Let there be Light

Basic lighting has been added to Decade. This adds another slight layer of realism to the scene. In my opinion the screenshot below does not do Decade Justice. The moving water being effected by light and shade creates an impressive effect. I have tried to create a video to upload to YouTube so I can show here but so far the quality hasn't been worth showing.

Patch Culling and Node Tree has been added to Brute Force Terrain. This now exceeds the frame rate of software rendered Geomipmapping, however Geomipping will soon be Hardware Rendered too and will hopefully increase in frame rate.

Other in progress work are Scriptable Particle Systems and GUI Components such as buttons, combo boxes etc...

Software Water

Although I hope that some day Decade is a high end 3D engine supporting the most advanced technologies and rendering techniques, at present I want to make sure that almost anyone can play my games.


My full blown water will be rendered using Bump Maps and Stencil Reflections, which not all Graphics Cards support therefore I have first implemented a simple alpha blended tessellating mesh with a sphere mapped texture. Results are not very realistic however give the impression of water with semi-realistic movement.


In Wire frame one can see the mesh clearly. As the water mesh is constantly moving and is alpha blended it does not have to be as high a resolution as the terrain. The terrain is the images shown is 512x512 whereas the water mesh is only 60x60.

Multiple View Ports

To take a little break from terrain programming I decided to try something else last night. While watching a Formula 1 Grand Prix over the weekend it reminded me of playing racing games and being able to turn on or off the rear view. Having always wanted to implement this I decided that now was the time.

I was amazed at how easy it is in OpenGL to achieve multiple view ports. After 10 minutes of reading an online document I realised that I already had all the code from my OpenGL setup functions so only a little reorganisation was required.


Decade can now support 1 t0 X view ports (I haven't tested an upper limit) and each view port is independently controlled, updated and rendered. They can share scene data or use entirely separate data.

Uses for this within my plans for Decade are currently limited. It was implemented for my enjoyment rather than for a real need, however it should become useful for rear view when in a car, split screen multiple players etc..

The Sky's the Limit

Sky Boxes have been added to Decade, and as a friend has commented they give the scene atmosphere in more than 1 sense. The sky boxes used were taken from Hazel Whorley who offers his creations free for use in non-commercial projects. They are some of the best free sky box textures I have ever seen.

I will use sky boxes for a while with Decade however I want to soon implement sky domes. They have many advantages over sky boxes. Due to the cube nature of the sky box it is very difficult to animate the sky without the cube structure becoming obvious to the user. The dome removes this and will allow me to set the time of day and add procedural clouds.

Erosion Filters

Having put the issue raised in blog entry If a man owns land, the land owns him on the to "Fix It Later" pile I continued development of Decade. All my documented issues are always on my mind as I research and develop, so yesterday while searching through random Terrain documents I found a Box Filtering Height Maps for Smooth Rolling Hills tutorial and immediately thought it might be useful. Even though I am not always going to want to have rolling hills I thought that such a method might enable me store the terrain in its original 1 or 2 byte format instead of using 4 byte floats.

Terrain with height values stored in 1 byte

Terrain with height values stored in 4 bytes

Terrain with height values stored in 1 byte and modified with Erosion Filter of Box Size 3 and 1 Iteration

As you can see, running the Erosion Filter on the terrain greatly improves the quality of the 1 byte height field. (When I say 1 byte height field I mean that the data in the .raw file was stored in bytes. The height field is still stored in 4 bytes (float) within Decade). There is a little loss of detail compared to the 4 byte terrain however depending on the game and environment this may be acceptable.

Terrain with height values stored in 1 byte and modified with Erosion Filter of Box Size 11 and 5 Iteration

Care has to be taken when using the Erosion Filter. As you can see above running with too large a box size over many iterations starts to remove allot of the detail from the terrain resulting in a flowing rolling landscape. Again, this may be desirable in certain instances and not in others.

What this has thought me is that there is no right answer to the question I am asking. It all depends on personal preference and the requirements of the game at that time. To accommodate this I am going to allow a broad range of options. My custom height map file will be modified to allow the user specify how the data is stored.

Currently the simple file type is
Width (2 Bytes)
Length (2 Bytes)
Data (Width * Length * 4 Bytes)

so by adding in a type field the user can save and load as they desire

Width (2 Bytes)
Length ( 2 Bytes)
Type (1 Byte)
Data( Width * Length * Type Bytes)

I hope that this,along with the box and any other Erosion Filters added later, will allow Decade deal with a large variety of requirements when rendering/storing its terrain.

A little forrest.

As I mentioned in a previous post, I really wanted to add trees and other vegetation to my terrain engine. I believed that this would greatly add to the atmosphere. My first desire was to create all these trees and plants procedurally. After searching online for a while I found a few good tutorials on how to achieve this but have decided to place that idea on hold for a while. Eventually I would love to do this. It would be great to have procedural plants on a procedural planet in a procedural solar system within a procedural universe. :)

For now I have decided to use mesh's for the plants. Again, rather than waste my time trying to model them myself or look for appropriate free models online (any I found either looked wrong or were to complicated) I choose to purchase the tree packs from Loopix These are decent quality, low poly trees which are ideal for my needs.

Currently a small selection of the available trees are just placed at random on the terrain. Already I think they add a whole new feeling to the demo.

Procedural Texture Mapping

Decade can now generate its terrain textures procedurally. This is a big step as each terrain created automatically gets textured based on its unique attributes. Instead of just showing you a screenshot I will briefly explain how the textures are created.

A set of base textures is gathered. These are plain textures of all the environments which will exist in the terrain. e.g. sand, grass, rock, mud, snow etc...



Each of these environments is given

• optimum height (The best height at which this environment exists)
• min height (The minimum height at which this environment exists)
• max height (The maximum height at which this environment exists)

By cross referencing these values with the height map, the textures assigned to each terrain which exits at the given height are blended together with higher preference going to the more optimal terrain.

The result is the above texture which is then applied to the terrain. For my first implementation of this algorithm I am happy with the results, however as always there are many improvements which need to be added.

• Tiling textures instead of stretching them
• Add support for applying the detail texture to the terrain texture at this stage to cards which do not support multi-texture can still have detail at no extra cost.
• Some better logic for texture blending instead of just checking the height. The environment in a valley is different to that of a cliff face at the same height, or rocky outcrops on a snow covered mountain etc...
• Add lighting so that features are enhanced.
• Add vegetation to add more realism.