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<td >Qt 5.12</td><td ><a href="qt3d-index.html">Qt 3D</a></td><td >Qt 3D: Simple Custom Material QML Example</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right"><a href="qt3d-index.html">Qt 5.12.6 Reference Documentation</a></td>
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<h3><a name="toc">Contents</a></h3>
<ul>
<li class="level1"><a href="#running-the-example">Running the Example</a></li>
<li class="level1"><a href="#specifying-the-scene">Specifying the Scene</a></li>
<li class="level1"><a href="#specifying-the-material">Specifying the Material</a></li>
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<h1 class="title">Qt 3D: Simple Custom Material QML Example</h1>
<span class="subtitle"></span>
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<p>Demonstrates creating a custom material in Qt 3D.</p>
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<div class="descr"> <a name="details"></a>
<p class="centerAlign"><img src="images/simple-custom-material.jpg" alt="" /></p><p><i>This</i> example demonstrates creating a simple custom material.</p>
<a name="running-the-example"></a>
<h2 id="running-the-example">Running the Example</h2>
<p>To run the example from Qt Creator, open the <b>Welcome</b> mode and select the example from <b>Examples</b>. For more information, visit Building and Running an Example.</p>
<a name="specifying-the-scene"></a>
<h2 id="specifying-the-scene">Specifying the Scene</h2>
<p>The example uses <a href="qml-qtquick-scene3d-scene3d.html">Scene3D</a> to render a scene which will use the custom material. The scene contains a plane model, which uses the custom material.</p>
<pre class="cpp">

  Entity {
      id: root

      components: [transform, mesh, material]

      SimpleMaterial {
          id: material
          maincolor: "red"
      }

      Transform {
          id: transform
          rotationX: 45
      }

      PlaneMesh {
          id: mesh
          width: 1.0
          height: 1.0
          meshResolution: Qt.size(2, 2)
      }
  }

</pre>
<a name="specifying-the-material"></a>
<h2 id="specifying-the-material">Specifying the Material</h2>
<p>The material is specified in <a href="qt3d-simplecustommaterial-simplematerial-qml.html">SimpleMaterial.qml</a> using <a href="qml-qt3d-render-material.html">Material</a> type. First the material specifies parameters, which are mapped to the corresponding uniforms in the shaders so that they can be changed from the qml.</p>
<pre class="qml">

  property color maincolor: Qt.rgba(0.0, 0.0, 0.0, 1.0)

  parameters: [
      Parameter {
          name: "maincolor"
          value: Qt.vector3d(root.maincolor.r, root.maincolor.g, root.maincolor.b)
      }
  ]

</pre>
<p>Next we specify which shaders are loaded. Separate versions of the shaders are provided for OpenGL ES 2 and OpenGL renderers.</p>
<pre class="qml">

  property string vertex: "qrc:/shaders/gl3/simpleColor.vert"
  property string fragment: "qrc:/shaders/gl3/simpleColor.frag"
  property string vertexES: "qrc:/shaders/es2/simpleColor.vert"
  property string fragmentES: "qrc:/shaders/es2/simpleColor.frag"

</pre>
<p>In the vertex shader we simply transform the position by the transformation matrices.</p>
<pre class="cpp">

  void main()
  {
      // Transform position, normal, and tangent to world coords
      worldPosition = vec3(modelMatrix * vec4(vertexPosition, 1.0));

      // Calculate vertex position in clip coordinates
      gl_Position = mvp * vec4(worldPosition, 1.0);
  }

</pre>
<p>In the fragment shader we simply set the fragment color to be the maincolor specified in the material.</p>
<pre class="cpp">

  uniform vec3 maincolor;
  void main()
  {
      //output color from material
      fragColor = vec4(maincolor,1.0);
  }

</pre>
<p>Next, we create <a href="qml-qt3d-render-shaderprogram.html">ShaderPrograms</a> from the shaders.</p>
<pre class="qml">

  ShaderProgram {
      id: gl3Shader
      vertexShaderCode: loadSource(parent.vertex)
      fragmentShaderCode: loadSource(parent.fragment)
  }
  ShaderProgram {
      id: es2Shader
      vertexShaderCode: loadSource(parent.vertexES)
      fragmentShaderCode: loadSource(parent.fragmentES)
  }

</pre>
<p>Finally the shader programs are used in the Techniques corresponding to a specific Api profile.</p>
<pre class="qml">

  // OpenGL 3.1
  Technique {
      filterKeys: [forward]
      graphicsApiFilter {
          api: GraphicsApiFilter.OpenGL
          profile: GraphicsApiFilter.CoreProfile
          majorVersion: 3
          minorVersion: 1
      }
      renderPasses: RenderPass {
          shaderProgram: gl3Shader
      }
  },

</pre>
<p>Files:</p>
<ul>
<li><a href="qt3d-simplecustommaterial-planemodel-qml.html">simplecustommaterial/PlaneModel.qml</a></li>
<li><a href="qt3d-simplecustommaterial-sceneroot-qml.html">simplecustommaterial/SceneRoot.qml</a></li>
<li><a href="qt3d-simplecustommaterial-simplematerial-qml.html">simplecustommaterial/SimpleMaterial.qml</a></li>
<li><a href="qt3d-simplecustommaterial-main-cpp.html">simplecustommaterial/main.cpp</a></li>
<li><a href="qt3d-simplecustommaterial-main-qml.html">simplecustommaterial/main.qml</a></li>
<li><a href="qt3d-simplecustommaterial-models-qrc.html">simplecustommaterial/models.qrc</a></li>
<li><a href="qt3d-simplecustommaterial-qml-qrc.html">simplecustommaterial/qml.qrc</a></li>
<li><a href="qt3d-simplecustommaterial-shaders-qrc.html">simplecustommaterial/shaders.qrc</a></li>
<li><a href="qt3d-simplecustommaterial-shaders-es2-simplecolor-vert.html">simplecustommaterial/shaders/es2/simpleColor.vert</a></li>
<li><a href="qt3d-simplecustommaterial-shaders-gl3-simplecolor-vert.html">simplecustommaterial/shaders/gl3/simpleColor.vert</a></li>
<li><a href="qt3d-simplecustommaterial-simplecustommaterial-pro.html">simplecustommaterial/simplecustommaterial.pro</a></li>
<li><a href="qt3d-simplecustommaterial-textures-qrc.html">simplecustommaterial/textures.qrc</a></li>
</ul>
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