DXOverArrayMMX function

Article
08/15/2017

Composites an array of source samples over an array of destination samples, using the MMX instruction set for large arrays of samples.

Syntax

void DXOverArrayMMX(
  _In_       DXPMSAMPLE    *pDest,
  _In_ const DXPMSAMPLE    *pSrc,
  _In_       unsigned long nCount
);

Parameters

pDest [in]
A pointer to the samples that will be modified by compositing the pSrc samples over the pDest samples.
pSrc [in]
A pointer to the array of samples to composite over the destination.
nCount [in]
A value of type unsigned long that specifies the number of samples in the array.

Return value

This function does not return a value.

Remarks

If the processor does not support MMX, you can still call this function, which will perform the same operation but not as quickly.

Note that it is less efficient to use this function if the majority of the samples in the pSrc buffer are clear (alpha = 0) or opaque (alpha = 255). This is because the MMX code must process every sample and cannot skip the clear or opaque samples. If there are many translucent samples, then this function is more efficient than DXOverArray.

Requirements

Minimum supported client	Windows XP
Minimum supported server	Windows 2000 Server
Header	Dxhelper.h

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