= jMonkeyEngine 3 Tutorial (6) - Hello Materials :author: :revnumber: :revdate: 2020/07/06 :keywords: documentation, beginner, intro, model, material, color, texture, transparency The term Material includes everything that influences what the surface of a 3D model looks like: The color, texture, shininess, and opacity/transparency. Plain coloring is covered in xref:beginner/hello_node.adoc[Hello Node]. Loading models that come with materials is covered in xref:beginner/hello_asset.adoc[Hello Asset]. In this tutorial you learn to create and use custom JME3 Material Definitions. image::beginner/beginner-materials.png[beginner-materials.png,320,240,align="center"] include::partial$add-testdata-tip.adoc[] == Sample Code [source,java] ---- package jme3test.helloworld; import com.jme3.app.SimpleApplication; import com.jme3.light.DirectionalLight; import com.jme3.material.Material; import com.jme3.material.RenderState.BlendMode; import com.jme3.math.ColorRGBA; import com.jme3.math.Vector3f; import com.jme3.renderer.queue.RenderQueue.Bucket; import com.jme3.scene.Geometry; import com.jme3.scene.shape.Box; import com.jme3.scene.shape.Sphere; import com.jme3.texture.Texture; import com.jme3.util.TangentBinormalGenerator; /** Sample 6 - how to give an object's surface a material and texture. * How to make objects transparent. How to make bumpy and shiny surfaces. */ public class HelloMaterial extends SimpleApplication { public static void main(String[] args) { HelloMaterial app = new HelloMaterial(); app.start(); } @Override public void simpleInitApp() { /** A simple textured cube -- in good MIP map quality. */ Box cube1Mesh = new Box( 1f,1f,1f); Geometry cube1Geo = new Geometry("My Textured Box", cube1Mesh); cube1Geo.setLocalTranslation(new Vector3f(-3f,1.1f,0f)); Material cube1Mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md"); Texture cube1Tex = assetManager.loadTexture("Interface/Logo/Monkey.jpg"); cube1Mat.setTexture("ColorMap", cube1Tex); cube1Geo.setMaterial(cube1Mat); rootNode.attachChild(cube1Geo); /** A translucent/transparent texture, similar to a window frame. */ Box cube2Mesh = new Box( 1f,1f,0.01f); Geometry cube2Geo = new Geometry("window frame", cube2Mesh); Material cube2Mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md"); cube2Mat.setTexture("ColorMap", assetManager.loadTexture("Textures/ColoredTex/Monkey.png")); cube2Mat.getAdditionalRenderState().setBlendMode(BlendMode.Alpha); // activate transparency cube2Geo.setQueueBucket(Bucket.Transparent); cube2Geo.setMaterial(cube2Mat); rootNode.attachChild(cube2Geo); /* A bumpy rock with a shiny light effect. To make bumpy objects you must create a NormalMap. */ Sphere sphereMesh = new Sphere(32,32, 2f); Geometry sphereGeo = new Geometry("Shiny rock", sphereMesh); sphereMesh.setTextureMode(Sphere.TextureMode.Projected); // better quality on spheres TangentBinormalGenerator.generate(sphereMesh); // for lighting effect Material sphereMat = new Material(assetManager, "Common/MatDefs/Light/Lighting.j3md"); sphereMat.setTexture("DiffuseMap", assetManager.loadTexture("Textures/Terrain/Pond/Pond.jpg")); sphereMat.setTexture("NormalMap", assetManager.loadTexture("Textures/Terrain/Pond/Pond_normal.png")); sphereMat.setBoolean("UseMaterialColors",true); sphereMat.setColor("Diffuse",ColorRGBA.White); sphereMat.setColor("Specular",ColorRGBA.White); sphereMat.setFloat("Shininess", 64f); // [0,128] sphereGeo.setMaterial(sphereMat); //sphereGeo.setMaterial((Material) assetManager.loadMaterial("Materials/MyCustomMaterial.j3m")); sphereGeo.setLocalTranslation(0,2,-2); // Move it a bit sphereGeo.rotate(1.6f, 0, 0); // Rotate it a bit rootNode.attachChild(sphereGeo); /** Must add a light to make the lit object visible! */ DirectionalLight sun = new DirectionalLight(); sun.setDirection(new Vector3f(1,0,-2).normalizeLocal()); sun.setColor(ColorRGBA.White); rootNode.addLight(sun); } } ---- You should see * Left – A cube with a brown monkey texture. * Right – A translucent monkey picture in front of a shiny bumpy rock. Move around with the WASD keys to have a closer look at the translucency, and the rock's bumpiness. == Simple Unshaded Texture Typically you want to give objects in your scene textures: It can be rock, grass, brick, wood, water, metal, paper… A texture is a normal image file in JPG or PNG format. In this example, you create a box with a simple unshaded Monkey texture as material. [source,java] ---- /** A simple textured cube -- in good MIP map quality. */ Box cube1Mesh = new Box( 1f,1f,1f); Geometry cube1Geo = new Geometry("My Textured Box", cube1Mesh); cube1Geo.setLocalTranslation(new Vector3f(-3f,1.1f,0f)); Material cube1Mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md"); Texture cube1Tex = assetManager.loadTexture("Interface/Logo/Monkey.jpg"); cube1Mat.setTexture("ColorMap", cube1Tex); cube1Geo.setMaterial(cube1Mat); rootNode.attachChild(cube1Geo); ---- Here is what we did: to create a textured box: . Create a Geometry `cube1Geo` from a Box mesh `cube1Mesh`. . Create a Material `cube1Mat` based on jME3's default `Unshaded.j3md` material definition. . Create a texture `cube1Tex` from the `Monkey.jpg` file in the `assets/Interface/Logo/` directory of the project. . Load the texture `cube1Tex` into the `ColorMap` layer of the material `cube1Mat`. . Apply the material to the cube, and attach the cube to the rootnode. == Transparent Unshaded Texture `Monkey.png` is the same texture as `Monkey.jpg`, but with an added alpha channel. The alpha channel allows you to specify which areas of the texture you want to be opaque or transparent: Black areas of the alpha channel remain opaque, gray areas become translucent, and white areas become transparent. For a partially translucent/transparent texture, you need: * A Texture with alpha channel * A Texture with blend mode of `BlendMode.Alpha` * A Geometry in the `Bucket.Transparent` render bucket. + This bucket ensures that the transparent object is drawn on top of objects behind it, and they show up correctly under the transparent parts. [source,java] ---- /** A translucent/transparent texture, similar to a window frame. */ Box cube2Mesh = new Box( 1f,1f,0.01f); Geometry cube2Geo = new Geometry("window frame", cube2Mesh); Material cube2Mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md"); cube2Mat.setTexture("ColorMap", assetManager.loadTexture("Textures/ColoredTex/Monkey.png")); cube2Mat.getAdditionalRenderState().setBlendMode(BlendMode.Alpha); // activate transparency cube2Geo.setQueueBucket(Bucket.Transparent); cube2Geo.setMaterial(cube2Mat); rootNode.attachChild(cube2Geo); ---- For non-transparent objects, the drawing order is not so important, because the z-buffer already keeps track of whether a pixel is behind something else or not, and the color of an opaque pixel doesn't depend on the pixels under it, this is why opaque Geometries can be drawn in any order. What you did for the transparent texture is the same as before, with only one added step for the transparency. . Create a Geometry `cube2Geo` from a Box mesh `cube2Mesh`. This Box Geometry is flat upright box (because z=0.01f). . Create a Material `cube2Mat` based on jME3's default `Unshaded.j3md` material definition. . Create a texture `cube2Tex` from the `Monkey.png` file in the `assets/Textures/ColoredTex/` directory of the project. This PNG file must have an alpha layer. . *Activate transparency in the material by setting the blend mode to Alpha.* . *Set the QueueBucket of the Geometry to `Bucket.Transparent`.* . Load the texture `cube2Tex` into the `ColorMap` layer of the material `cube2Mat`. . Apply the material to the cube, and attach the cube to the rootnode. [TIP] ==== Learn more about creating PNG images with an alpha layer in the help system of your graphic editor. ==== == Shininess and Bumpiness But textures are not all. Have a close look at the shiny sphere – you cannot get such a nice bumpy material with just a plain texture. You see that JME3 also supports so-called Phong-illuminated materials: In a lit material, the standard texture layer is referred to as _DiffuseMap_, any material can use this layer. A lit material can additionally have lighting effects such as _Shininess_ used together with the _SpecularMap_ layer and _Specular_ color. And you can even get a realistically bumpy or cracked surface with help of the _NormalMap_ layer. Let's have a look at the part of the code example where you create the shiny bumpy rock. . Create a Geometry from a Sphere shape. Note that this shape is a normal smooth sphere mesh. + [source,java] ---- Sphere sphereMesh = new Sphere(32,32, 2f); Geometry sphereGeo = new Geometry("Shiny rock", sphereMesh); ---- .. (Only for Spheres) Change the sphere's TextureMode to make the square texture project better onto the sphere. + [source,java] ---- sphereMesh.setTextureMode(Sphere.TextureMode.Projected); ---- .. You must generate TangentBinormals for the mesh so you can use the NormalMap layer of the texture. + [source,java] ---- TangentBinormalGenerator.generate(sphereMesh); ---- . Create a material based on the `Lighting.j3md` default material. + [source,java] ---- Material sphereMat = new Material(assetManager, "Common/MatDefs/Light/Lighting.j3md"); ---- .. Set a standard rocky texture in the `DiffuseMap` layer. + image::https://github.com/jMonkeyEngine/jmonkeyengine/raw/445f7ed010199d30c484fe75bacef4b87f2eb38e/jme3-testdata/src/main/resources/Textures/Terrain/Pond/Pond.jpg[Pond.jpg,64,64,align="right"] + [source,java] ---- sphereMat.setTexture("DiffuseMap", assetManager.loadTexture("Textures/Terrain/Pond/Pond.jpg")); ---- .. Set the `NormalMap` layer that contains the bumpiness. The NormalMap was generated for this particular DiffuseMap with a special tool (e.g. Blender). + image::https://github.com/jMonkeyEngine/jmonkeyengine/raw/445f7ed010199d30c484fe75bacef4b87f2eb38e/jme3-testdata/src/main/resources/Textures/Terrain/Pond/Pond_normal.png[Pond_normal.png,64,64,align="right"] + [source,java] ---- sphereMat.setTexture("NormalMap", assetManager.loadTexture("Textures/Terrain/Pond/Pond_normal.png")); ---- .. Set the Material's Shininess to a value between 1 and 128. For a rock, a low fuzzy shininess is appropriate. Use material colors to define the shiny Specular color. + [source,java] ---- sphereMat.setBoolean("UseMaterialColors",true); sphereMat.setColor("Diffuse",ColorRGBA.White); // minimum material color sphereMat.setColor("Specular",ColorRGBA.White); // for shininess sphereMat.setFloat("Shininess", 64f); // [1,128] for shininess ---- . Assign your newly created material to the Geometry. + [source,java] ---- sphereGeo.setMaterial(sphereMat); ---- . Let's move and rotate the geometry a bit to position it better. + [source,java] ---- sphereGeo.setLocalTranslation(0,2,-2); // Move it a bit sphereGeo.rotate(1.6f, 0, 0); // Rotate it a bit rootNode.attachChild(sphereGeo); ---- Remember that any Lighting.j3md-based material requires a light source, as shown in the full code sample above. [TIP] ==== To deactivate Shininess, do not set `Shininess` to 0, but instead set the `Specular` color to `ColorRGBA.Black`. ==== == Default Material Definitions As you have seen, you can find the following default materials in `jme/core-data/Common/MatDefs/…`. [cols="20,40,40", options="header"] |=== a| Default Definition a| Usage