So... In the good old days of making games, when you were drawing sprites to the screen, you'd use ROPs to draw only the "non-transparent" part of your sprite. (Yes, I haven't done any game coding in a loooong time)
(In case you have no idea what I'm talking about, check this out. It was a beautiful hack)
I'm now trying to do some "HTML5 games", and I'm experimenting with different ways of doing things and measuring their performance, and I noticed that there seem to be no ROPs in Canvas. When you draw something, that "something" has a full alpha channel, and actually drawing semi-transparent things is exactly as fast as drawing "opaque" things.
Now, this is great if you're drawing semi-transparent stuff, but for 99.999% of what you're doing, this sounds incredibly wasteful, and it feels like if we did have ROPs, we could probably draw 10 times as fast using the old mask trick.
Am I missing something here?
Is there already a way with Canvas to "turn off alpha" to make it draw faster?
Am I completely crazy, and this doesn't matter because, really, I can actually already draw 1000 sprites in 3ms (300 FPS), plus the video card is probably doing it directly, or will soon, so what do I care?
What do you think?
Thank you!
Daniel
Am I missing something here?
Nay
Is there already a way with Canvas to "turn off alpha" to make it draw faster?
Nay, sorry. Alpha is simply in the element no matter what, as a fact of HTMLElement conventions to date I imagine. In fact the default state of canvas is 100% black pixels with full transparency.