How Fast DirectX?

[Farabi]

Anybody ever test directX for plot a pixel on the screen? How fast is that? 10 milion loop? How micro second?

[daydreamer]

Anybody ever test directX for plot a pixel on the screen? How fast is that? 10 milion loop? How micro second?

you talk about ddraw or d3d?, because d3d, you just have an api call for rendering lots of pixels, one for lines, one for polys, one for number of polys shaping a fan, one for a trianglestrip and speed is depending if you have latest gfx card or just a crappy old card

ddraw, first you dont lock/unlock for each pixel, lock/unlock can take millis, but because ddraw is just api calls to open up vram to low-level access, its up to the speed of your own render algos, if you have mul for each pixel, to calculate adress it gets slower than just a loop with add's
and reading vram is very slow, if you for example gonna do blending

[Farabi]

Is reading VRAM as slow as getbitmapbits?

[daydreamer]

Is reading VRAM as slow as getbitmapbits?

no idea as I used ddraw from the start and never used these windows api functions