Creating visually impressive effects in Unreal Engine 4 (UE4) often requires writing your own shaders. Although UE4 offers a powerful material system through its visual editor, knowledge of HLSL (High-Level Shading Language) opens up new possibilities for customization and optimization of graphics. In this guide, we will cover the key aspects of working with shaders in UE4, practical tips, and useful notes.
Shader Basics in UE4
In UE4, shaders are created through the Material Editor, but behind the scenes, they are all compiled into HLSL. Developers can insert their own HLSL code through the Custom node in the Material Editor, which allows them to:
- Implement non-standard visual effects;
- Optimize calculations;
- Use complex mathematical formulas and lighting algorithms.
It is important to remember that UE4 uses deferred rendering, so all shaders must interact correctly with the G-buffer and post-processing.
Types of shaders
There are several key types of shaders in UE4:
- Vertex Shader – responsible for vertex positioning, deformation, and mesh animation.
- Pixel (Fragment) Shader – calculates the color of each pixel; this is where most of the work with textures, lighting, and effects takes place.
- Compute Shader – allows arbitrary parallel calculations to be performed on the GPU, for example, for particles or complex physics.
- Geometry/Domain/Hull Shaders – used less frequently, but allow you to create dynamic geometry or work with tessellation.
Optimization tips
Minimize complex operations in Pixel Shader – Pixel Shader is executed for each pixel, so heavy calculations can significantly reduce FPS.
Use LOD and mipmaps for textures – this reduces the load on the GPU when objects are far away.
Prefer built-in UE4 functions – such as LinearInterpolate, Saturate, and TextureSample – to make your shader compatible with different platforms.
Profile your shaders – use the Shader Complexity View tool in UE4 to visualize the load on pixel shaders.
Practical notes
HLSL in UE4 is slightly different from the standard: UE4 material functions and macros are used to access textures, normals, and lighting.
All custom shaders must take into account the material’s Lighting Model. For example, for PBR materials, lighting calculations must be correct.
Post-processing affects the perception of the shader. It is often useful to test shaders in the context of a scene rather than on an isolated object.
Examples of interesting effects
Holograms and neon outlines – use Fresnel and Custom Node to calculate brightness by viewing angle.
Wavy water surfaces – Vertex Shader with sinusoidal deformation and manually calculated normals.
Pseudo-3D effects – combining UV decoration and fragment shader to simulate depth on flat surfaces.
Conclusion
Developing shaders in UE4 with HLSL allows you to go beyond standard materials and create unique visual effects. The main thing is to understand the architecture of UE4, optimize shaders, and test them in real scenes. Using Custom Node, Material Functions, and profiling will help you create shaders that are not only beautiful but also effective.