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SrcTransBltSys

Copy a block of system memory to a location in video memory with source transparency.

Declaration

void NAPI GA_2DRenderFuncs::SrcTransBltSys(
void *srcAddr,
N_int32 srcPitch,
N_int32 srcLeft,
N_int32 srcTop,
N_int32 width,
N_int32 height,
N_int32 dstLeft,
N_int32 dstTop,
N_int32 mix,
GA_color transparent,
N_int32 flipY)

Prototype In

snap/graphics.h

Parameters

srcAddr | Address of source bitmap in system memory
srcPitch | Pitch of source bitmap in bytes
srcLeft | Left coordinate within source bitmap to copy
srcTop | Top coordinate within source bitmap to copy
width | Width of the rectangle in pixels
height | Height of the rectangle in scanlines
dstLeft | Left coordinate of destination
dstTop | Top coordinate of destination
mix | Mix code for the copy (GA_mixCodesType)
transparent | Transparent color value
flipY | True if the image should be flipped vertically

Description

This routine will copy a bitmap from system memory with a starting address of srcAddr to the destination rectangle (dstLeft, dstTop, dstLeft+width-1, dstTop+height-1) with the specified mix and with source transparency. The mix code will be used to combine the source bitmap data with the pixels in the destination bitmap. The transparent color passed will be used to /mask out/ pixels in the source bitmap from being written to the destination area. Where a pixel in the source bitmap matches the transparent color, the pixel will not be written to the destination bitmap.

Note that the srcLeft and srcTop coordinates define an offset within the source bitmap to be copied, so it will copy only a portion of the memory bitmap.

Note: Although you can achieve the same effect of this routine using the generic BitBltFxSys function, this function is provided separately as it is usually a workhorse function for sprite based game applications and needs to be as efficient as possible.

See Also

SrcTransBlt, SrcTransBltLin, SrcTransBltBM, DstTransBlt, BitBlt, BitBltFx

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