On 9/12/06, Kris Schnee <[EMAIL PROTECTED]> wrote:
So I tested the isometric version. 6 FPS, even with the logo and interface turned off. Not good. How can my pasting tiles on a 2D surface be slower than calling an OpenGL list of lists of 3D cube-drawing instructions?
How can OpenGL textured poly rendering be faster than software? well... Parallelism between CPU and GPU (they can execute things at the same time), parallelism between the cpu memory bus and the video card memory bus (the video card adds a bunch of extra memory that can read and write while your cpu is calculating things), saving the time of copying the software surface to the video card and locks both buses (the video card can shove memory from it's texture buffers to back buffers straight to the display buffer all using it's caches and high speed buses, while the mem copy would have to use the much slower AGP or (god forbid) PCI buses) and the many many benefits of a dedicated HW design vs. a general purpose one (most of which are a form of parallelism on the video card itself, like having dedicated z-buffer mem channels to get z-buffer at no additional cost, being able to do multiple texture lookups at once over a range of pixels, being able to do complex texture interpolation in a single op, being able to interleave the screen buffer memory into multiple channels so that it can render multiple zones all at once) ... so lots of reasons... honestly, I'm really just suprised you are only getting 12 fps for what's drawn on the opengl screenshot, especially if you are using display lists and already have all your textures loaded... (mobo with integrated gfx in the chipset?) -- For that that whole SDL version screenshot, if you are redrawing every frame as a bunch of overlapping rectangular tiles with alpha blending and no RLE... well than 6 fps seems about right for an older comp I think You may have dramatically different results based on RLE and HW_ACCEL flags for your surfaces and bit depth conversion issues, but In my experience you usually can't get an app that is redrawing a full 800x600 screen with significant overdraw to ever go fast with SW rendering... ...now if your software thing were blitting those tiles to a flattened scrolling buffer (saving you a lot of alpha blending of rects with a larger area than the tile and eliminating most of the overdraw) I would expect you could get more like 12fps or so (i.e. you could do a scrolling game at a decent rate) So what's the details on the SW guy? --- (PS. Aesthetically, I like the isometric i.e. no perspective transform look a lot better... you can tell openGL to do that, if you want)
