Tuesday, 9 December 2014

Tech Feature - Visuals and Performance

 . I wasn't using FBOs at the time so performance is not as good as it could have been

This is the first entry in my tech feature series, which will help give you a better understanding of the tech powering Legacy. Legacy is built on top of the Jenesis Engine (JE) which is written in Java. The Jenesis Engine uses an OpenGL wrapper library called JOGL to render 3D graphics.
The specific version of OpenGL being used is 3.2 Core along with GLSL 1.5. In Windows terms, this is the equivalent of DirectX 10 with Shader Model 4. This spec is fully supported across Linux, Mac OSX and Windows. If you have any GPU from Nvidia or AMD then your machine is probably capable of rendering with OpenGL 3.2. Only the most recent iterations of Intel GPUs fully implement this spec.
The following features of OpenGL are used in Legacy.
VAOs are used to render all geometry within the game. FBOs and PBOs are used in conjunction with GLSL to implement various post effects. Hardware Instancing is used to create believable “particles effects” (fire, flames, smoke).
The game is still in Alpha, and currently has 4 graphics quality presets: Ultra, High, Medium, Low. The screens below show their effect in game and their FPS at 1080p. These are the development machines specs, hardly top of the line yet more powerful than your average off the shelf PC.
  • 1GB GDDR5 AMD Radeon 5670HD
  • 4GB DD3 RAM
  • AMD Bulldozer 4100FX 3.6GHz Quad Core
  • Tested in Ubuntu 12.04 64bit on JRE 1.7_3 platform
The summary of each spec is shown below
Character SpritesHighHighMediumLow
Environment SpritesHighMediumMediumLow
Particle(Instance) DensityUltraHighMediumLow
Post EffectsOnOnOffOff
Depth of FieldOnOffOffOff
Radial BlurOnOnOffOff
Sketch PaintingOnOnOffOff

Illustration 1: 1080p :: Ultra Spec :: 29 fps average

Illustration 2: 1080p :: High Spec :: 60 fps average

Illustration 3: 1080p :: Medium Spec :: 82 fps average
Illustration 4: 1080p :: Low Spec :: 88 fps average

The table below shows a summary of the results, as well as scores for a resolution of 1024 x 768.

The Ultra Specs Depth of Field effect hammers performance, though it runs at a solid 60 fps at lower resolutions. The games performance is dependent on your selected resolution and your graphics cards raw horsepower. I suspect most will play this game at 1366 x 768 up to 1680 x 1050 at High Settings. Legacy wont be released until 2013 but I don't expect drastic changes to made to the rendering tech.

I hope this brief feature gave you an idea of what to expect from the final version of Legacy. If you have any comments, queries or suggestions please feel free to comment below. Im particularly interested to hear your opinions on the scaling of its graphics presets.
Take care.

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