Final Video Script: Basic Texture Layers
Basic Texture Layers
In this section I’ll be explaining what makes up the textures that are used on our game objects. The basic concepts of surface normals and color maps will be explored to some degree. The materials in our game rely on multiple layers of shading in order to achieve a detailed look. Our two main layers are the color and the normal maps. Custom texture layouts are generated for each game object. After I have made a group of unique objects, I can copy them and distribute them in our game world, applying simple size, shape and rotation variations to each copy.
I will be using one of the large rocks from our scene as the example I am showing you today.
Show rock
basic lighting, simple object
show unwrapping
turn on set smooth- smooths shading between faces
Open up color map in UV editor
show how unwrapping corresponds with color map
Turn on color map
many ways to generate color maps
I use a two step method, the steps are combined into one color map on the rock, on the tree they can be seen as separate layers in Blender.
Show tree trunk
basic color layer and detail color layer
there are advantages and disadvantages to combining them into one layer in Blender, it depends on the object.
Intro to surface normals
go into edit mode and show face normals
-each face is flat as a triangle, triangle being the simplest type of polygon
-surface normal tells the program what way that face is pointing, this defines how light hits it
-too many faces bog computer down
Unhide complex rock
show normals on complex rock
open UV editor, show normal map
Open normal map in GIMP, show channels
all computer images are a mix of red, green, and blue, each channel contains different levels of RGB, from 0-100%. Blender reads the normal map like a code, the combination of red green and blue in a normal map tells Blender how to shade the surface when light hits it. With a texture map, each pixel can be lit as if it were a face and with many pixels mapped to each face, it is an efficient way to increase detail of an object.
Turn on normal map channel, show off rock, show normal map by itself. Go to tree trunk and do the same
This is a performance saving cheat and is used in high end game production these days.
Blender allows you to take the normals from one object and bake them to a normal map for use with another object. Will cover texture baking in another section.
The biggest weakness of normal maps is that they don’t hold up when viewed from the side. There are other forms of mapping that can make the illusion even more real, but are harder to achieve.
Other considerations
Specularity: how shiny the object is, this can help accentuate your normal maps. Texture maps can be used to control this as well.
In this section I covered the two basic texture layers that we are utilizing in this demo. The first layer is the color map, this is a simple image that gives the object a colored and detailed surface. The second layer is the normal map. This layer serves a more complex purpose than the color map since it creates the illusion of a much more detailed physical surface than is actually represented by geometry. The normal map changes how light hits the surface, allowing for a very nice look.
