initial commit

8 files changed, 365 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
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index 0000000..eb5a316
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+target
diff --git a/.project b/.project
new file mode 100644
index 0000000..6550b29
--- /dev/null
+++ b/.project
@@ -0,0 +1 @@
+project_name="raytrace"
diff --git a/build.sbt b/build.sbt
new file mode 100644
index 0000000..d52ea1b
--- /dev/null
+++ b/build.sbt
@@ -0,0 +1,3 @@
+name := "DIFFS LOL"
+
+scalaSource in Compile := baseDirectory.value / "src"
diff --git a/src/Math.scala b/src/Math.scala
new file mode 100644
index 0000000..601e457
--- /dev/null
+++ b/src/Math.scala
@@ -0,0 +1,14 @@
+package net.iximeow.raytrace
+
+import Objects._
+
+object Raymath {
+  def angleBetween(a: Point, b: Point, c: Point): Double = {
+    val lineA = a - b
+    val lineB = c - b
+    Math.acos(lineA.dot(lineB) / (lineA.magnitude * lineB.magnitude))
+  }
+
+  def toDegrees(rad: Double): Double = rad * 360 / 2 / Math.PI
+  def toRadians(deg: Double): Double = deg / 360 * 2 * Math.PI
+}
diff --git a/src/Objects.scala b/src/Objects.scala
new file mode 100644
index 0000000..b4e6435
--- /dev/null
+++ b/src/Objects.scala
@@ -0,0 +1,151 @@
+package net.iximeow.raytrace
+
+import java.awt.image.BufferedImage
+
+object Objects {
+  /*
+   * 3d nah
+  case class Point(x: Double, y: Double, z: Double)
+  case class Plane(pitch: Double, roll: Double, altitude: Double)
+  case class BoundedPlane(pitch: Double, roll: Double, center: Point, h: Point, w: Point)
+  */
+
+  case class Point(x: Double, y: Double) {
+    def +(other: Point): Point = Point(x + other.x, y + other.y)
+    def -(other: Point): Point = Point(x - other.x, y - other.y)
+    def /(scale: Double): Point = Point(x / scale, y / scale)
+    def *(scale: Double): Point = Point(x * scale, y * scale)
+    def magnitude: Double = distTo(Point.Zero)
+    def distTo(other: Point) = Math.sqrt(sqDistTo(other))
+    def sqDistTo(other: Point) = (other.x - x) * (other.x - x) + (other.y - y) * (other.y - y)
+    def dot(other: Point): Double = x * other.x + y * other.y
+  }
+  object Point {
+    val Zero = Point(0, 0)
+  }
+  case class Line(m: Double, b: Double)
+  object Line {
+    def fromPoints(p1: Point, p2: Point): Line = {
+      val m = (p2.y - p1.y) / (p2.x - p1.x)
+      val b = p1.y - m*p1.x
+      Line(m, b)
+    }
+  }
+  /*
+   * Segments are defined for t in [0, 1]
+   */
+  case class Segment(x: Double, y: Double, initial: Point) {
+    def at(t: Double): Point = Point(x * t, y * t) + initial
+    def apply = at _
+    def length = Math.sqrt(x * x + y * y)
+    def intersect(other: Segment): Double = {
+      /*
+       *  P1 = ai + t * a
+       *  P2 = bi + u * b
+       *  P1 == P2, so
+       *  ai + t * a = bi + u * b
+       *  ...
+       *  ai.x + t * a.x = bi.x + u * b.x
+       *  ai.y + t * a.y = bi.y + u * b.y
+       *  t = (bi.x + u * b.x - ai.x) / a.x
+       *  ai.y + a.y * (bi.x + u * b.x - ai.x) / a.x = bi.y + u * b.y
+       *  ai.y + a.y * bi.x / a.x + u * b.x * a.y / a.x - ai.x * a.y / a.x = bi.y + u * b.y
+       *  ai.y - bi.y + (a.y / a.x) (bi.x - ai.x) = u * b.y - u * b.x * a.y / a.x
+       *  ai.y - bi.y + (a.y / a.x) (bi.x - ai.x) / (b.y - b.x * a.y / a.x) = u
+       *
+       *  (a.x * (ai.y - bi.y) + a.y * (bi.x - ai.x)) / (b.y - b.x * a.y)
+       */
+      val u = (
+        x * (initial.y - other.initial.y) +
+        y * (other.initial.x - initial.x)
+      ) / (
+        other.y * x - other.x * y
+      )
+
+      u
+    }
+
+    def intersectChecked(other: Segment): Option[Point] = {
+      val u = intersect(other)
+      if (u >= 0 && u <= 1) {
+        //println("Intersection is at u=" + u)
+
+        Some(other.at(u))
+      } else {
+        None
+      }
+    }
+    def tFor(p: Point): Option[Double] = {
+      (x, y) match {
+        case (0, _) => Some((p.y - initial.y) / y)
+        case (_, 0) => Some((p.x - initial.x) / x)
+        case (_, _) => {
+          val xT = (p.x - initial.x) / x
+          val yT = (p.y - initial.y) / y
+          if (Math.abs(xT - yT) < 0.000001) {
+            Some(xT)
+          } else {
+            None
+          }
+        }
+      }
+    }
+    def rotate(angle: Double, about: Point = Point(0, 0)): Segment = {
+      val start = this.at(0)
+      val end = this.at(1)
+      val newStart = {
+        val offset = start - about
+        val m = offset.magnitude
+        val newAngle = Math.atan2(offset.y, offset.x) + angle
+        Point(Math.cos(newAngle) * m, Math.sin(newAngle) * m) + about
+      }
+      val newEnd = {
+        val offset = end - about
+        val m = offset.magnitude
+        val newAngle = Math.atan2(offset.y, offset.x) + angle
+        Point(Math.cos(newAngle) * m, Math.sin(newAngle) * m) + about
+      }
+      Segment.fromPoints(newStart, newEnd)
+    }
+    def renderTo(buf: BufferedImage, scale: Double = 1, xoff: Int = 0, yoff: Int = 0, color: Int = 0x808000): Unit = {
+      try {
+        for (i <- (0 to 100)) {
+          val point = this.at(i / 100.0)
+          buf.setRGB(Math.round((point.x * scale).toFloat) + xoff, Math.round((point.y * scale).toFloat) + yoff, color)
+        }
+      } catch {
+        case (x: ArrayIndexOutOfBoundsException) => { /* well, we're not properly rendering a region so uh just ignore the failure i guess lol */ }
+      }
+    }
+    def normal: Segment = {
+      val normalMag = Math.sqrt(x * x + y * y)
+      val finalNormMult = 1.5 / normalMag
+      Ray(-y * finalNormMult, x * finalNormMult, (at(0) + at(1)) / 2).toSegment
+    }
+  }
+  object Segment {
+    def fromPoints(p1: Point, p2: Point): Segment = {
+      val (x0, y0) = (p2.x - p1.x, p2.y - p1.y)
+      Segment(x0, y0, p1)
+    }
+    def fromPointWithAngle(p: Point, angle: Double): Segment = {
+      val (x0, y0) = (Math.cos(angle), Math.sin(angle))
+      Segment(x0, y0, p)
+    }
+  }
+  case class Ray(x: Double, y: Double, initial: Point) {
+    def toSegment: Segment = Segment(x, y, initial)
+    def endingAt(p: Point): Ray = {
+      val intersectAt = this.toSegment.tFor(p)
+      intersectAt.map(t =>
+        Ray(x * t, y * t, initial)
+      ).getOrElse(this)
+    }
+    def dot(other: Ray): Double = {
+      x * other.x + y * other.y
+    }
+    def mag: Double = {
+      Math.sqrt(x * x + y * y)
+    }
+  }
+}
diff --git a/src/Scene.scala b/src/Scene.scala
new file mode 100644
index 0000000..9b59f7b
--- /dev/null
+++ b/src/Scene.scala
@@ -0,0 +1,152 @@
+package net.iximeow.raytrace
+
+import Objects._
+
+import java.awt.image.BufferedImage
+import javax.imageio._
+import java.io.File
+
+case class Scene(walls: Seq[Segment]) {
+  val buffer = new BufferedImage(800, 600, BufferedImage.TYPE_INT_RGB)
+
+  def render(scale: Double = 1, xoff: Int = 0, yoff: Int = 0, color: Int = 0x808000, normals: Boolean = false): Unit = {
+    for (wall <- walls) {
+      wall.renderTo(buffer, scale, 400, 300, color = color)
+    }
+    for (wall <- walls) {
+      wall.normal.renderTo(buffer, scale, 400, 300, color = 0xc00000)
+    }
+  }
+
+  def save(path: String = "render.png"): Unit = {
+    ImageIO.write(buffer, "png", new File(path))
+  }
+
+  def cast(r: Ray, steps: Int): Seq[Segment] = {
+    (0 until steps).foldLeft(Seq.empty[Segment] -> r) { case (p: (Seq[Segment], Ray), i: Int) => {
+      val (prevRay, nextRay)  = castSingle(p._2)
+      ((p._1 :+ prevRay.toSegment) -> nextRay): (Seq[Segment], Ray)
+    }}._1
+  }
+
+  def castSingle(r: Ray): (Ray, Ray) = {
+    val asSeg = r.toSegment
+
+    def reflect(firstIntersection: (Segment, Point)): (Ray, Ray) = {
+      val minAngle = {
+        val fromStart = Raymath.angleBetween(
+          r.initial,
+          firstIntersection._2,
+          firstIntersection._1.at(0)
+        )
+        val fromEnd = Raymath.angleBetween(
+          r.initial,
+          firstIntersection._2,
+          firstIntersection._1.at(1)
+        )
+
+        println("Fromstart: " + Raymath.toDegrees(fromStart))
+        println("Fromend:  " + Raymath.toDegrees(fromEnd))
+
+        if (Math.abs(fromStart) < Math.PI / 2) {
+          fromStart
+        } else {
+          fromEnd
+        }
+
+        fromStart
+      }
+
+      val maxAngle = Math.PI - minAngle
+
+      val baseAngle = Math.atan2(firstIntersection._1.y, firstIntersection._1.x)
+      println("base angle: " + Raymath.toDegrees(baseAngle))
+
+      val reflectedAngle = baseAngle + minAngle
+
+      if (minAngle < 0 || minAngle > Math.PI * 2) {
+        println("lol")
+        (r.endingAt(firstIntersection._2), r.endingAt(firstIntersection._2)) //Ray(0, 0, firstIntersection._2))
+      } else {
+        val (x, y) = (
+          Math.cos(reflectedAngle) * 3,
+          Math.sin(reflectedAngle) * 3
+        )
+
+        // Sure hope this is right...
+        (r.endingAt(firstIntersection._2), Ray(x, y, firstIntersection._2))
+      }
+    }
+    val intersections: Seq[(Segment, Point)] = walls.flatMap(w => {
+      w.intersectChecked(asSeg)
+        .map(x => (w, x))
+    })
+      .filter { case (w: Segment, x: Point) => asSeg.tFor(x).map(_ > 0.0000001).getOrElse(false) }
+
+    def isBehind(start: Segment, wall: Segment): Boolean = {
+      val normal = Ray(-wall.y, wall.x, Point(0, 0))
+      val rebased = Ray(start.x, start.y, Point(0, 0))
+      val cosAngle = normal.dot(rebased) / (normal.mag * rebased.mag)
+      cosAngle > 0
+    }
+
+    val continuedIntersections = intersections
+      .filter(i => {
+        val otherT = i._1.tFor(i._2)
+        otherT.map(t => t >= 0 && t <= 1).getOrElse(true)
+      })
+
+    val stoppedIntersections = intersections
+      .filter(i => {
+        val otherT = i._1.tFor(i._2)
+        otherT.map(t => t >= 0 && t <= 1 && isBehind(asSeg, i._1)).getOrElse(false)
+      })
+
+    def fnMin(x: (Segment, Point), y: (Segment, Point)) = if (asSeg.tFor(x._2).get < asSeg.tFor(y._2).get) x else y
+    val firstStop: Option[(Segment, Point)] = stoppedIntersections.reduceOption(fnMin(_, _))
+    val firstReflect: Option[(Segment, Point)] = continuedIntersections.reduceOption(fnMin(_, _))
+
+    (firstStop, firstReflect) match {
+      case (None, None) =>
+        (r, Ray(r.x, r.y, r.toSegment.at(1)))
+      case (Some(stop), None) =>
+        (r.endingAt(stop._2), Ray(0, 0, r.initial))
+      case (None, Some(cont)) => reflect(cont)/* reflect */
+      case (Some(stop), Some(cont)) => {
+        if (fnMin(stop, cont) == stop) {
+          (r.endingAt(stop._2), Ray(0, 0, r.initial))
+          // stop
+        } else {
+          reflect(cont)
+          // reflect
+        }
+      }
+    }
+  }
+}
+
+object Scene {
+  def generateMirror(r: Double, segments: Int, arcSize: Double, at: Point, rotated: Double): Seq[Segment] = {
+    val sizePerSegment = arcSize / segments
+    val points = (0 to segments) map { i =>
+      val angle = i * sizePerSegment + rotated
+      at + Point(Math.cos(angle) * r, Math.sin(angle) * r)
+    }
+    points.sliding(2).map { case Seq(start, end) =>
+      Segment.fromPoints(start, end)
+    }.toSeq
+  }
+
+  def generateParabola(a: Double, b: Double, w: Double, w_i: Double, segments: Int, at: Point, rotated: Double): Seq[Segment] = {
+    val points = (-segments / 2 to segments / 2) map { i =>
+      val w_curr = (i / segments.toDouble) * w + w_i
+      at + Point(a * w_curr, b * w_curr * w_curr)
+    }
+    points.sliding(2).map { case Seq(start, end) =>
+      Segment.fromPoints(start, end)
+    }.toSeq
+  }
+
+  def rotate(walls: Seq[Segment], angle: Double) =
+    walls.map(_.rotate(angle))
+}
diff --git a/src/main.scala b/src/main.scala
new file mode 100644
index 0000000..8883cc7
--- /dev/null
+++ b/src/main.scala
@@ -0,0 +1,40 @@
+import net.iximeow.raytrace._
+import Objects._
+
+object main extends App {
+//  val mirror = Scene(Scene.generateMirror(10, 60, Raymath.toRadians(180), Point(0, 0), 0))
+  val offset = Point(0.0, -9)
+  val mirror = Scene(Scene.generateParabola(-0.9, -0.0075, 16, 0, 42, Point(0, 14), 0) :+ Segment.fromPoints(
+    Point(-0.5, 0.5) + offset,
+    Point(0.5, -0.5) + offset
+  ))
+//  val mirror = Scene(Seq(Segment(4, -4, Point(-2, 2))))
+  //val ray = mirror.cast(Ray(0, 2, Point(0.8, -1)), 4)
+  mirror.render(scale = 20, color = 0xc0c0c0, normals = true)
+  //for (segment <- ray) {
+  //  segment.renderTo(mirror.buffer, 20, 400, 300)
+  //}
+/*
+  for (i <- -4 to 4 by 1) {
+    for (segment <- mirror.cast(Ray(i / 2.0, 2, Point(0.8, -1)), 4)) {
+      segment.renderTo(mirror.buffer, 20, 400, 300)
+    }
+  }
+*/
+  def rays(number: Int, spacing: Double, centerpoint: Point, direction: Point): Seq[Ray] = {
+    (0 until number).map { i =>
+      val x = (i.toDouble - number.toDouble / 2) * spacing
+      val y = 0
+      val dx = direction.x
+//        * Math.cos((i.toDouble - number.toDouble) / (number.toDouble / 4))
+      val dy = direction.y
+      Ray(dx, dy, Point(x, y) + centerpoint)
+    }
+  }
+
+  rays(63, 0.165, Point(-0, -10), Point(0.0, 2))
+    .flatMap(x => mirror.cast(x, 30))
+    .map(_.renderTo(mirror.buffer, 20, 400, 300))
+  //println(ray)
+  mirror.save()
+}
diff --git a/src/test.scala b/src/test.scala
new file mode 100644
index 0000000..5780509
--- /dev/null
+++ b/src/test.scala
@@ -0,0 +1,3 @@
+object foo extends App {
+  println("hello world")
+}