Real-time lighting via Light Linked List
Seems like the basic idea is as follows,
Render G-buffer.
Get min/max depth for each 8x8 tile.
For 1/64 area (1600/8 by 900/8), raster lights with software depth test.
For each tile, build linked list of lights intersecting tile.
Linked lists of {half depthMin, half depthMax, uint8 lightIndex, uint24 nextStructureIndex}.
Keeping light bounds helps avoid shading when tile has large depth range.
Full screen pass shading for all lights intersecting a tile.
Would This be Faster?
Given the maximum of 256 lights, have a fixed 32-bytes per tile which is a bitmask of the lights intersecting the tile. Raster the lights via AtomicOr() with no return (no latency to hide), setting the bit in the bitmask. At deferred shading time per workgroup (workgroup shades a tile), first load the bitmask into LDS, then in groups of lights which fit in the LDS, do a ballot based scan of the remaining lights in the bitmask, load the active bit lights into the LDS, then switch to shading pixels with the light data, then repeat.
Seems like the basic idea is as follows,
Render G-buffer.
Get min/max depth for each 8x8 tile.
For 1/64 area (1600/8 by 900/8), raster lights with software depth test.
For each tile, build linked list of lights intersecting tile.
Linked lists of {half depthMin, half depthMax, uint8 lightIndex, uint24 nextStructureIndex}.
Keeping light bounds helps avoid shading when tile has large depth range.
Full screen pass shading for all lights intersecting a tile.
Would This be Faster?
Given the maximum of 256 lights, have a fixed 32-bytes per tile which is a bitmask of the lights intersecting the tile. Raster the lights via AtomicOr() with no return (no latency to hide), setting the bit in the bitmask. At deferred shading time per workgroup (workgroup shades a tile), first load the bitmask into LDS, then in groups of lights which fit in the LDS, do a ballot based scan of the remaining lights in the bitmask, load the active bit lights into the LDS, then switch to shading pixels with the light data, then repeat.