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BitBltPlaneMaskedBM

Copy a block of system memory to a location in video memory with Bus Mastering using an associated bit plane mask

Declaration

void NAPI GA_2DRenderFuncs::BitBltPlaneMaskedBM(
void *srcAddr,
N_int32 srcPhysAddr,
N_int32 srcPitch,
N_int32 srcLeft,
N_int32 srcTop,
N_int32 width,
N_int32 height,
N_int32 dstLeft,
N_int32 dstTop,
N_uint32 planeMask)

Prototype In

snap/graphics.h

Parameters

srcAddr | Address of source bitmap in system memory
srcPhysAddr | Physical 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
planeMask | Plane mask to use during the copy

Description

This routine will copy a bitmap from system memory with a physical starting address of srcPhysAddr to the destination rectangle (dstLeft, dstTop, dstLeft+width-1, dstTop+height-1) with the specified plane mask. The plane mask is used to determine which bits in the destination pixels will be affected by the copy. Each bit in the plane mask is used to mask out a bit in the destination pixel values, and where a bit is a 1 the destination bit comes from the source pixel while where a bit is 0 the destination bit is left unchanged.

This version is different to the BitBltSys function in that the bitmap data is copied using Bus Mastering by the graphics accelerator, which allows this function to return before the copy has completed and the accelerator will complete the copy in the background with a DMA Bus Master operation. If this hardware supports Bus Mastering and this function is available, it will usually be the fastest method to copy a block of system memory to video memory.

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.

See Also

BitBlt, BitBltPlaneMasked, BitBltPlaneMaskedLin, BitBltPlaneMaskedSys

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