BDE_ParticleSys/src/main/kotlin/com/bytedice/bde_particles/Math.kt

package com.bytedice.bde_particles

import net.minecraft.server.network.ServerPlayerEntity
import net.minecraft.util.hit.HitResult
import net.minecraft.util.math.Vec3d
import net.minecraft.world.RaycastContext
import net.minecraft.world.World
import org.joml.Vector2f
import org.joml.Vector3f
import org.joml.Vector4f
import java.util.SplittableRandom
import kotlin.math.*
import kotlin.random.Random


class LerpCurves(val function: (Float) -> Float) {
  companion object {
    val Constant = LerpCurves { _ -> 1.0f }
    val Linear = LerpCurves { y -> y }
    val Sqrt = LerpCurves { y -> sqrt(y) }
    val Exponent = LerpCurves { y -> y.pow(2.0f) }
    val Cubic = LerpCurves { y -> y.pow(3.0f) }
    val Sine = LerpCurves { y -> sin(y * PI.toFloat() / 2) }
    val Cosine = LerpCurves { y -> 1 - cos(y * PI.toFloat() / 2) }
    val Inverse = LerpCurves { y -> 1 - y }
    val Log = LerpCurves { y -> if (y > 0) ln(y + 1) else 0f }
    val Exp = LerpCurves { y -> exp(y) - 1 }
    val Bounce = LerpCurves { y ->
      val n1 = 7.5625f
      val d1 = 2.75f
      when {
        y < 1 / d1 -> n1 * y * y
        y < 2 / d1 -> {
          val t = y - 1.5f / d1
          n1 * t * t + 0.75f
        }
        y < 2.5 / d1 -> {
          val t = y - 2.25f / d1
          n1 * t * t + 0.9375f
        }
        else -> {
          val t = y - 2.625f / d1
          n1 * t * t + 0.984375f
        }
      }
    }

    fun custom(equation: (Float) -> Float) = LerpCurves(equation)
  }
}


fun raycastFromPlayer(player: ServerPlayerEntity, maxDistance: Double): HitResult? {
  val world: World = player.world
  val eyePos: Vec3d = player.getCameraPosVec(1.0f)
  val lookVec: Vec3d = player.getRotationVec(1.0f)
  val targetPos: Vec3d = eyePos.add(lookVec.multiply(maxDistance))

  val blockHitResult = world.raycast(
    RaycastContext(
      eyePos,
      targetPos,
      RaycastContext.ShapeType.OUTLINE,
      RaycastContext.FluidHandling.NONE,
      player
    )
  )

  return if (blockHitResult.type == HitResult.Type.BLOCK) {
    blockHitResult
  } else {
    null
  }
}


fun randomFloatBetween(min: Float, max: Float) : Float {
  return Random.nextFloat() * (max - min) + min
}


fun randomIntBetween(min: Int, max: Int) : Int {
  return Random.nextInt(max - min) + min
}


fun eulerToQuat(euler: Vector3f): Vector4f {
  val roll  = euler.x * (Math.PI / 180).toFloat()
  val pitch = euler.y * (Math.PI / 180).toFloat()
  val yaw   = euler.z * (Math.PI / 180).toFloat()

  val cy = cos(yaw * 0.5)
  val sy = sin(yaw * 0.5)
  val cp = cos(pitch * 0.5)
  val sp = sin(pitch * 0.5)
  val cr = cos(roll * 0.5)
  val sr = sin(roll * 0.5)

  val w = cr * cp * cy + sr * sp * sy
  val x = sr * cp * cy - cr * sp * sy
  val y = cr * sp * cy + sr * cp * sy
  val z = cr * cp * sy - sr * sp * cy

  return Vector4f(x.toFloat(), y.toFloat(), z.toFloat(), w.toFloat())
}


fun quatToEuler(quat: Vector4f): Vector3f {
  val x = quat.x
  val y = quat.y
  val z = quat.z
  val w = quat.w

  val sinRCosP = 2 * (w * x + y * z)
  val cosRCosP = 1 - 2 * (x * x + y * y)
  val roll = atan2(sinRCosP, cosRCosP)

  val sinP = 2 * (w * y - z * x)
  val pitch = if (abs(sinP) >= 1) {
    sign(sinP) * (Math.PI.toFloat() / 2)
  } else {
    asin(sinP)
  }

  val sinYCosP = 2 * (w * z + x * y)
  val cosYCosP = 1 - 2 * (y * y + z * z)
  val yaw = atan2(sinYCosP, cosYCosP)

  return Vector3f(roll, pitch, yaw)
}


fun transformOffsetByQuat(offset: Vector3f, rotation: Vector4f): Vector3f {
  val x = offset.x
  val y = offset.y
  val z = offset.z

  val qx = rotation.x.toDouble()
  val qy = rotation.y.toDouble()
  val qz = rotation.z.toDouble()
  val qw = rotation.w.toDouble()

  val t2 = qw * x + qy * z - qz * y
  val t3 = qw * y + qz * x - qx * z
  val t4 = qw * z + qx * y - qy * x
  val t5 = -qx * x - qy * y - qz * z

  val newX = t2 * qw + t5 * -qx + t3 * -qz - t4 * -qy
  val newY = t3 * qw + t5 * -qy + t4 * -qx - t2 * -qz
  val newZ = t4 * qw + t5 * -qz + t2 * -qy - t3 * -qx

  return Vector3f(newX.toFloat(), newY.toFloat(), newZ.toFloat())
}


fun transformOffsetByScale(offset: Vector3f, scale: Vector3f): Vector3f {
  return Vector3f(offset).mul(scale)
}


fun lerp(x: Float, y: Float, t: Float) : Float {
  val clampedT = t.coerceIn(0f, 1f)
  return x + (y - x) * clampedT
}


fun lerpArray(array: Array<Any>, t: Float, curve: LerpCurves = LerpCurves.Linear) : Any {
  val idx = round(lerp(0.0f, array.lastIndex.toFloat(), t) * curve.function(t)).toInt()
  return array[idx]
}


fun sdfSphere(pos: Vector3f, radius: Float, objectPos: Vector3f): Float {
  val dx = objectPos.x - pos.x
  val dy = objectPos.y - pos.y
  val dz = objectPos.z - pos.z

  val distanceFromCenter = sqrt(dx * dx + dy * dy + dz * dz)
  return (distanceFromCenter - radius)
}


fun sdfCube(pos: Vector3f, size: Vector3f, objectPos: Vector3f): Float {
  val px = objectPos.x - pos.x
  val py = objectPos.y - pos.y
  val pz = objectPos.z - pos.z

  val sx = size.x.toDouble()
  val sy = size.y.toDouble()
  val sz = size.z.toDouble()

  val halfSize = Triple(sx / 2, sy / 2, sz / 2)

  val absPoint = Triple(abs(px), abs(py), abs(pz))

  val dx = absPoint.first - halfSize.first
  val dy = absPoint.second - halfSize.second
  val dz = absPoint.third - halfSize.third

  val outside = Triple(max(dx, 0.0), max(dy, 0.0), max(dz, 0.0))
  val outsideDistance = sqrt(outside.first * outside.first + outside.second * outside.second + outside.third * outside.third)

  val insideDistance = min(max(dx, max(dy, dz)), 0.0)

  return (outsideDistance + insideDistance).toFloat()
}


fun normalizeSdf(sdf: Float, radius: Float): Float {
  return if (sdf < 0) (sdf + radius) / radius else 0f
}