I've been reading the scrolling docs on the wiki and the phrase "If rendering is enabled..." is encountered a lot. I'm just trying to clarify what it means for rendering to be considered "enabled."
I'm interpreting it as:
- Either bit 3 or 4 is set on PPUMASK
- Not in Vlank or Forced blank
Am I correct here? The first bullet point is the thing I'm least sure of.
Thanks in advance,
Brian
Yes. Forced blanking = when bits 3 and 4 are both clear in PPUMASK.
Per
https://wiki.nesdev.com/w/index.php/GlossaryQuote:
Forced blanking
Turning off the rendering circuitry by writing zero to $2001, giving the CPU the same access to VRAM through the PPU ports that the CPU normally has during vertical blanking.
I guess this is where I'm getting confused since it implies that every bit is clear during forced blanking. So more accurately, forced blanking occurs when bits 3 and 4 are clear?
Yeah. The other bits in
PPUMASK don't the rendering/evaluation process.
I/someone should fix the glossary, but I'm having trouble with phrasing.
I've introduced the concepts of "rendering enabled" and "rendering in progress" in the glossary.
Much appreciated! Thanks for the quick responses.