veeableful
commented
5 years ago Hi @madmagi, do you have any specific example in mind? I created this example as a starter.
package main
import (
"log"
"os"
"github.com/veandco/go-sdl2/sdl"
)
var (
mouseX int32
mouseY int32
rects []sdl.Rect
)
func run() int {
sdl.Init(sdl.INIT_EVERYTHING)
window, err := sdl.CreateWindow("Render Event Loop", sdl.WINDOWPOS_UNDEFINED, sdl.WINDOWPOS_UNDEFINED, 640, 480, 0)
if err != nil {
log.Println(err)
return 1
}
defer window.Destroy()
renderer, err := sdl.CreateRenderer(window, -1, sdl.RENDERER_ACCELERATED|sdl.RENDERER_PRESENTVSYNC)
if err != nil {
log.Println(err)
return 2
}
defer renderer.Destroy()
running := true
for running {
renderer.SetDrawColor(0, 0, 0, 255)
renderer.Clear()
for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
switch t := event.(type) {
case *sdl.QuitEvent:
running = false
case *sdl.KeyboardEvent:
if t.Keysym.Sym == sdl.K_BACKSPACE {
rects = rects[0:0]
}
case *sdl.MouseButtonEvent:
if t.Button == sdl.BUTTON_LEFT {
rects = append(rects, sdl.Rect{X: t.X, Y: t.Y, W: 10, H: 10})
}
case *sdl.MouseMotionEvent:
mouseX = t.X
mouseY = t.Y
}
}
draw(renderer)
renderer.Present()
sdl.Delay(1000 / 60)
}
return 0
}
func draw(renderer *sdl.Renderer) {
renderer.SetDrawColor(255, 255, 255, 255)
for _, rect := range rects {
renderer.FillRect(&rect)
}
renderer.FillRect(&sdl.Rect{X: mouseX, Y: mouseY, W: 10, H: 10})
}
func main() {
os.Exit(run())
}
madmagi
Thanks for a great library.
Almost all of your samples are what would call "one and done" examples; that is build up something, draw it and that is it. Which is great, can learn specifically how a particular thing works.
However, in real life you end up building up objects, drawing and redrawing over and over. And that is where where I am struggling.
For example, draw A window, react to some input, now redraw, perhaps just adding a new item to the window.
When I look at how the sample code is done, i see ..
..renderer.Clear() Do build up of graphic routines, i.e. DrawLine, DrawImages, etc ..renderer.Present() ..renderer.UpdateSurface()
I look at the android code it is more comples with events, but of course your are trying to do other things in that code as well, .
when i try to do a basic event model where i put up something and listen to events i end up either blocking the redraws, or having some other issues either not redrawing, redrawing so much events don't occur, thread issues, or some other problems.
Would I would suggest is a simple example that shows a simple eventing model with redraw/update logic.
Thoughts?