diff --git a/src/Ray.kt b/src/Ray.kt index 9adc8d5..38631bf 100644 --- a/src/Ray.kt +++ b/src/Ray.kt @@ -4,7 +4,7 @@ import kotlin.math.min import kotlin.math.pow import kotlin.math.sqrt -data class Hit(val point: Point, val normal: Vector, val color: MaterialColor) +data class Hit(val point: Point, val normal: Vector, val distance: Float, val color: MaterialColor) data class MaterialColor(val r: Float, val g: Float, val b: Float) { fun toColor(): Color = Color( @@ -16,14 +16,30 @@ data class MaterialColor(val r: Float, val g: Float, val b: Float) { operator fun times(rhs: MaterialColor) = MaterialColor(r * rhs.r, g * rhs.g, b * rhs.b) operator fun plus(rhs: MaterialColor) = MaterialColor(r + rhs.r, g + rhs.g, b + rhs.b) } + operator fun Float.times(rhs: MaterialColor) = MaterialColor(this * rhs.r, this * rhs.g, this * rhs.b) data class Ray(val origin: Point, val direction: Vector) { fun at(t: Float) = origin + t * direction } -data class Sphere(val center: Point, val radius: Float, val color: MaterialColor) { - fun intersects(ray: Ray): Hit? { +interface Thing { + fun intersects(ray: Ray): Hit? +} + + +data class Plane(val point: Point, val normal: Vector, val color: MaterialColor) : Thing { + override fun intersects(ray: Ray): Hit? { + val bottom = dot(normal, ray.direction) + if (bottom == 0.0f) return null + val t = dot(normal, point - ray.origin) / bottom + if (t <= 0.0f) return null + return Hit(ray.at(t), normal, t, color) + } +} + +data class Sphere(val center: Point, val radius: Float, val color: MaterialColor) : Thing { + override fun intersects(ray: Ray): Hit? { val l = center - ray.origin val tc = dot(l, ray.direction) if (tc < 0f) return null @@ -37,9 +53,8 @@ data class Sphere(val center: Point, val radius: Float, val color: MaterialColor val t = min(tc - thc, tc + thc) - val hitPoint = ray.at(t) - return Hit(hitPoint, (hitPoint - center).normalized(), color) + return Hit(hitPoint, (hitPoint - center).normalized(), t, color) } } @@ -47,11 +62,32 @@ fun dot(lhs: Vector, rhs: Vector): Float = lhs.x * rhs.x + lhs.y * rhs.y + lhs.z data class PointLight(val point: Point, val color: MaterialColor) +data class Scene(val things: List): Thing { + override fun intersects(ray: Ray): Hit? { + var closest: Hit? = null + for (thing in things) { + val hit = thing.intersects(ray) + if (hit != null && (closest == null || hit.distance < closest.distance)) { + closest = hit + } + } + + return closest + } +} + fun main() { val bmp = Bitmap(1000, 1000) val origin = Point(500f, 500f, -500f) val sphere = Sphere(Point(500f, 500f, 500f), radius = 500f, color = MaterialColor(0f, 1.0f, 0f)) + val plane = Plane( + Point(0f, -500f, 0f), + normal = Vector(0f, 1f, 0f), + color = MaterialColor(0.5f, 0.5f, 0.5f) + ) + + val scene = Scene(listOf(sphere, plane)) val ambient = MaterialColor(0.1f, 0.1f, 0.1f) @@ -63,12 +99,12 @@ fun main() { val point = Point(x.toFloat(), y.toFloat(), 0f) val ray = origin.rayTo(point) - val hit = sphere.intersects(ray) + val hit = scene.intersects(ray) if (hit != null) { var color = hit.color * ambient val rayToLight = hit.point.rayTo(light.point) - if (sphere.intersects(rayToLight) == null) { + if (scene.intersects(rayToLight) == null) { val lambert = max(0f, dot(hit.normal, rayToLight.direction)) color += lambert * light.color