alt Hacker NewsPictures and frame buffers. If you're running fullscreen at 4k, you're probably gonna take two roughly 3840x2160x3 byte frame buffers for the window. Your designers want a background image which moves as you scroll in some parallax style; that's over 3840x2160x3 bytes more for the pixel buffer backing the image layer. And let's say roughly 50% of your screen is text with subpixel (aka full color) anti aliasing; that means another 3840x2160x3x0.5 bytes for the pre rendered text.
3840x2160x3x3.5. That's 87MB, in pixel data only. And it's a very minimal example; for the parallax image, you're gonna want the image to be significantly taller than the window; you're gonna want a ton of smaller (tho still high DPI) images for icons; a few different font atlases for different font faces you've loaded at once; maybe pre rendered pixel buffers for all sorts of UI components; etc.
And lord help you if your designers want any part of this to be animated.
(I'm playing a bit fast and loose with what lives on the GPU and what lives on the CPU here. On many systems, they share a memory pool anyway. But on systems with discrete GPUs, most of this is gonna be video memory. Though applications may wanna store CPU-side copies as well for various reasons.)
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> i'm playing a bit fast and loose with what lives on the GPU and what lives on the CPU here. On many systems, they share a memory pool anyway. But on systems with discrete GPUs, most of this is gonna be video memory
Yeah this is irrelevant here, windows doesn't share both in 99 of the case.
Good point. Though 4k image assets mean more that they look in 4k, not that their size is 4k. It might not be 87mb, but still way more than the couple mb I suggested.
??? Fast and loose is an understatement, at best it's a view from a rendering engineer that thinks all software acquires a DXGI swap chain and handles buffering itself, but it's flat out wrong and over two times too high at the very least.
* Not every app is full screen (especially not a weather widget.)
* Very few people actually have a 4K display. 1080p and 1440p cover over 75% of users already.
* You do not allocate a separate buffer for the main content and the parallax, applying a different transform does not need a dedicated buffer, just something the size of your asset. It can be a 640x480 upscaled asset for all you care.
* You also don't allocate a dedicated buffer for text rendering/hinting. Your text rendering engine keeps a texture atlas in a buffer which is eventually maaaaaybe reach a 4k texture if you display a TON of various glyphs, realistically they won't. DirectWrite will also share this atlas with other executables unless you explicitly ask for isolation.
* On windows, you write to DWM, which keeps a single buffet for all your windows. Every window does not pay that memory price. I'm pretty sure most compositors do something similar.
>Your designers want
Sometimes, you need to tell the designers NO. Moving background images don't help people figure out what the weather is going to be.