Files
OpenRA/OpenRA.Mods.Common/Traits/PaletteEffects/GlobalLightingPaletteEffect.cs

111 lines
3.7 KiB
C#

#region Copyright & License Information
/*
* Copyright 2007-2019 The OpenRA Developers (see AUTHORS)
* This file is part of OpenRA, which is free software. It is made
* available to you under the terms of the GNU General Public License
* as published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version. For more
* information, see COPYING.
*/
#endregion
using System.Collections.Generic;
using System.Linq;
using OpenRA.Graphics;
using OpenRA.Traits;
namespace OpenRA.Mods.Common.Traits
{
[Desc("Used for day/night effects.")]
class GlobalLightingPaletteEffectInfo : ITraitInfo, ILobbyCustomRulesIgnore
{
[Desc("Do not modify graphics that use any palette in this list.")]
public readonly HashSet<string> ExcludePalettes = new HashSet<string> { "cursor", "chrome", "colorpicker", "fog", "shroud", "alpha" };
[Desc("Do not modify graphics that start with these letters.")]
public readonly HashSet<string> ExcludePalettePrefixes = new HashSet<string>();
public readonly float Red = 1f;
public readonly float Green = 1f;
public readonly float Blue = 1f;
public readonly float Ambient = 1f;
public object Create(ActorInitializer init) { return new GlobalLightingPaletteEffect(this); }
}
class GlobalLightingPaletteEffect : IPaletteModifier
{
readonly GlobalLightingPaletteEffectInfo info;
public float Red;
public float Green;
public float Blue;
public float Ambient;
public GlobalLightingPaletteEffect(GlobalLightingPaletteEffectInfo info)
{
this.info = info;
Red = info.Red;
Green = info.Green;
Blue = info.Blue;
Ambient = info.Ambient;
}
public void AdjustPalette(IReadOnlyDictionary<string, MutablePalette> palettes)
{
// Calculate ambient color multipliers as integers for speed. To handle fractional ambiance, we'll increase
// the magnitude of the result by 8 bits.
var ar = (uint)((1 << 8) * Ambient * Red);
var ag = (uint)((1 << 8) * Ambient * Green);
var ab = (uint)((1 << 8) * Ambient * Blue);
foreach (var kvp in palettes)
{
if (info.ExcludePalettes.Contains(kvp.Key))
continue;
if (info.ExcludePalettePrefixes.Any(kvp.Key.StartsWith))
continue;
var palette = kvp.Value;
for (var x = 0; x < Palette.Size; x++)
{
/* Here is the reference code for the operation we are performing.
var from = palette.GetColor(x);
var r = (int)(from.R * Ambient * Red).Clamp(0, 255);
var g = (int)(from.G * Ambient * Green).Clamp(0, 255);
var b = (int)(from.B * Ambient * Blue).Clamp(0, 255);
palette.SetColor(x, Color.FromArgb(from.A, r, g, b));
*/
// PERF: Use integer arithmetic to avoid costly conversions to and from floating point values.
var from = palette[x];
// 1: Extract each color component and shift it to the lower bits, then multiply with ambiance.
// 2: Because the ambiance was increased by 8 bits, our result has been shifted 8 bits up.
// If the multiply overflowed we clamp the value, otherwise we mask out the fractional bits.
// 3: Finally, we shift the color component back to its correct place. We're already 8 bits higher
// than expected due to the multiply, so we don't have to shift as far to get back.
var r1 = ((from & 0x00FF0000) >> 16) * ar;
var r2 = r1 >= 0x0000FF00 ? 0x0000FF00 : r1 & 0x0000FF00;
var r3 = r2 << 8;
var g1 = ((from & 0x0000FF00) >> 8) * ag;
var g2 = g1 >= 0x0000FF00 ? 0x0000FF00 : g1 & 0x0000FF00;
var g3 = g2 << 0;
var b1 = ((from & 0x000000FF) >> 0) * ab;
var b2 = b1 >= 0x0000FF00 ? 0x0000FF00 : b1 & 0x0000FF00;
var b3 = b2 >> 8;
// Combine all the adjusted components back together.
var a = from & 0xFF000000;
palette[x] = a | r3 | g3 | b3;
}
}
}
}
}