Initial commit

render/engine.go

@@ -0,0 +1,47 @@
+package render
+
+import (
+	"github.com/pnx/go-raytracer/graphics"
+	"github.com/pnx/go-raytracer/math"
+	"github.com/pnx/go-raytracer/world"
+)
+
+func DrawColumn(ctx *graphics.Context, x int32, wall_h int32, color math.Color) {
+	if wall_h < ctx.Height() {
+		y1 := (ctx.Height() - wall_h) / 2
+		y2 := (ctx.Height() + wall_h) / 2
+
+		// Top
+		// renderer.SetDrawColor(90, 90, 0, 255)
+		ctx.DrawLine(x, 0, int32(x), y1, math.Color{R: 90, G: 90, B: 0, A: 255})
+
+		// // Middle
+		// renderer.SetDrawColor(color.R, color.G, color.B, color.A)
+		ctx.DrawLine(x, y1, int32(x), y2, color)
+
+		// Bottom
+		if y2 < ctx.Height() {
+			// renderer.SetDrawColor(50, 50, 50, 255)
+			ctx.DrawLine(x, y2, int32(x), ctx.Height(), math.Color{R: 50, G: 50, B: 50, A: 255})
+		}
+		return
+	}
+
+	// ctx.SetDrawColor(color.R, color.G, color.B, color.A)
+	ctx.DrawLine(x, 0, int32(x), ctx.Height(), color)
+}
+
+func DrawScene(ctx *graphics.Context, camera math.Transform, level *world.Level, colorMap []math.Color) {
+	for x := range ctx.Width() {
+		result := CastRay(camera, level, int(x), int(ctx.Width()))
+		lineHeight := int(float64(ctx.Height()) / result.Distance)
+
+		color := colorMap[level.Cell(int(result.Cell.X), int(result.Cell.Y))-1]
+
+		if result.Side > 0 {
+			color = color.Shade(2)
+		}
+
+		DrawColumn(ctx, int32(x), int32(lineHeight), color)
+	}
+}

render/minimap.go

@@ -0,0 +1,36 @@
+package render
+
+import (
+	"github.com/pnx/go-raytracer/graphics"
+	"github.com/pnx/go-raytracer/math"
+	"github.com/pnx/go-raytracer/world"
+)
+
+func DrawMiniMap(ctx *graphics.Context, camera math.Transform, level *world.Level) {
+	const tileSize = 32
+	const scale = float64(tileSize) / float64(world.TileSize)
+	// offset := math.Vec2i32{X: 25, Y: 25}
+	// size := math.Vec2i32{X: 200, Y: 100}
+
+	ctx.DrawRect(0, 0, int32(level.W*tileSize)+3, int32(level.H*tileSize)+3, math.Color{})
+
+	for y := range level.H {
+		for x := range level.W {
+			if level.Wall(x, y) {
+				ctx.DrawRect(int32(x*tileSize), int32(y*tileSize), tileSize, tileSize, math.Color{R: 255, G: 255, B: 255, A: 255})
+			}
+		}
+	}
+
+	// Camera Position
+	cPos := camera.Position.Get().Scale(scale)
+	ctx.DrawRect(int32(cPos.X-2), int32(cPos.Y-2), 4, 4, math.Color{R: 255, G: 0, B: 255, A: 255})
+
+	// Rays
+	for x := range ctx.Width() {
+		hit := CastRay(camera, level, int(x), int(ctx.Width()))
+		end := camera.Position.Get().AddVec(hit.Pos.Scale(world.TileSize)).Scale(scale)
+
+		ctx.DrawLine(int32(cPos.X), int32(cPos.Y), int32(end.X), int32(end.Y), math.Color{R: 150, G: 150, B: 0, A: 255})
+	}
+}

render/raycaster.go

@@ -0,0 +1,85 @@
+package render
+
+import (
+	stdmath "math"
+
+	"github.com/pnx/go-raytracer/math"
+	"github.com/pnx/go-raytracer/world"
+)
+
+type RayHit struct {
+	Cell     math.Vec2u8
+	Side     int
+	Distance float64
+	Pos      math.Vec2f
+}
+
+func CastRay(camera math.Transform, level *world.Level, x int, max_rays int) RayHit {
+	angle := camera.Direction.Get()
+	cameraX := 2*float64(x)/float64(max_rays) - 1
+	rayDirX := stdmath.Cos(angle) + cameraX*stdmath.Cos(angle+stdmath.Pi/2)
+	rayDirY := stdmath.Sin(angle) + cameraX*stdmath.Sin(angle+stdmath.Pi/2)
+
+	mapX := int(camera.X) / world.TileSize
+	mapY := int(camera.Y) / world.TileSize
+
+	deltaDistX := stdmath.Abs(1 / rayDirX)
+	deltaDistY := stdmath.Abs(1 / rayDirY)
+
+	var stepX, stepY int
+	var sideDistX, sideDistY float64
+
+	if rayDirX < 0 {
+		stepX = -1
+		sideDistX = (float64(camera.X)/world.TileSize - float64(mapX)) * deltaDistX
+	} else {
+		stepX = 1
+		sideDistX = (float64(mapX+1) - float64(camera.X)/world.TileSize) * deltaDistX
+	}
+	if rayDirY < 0 {
+		stepY = -1
+		sideDistY = (float64(camera.Y)/world.TileSize - float64(mapY)) * deltaDistY
+	} else {
+		stepY = 1
+		sideDistY = (float64(mapY+1) - float64(camera.Y)/world.TileSize) * deltaDistY
+	}
+
+	// DDA loop
+	var side int // 0 = x, 1 = y
+	for {
+		if sideDistX < sideDistY {
+			sideDistX += deltaDistX
+			mapX += stepX
+			side = 0
+		} else {
+			sideDistY += deltaDistY
+			mapY += stepY
+			side = 1
+		}
+
+		if mapX < 0 || mapX >= level.W || mapY < 0 || mapY >= level.H {
+			break // out of bounds
+		}
+		if level.Wall(mapX, mapY) {
+			break
+		}
+	}
+
+	// Calculate distance to wall
+	var perpWallDist float64
+	if side == 0 {
+		perpWallDist = (float64(mapX) - float64(camera.X)/world.TileSize + float64(1-stepX)/2) / rayDirX
+	} else {
+		perpWallDist = (float64(mapY) - float64(camera.Y)/world.TileSize + float64(1-stepY)/2) / rayDirY
+	}
+
+	return RayHit{
+		Cell:     math.Vec2u8{X: uint8(mapX), Y: uint8(mapY)},
+		Side:     side,
+		Distance: perpWallDist,
+		Pos: math.Vec2f{
+			X: rayDirX * perpWallDist,
+			Y: rayDirY * perpWallDist,
+		},
+	}
+}