GOingTunneling/graphics.go

package main

import (
	"github.com/veandco/go-sdl2/sdl"
)

func initializeSDL() {
	if err := sdl.Init(sdl.INIT_EVERYTHING); err != nil {
		panic(err)
	}
}

func setupWindowAndSurface() (*sdl.Window, *sdl.Surface) {
	const windowWidth, windowHeight = 160, 100
	window, err := sdl.CreateWindow("test", sdl.WINDOWPOS_UNDEFINED, sdl.WINDOWPOS_UNDEFINED, windowWidth, windowHeight, sdl.WINDOW_SHOWN|sdl.WINDOW_RESIZABLE)
	if err != nil {
		panic(err)
	}

	logicalSurface, err := sdl.CreateRGBSurface(0, windowWidth, windowHeight, 32, 0, 0, 0, 0)
	if err != nil {
		panic(err)
	}

	return window, logicalSurface
}

func setupPlaySurface() (*sdl.Surface, *sdl.Rect, *sdl.Rect) {
	playSurface, err := sdl.CreateRGBSurface(0, 76, 76, 32, 0, 0, 0, 0)
	if err != nil {
		panic(err)
	}
	playSurfaceRect := &sdl.Rect{X: 0, Y: 0, W: 76, H: 76}
	playSurfaceTargetRect := &sdl.Rect{X: 42, Y: 0, W: 76, H: 76}

	return playSurface, playSurfaceRect, playSurfaceTargetRect
}

func setupHUDSurface() (*sdl.Surface, *sdl.Rect, *sdl.Rect) {
	HUDSurface, err := sdl.CreateRGBSurface(0, 112, 25, 32, 0, 0, 0, 0)
	if err != nil {
		panic(err)
	}
	HUDSurfaceRect := &sdl.Rect{X: 0, Y: 0, W: 112, H: 25}
	HUDSurfaceTargetRect := &sdl.Rect{X: 24, Y: 76, W: 112, H: 25}

	return HUDSurface, HUDSurfaceRect, HUDSurfaceTargetRect
}

func handleEvents(window *sdl.Window, logicalSurface *sdl.Surface) bool {
	for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
		switch e := event.(type) {
		case *sdl.QuitEvent:
			return false
		case *sdl.WindowEvent:
			if e.Event == sdl.WINDOWEVENT_RESIZED {
				handleWindowResize(window, logicalSurface)
			}
		}
	}
	return true
}

func handleWindowResize(window *sdl.Window, logicalSurface *sdl.Surface) {
	windowSurface, err := window.GetSurface()
	if err != nil {
		panic(err)
	}

	windowWidth, windowHeight := windowSurface.W, windowSurface.H

	aspectRatio := float64(logicalSurface.W) / float64(logicalSurface.H)
	newWidth := windowWidth
	newHeight := int32(float64(windowWidth) / aspectRatio)

	if newHeight > windowHeight {
		newHeight = windowHeight
		newWidth = int32(float64(windowHeight) * aspectRatio)
	}

	letterboxX := (windowWidth - newWidth) / 2
	letterboxY := (windowHeight - newHeight) / 2

	windowSurface.FillRect(nil, 0)
	srcRect := &sdl.Rect{X: 0, Y: 0, W: logicalSurface.W, H: logicalSurface.H}
	dstRect := &sdl.Rect{X: letterboxX, Y: letterboxY, W: newWidth, H: newHeight}

	logicalSurface.BlitScaled(srcRect, windowSurface, dstRect)
	window.UpdateSurface()
}

func renderScene(logicalSurface, playSurface, HUDSurface *sdl.Surface, gameMap *GameMap, players *[]*Player, bases *[]*Base, bullets *[]*Bullet, bulletParticles *[]*BulletParticle, camera *sdl.Rect, playSurfaceRect, playSurfaceTargetRect, HUDSurfaceRect, HUDSurfaceTargetRect *sdl.Rect) {
	HUDColor := sdl.MapRGBA(HUDSurface.Format, 101, 101, 101, 255)
	logicalColor := sdl.MapRGBA(HUDSurface.Format, 101, 101, 0, 255)
	playColor := sdl.MapRGBA(HUDSurface.Format, 101, 0, 101, 255)

	logicalSurface.FillRect(nil, logicalColor)
	playSurface.FillRect(nil, playColor)
	HUDSurface.FillRect(nil, HUDColor)

	(*players)[0].track(camera)

	gameMap.render(camera, playSurface)

	for _, bullet := range *bullets {
		(*bullet).render(camera, playSurface)
		(*bullet).tick(gameMap, bulletParticles, bullets, players)
	}

	for _, base := range *bases {
		(*base).render(camera, playSurface)
		(*base).tick(players)
	}

	for _, player := range *players {
		(*player).render(camera, playSurface)
		(*player).tick()
	}

	for _, bulletParticle := range *bulletParticles {
		bulletParticle.render(camera, playSurface)
		bulletParticle.tick(bulletParticles)
	}

	renderHud((*players)[0], HUDSurface)

	playSurface.BlitScaled(playSurfaceRect, logicalSurface, playSurfaceTargetRect)
	HUDSurface.BlitScaled(HUDSurfaceRect, logicalSurface, HUDSurfaceTargetRect)
}

func adjustWindow(window *sdl.Window, logicalSurface *sdl.Surface, pixelBG uint32) {
	windowSurface, err := window.GetSurface()
	if err != nil {
		panic(err)
	}

	windowWidth, windowHeight := windowSurface.W, windowSurface.H
	aspectRatio := float64(logicalSurface.W) / float64(logicalSurface.H)
	newWidth := windowWidth
	newHeight := int32(float64(windowWidth) / aspectRatio)

	if newHeight > windowHeight {
		newHeight = windowHeight
		newWidth = int32(float64(windowHeight) * aspectRatio)
	}

	letterboxX := (windowWidth - newWidth) / 2
	letterboxY := (windowHeight - newHeight) / 2

	windowSurface.FillRect(nil, pixelBG)
	srcRect := &sdl.Rect{X: 0, Y: 0, W: logicalSurface.W, H: logicalSurface.H}
	dstRect := &sdl.Rect{X: letterboxX, Y: letterboxY, W: newWidth, H: newHeight}

	logicalSurface.BlitScaled(srcRect, windowSurface, dstRect)
	window.UpdateSurface()
}