Fastest SetPixel

This demo demonstrates the use of memory pointer tricks, bitwise operations and parallelization to reach extremely high speeds of SetPixel. This demo is written in C#.

These are the benchmarks for a 1920x1080 32bpp buffer:

Method	Color?	Alpha?	Safe?	ARGB Speed	RGB Speed	Parallel.For?
Byte Array	Yes	Yes	Yes	3.77ms	3.62ms	Yes
Byte Set	Yes	Yes	No	1.18ms	0.91ms	Yes
Integer Set	Yes	Yes	No	0.47ms	0.47ms	Yes
Bitwise Set	Yes	Yes	No	0.83ms	0.78ms	Yes
RtlZeroMemory	No	No	Yes	0.31ms	0.31ms	No
RtlZeroMemory2	No	No	Yes	0.22ms	0.22ms	Yes

_{Tested on i7-4710HQ 16GB DDR3 Win8.1, NET 4.5. Speeds calculated from the average of 100 tries.

With the exception of Byte Array, all parallelized loops used lambdas for ~0.4ms time save.

Resolution values were hardcoded, so expect a slight performance impact for runtime resolved resolutions.

With hardcoded color values, Integer and Bitwise Set can reach 0.40ms speeds, due to the same IL Code.

Integer Set only supports ARGB colors, RtlZeroMemory only supports zeroing out.

memset was not included as its performance is lackluster.

All tests were run in release mode, outside of Visual Studio.}

Safe Methods

Byte Array uses a simple 1920x1080 Parallel.For loop to set each individual pixel with a managed array.
RtlZeroMemory simply zeros the entire buffer out. It is it the fastest non parallelized method.
RtlZeroMemory2 uses a 1080x Parallel.For loop to zero out 1920 pixels horizontally, 1080 times.

Unsafe Methods

All unsafe methods use a split 1080x Parallel.For loop which then calls a lambda which then sets 1920 pixels.

Byte Set sets each ARGB/RGB byte value individually via byte* pointer.
Integer Set treats each pixels ARGB/RGB values as an integer, and sets them with a precalculated integer via int* pointer
Bitwise Set bit shifts ARGB/RGB byte values into each individual pixel via int* pointer.

Conclusion

For Color Clear, use Integer Set, and calculate the integer ARGB bytes from a bitwise operation.
For Black Clear, use RtlZeroMemory as it is the fastest method.

theproadam / FastestSetPixel