Best Practice For Treating Light Volumes in Deferred Lighting Pipline

pavixavi · 2021-12-06T10:20:19

This topic is about ways to handle light volumes in a deferred lighting pipeline. I currently have a deferred lighting pipeline where spheres are sent to an openGL GLSL lighting shader. The sphere frags are shaded using my point and spotlight GLSL functions. Currently, I calculate the radius/position of the volume sphere individually for each light and send to the lighting shader which calculates accumulated light for every light in the scene for each frag in the sphere. So currently I am calculating number-of-lights * number-of-lights iterations in my loop. There must be a more efficient way to handle this for large volumes of lights. Two alternatives I can think of are: Combine sphere volumes into a single buffer (especially easy if light positions are static) and make a single drawing call in which the shader iterates over all the spot and point lights for each frag. Draw each volume seperately and specify single lights to calculate for each volume. Many more drawing calls but calculations limited to total-number-of-lights. I think this may be expensive for large volumes of lights, and I am always trying to reduce the number of my drawing calls. Any thoughts specific or general appreciated.

Graphics and GPU Programming Programming OpenGL C++ deferredlighting lighting GLSL

Started by pavixavi December 04, 2021 02:28 PM

11 comments, last by pavixavi 3 years, 1 month ago

pavixavi

Author

December 06, 2021 09:55 AM

@MJP Thank you for expanding on the approaches. So helpful. Clustered makes a great deal of sense to me. Personally I am not creating vast worlds with thousands of lights so I am hoping profiling a simpler classic apprach will meet my needs. Also I am finding keeping to a sensible time target for development and learning tricky given the steepness of the learning curve for some items. I am having to choose roadmap items very tightly now. Anyway thats a subject for a different post…

pavixavi

Author

December 06, 2021 10:20 AM

@Juliean Huge Sincere Thanks, Juliean. I have been stuck on this for over 24 hours. I clearly misunderstand how the blend function works and need to research. I am struggling to see why your correction works… my understanding was that glBlendFunc(GL_SRC_COLOR, GL_DST_COLOR) would add the previous and new values together for the frag and clamp to upper boundary of 1.

Best Practice For Treating Light Volumes in Deferred Lighting Pipline

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Best Practice For Treating Light Volumes in Deferred Lighting Pipline

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