LOAD ATLAS

The LOAD IMAGE command allows you to load an set of images and to convert each one into an ATLAS. An Atlas is a set of images, numbered by 0 to frame count, which can be used individually with the PUT IMAGE command, referring to the corresponding frame. The frames are cut out of the original image, using the size provided in the FRAME SIZE (w, h). It should be noted that, for this reason, ATLAS images must have a total of a size equal to an entire multiple of the size of the individual frame. It is also possible to indicate an offset from which you will have to start cutting the image (parameter ORIGIN(zx,zy)) and one related to each individual cutout (OFFSET (dx, dy)).

So, the first parameter is the filename to parse. The command support a set of modern image format, like JPEG baseline & progressive, PNG 1/2/4/8/16-bit-per-channel, TGA, BMP (non-1bpp, non-RLE), PSD (composited view only, no extra channels, 8/16 bit-per-channel), GIF, HDR (radiance rgbE format), PIC (Softimage PIC) and PNM (PPM and PGM binary only) The image will be converted into a way that can be efficiently drawn on the screen.

The second parameter is the mode to use to convert the given data (by default, it is equal to current mode)

Since it is possible to load only one file of the same type at a time, it is necessary to be able to indicate an "alias" with which to exceed this limit. In this regard, there is also the AS syntax, which allows you to load the same file several times but with different names.

A series of flags, separated by spaces, can be added at loading time to modify the behavior of ugBASIC.

The FLIP X flag allows you to flip the (entire) image horizontally, before cutting and translating it into the native format. The same is true for the FLIP Y command, which instead inverts the (entire) image vertically. There is also the FLIP XY (or FLIP YX) parameter to act, simultaneously, on both directions.

The ROLL X flag allows you to SHIFT the (entire) image horizontally, for the entire size of a frame, in order to generate intermediate frames. The very same for ROLL Y command, which does the same vertically. There is also the ROLL XY (or ROLL YX) parameter to act, simultaneously, on both directions.

The COMPRESSED flag allows you to compress the image, if possible. Compression is a space-saving mechanism, in which the native data of the image is represented in a more compact form, which ugBASIC will be able to quickly convert into graphics at the appropriate time.

The OVERLAYED flag can be used on systems with a palette of few colors, to indicate which of them must be preserved during the drawing phase, to have the transparency effect.

The EXACT flag allows you to bypass the automatic detection of the palette, opting for the representation of the colors according to what is contained in it.

The (entire) image can be loaded as a transparent image (if the original image has no transparency) using the keyword TRANSPARENCY, followe by an optional parameter that represent the color to consider as transparent.

The (entire) image can be loaded as a transparent image (if the original image has no transparency) using the keyword OPACITY, followe by an optional parameter that represent the color to consider as pavement,.

The resulting ATLAS can be loaded directly into the expansion memory using the BANKED keyword. The number represent the shared resident to use as target for this image. For some targets this is the default. If you want, you can move the image onto the resident memory by using the UNBANKED keyword.

Finally, if the image is not expected to change during gameplay, it can be marked with the READONLY attribute: in this case, the image will be stored in read-only memory, if available.

EXAMPLE

 starship = LOAD ATLAS("starship.png") FRAME SIZE (16, 16)
 starship2 = LOAD ATLAS("starship.png" AS "starship2") FRAME SIZE (32, 32) OFFSET(2,2)
 alienAt11 = LOAD ATLAS("alien.jpg",11) FRAME SIZE AUTO
 alien2 = LOAD ATLAS("alien.jpg" AS "alien2",11) FRAME SIZE(8,8) TRANSPARENCY