Abalanche - Unity Shader Graph #1: Shader & PBR Materials
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This document discusses the basics of shaders and the rendering pipeline, including vertex and fragment processing. It covers various types of shaders, material properties in physically-based rendering (PBR), and specific parameters like albedo, normal, and smoothness for realistic material representation. Additional information includes techniques such as cel-shading and the impact of light on rendering effects.
Abalanche - Unity Shader Graph #1: Shader & PBR Materials
- 4. Basic rendering pipeline Vertex Data Vertex Processing Rasterizing Display Output Merging Fragment Processing
- 5. Basic rendering pipeline Vertex Data Vertex Processing Rasterizing Display Output Merging Fragment Processing SHADER SHADER
- 6. Vertex shader Modify vertex data (mostly position) Example: Waving flags Displace vertices’ positions by sine wave and noise
- 7. Fragment shader Modify pixel/fragment data (mostly color) Example: See through / Infrared Vision Render specific object in front of the others
- 8. A material consists of a shader and visible parameters from that shader. Could be considered as a shader preset. Example: Change base texture of the MatCap shader to create different materials Material
- 9. PBR ?
- 10. Unlit NOT affected by light -> very fast. Example: 2D sprites. Example: Anime style without light.
- 11. Lit Affected by light. Approximated by a math model. Example: Phong shading. *Image: Phong & his friends were measuring a car to render in 3D
- 12. Flat Gouraud Phong 0.0 1.0 Phong shading Diffuse: Calculate the angle between normal vector and light direction. Specular: Calculate the angle between reflected light ray and view direction. Smaller angle means brighter color.
- 13. Cel-shading Is a Lit shading technique !!! Transitions between dark & light areas are controlled by a “shading ramp” image. Immediate transitions Shading ramp image More: Daniel Ilette’s tutorial
- 14. PBR Physically-Based Rendering. A group of light simulation techniques. Control by multiple images called textures. Ref: Wikipedia Ref: Unity’s Standard Shaders *Image: The blue turtle
- 17. PBR Textures – Albedo A base color without lighting factors (specular, shadow...). Could be a texture (RGB), a solid color, or both. Depend on light direction. Other common names are main / base / diffuse textures. More: Unity’s Albedo Color
- 18. PBR Textures – Smoothness Smoother surface means clearer reflection. Smoothness = 0 Smoothness = 0.4 Smoothness = 0.7 !!! Specular highlight 0.0 1.0
- 19. PBR Textures: Smoothness Smoother surface means clearer reflection. Could be a number / a texture. Specular highlight depends on light and view direction. More: Unity's Smoothness Smoothness = 0 Smoothness = 0.4 0.0 1.0
- 20. PBR Textures: Normal Normal vector is perpendicular to a tangent plane at a surface point. Normal vector is important in calculating light effect. Normal vector usually points outward. More: Wikipedia
- 21. Without Normal Map With Normal Map Texture type must be Normal Map. Fun: It's mostly purple. Ref: Unity's Normal Map PBR Textures: Normal
- 22. PBR Textures: Normal Could simulate the details with a low-poly mesh very efficiently. Bump map is a more general map whose values indicating the height adjustment amount, not the direction.
- 23. Metallic parameter controls specular reflection. *Smoothness affects specular highlight, too. Could be a number / a texture (single channel). More: Unity's Metallic Workflow PBR Textures: Metallic More albedo More environment reflection 0.0 1.0 Environment Reflection Specular Highlight
- 24. You must pick Metallic or Specular workflow. Specular gives you more control (color, brightness, blending with environment ...). Could be a texture (RGB) or a solid color. *Not recommended for newbie. More: Unity's Specular Workflow PBR Textures – Specular
- 26. Glass Smoothness = 0.95 Metallic = 1 Golden Smoothness = 0.75 Metallic = 1 Plastic Smoothness = 0.75 Metallic = 0 Render both outward and inward faces Alpha = 0.2
- 28. A single number might not be enough. Different parts need different PBR configurations. That's why we need textures for fine-control. Varied parameters By sharing metallic & smoothness, WOOD looks like BRONZE
- 29. Metallic Smoothness Albedo WOOD Non-metallic & rough Mixed physical materials
- 30. Metallic Smoothness PBR Textures Preprocessing RED GREEN BLUE ALPHA Metallic (R) Smoothness (A) Roughness Invert *Details in next parts
- 32. Other common PBR parameters ALPHA Control opacity of transparent object. *For opaque object, pixels with alpha lower than a threshold would be invisible. AMBIENT OCCLUSION Control how much indirect light should be received (specially for cracks, intersections). EMISSION Control which area emitting light, and the emitted light color.
- 33. GOOGLE TIME § Glossiness / Roughness § Fresnel effect § Rim light § Height map § Clear coat
- 34. Summary 1 2 3 SHADER It's the code to manipulate vertex and fragment data for rendering. PBR SHADERS They're flexible and powerful to create realistic materials. ALBEDO, NORMAL, SMOOTHNESS They're common properties essential for further study.
- 35. MAKE IT BREAK IT EXPAND IT
- 36. § Shader Graph § UV Mapping § Effects (Dissolve, Hologram ...) § Special rendering (Grass, Water ...) § …