Whereas Unity Legacy Shaders use individual Reflection Cubemaps per material, the new Standard Shader gets its reflection from the scene's Reflection Source, as configured in the Scene section of the Lighting window. The level of reflectiveness for each material is now given by its Metallic value or Specular value (for materials using Specular setup). This new method can be a real time saver, allowing you to quickly assign the same reflection map to every object in the scene. Also, as you can imagine, it helps keep the overall look of the scene coherent and cohesive. In this recipe, we will learn how to take advantage of the Reflection Source feature.
For this recipe, we will prepare a Reflection Cubemap, which is basically the environment to be projected as a reflection onto the material. It can be made from either six or, as shown in this recipe, a single image file.
To help us with this recipe, it's been provided a Unity package, containing a prefab made of a 3D object and a basic Material (using a TIFF as Diffuse map), and also a JPG file to be used as the reflection map. All these files are inside the 1362_06_02 folder.
To add Reflectiveness and Specularity to a material, follow these steps:
- Import
batteryPrefab.unitypackageto a new project. Then, selectbattery_prefabobject from the Assets folder, in the Project view. - From the Inspector view, expand the Material component and observe the asset preview window. Thanks to the Specular map, the material already features a reflective look. However, it looks as if it is reflecting the scene's default Skybox, as shown:
- Import the
CustomReflection.jpgimage file. From the Inspector view, change its Texture Type to Cubemap, its Mapping to Latitude - Longitude Layout (Cylindrical), and check the boxes for Glossy Reflection and Fixup Edge Seams. Finally, change its Filter Mode to Trilinear and click on the Apply button, shown as follows:
- Let's replace the Scene's Skybox with our newly created Cubemap, as the Reflection map for our scene. In order to do this, open the Lighting window by navigating to the Window | Lighting menu. Select the Scene section and use the drop-down menu to change the Reflection Source to Custom. Finally, assign the newly created
CustomReflectiontexture as the Cubemap, shown as follows:
- Check out for the new reflections on the
battery_prefabobject.
While it is the material's specular map that allows for a reflective look, including the intensity and smoothness of the reflection, the refection itself (that is, the image you see on the reflection) is given by the Cubemap that we have created from the image file.
Reflection Cubemaps can be achieved in many ways and have different mapping properties.
The Cylindrical mapping that we applied was well-suited for the photograph that we used. However, depending on how the reflection image is generated, a Cubic or Spheremap-based mapping can be more appropriate. Also, note that the Fixup Edge Seams option will try to make the image seamless.
You might have noticed that the reflection is somewhat blurry compared to the original image; this is because we have ticked the Glossy Reflections box. To get a sharper-looking reflection, deselect this option; in which case, you can also leave the Filter Mode option as default (Bilinear).
At 512 x 512 pixels, our reflection map will probably run fine on the lower-end machines. However, if the quality of the reflection map is not so important in your game's context, and the original image dimensions are big (say, 4096 x 4096), you might want to change the texture's Max Size at the Import Settings to a lower number.