[Coco] wanting to patch HPUT routine... (ping RG!)

[theother_bob]

I'm experimenting with speeding up the cursor drawing routine in Color FOG. I've found that while I can get faster results with HPUT, it actually looks a bit more "flickery" due to the process...

Original method was to HPUT a box erasing the old cursor, then HDRAW the cursor in the new location. HDRAW benchmarks @ 200 timer clicks/100 cursor drawing cycles (obviously dependent on complexity of cursor. I use three colors but kept it small and drawn efficiently.)

Modified routine uses HPUT to put cursor on the screen, but requires more overhead... one HBUFF with a 00/FF mask of the cursor, HPUT with AND option, followed by HPUT real cursor with OR option. Benchmarks at <150 timer clicks/100 double-HPUTs, but looks a little more flickery as a solid black cursor is placed and then the "colored in" cursor in a follow-up HPUT command.

My goal is to speed up the process to a single HPUT operation. Basically I want to support "transparency" in HPUT by ignoring pixels of palette 0.

One approach would be to intercept one of the options and make a new HPUT routine that compares pixels to 0, ignoring if 0, basically using PSET option if non 0. I'm thinking this would probably be a semi-complex subroutine compared to my next thought...

I suppose an easier way would be to intercept one of the options. Maybe HPUT the mask but hijack the exit from AND at $EF04 and then (without returning to Basic) increment the HBUFF number, set the OR option flag and re-run the same HPUT command (reset X,Y locations?). This would just require two HBUFFers, mask and cursor, to be defined adjacently.

Thoughts? Coding help?

TIA,
Bob