Converts a 256 colour windows .bmp format file to raw pixel data in the form 1 byte = pixel, suitable for direct use in the VxZ80P as sprite data.

When building up the output file, the source picture is scanned in blocks 16×16 pixels in size, from top to bottom, left to right (ie: vertical block slices) So sprite block 0 is taken from 0,0 block 1: 0,16.. block 2: 0,32 etc.. until the bottom of the image, then source coords go: 16,0, 16,16, 16,32.. etc.

You have the option of skipping any 16×16 blocks that contains nothing but zeroes.

Similar to above, except the source image is scanned in 16×16 blocks from left to right, top to bottom. So tile block 0 starts at 0,0 block 1 at 16,0 block 2 at 32,0 etc.

As above, except the source image is scanned in 8×8 blocks from left to right, top to bottom. So tile block 0 starts at 0,0 block 1 at 8,0 block 2 at 16,0 etc.

Similar to above, except the image is simply scanned in its entirity from left to right, top to bottom, a pixel at a time (not divided into blocks).

This converts 256 colour .bmp format images which are natively in 1 byte = 1 pixel indexed format to linear bitplanes. You can take 1 to 8 bitplanes from the source picture, but note that no colour scaling is done - upper colours will just be cropped off. The image is scanned left to right, top to bottom.

The bitplanes are saved in sequence, all bit zeroes first, hence..

Pixel BYTE    0, 1, 2, 3, 4, 5, 6, 7 
              !  !  !  !  !  !  !  !
Bit select:0  !  !  !  !  !  !  !  !
              V  V  V  V  V  V  V  V 
bitplane bit  7  6  5  4  3  2  1  0  <- Plane 0 Output Byte 0

Pixel BYTE    8, 9, a, b, c, d, e, f
              !  !  !  !  !  !  !  !
Bit select:0  !  !  !  !  !  !  !  !
              V  V  V  V  V  V  V  V 
bitplane bit  7  6  5  4  3  2  1  0  <- Plane 0 Output Byte 1

repeated for all pixels in image.. then next bitplane is made, if required..

 
Pixel BYTE    0, 1, 2, 3, 4, 5, 6, 7
              !  !  !  !  !  !  !  !
Bit select:1  !  !  !  !  !  !  !  !
              V  V  V  V  V  V  V  V 
bitplane bit  7  6  5  4  3  2  1  0  <- Plane 1 Output Byte 0

Pixel BYTE    8, 9, a, b, c, d, e, f
              !  !  !  !  !  !  !  !
Bit select:1  !  !  !  !  !  !  !  !
              V  V  V  V  V  V  V  V 
bitplane bit  7  6  5  4  3  2  1  0  <- Plane 1 Output Byte 1          

The original 24 bit platte colours from the .bmp file are by default scaled down to 12 bit, padded with 4 zero bits at 15:12 (0000:R4:G4:B4) and saved as little endian words. You can also save the palette unscaled in 3 byte groups (Red, Green, Blue.. if you wish)

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