﻿using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Graphics; namespace Krypton { public static class LightTextureBuilder { /// /// Create a Point Light based on a size. /// /// Your game's GraphicsDevice /// Maximum Size /// Light Texture public static Texture2D CreatePointLight(GraphicsDevice device, int size) { return CreateConicLight(device, size, MathHelper.TwoPi, 0); } /// /// Create a Conic Light based on the size, and field of view. /// /// Your game's GraphicsDevice /// Maximum Size /// Maximum Field of View /// Light Texture public static Texture2D CreateConicLight(GraphicsDevice device, int size, float FOV) { return CreateConicLight(device, size, FOV, 0); } /// /// Create a Conic Light based on the size, field of view, and near plane distance. /// /// Your game's GraphicsDevice /// Maximum size /// Maximum Field of View /// Prevents texture from being drawn at this plane distance, originating from the center of light /// Light Texture public static Texture2D CreateConicLight(GraphicsDevice device, int size, float FOV, float nearPlaneDistance) { /*if (!IsPowerOfTwo(size)) throw new Exception("The size must be a power of 2");*/ float[,] Data = new float[size, size]; float center = size / 2; FOV = FOV / 2; for (int x = 0; x < size; x++) for (int y = 0; y < size; y++) { float Distance = Vector2.Distance(new Vector2(x, y), new Vector2(center)); Vector2 Difference = new Vector2(x, y) - new Vector2(center); float Angle = (float)Math.Atan2(Difference.Y, Difference.X); if (Distance <= center && Distance >= nearPlaneDistance && Math.Abs(Angle) <= FOV) Data[x, y] = (center - Distance) / center; else Data[x, y] = 0; } Texture2D tex = new Texture2D(device, size, size); Color[] Data1D = new Color[size * size]; for (int x = 0; x < size; x++) for (int y = 0; y < size; y++) Data1D[x + y * size] = new Color(new Vector3(Data[x, y])); tex.SetData(Data1D); return tex; } /// /// Math helper to determine if integer is a power of two /// /// Integer value private static bool IsPowerOfTwo(int x) { return (x & (x - 1)) == 0; } } }