Qt Quick 3D - Principled Material Example

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import QtQuick import QtQuick.Controls import QtQuick.Layouts import QtQuick3D ScrollView { id: rootView required property PrincipledMaterial targetMaterial ScrollBar.horizontal.policy: ScrollBar.AlwaysOff width: availableWidth ColumnLayout { width: rootView.availableWidth MarkdownLabel { text: "# Refraction The properties in this section would probably be best described as advanced transparency. In the previous section on transparency we discussed alpha blending, which is about blending colors together using the alpha channel of the material's color. What makes the transparency effects in this section different is that the goal is to handle transparency in a way that more physically represents how light works. To achieve this blending requires that all content that is blended with needs to be rendered to a texture in separate pass. Using any properties on this page is as expensive as rendering all opaque content in the scene at least twice. Once to get the background items, and again including the items using the refractive transparency effects. The advantage of this approach though is that we are not limited in how we can blend, but comes with the caveat that only opaque items are visible through refracted objects." } MarkdownLabel { text: "## Transmission Transmission refers to lights ability to transmit, or pass through a surface. Not all light will penetrate a surface and some will still be reflected as a specular reflection. This ability to transmit light only concerns the surface of a material, and not its depth. Without the use of further properties in this section, a material that has transmission alone can be assumed to be infinitely thin. ### Transmission Factor The Transmission Factor property controls the percentage of light that is transmitted by a materials surface. This value is a single value between 0.0 meaning no light is transmitted and 1.0 meaning that 100% of the light that penetrates the surface of the material is transmitted through. Note: If you adjust the Transmission Factor to 1.0 and you still can't see through the models, it could be that your material is metallic. Metallic materials cannot transmit light." } Button { text: "Reset Metalness to 0.0" onClicked: targetMaterial.metalness = 0.0 } RowLayout { Label { text: "Transmission Factor (" + targetMaterial.transmissionFactor.toFixed(2) + ")" Layout.fillWidth: true } Slider { from: 0 to: 1 value: targetMaterial.transmissionFactor onValueChanged: targetMaterial.transmissionFactor = value } } MarkdownLabel { text: "### Transmission Map Like most other single floating point value properties, the Transmission property also allows for the use of a single channel of a texture to map transmission values to a mesh. And like many other textures, the final value of transmission will be the multiplication of Transmission Factor and the value sampled from Transmission Map. So when using a Transmission Map, it typically makes sense to set the Transmission Factor to 1.0. " } Button { text: "Reset Transmission" onClicked: targetMaterial.transmissionFactor = 1.0 } ComboBox { id: transmissionChannelComboBox textRole: "text" valueRole: "value" implicitContentWidthPolicy: ComboBox.WidestText onActivated: targetMaterial.transmissionChannel = currentValue Component.onCompleted: currentIndex = indexOfValue(targetMaterial.transmissionChannel) model: [ { value: PrincipledMaterial.R, text: "Red Channel"}, { value: PrincipledMaterial.G, text: "Green Channel"}, { value: PrincipledMaterial.B, text: "Blue Channel"}, { value: PrincipledMaterial.A, text: "Alpha Channel"} ] } TextureSourceControl { defaultTexture: "maps/noise.png" defaultClearColor: "black" onTargetTextureChanged: { targetMaterial.transmissionMap = targetTexture } } VerticalSectionSeparator {} MarkdownLabel { text: "## Index of Refraction (IOR) The Index of Refraction or refraction index refers to the physical property of how fast light passes through a material. This number then is used to determine how light is bent or refracted when it enters a material. Since this value is a physical value, it's possible to plug in the same values as real life materials as well. The default value that the PrincipledMaterial uses for all lighting calculations is 1.5, which is very close to window glass. Below are several other materials' IOR values that will produce different results when used with a refractive material (especially ones with thickness)." } ComboBox { id: iorChannelComboBox textRole: "text" valueRole: "value" implicitContentWidthPolicy: ComboBox.WidestText onActivated: targetMaterial.indexOfRefraction = currentValue Component.onCompleted: currentIndex = 0 model: [ { value: 1.5, text: "Custom"}, { value: 1.4, text: "Acrylic glass"}, { value: 1.0, text: "Air"}, { value: 1.33, text: "Water"}, { value: 1.76, text: "Sapphire"}, { value: 2.42, text: "Diamond"} ] } RowLayout { Label { text: "IOR (" + iorSlider.value.toFixed(2) + ")" Layout.fillWidth: true } Slider { id: iorSlider from: 1.0 to: 3.0 value: targetMaterial.indexOfRefraction onValueChanged: { if (iorChannelComboBox.currentValue != value) iorChannelComboBox.currentIndex = 0; targetMaterial.indexOfRefraction = value } } } VerticalSectionSeparator {} MarkdownLabel { text: "## Thickness The Thickness properties are for giving refractive materials volume. A transmissive material alone is considered to be infinitely thin so any Index of Refraction values will only affect the specular and fresnel effects of a material. However when a transmissive material is given volume via the thickness properties, then light passing through the material is bent as it passes through. ### Thickness Factor The Thickness Factor property defines the thickness of the volume beneath the surface of the mesh. Unlike other factors, the Thickness Factor Property is not clipped at 1.0, but rather refers to the distance in the coordinate space of the mesh itself. When used in conjunction with the Thickness Map, the Thickness Factor would be the point of maximum thickness. " } RowLayout { Label { text: "Thickness Factor (" + targetMaterial.thicknessFactor.toFixed(2) + ")" Layout.fillWidth: true } Slider { from: 0 to: 100.0 value: targetMaterial.thicknessFactor onValueChanged: targetMaterial.thicknessFactor = value } } MarkdownLabel { text: "### Thickness Map The Thickness Map is a single channel (greyscale) texture that defines the thickness (or volume) of a mesh. The values sampled from the Thickness Map are multiplied against the value of Thickness Factor to get the thickness of the mesh under the surface in the meshe's coordinate space. Thickness Maps are baked in 3D content creation tools using ray tracers. The process of baking thickness is similar to the process for baking ambient occlusion, but the rays are cast in the opposite direction of the surface normal (into the mesh). Darker values represent thin sections, and lighter values will be thicker. Provided is a baked thickness map of the Monkey model. (The other models would have uniform thicknesses)." } ComboBox { id: thicknessChannelComboBox textRole: "text" valueRole: "value" implicitContentWidthPolicy: ComboBox.WidestText onActivated: targetMaterial.thicknessChannel = currentValue Component.onCompleted: currentIndex = indexOfValue(targetMaterial.thicknessChannel) model: [ { value: PrincipledMaterial.R, text: "Red Channel"}, { value: PrincipledMaterial.G, text: "Green Channel"}, { value: PrincipledMaterial.B, text: "Blue Channel"}, { value: PrincipledMaterial.A, text: "Alpha Channel"} ] } TextureSourceControl { defaultTexture: "maps/monkey_thickness.jpg" defaultClearColor: "black" onTargetTextureChanged: { targetMaterial.thicknessMap = targetTexture } } VerticalSectionSeparator {} MarkdownLabel { text: "## Attenuation As light passes through a volume it will be subject to absorption and scattering. To simulate this interaction, two properties are provided for determining this attenuation. ### Attenuation Color The Attenuation Color property refers to the color that white light turns into due to the absorption when reaching the attenuation distance. " } RowLayout { Label { text: "Red (" + targetMaterial.attenuationColor.r.toFixed(2) + ")" Layout.fillWidth: true } Slider { from: 0 to: 1 value: targetMaterial.attenuationColor.r onValueChanged: targetMaterial.attenuationColor.r = value } } RowLayout { Label { text: "Green (" + targetMaterial.attenuationColor.g.toFixed(2) + ")" Layout.fillWidth: true } Slider { from: 0 to: 1 value: targetMaterial.attenuationColor.g onValueChanged: targetMaterial.attenuationColor.g = value } } RowLayout { Label { text: "Blue (" + targetMaterial.attenuationColor.b.toFixed(2) + ")" Layout.fillWidth: true } Slider { from: 0 to: 1 value: targetMaterial.attenuationColor.b onValueChanged: targetMaterial.attenuationColor.b = value } } MarkdownLabel { text: "### Attenuation Distance Attenuation Distance defines material density, but does so by describing the average distance light must travel through the medium before interacting with a particle (absorption). In this case the distance is specified in world coordinate space (scene space). This distance can be any positive floating point value. This means the attenuation color will start to appear when the thickness is greater than the attenuation distance, with the caveat that the Attenuation Color assumes white light is passing through the model, so any other light will create a blended result. For this demonstration the slider value is limited to 100, which should be the maximum thickness for all 3 models." } RowLayout { Label { text: "Attenuation Distance (" + targetMaterial.attenuationDistance.toFixed(2) + ")" Layout.fillWidth: true } Slider { from: 0 to: 100 value: targetMaterial.attenuationDistance onValueChanged: { if (value != targetMaterial.attenuationDistance) targetMaterial.attenuationDistance = value } } } } }