updates

engine/fov/fov.go

@@ -0,0 +1,88 @@
+package fov
+
+import (
+	"github.com/jcerise/gogue/gamemap"
+	"math"
+)
+
+type FieldOfVision struct {
+	cosTable    map[int]float64
+	sinTable    map[int]float64
+	torchRadius int
+}
+
+func (f *FieldOfVision) Initialize() {
+
+	f.cosTable = make(map[int]float64)
+	f.sinTable = make(map[int]float64)
+
+	for i := 0; i < 360; i++ {
+		ax := math.Sin(float64(i) / (float64(180) / math.Pi))
+		ay := math.Cos(float64(i) / (float64(180) / math.Pi))
+
+		f.sinTable[i] = ax
+		f.cosTable[i] = ay
+	}
+}
+
+func (f *FieldOfVision) SetTorchRadius(radius int) {
+	if radius > 1 {
+		f.torchRadius = radius
+	}
+}
+
+func (f *FieldOfVision) SetAllInvisible(gameMap *gamemap.Map) {
+	for x := 0; x < gameMap.Width; x++ {
+		for y := 0; y < gameMap.Height; y++ {
+			gameMap.Tiles[x][y].Visible = false
+		}
+	}
+}
+
+func (f *FieldOfVision) RayCast(playerX, playerY int, gameMap *gamemap.Map) {
+	// Cast out rays each degree in a 360 circle from the player. If a ray passes over a floor (does not block sight)
+	// tile, keep going, up to the maximum torch radius (view radius) of the player. If the ray intersects a wall
+	// (blocks sight), stop, as the player will not be able to see past that. Every visible tile will get the Visible
+	// and Explored properties set to true.
+
+	for i := 0; i < 360; i++ {
+
+		ax := f.sinTable[i]
+		ay := f.cosTable[i]
+
+		x := float64(playerX)
+		y := float64(playerY)
+
+		// Mark the players current position as explored
+		tile := gameMap.Tiles[playerX][playerY]
+		tile.Explored = true
+		tile.Visible = true
+
+		for j := 0; j < f.torchRadius; j++ {
+			x -= ax
+			y -= ay
+
+			roundedX := int(Round(x))
+			roundedY := int(Round(y))
+
+			if x < 0 || x > float64(gameMap.Width-1) || y < 0 || y > float64(gameMap.Height-1) {
+				// If the ray is cast outside of the gamemap, stop
+				break
+			}
+
+			tile := gameMap.Tiles[roundedX][roundedY]
+
+			tile.Explored = true
+			tile.Visible = true
+
+			if gameMap.Tiles[roundedX][roundedY].BlocksSight == true {
+				// The ray hit a wall, go no further
+				break
+			}
+		}
+	}
+}
+
+func Round(f float64) float64 {
+	return math.Floor(f + .5)
+}