Outline effect unity

You will learn to write a screen space shader to draw outlines around objects. This shader will be integrated with Unity's post-processing stack.

Rendering outlines is a technique that is often used in games either for aesthetic reasons or for supporting gameplay by using it for highlights and selections around an object. For example in the game Sable, outlines are used to create a comic-book-like style. In The Last of Us, outlines are used to highlight enemies when the player goes into stealth mode. However, when using it for rendering outlines, this physical meaning of the effect is not important. The following formula is used to form the outline. Then, this gets exponentiated with a power P P P. It is important to note that this is only an approximation of the fresnel effect, but it works well for our outlines.

Outline effect unity

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As previously stated, effects integrated with the post-processing stack use a variety of macros to ensure multi-platform compatibility. In this scene are several objects, each with a different shape outline effect unity silhouette. Note that it also contains a large amount of comments in the created shader and C files to aid understanding.

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You will learn to write a screen space shader to draw outlines around objects. This shader will be integrated with Unity's post-processing stack. Outline , or edge detection effects are most commonly associated and paired with toon style shading. However, outline shaders have a wide variety of uses, from highlighting important objects on screen to increasing visual clarity in CAD rendering. This tutorial will describe step-by-step how to write an outline shader in Unity. The shader will be written as a custom effect for Unity's post-processing stack , but the code can also be used in a regular image effect. Concepts introduced here can be found in the Recolor effect from the Kino repository by keijiro , a Unity project that contains a variety of custom effects for the post-processing stack. To complete this tutorial, you will need a working knowledge of Unity engine, and an intermediate knowledge of shaders.

Outline effect unity

In this tutorial, we are going to create an outline effect for basic meshes using Shader Graph in Unity3D. We will encounter some restrictions of Shader Graph and learn how we can overcome this kind of restrictions. At the end of the tutorial, we are going to obtain the following effect:. In order to create an outline for an object, we render an additional image with the same geometry and scale it a little bit to obtain the outline. Nevertheless, we also need to prevent to render the pixels of the newly created image when both images overlap.

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A second common artifact is unwanted edges showing up on objects at small grazing angles. The duplicate object is usually just rendered with a flat color. This will be apparent in meshes that are more complex. Any model with sharp angles will have these kind of artifacts. This large depth delta along these surfaces is causing our algorithm to detect "edges" on them. Another option is to use a stencil mask to prevent the duplicate mesh from showing up in front of the original mesh. Properties are created a bit differently with the post-processing stack. For this approach, the objects that need to have an outline get rendered using a custom shader. To achieve this, we will use the dot product. The view to clip called the projection matrix here is exposed in the Camera class. We are going to modulate depthThreshold based on the difference between the camera's viewing normal and the normal of the surface. This ensures that the resulting matrix is correctly configured for our shader. This duplicate object gets shown behind the original object and its vertices get extruded in order to make the duplicate object larger than the original one. To generate outlines, we will sample adjacent pixels and compare their values. Instead, we will modulate depthThreshold by the surface's normal.

Rendering outlines is a technique that is often used in games either for aesthetic reasons or for supporting gameplay by using it for highlights and selections around an object.

As our normalFiniteDifference values are vectors , and not scalars , we need to transform them from a 3-dimensional value to a single dimensional value before computing the edge intensity. This is done by moving each vertex position along the vertex position. These transformations will alter the shape of the outline, distorting it in the process. This ensures that the resulting matrix is correctly configured for our shader. In order to make the duplicate mesh larger, we need to change the positions of its vertices. Discontinuities can be detected between the depth buffer value, the normal vector, the albedo color or any other data that is made available. The duplicate object is usually just rendered with a flat color. Outline , or edge detection effects are most commonly associated and paired with toon style shading. Adding variable edge thickness via dilation can create strokes reminiscent of 2D illustration, as described in this paper by Pixar. There are issues with sharp corners but these can be mitigated by using custom normals, which do require some extra setup. Currently, the Outline file contains a simple fragment shader named Frag that samples the image on-screen and returns it without modification. If the values are very different, we will draw an edge. Still, if not using custom-authored normals the method has issues with meshes that have sharp-corners, resulting in gaps in the outline. Another option is to use a stencil mask to prevent the duplicate mesh from showing up in front of the original mesh. The clip space position which ranges from -1, -1 at the top left of the screen to 1, 1 at the bottom right can be interpreted as a the camera's view direction to each pixel, in clip space.