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I am playing Kingdom Rush and Kingdom Rush Frontier.

The purpose of GPU is to do matrix multiplication that are relevant for 3D rendering.

But what about 2D?

Does it make sense for 2D games like GPU to require GPU to improve performance?

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  • No, the purpose of a GPU is to render graphics to a screen. We still called them GPUs long before 3d graphics existed.. and yes, it is still the GPUs responsibility to render 2d graphics (and text.. and everything else you look at). Yes, the GPU improves 2D performance as well. In fact, back before 3d.. that was what the selling points of them were. Mar 30, 2021 at 5:20
  • @SeñorCMasMas Is it though? GPUs have become generic enough to have their own programming language (eg CUDA) and do non-graphics stuff (eg bitcoin mining, password cracking, ai/machine learning ). Text graphics existed long before gpu's or even graphics cards - The commodore 64 had neither - you somply wrote bytes to memory which mapped to the screen - and for 2d I dont see where the gpu is needed - as opposed to a regular graphics card)
    – davidgo
    Mar 30, 2021 at 18:08
  • 2d games are generally recognized now as a special case of 3d with a fixed Z-buffer, and most of the useful functions for hardware-accelerated sprite rendering are in e.g. direct3d. Kingdom rush for PC was developed using love2d, but love2d engine does actually support some 3D functions out of the box. Philosophical discussion about what constitutes a GPU is kind of a red herring, but GPUs are mandatory now because of abstracted software interfaces for modern OS. Opengl was specified in a way that it allowed for fully software-based rendering without any sort of hardware acceleration.
    – Yorik
    Mar 30, 2021 at 18:46
  • @davidgo , the C64 used the VIC-II for its GPU.. ?? .. Am I wrong?? I coded on the VIC-20 .. but close enough.. I guess it doesn't matter.. we all get how a computer works apparently. Mar 30, 2021 at 20:57

2 Answers 2

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A GPU is required in order for a computer to output anything on a screen. In the majority of cases, a PC won't even boot without a GPU, which highlights how important a component it is.

The purpose of GPU is to do matrix multiplication that are relevant for 3D rendering.

That's a capability of a GPU, not it's sole purpose.

In order to render anything on a screen, you need a GPU. That includes 2D and 3D graphics. So yes, it makes sense that a 2D game uses the GPU - same with everything else on your monitor.

Edit: Just to clarify, when I say GPUs, I am referring to both proper GPUs and CPU integrated graphics.

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    This is not quite correct - for example, historically screen has been memory-mapped. This is still the case with for example embedded systems. The CPU just has to write bytes into a specific RAM area corresponding to screen pixels. By setting/unsetting pixels software can draw lines, characters, whatever... no GPU involved. It's quite similar to the framebuffer method used in Linux or macOS at boot time; and no, it hasn't to do with "integrated graphics"... one just can move bytes around and draw to RAM, and have some circuitry to create a video signal from some RAM area.
    – jvb
    Mar 30, 2021 at 18:58
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    @jvb Even with a memory-mapped screen, you'll still need something that will read that RAM area and transform the contents into a display output signal. And that is not just "some circuitry" - that is the fundamental job of a display controller. Add more and more functionality into a display controller, and it eventually becomes a GPU as we understand now.
    – telcoM
    Apr 11, 2021 at 6:39
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With respect of Kingdom Rush - it is so old that a discrete video card is not required. The minimum specs are apparently a GEForce 205. I could not find a comparison with that card, but the more powerful 210 is slower then the GPU built into the Intel CPU's of the time - and that was 7 years ago. (See https://gpu.userbenchmark.com/Compare/Nvidia-GeForce-G210M-vs-Intel-HD-4000-Mobile-125-GHz/m8875vsm7653). Similarly with the 8500GT - https://gpu.userbenchmark.com/Compare/Nvidia-GeForce-8500-GT-vs-Intel-HD-4000-Mobile-125-GHz/m7777vsm7653

Fom a practical POV,in general a 2d game does not require a discrete GPU as built in GPUs are more then fast enough. (Im not a gamer. I can posit some edge cases with 2d games at 4k or 8k resolution which might struggle, but that does not make a lot of sense in the general case)

As others have answered, technically a GPU is required - however a reasonable GPU is often built into CPU's - this is certainly the case for the overwhelming majority of non ancient Intel CPU's. A discrete GPU can help with complex rendering - typically associated with 3d (but usable for a lot of ither things as well)

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