在SDL Go程序中复制纹理时运行时出现紧急情况

Question

I have an SDL2 go program which tries to write a pixel array to the screen. When I try and update the texture with the new pixels the program panics with a runtime error:

fatal error: unexpected signal during runtime execution

Unfortunately I can find little to no documentation about how to pass around unsafe pointers in Go and I'm not sure if I'm approaching this correctly, here is some example code that exhibits the problem:

func main() {
    window := sdl.CreateWindow("test", sdl.WINDOWPOS_UNDEFINED, sdl.WINDOWPOS_UNDEFINED,
        800, 600, sdl.WINDOW_SHOWN)
    renderer := sdl.CreateRenderer(window, -1, 0)
    texture := sdl.CreateTexture(renderer, sdl.PIXELFORMAT_ARGB8888,
        sdl.TEXTUREACCESS_STATIC, 800, 600)

    defer renderer.Destroy()
    defer texture.Destroy()
    defer window.Destroy()

    for {
        pixels := make([]uint32, 800*600)

        texture.Update(nil, unsafe.Pointer(&pixels), int(800*unsafe.Sizeof(pixels)))
        window.UpdateSurface()

        renderer.Clear()
        renderer.Copy(texture, nil, nil)
        renderer.Present()
    }

    sdl.Delay(1000)
    sdl.Quit()
}

This code will compile with no errors, but when ran it will produce a runtime panic, but I can't see what would cause that in this code.

I am using these SDL2 Go bindings: https://github.com/veandco/go-sdl2

Answer 1

The pitch parameter expects the surface's width * sizeof(int32) as far as I can, this code works and prints random pixels every loop:

func main() {
    window, err := sdl.CreateWindow("test", sdl.WINDOWPOS_UNDEFINED,
        sdl.WINDOWPOS_UNDEFINED, 800, 600, sdl.WINDOW_SHOWN)
    if err != nil {
        log.Fatal(err)
    }
    defer window.Destroy()

    renderer, err := sdl.CreateRenderer(window, -1, 0)
    if err != nil {
        log.Fatal(err)
    }
    defer renderer.Destroy()

    texture, err := renderer.CreateTexture(sdl.PIXELFORMAT_ARGB8888,
        sdl.TEXTUREACCESS_STATIC, 800, 600)

    if err != nil {
        log.Fatal(err)
    }
    defer texture.Destroy()

    pixels := make([]uint32, 800*600)
L:
    for {
        for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
            if _, ok := event.(*sdl.QuitEvent); ok {
                break L
            }
        }
        for i := range pixels {
            pixels[i] = 0x00777777 + uint32(rand.Intn(0x00AAAAAA))
        }
        //4 == sizeof(int32), unsafe.Sizeof(pixels) returns the actual size of
        //the slice header which is 24
        texture.Update(nil, unsafe.Pointer(&pixels[0]), 800*4)
        window.UpdateSurface()

        renderer.Clear()
        renderer.Copy(texture, nil, nil)
        renderer.Present()
    }

    sdl.Delay(1000)
    sdl.Quit()
}

//edit it should be unsafe.Pointer(&pixels[0]) not unsafe.Pointer(&pixels).