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How Forward rendering affects performance and appearance?

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    How Forward rendering affects performance and appearance?

    Compared to deferred rendering that is. There seems to be very little on this.

    We just switched in the middle of a project to forward rendering and virtually no difference in appearance for maybe 15-20% FPS improvement. Allegedly it supports "fewer shader options" but our fanciest shader is volumetric fog which still works perfectly.

    Anyway, changing over is just a single project setting and wait for shaders to compile. Easy to test it for a week and change back if any issues.


      Did you read the documentation?

      It definitely effects some translucent materials but there's a lot going on that it changes. You also lose the ability to write out frames from buffers (passes) because of the way the final image is generated in forward shading. This is guarenteed to break materials that rely on "SceneTexture" nodes.


        We have noticed an increase in FPS performance, which is really not a true indication of performance in UE4, as to resources that would benefit from forward rendering in the first place.

        Shader complexity seems to be less critical and more so in the area of transparency.

        The use of sub surface profiles is out

        Landscape materials tends to create missing texture errors requiring they be switched to shared wrap.

        Ambient cube maps (HDRI) do not work in FR.

        Consideration for use.

        If your game has an on line component or plan on using VR any performance bump is desirable and to this point working around some of the feature issues is a matter of finding a different way of doing something.

        If your game is stand alone and able to maintain a height performance curve then I would consider to defer the switch until the game is in the final polish stage and can be properly tested and profile as being fit to finish.

        Personal opinion as to looks?

        Some say FR looks better but I would suggest that it only looks different and neither better or worse.
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