Gadgetory

ambient occlusion is a term that's thrown around a lot in 3d rendering and to gamers but what is it and how does it work first let's determine what occlusion means the columns world English dictionary defines occlusion as to block stop or obstruct so for our discussion today we can comfortably describe occlusion as the amount of obstruction there is between one point or region of a 3d scene and a light source now let's add the whole ambient part into the mix from Wikipedia ambient occlusion is a render technique used to calculate how exposed each object or pointed as scene is to the ambient lighting to expand on that it's a global method of illuminating a scene whereby each point or object is lit by taking all the other geometry in the scene into account so even though a shadow is not clearly defined or hard-coded areas that are less exposed naturally to direct or indirect light like corners will appear dark and shadowy now even though it's more comprehensive than local methods like Phong shading an early technique for approximating the shading of a smooth surface in 3d graphics ambient lighting is still a pretty crude method of achieving global illumination more on that later okay so it's a lighting effect that graphic designers and game developers use to add realistic shading to a scene but how does it work and why should I care great question an amine occlusion was first introduced to gaming in 2007 by the developers of crisis due to hardware limitations Crytek implemented a scaled-down version of ambient occlusion called screen space ambient occlusion or SSAO SSAO works by using pixel depth rather than scene geometry to form an ambient occlusion map it is a much more simple process as it applies a somewhat realistic amount of occlusion to each pixel in relation to those around it rather than evaluating the shading of an entire room for example based on a light source or multiple light sources SSA OS advantages include zero load time and no pre-processing so it works the same for every pixel on the screen and no CPU usage that's right it can add a huge amount of depth and complexity to a scene and only ends up TAC the GPU pretty cool it does have disadvantages though it will not represent the scene as accurately as true ambient occlusion would as it only takes what you can see on screen into account and there are some issues with accurately blurring and smoothing out noise without interfering with depth discontinuities like hard edges it's certainly not a perfect solution so in 2009 we got an upgrade to SS vo screen space directional occlusion this allowed game engines to calculate local indirect illumination and cast directional shadows without the aid of an environmental map SSTO allowed for a wider variety of shades by taking the angle from which the light approaches the object as well as the bounce of the light off an object behind the initial object into account this helps but it's still a far cry from true ambient occlusion so we covered the approximations but what would true ambient occlusion look like well in a perfect world with uber computers every aspect of the scenes geometry would be taken into account from your character's model to the bridge directly in front of you all the way down to the tree 300 yards behind you light would bounce off all of these elements to create a photo realistic lighting model like the groundbreaking full global illumination method that Pixar implemented in monsters you unfortunately rendering all of this in real time would be extremely taxing on your hardware which is what makes it nearly impossible to achieve in games with modern technology some advances have been made though through pre-rendering parts of the scenes occlusion like the occlusion caused by your character's model or static objects and outdoor scenes or by separating high-frequency detailed ambient occlusion for objects close to you from low-frequency ambient occlusion on distant objects but we're still unable to achieve true ambient occlusion in real time so for now we'll have to deal with the approximations first world problem right speaking of first world problems waiting for your computer to start up with a little hard drive can be a real pain in the butt which is why today's video is brought to you by the letter A data a data right featuring their SP 910 series of SSDs their Marvell controller offers outstanding performance with sequential read and write speeds of up to 560 460 megabytes per second and 4k random read/write speeds of up to 90 1077 thousand i ops which means a massive performance improvement over your hard drive out-of-the-box and thanks to support for trim and smart great performance and reliability over time as well they are available now in 128 256 512 gig and even one terabyte capacities so if you like tech quickie and you like the companies who sponsor it be sure to give a data a look if you're in the market for a new SSD anyway guys thanks for watching like if you 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