GOingTunneling/bullet.go

package main

import (
	"github.com/veandco/go-sdl2/sdl"
	"image/color"
	"math/rand"
)

type Bullet struct {
	posX, posY int32
	direction  uint8
	color      color.Color
	super      bool
}

type BulletParticle struct {
	posX, posY      int32
	expirationTimer uint8
	color           color.Color
}

func (bulletParticle *BulletParticle) render(camera *sdl.Rect, surface *sdl.Surface) {
	if camera.IntersectLine(&bulletParticle.posX, &bulletParticle.posY, &bulletParticle.posX, &bulletParticle.posY) {
		relativeBulletX := bulletParticle.posX - camera.X
		relativeBulletY := bulletParticle.posY - camera.Y
		surface.Set(int(relativeBulletX), int(relativeBulletY), bulletParticle.color)
	}
}

func (bulletParticle *BulletParticle) tick(particles *[]*BulletParticle) {
	if bulletParticle.expirationTimer <= 0 {
		for i, particle := range *particles {
			if particle == bulletParticle {
				*particles = append((*particles)[:i], (*particles)[i+1:]...)
			}
		}
	}
	bulletParticle.expirationTimer--
}

func (bullet *Bullet) render(camera *sdl.Rect, surface *sdl.Surface) {
	if camera.IntersectLine(&bullet.posX, &bullet.posY, &bullet.posX, &bullet.posY) {
		relativeBulletX := bullet.posX - camera.X
		relativeBulletY := bullet.posY - camera.Y
		surface.Set(int(relativeBulletX), int(relativeBulletY), bullet.color)
	}
}

func (bullet *Bullet) explode(gameMap *GameMap, bulletParticleMap *[]*BulletParticle) {
	// Define the possible directions with their x and y velocity components.
	directions := [][2]int{
		{0, -1},  // Up
		{0, 1},   // Down
		{-1, 0},  // Left
		{1, 0},   // Right
		{-1, -1}, // Up-Left Diagonal
		{1, -1},  // Up-Right Diagonal
		{-1, 1},  // Down-Left Diagonal
		{1, 1},   // Down-Right Diagonal
	}

	if !bullet.super {
		// Loop through each direction to generate particle streams.
		for _, dir := range directions {
			// Randomize the number of particles in each stream.
			particlesInStream := rand.Intn(5)
			for i := 0; i < particlesInStream; i++ {
				// Determine particle's position based on its direction and step count.
				step := rand.Intn(3) + 1 // Step can be 1, 2, or 3 units.
				xOffset := dir[0] * step
				yOffset := dir[1] * step

				xPos, yPos := bullet.posX+int32(xOffset), bullet.posY+int32(yOffset)
				collision := gameMap.checkCollision(xPos, yPos)

				// Check for collision and bullet behavior (normal or super).
				if collision == 1 || collision == 0 || (bullet.super && collision == 2) {
					*bulletParticleMap = append(*bulletParticleMap, &BulletParticle{
						posX:            xPos,
						posY:            yPos,
						expirationTimer: uint8(5 + rand.Intn(10)), // Randomize expiration time between 15 and 25.
						color:           bullet.color,
					})
					if xPos > 0 && yPos > 0 && xPos < MapWidth && yPos < MapHeight {
						gameMap.tiles[xPos][yPos] = 0
					}
				}
			}
		}
	} else {
		for xOffset := -3; xOffset <= 3; xOffset++ {
			for yOffset := -3; yOffset <= 3; yOffset++ {
				xPos, yPos := bullet.posX+int32(xOffset), bullet.posY+int32(yOffset)
				collision := gameMap.checkCollision(xPos, yPos)
				if collision == 1 || collision == 0 || (bullet.super && collision == 2) {
					*bulletParticleMap = append(*bulletParticleMap, &BulletParticle{
						posX:            xPos,
						posY:            yPos,
						expirationTimer: uint8(15 + rand.Intn(15)),
						color:           bullet.color,
					})
					gameMap.tiles[xPos][yPos] = 0
				}
			}
		}
	}
}

func (bullet *Bullet) tick(gameMap *GameMap,
	bulletParticleMap *[]*BulletParticle, bulletMap *[]*Bullet, players *[]*Player) {
	var nextX, nextY int32
	nextX, nextY = bullet.posX, bullet.posY
	switch bullet.direction {
	case 0: //up
		nextY -= 1
		break
	case 1: //right
		nextX += 1
		break
	case 2: //down
		nextY += 1
		break
	case 3: //left
		nextX -= 1
		break
	case 4: //up right
		nextY -= 1
		nextX += 1
		break
	case 5: //up left
		nextY -= 1
		nextX -= 1
		break
	case 6: //down right
		nextY += 1
		nextX += 1
		break
	case 7: //down left
		nextY += 1
		nextX -= 1
		break
	}
	collisionResult := gameMap.checkCollision(nextX, nextY)
	bulletRect := sdl.Rect{
		X: bullet.posX,
		Y: bullet.posY,
		W: 1,
		H: 1,
	}
	hitPlayer := false
	for _, player := range *players {
		if player.rect1.HasIntersection(&bulletRect) ||
			player.rect2.HasIntersection(&bulletRect) ||
			player.rect3.HasIntersection(&bulletRect) ||
			player.rect4.HasIntersection(&bulletRect) {
			hitPlayer = true
			player.health -= 20
			break
		}
	}
	if collisionResult != 0 || hitPlayer {
		bullet.explode(gameMap, bulletParticleMap)
		for i, bulletInMap := range *bulletMap {
			if bulletInMap == bullet {
				*bulletMap = append((*bulletMap)[:i], (*bulletMap)[i+1:]...)
			}
		}
	} else {
		bullet.posX = nextX
		bullet.posY = nextY
	}
}