What is SSAO?
The SSAO technology appears more and more frequently in the option menus of many computer and video games. But what is SSAO and what are the benefits for the player?
What is SSAO in games?
- SSAO means Screen Space Ambient Occlusion in full. Ambient occlusion describes the fact that less light comes into corners and edges through reflection and these corners are darker as a result.
- In order to be able to calculate this effect of the dark corners in real time, the SSAO is used. The sub-term "Screen Space" means that the surrounding obscuration covers the entire area of the Screen is applied, but not to edges that are outside the field of vision of the player lie.
- Due to this limitation, the calculation of the shadow edges is relatively resource-saving, which has accelerated the spread of the technology since it was developed in 2007 for the game "Crysis".
How is SSAO calculated?
- SSAO is not an exact calculation, but a realistic estimate of the surrounding obscuration using various methods. The procedure that is currently most widespread is called "Inside-Out". In doing so, rays are sent in a spherical shape across the screen from one point.
- If one of these rays collides with the 3D geometry that has already been calculated, the starting point cannot receive any light from the point of contact and is marked in gray. Conversely, the origin of a ray that does not hit any geometry is marked with a lighter point.
- This will be for each point on the screen Repeated in all directions until the entire screen content (screen space) has been processed and an area-wide image of the edge structure is obtained.
- The results of these calculations are superimposed and then result in different shades of gray. Places that were more rarely the "origin" of a successful ray calculation are marked in a darker shade.
- The image generated in this way is now placed over the completely finished 3D image ("multiplied") and results in darkening along the edges where the shading was calculated in the previous steps became.
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The final image with SSAO therefore does not contain "real" lighting information, but only a calculation of the probable lighting. This bypasses an even more extensive calculation of the light reflections from different bodies. However, the disadvantage of SSAO is that the calculation can contain noise that is disruptive and cannot be removed or reduced. This is due to the type of calculation and can only be compensated for by more complicated methods of surrounding obscuration.
