Computer Graphics  
Lecture 09Textures and Materials  
Edirlei Soares de Lima  
<edirlei.lima@universidadeeuropeia.pt>  
Materials, Shaders and Textures  
Materials: define how a surface should be rendered, including  
references to textures, tiling information, color, etc.  
The options available depend on which Shader the Material is using.  
Shaders: small scripts that contain the mathematical  
calculations and algorithms for calculating the color of each  
pixel rendered, based on the lighting input and the Material  
configuration.  
Textures: are bitmap images.  
A Material can contain references to textures, so that the Material’s  
Shader can use the textures while calculating the surface color.  
Textures can also represent other aspects of a Material’s surface such  
as its reflectivity or roughness.  
Unity Standard Shader  
Standard Shader: built-in shader with a comprehensive set of  
features.  
Supports reflection, bump mapping, occlusion mapping, emission,  
transparency, shadows, indirect light, etc.  
Physically Based Shading: render objects in a way that accurately  
simulates the flow of light of the real world.  
Example of scene rendered using the standard shader on all models:  
Standard Shader: Content and Context  
The appearance of material based on the Standard Shader is  
influenced by the content and context of the scene.  
Context: light sources, skybox, indirect light, etc.  
Content: scene objects, textures, etc.  
Example of scene with variations in context:  
Metallic vs. Specular Workflow  
There are two options of workflow when creating a material  
using the Standard shader: "Standard" and "Standard  
(Specular setup)“.  
Standard (Metallic setup): the shader exposes a “metallic” value that  
states whether the material is metallic or not.  
The Albedo color will control the color of the specular reflection and most light will  
be reflected as specular reflections.  
Standard (Specular setup): a specular color is used to control the color  
and strength of specular reflections in the material.  
This makes it possible to have a specular reflection of a different color than the  
diffuse reflection for instance.  
Metallic vs. Specular Workflow  
Standard Shader  
Parameters:  
Rendering Mode  
Albedo  
Specular Mode: Specular  
Metallic Mode: Metallic  
Smoothness  
Normal Map (Bump Mapping)  
Height Map (Parallax Mapping)  
Occlusion Map  
Emission  
Detail Mask & Maps  
Textures: http://www.inf.puc-rio.br/~elima/cg/textures.html  
Standard Shader: Rendering Mode  
Rendering Mode: defines whether the  
object uses transparency, and if so,  
which type of blending mode to use.  
Opaque: suitable for normal solid objects with  
no transparent areas.  
Cutout: used to create a transparent effect that  
has hard edges between the opaque and  
transparent areas. Useful to create leaves or  
cloth with holes.  
Transparent: suitable for rendering realistic  
transparent materials such as clear plastic or  
glass. Reflections and lighting highlights will  
remain visible.  
Fade: allows the transparency values to  
entirely fade an object out, including any  
specular highlights or reflections it may have.  
Standard Shader: Rendering Mode  
Cutout Mode Example  
Standard Shader: Rendering Mode  
Transparent Mode Example  
Standard Shader: Rendering Mode  
Transparent Mode Example with fully opaque areas  
Standard Shader: Rendering Mode  
Fade Mode Example  
Standard Shader: Albedo  
Albedo: defines the base color or  
texture of the material.  
The alpha value of the Albedo color  
controls the transparency level for the  
material.  
This only has an effect if the Rendering  
Mode for the material is not set to  
opaque.  
Standard Shader: Albedo  
Transparencies in areas of the material must be specified  
in the texture alpha channel.  
Standard Shader: Albedo  
Transparencies in areas of the material must be specified  
in the texture alpha channel.  
Standard Shader: Specular  
Specular (Specular Mode): represents  
the direct reflections of light sources,  
which typically show up as bright  
highlights on the surface of objects.  
Example:  
Standard Shader: Specular  
The color of the Specular parameter controls the strength and  
color of the specular reflectivity.  
The Smoothness parameter controls the clarity of the specular  
effect.  
Low smoothness value = even strong specular reflections appear  
blurred and diffuse.  
High smoothness value = specular reflections are crisper and clearer.  
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ꢄꢅꢃꢆ  
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ꢐꢀꢑ  
ꢒꢃꢀꢎꢉꢂꢑꢊꢐꢂꢆꢍꢌ  
Standard Shader: Metallic  
Metallic (Metallic Mode): specular  
reflections arise naturally depending  
on the settings of the Metallic and  
Smoothness levels (rather than being  
explicitly defined as in the specular  
mode).  
Example:  
Standard Shader: Metallic  
The metallic parameter determines how “metal-like” the  
surface is.  
When a surface is more metallic, it reflects the environment more and  
its albedo color becomes less visible.  
When a surface is less metallic, its albedo color is more clear and any  
surface reflections are visible on top of the surface color.  
Standard Shader: Smoothness  
Smoothness: defines how light scatters when  
it hits the surface of the object. Represents  
microsurface details” of the object.  
Low Smoothness:  
Standard Shader: Smoothness  
Smoothness: defines how light scatters when  
it hits the surface of the object. Represents  
microsurface details” of the object.  
Median Smoothness:  
Standard Shader: Smoothness  
Smoothness: defines how light scatters when  
it hits the surface of the object. Represents  
microsurface details” of the object.  
High Smoothness:  
Standard Shader: Normal Map  
Normal Map (Bump Mapping): adds  
surface detail such as bumps, grooves,  
and scratches to a model which catch  
the light as if they are represented by  
real geometry.  
Example of Normal Map texture:  
Standard Shader: Normal Map  
Example: screws in metal surface (without bump mapping)  
Standard Shader: Normal Map  
Example: screws in metal surface (with bump mapping)  
Standard Shader: Normal Map  
Bump mapping is a technique for simulating bumps on the  
surface of an object. This is achieved by perturbing the  
surface normals of the object and using the perturbed  
normal during lighting calculations.  
What are Surface Normals?  
Standard Shader: Normal Map  
What are Surface Normals?  
Flat Surface:  
Smooth Surface:  
Standard Shader: Normal Map  
What is Normal Mapping?  
Standard Shader: Normal Map  
What is Normal Mapping?  
Standard Shader: Normal Map  
How do I get or make normal maps?  
During the 3D modelling process:  
Very high resolution model + lower resolution “game ready” model.  
From a texture:  
ShaderMap - http://shadermap.com/  
Can be produced by hand.  
Standard Shader: Normal Map  
Result:  
Without Normal Mapping  
Standard Shader: Normal Map  
Result:  
With Normal Mapping (directional light)  
Standard Shader: Normal Map  
Result:  
With Normal Mapping (point light)  
Standard Shader: Height Map  
Height Map: as normal maps, height  
maps add surface details. Are used to  
give extra definition to surfaces and  
render large bumps and protrusions.  
Example of Height Map texture:  
Standard Shader: Height Map  
Height mapping (also known as parallax  
mapping) is a similar concept to normal  
mapping, however this technique is more  
complex - and therefore also more  
performance-expensive.  
While normal mapping modifies the lighting  
across the surface of the texture, parallax  
height mapping goes a step further and  
actually shifts the areas of the visible surface  
texture around.  
The effect is drawn onto the surface of the model  
and does not modify the actual geometry.  
Standard Shader: Height Map  
Without Bump Mapping  
With Normal Mapping  
With Hight Mapping  
Standard Shader: Occlusion Map  
Occlusion Map: used to provide  
information about which areas of the  
model should receive high or low  
indirect lighting.  
Example: concave areas usually do not  
receive much indirect light.  
Example of Occlusion Map texture:  
Standard Shader: Occlusion Map  
Without Occlusion Mapping  
With Occlusion Mapping  
Standard Shader: Emission  
Emission: controls color and intensity of  
light emitted from the surface. When  
an emissive material is used in your  
scene, it appears to be a visible source  
of light itself.  
Example:  
Standard Shader: Emission  
It is also possible to assign an emission map texture:  
Standard Shader: Secondary Maps &  
Detail Mask  
Secondary Maps: allows the overlay of  
a second set of textures on top of the  
main textures (second Albedo color  
map and a second Normal map).  
The reason to use secondary maps is  
to allow the material to have sharp  
detail when viewed up close, while  
also having a normal level of detail  
when viewed from further away.  
Without using a single extremely high  
texture map to achieve both goals.  
Standard Shader: Secondary Maps &  
Detail Mask  
Typical uses for detail textures are: adding skin detail,  
adding tiny cracks and lichen growth to brick walls, adding  
small scratches to metal containers.  
Example (without secondary maps):  
Standard Shader: Secondary Maps &  
Detail Mask  
Typical uses for detail textures are: adding skin detail,  
adding tiny cracks and lichen growth to brick walls, adding  
small scratches to metal containers.  
Example (with secondary maps):  
Other Built-in Shaders  
FX: Lighting and glass effects.  
GUI and UI: For user interface graphics.  
Mobile: Simplified high-performance shader for mobile devices.  
Nature: For trees and terrain.  
Particles: Particle system effects.  
Skybox: For rendering background environments behind all geometry.  
Sprites: For use with the 2D sprite system.  
Toon: Cartoon-style rendering.  
Unlit: For rendering that entirely bypasses all light & shadowing.  
Legacy: The large collection of older shaders which were superseded by the Standard Shader.  
Exercise 1  
1
) Update the “Make Your Fantasy Game - Lite” demo scene to  
make better use of the Standard Shader features.  
Download: https://assetstore.unity.com/packages/3d/environments/fantasy/make-  
your-fantasy-game-lite-8312  
The updated scene must:  
Use normal mapping;  
Improve specular configuration;  
You can find better textures in the asset store. Examples:  
https://assetstore.unity.com/packages/2d/textures-materials/floors/outdoor-  
ground-textures-12555  
Further Reading  
Hughes, J. F., et al. (2013). Computer Graphics: Principles  
and Practice (3rd ed.). Upper Saddle River, NJ: Addison-  
Wesley Professional. ISBN: 978-0-321-39952-6.  
Chapter 20: Textures and Texture Mapping;  
Marschner, S., et al. (2015). Fundamentals of Computer  
Graphics (4th ed.). A K Peters/CRC Press. ISBN: 978-  
1482229394.  
Chapter 11: Texture Mapping  
Web:  
https://docs.unity3d.com/Manual/Shaders.html