Writing multiple VSRAM values per scanline
Posted: Sat Jan 23, 2021 11:58 pm
I've been experimenting with writing multiple values to VSRAM in the HInt routine each line in order to set vertical scroll values for a number of two-tile columns.
In the example shown here, this is used to generate a fake transparent highlight bar by setting the vertical scroll value to select a specific brightness level per line. (In the Gens VDP Plane Explorer you can see the different versions of the SEGA logo.) If we are in two-tile scrolling mode, we can exploit this to tilt the highlight bar a little.
This example looks OK in emulators, I have also tested it on real hardware on a PAL MegaDrive 1. It would be great if other could try it on different machines and let me know it works or if it flickers Binary and source can be found in the attached ZIP file.
Thanks!
In the example shown here, this is used to generate a fake transparent highlight bar by setting the vertical scroll value to select a specific brightness level per line. (In the Gens VDP Plane Explorer you can see the different versions of the SEGA logo.) If we are in two-tile scrolling mode, we can exploit this to tilt the highlight bar a little.
This example looks OK in emulators, I have also tested it on real hardware on a PAL MegaDrive 1. It would be great if other could try it on different machines and let me know it works or if it flickers Binary and source can be found in the attached ZIP file.
Thanks!