sfb

README

sfb

This is kind of an expiremental project and possibly a bad idea. So, I wouldn't necessarily recommend using it.

high level goal

build a software renderer that can be used reasonably easily on machines with low or no gpu

justifications

• to get some experience writing a wrapper around C for go libraries
• to explore the possibilities of making a software renderer (for machines with no gpu)
• to get some concurrency reps in

how does it work?

1. The C layer calls SDL2 to load a window.
2. We create a texture.
3. we fill a buffer with pixels and then load it to that texture
4. a small api is exposed through a shared object file
5. there's a go wrapper library that hooks into that .so file and allows us to set individual pixels in the buffer
6. to draw shapes, we use some well known drawing algorithms that I tried to concurrency-ify

obviously, there are some limitations here. Like the larger your window is the slower it will run and the cost of rendering a shape is bound to the size of the shape. However, I was able to get these circles moving around at over 100fps (granted that's on a computer that has a pretty fast cpu)

I'd like to play around with rewriting the drawing functions in C to explore simd operations. That's unexplored terrority for me, but maybe I'll jump down that rabbit hole someday.

how to run

You need sdl on your system:

apt install libsdl2-dev

make # make the .so file
go run ./examples/big_circle/ # run one of the examples

Documentation

Index

• Constants
• func PollEvent() (eventType, keySym uint32, eventAvailable bool)
• func Run(update func(s Screen))
• type Pixel
• type Screen

Constants

const (
	FB_QUIT       = C.SDL_QUIT
	FB_KEYDOWN    = C.SDL_KEYDOWN
	FB_KEY_ESCAPE = C.SDLK_ESCAPE
)

Functions

func PollEvent

func PollEvent() (eventType, keySym uint32, eventAvailable bool)

func Run

func Run(update func(s Screen))

Types

type Pixel

type Pixel struct {
	R, G, B, A uint8
}

type Screen

type Screen interface {
	SetWidth(width int16)
	SetHeight(height int16)
	SetTitle(title string)
	EnableFPS()
	// contains filtered or unexported methods
}