What'd you do? I thought about doing this sometime by taking each line and stretching it as appropriate, but that would probably be even slower.

that's pretty awesome. How are you achieving the lighting and shadowing of the clouds? And is it running fast enough to see practical use in something?

You don't need to scale every line. It's close enough doing every 8 pixels of height. I will say again, though, that it is still fairly slow (probably around 8-10 frames/second).

The clouds are just greyscale images which are placed with additiveblit (the shadows are the same image done using subtractiveblit). The lighting towards the top of the image is just another gradient placed with additiveblit.

It uses a big-ass nested loop to redraw a portion of the map from about 200 pixels above the screen to near the bottom of the screen, and about 176 pixels beyond either side of the screen. Fortunately, Verge3 does not generate an error when you try to draw tiles that are out of the map's dimensions. It is then scaled by row (after using grabregion to break it into 8-pixel rows) so that the top row is equal to the screen width, and the bottom row is about twice the screen width. For the height of each row it uses a linear function (y/4 + 1, in this case) to define the height of each row and at what point to draw specific rows. To avoid that 'inside a cylinder' look, you need to make sure that you are increasing the width of the row at the same rate you are increasing the height (to keep a constant slope). The variable that defines the height of the row is the same variable that determines the width.

Lots of trial and error (about 3 days straight in my case) also help. :-)

Exactly. :)

I have to say that that's a pretty damn swank screenshot. I can't wait to see it in action.

What if you render the actual map in 320x240?

IE, use scaleblit to display the map on 640x480, but only use 320x240 real pixels to do so. It would mean half as less work (vertically speaking -- I doubt the speed increase gained by cutting pixels horizontally matters, as the big speed gain probably comes from half as less blit function calls, not the amount of data the blit processes) and would still work without changing the system resolution.

I think emulators like ZSNES run Mode7 by default in a less than high (640x480) resolution. It would be a quick and easy way to gain speed.

Oh, yeah, sure, maybe...while we're at it, we can expose all of Direct3D too :)

LOLOL