: [
          DefaultMaterial {
              diffuseColor: Qt.rgba(0.9, 0.9, 0.9, 1.0)
          }
      ]

      NumberAnimation  on rotation.y {
          loops: Animation.Infinite
          duration: 5000
          from: 0
          to: 360
      }
  }

We also add small cube models to demonstrate position & rotation of each light type. These cubes scale bigger when user is accessing related sliders.


  Model {
      source: "#Cube"
      position: light1.position
      rotation: light1.rotation
      property real size: slider1.highlight ? 0.2 : 0.1
      scale: Qt.vector3d(size, size, size)
      materials: [
          DefaultMaterial {
              diffuseColor: light1.color
              opacity: 0.4
          }
      ]
  }
  Model {
      source: "#Cube"
      position: light2.position
      rotation: light2.rotation
      property real size: slider2.highlight ? 0.2 : 0.1
      scale: Qt.vector3d(size, size, size)
      materials: [
          DefaultMaterial {
              diffuseColor: light2.color
              opacity: 0.4
          }
      ]
  }
  Model {
      source: "#Cube"
      position: light3.position
      rotation: light3.rotation
      property real size: slider3.highlight ? 0.2 : 0.1
      scale: Qt.vector3d(size, size, size)
      materials: [
          DefaultMaterial {
              diffuseColor: light3.color
              opacity: 0.4
          }
      ]
  }

From the settings panel user can then enable shadows and control visibility and brightness of each light separately.

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