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IDProjectCategoryView StatusLast Update
0005851The Dark ModGraphicspublic21.12.2021 17:22
Reporterstgatilov Assigned To 
Status newResolutionopen 
Product VersionTDM 2.10 
Target VersionTDM 2.11 
Summary0005851: Stencil shadows with multisampling: don't blit whole framebuffer
DescriptionAfter real multisampling was returned back (I guess it was in 2.08), we had very inefficient implementation of stencil shadows.
I have fixed the simple issue causing huge slowdowns for 2.10, but some inefficiency still remains.

After we finish rendering the stencil buffer, we always blit-resolve the whole screen.
This means increased memory bandwidth, which is often the main bottleneck.
The original Doom 3 was very careful to limit light-related operations to the scissor rectangle, and we should do the same for blit-resolve.

Of course, there will be issues, e.g. currently Framebuffer class does not support blitting rectangle.
Moreover, if we blit a rectangle, it is not obvious how to specify the rectangle (there are different many ways due to e.g. "render scale").
Maybe it makes sense to add a flag "respect scissor", and specify the rectangle via OpenGL scissor (which already has multiple functions to set it).
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Date Modified Username Field Change
21.12.2021 17:22 stgatilov New Issue