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