Heightmap Area
Introduction
The height map provides the data determining the height at a particular position. It is this information together with the inputs that make up the final output texture and mesh. The heightmap is normally a grey scale image where black represents the lowest height (0) and white represents the largest height (255).
The height map area contains two menus, a main image view of the currently selected heightmap and a set of thumbnails of all the heightmaps in the project. Below the image is the heightmap name and information showing height and slope at the point under the mouse cursor.
On this page:
Tip: double clicking on any of the large images on the main screen opens an image viewer
Height Map View
The main image area shows the current heightmap. If there are more than one heightmap in the project clicking on a heightmap thumbnail changes the main view to that heightmap.
Normally the heightmap is shown as it is on disk. Normally heightmaps are grayscale images and sometimes this cannot show enough detail of how the image will map to heights so by clicking the Heat Map button below the thumbnails the view can be changed to a coloured representation of the image.
The real name for this representation is a Hypsometric Tint but heat map seems more intuitive. Below is an example of a height map in normal view and in Heat Map view:
File Menu
Load New
Use the file menu to load heightmaps. You can load many different graphic formats (bmp, tga, tif, gif, jpg, png, wmf, ico, bt, dds and dib). bt (Binary Terrain) files are a way of storing scientific elevation data. You can find some here: http://www.vterrain.org/BT/index.html
The way the data is interpreted into heights is determined in the settings dialog (via the current menu). This defaults to using the red channel which is correct for most cases, see below.
Replace Current
Rather than select Delete and then Load this allows you to swap heightmaps in one operation.
Delete
Delete removes the heightmap from the project.
Reload
Reload is useful if you have edited the heightmap outside of T2 and want to refresh it.
Edit
Loads the height map in an external editor. Which editor is used depends on your file associations. e.g. if the heightmap is a tga file and you have Photoshop installed and set to load tga files by default it will open the file in Photoshop.
Current Menu
This menu is titled 'Current Menu' because its functions relate only to the currently selected heightmap.
Higher Order and Lower Order
When using more than one heightmap the data is combined together based on rules defined in the settings dialog. The order the data is combined can affect the output so these two menu options can be used to move a heightmap up or down the order. The thumbnails to the right of the heightmap area show the current order with the heightmap at the top the first in the chain to be processed.
Summarise Chain
When a number of heightmaps are used and combined together it can be confusing to keep control of what is happening. This menu option puts up a dialog that explains in English sentences the order of operations.
Settings
This menu option brings up a settings dialog so the current heightmap parameters can be changed:
Texture Creation Operation
Determines how this heightmap will be used when the output texture is created. If set to replace then the raw values from this heightmap will determine the output and any heightmap that came before this in the chain now has no affect. Add, adds the affects of this heightmap to previous ones and average averages them. Not Used allows you to use this heightmap for mesh creation only and it will not affect texture generation. See below for an example of how all this works.
Mesh Creation Operation
This has the same types of settings as Texture creation but determines how the heightmap affects the creation of the mesh.
So how does this all work? Well say you wanted to take a nice hilly heightmap, like the island one included with T2, and you want to add some man-made things like roads to it. Normally this would be impossible to do with just one heightmap since the inputs affect different heights and slopes you could not get a road texture to represent a road, how could you? So by using more than one heightmap you can add features. Taking the previous example to add roads to our island we could load a second heightmap which is black in most places apart from the areas that need roads. We then add an input for the road colour and assign it only to the road heightmap (all other inputs are assigned to the first, island height map). When we create our texture we now find a road on top of the island. Often you want the road just to hug the surface of the island so then you would set the texture creation operation to 'replace' and the mesh creation operation to 'not used' i.e. you are only using the second heightmap to define road positions not to affect the resultant mesh.
The sleepingDragon example included with the program shows this in action. It uses the second heightmap solely to draw the eyes.
Height Mode
Determines which colour channel(s) are used to represent the height. For a grey scale image this can be either red, green or blue.
Height Adjustment
This allows the height value to be scaled by a set amount. This occurs before creation of the output textures so will affect the slopes etc. It is useful if you are using a small sized heightmap and would like to scale the heights down so they are better proportioned to the overall size. The value cannot go above 1.0 so heights cannot be scaled up. If you wish to scale heights upward use the y scale slider on the mesh screen.
Information
Below the heightmap is the heightmaps name (edited by double clicking on it) and also details of the height and slope under the mouse cursor. When the mouse moves over the heightmap it changes to a cross to indicate it is sampling at that point.
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