eaglercraft-1.8/sources/main/java/net/optifine/render/Blender.java

package net.optifine.render;

import net.lax1dude.eaglercraft.v1_8.opengl.GlStateManager;
import net.optifine.Config;

public class Blender {
	public static final int BLEND_ALPHA = 0;
	public static final int BLEND_ADD = 1;
	public static final int BLEND_SUBSTRACT = 2;
	public static final int BLEND_MULTIPLY = 3;
	public static final int BLEND_DODGE = 4;
	public static final int BLEND_BURN = 5;
	public static final int BLEND_SCREEN = 6;
	public static final int BLEND_OVERLAY = 7;
	public static final int BLEND_REPLACE = 8;
	public static final int BLEND_DEFAULT = 1;

	public static int parseBlend(String str) {
		if (str == null) {
			return 1;
		} else {
			str = str.toLowerCase().trim();

			if (str.equals("alpha")) {
				return 0;
			} else if (str.equals("add")) {
				return 1;
			} else if (str.equals("subtract")) {
				return 2;
			} else if (str.equals("multiply")) {
				return 3;
			} else if (str.equals("dodge")) {
				return 4;
			} else if (str.equals("burn")) {
				return 5;
			} else if (str.equals("screen")) {
				return 6;
			} else if (str.equals("overlay")) {
				return 7;
			} else if (str.equals("replace")) {
				return 8;
			} else {
				Config.warn("Unknown blend: " + str);
				return 1;
			}
		}
	}

	public static void setupBlend(int blend, float brightness) {
		switch (blend) {
		case 0:
			GlStateManager.disableAlpha();
			GlStateManager.enableBlend();
			GlStateManager.blendFunc(770, 771);
			GlStateManager.color(1.0F, 1.0F, 1.0F, brightness);
			break;

		case 1:
			GlStateManager.disableAlpha();
			GlStateManager.enableBlend();
			GlStateManager.blendFunc(770, 1);
			GlStateManager.color(1.0F, 1.0F, 1.0F, brightness);
			break;

		case 2:
			GlStateManager.disableAlpha();
			GlStateManager.enableBlend();
			GlStateManager.blendFunc(775, 0);
			GlStateManager.color(brightness, brightness, brightness, 1.0F);
			break;

		case 3:
			GlStateManager.disableAlpha();
			GlStateManager.enableBlend();
			GlStateManager.blendFunc(774, 771);
			GlStateManager.color(brightness, brightness, brightness, brightness);
			break;

		case 4:
			GlStateManager.disableAlpha();
			GlStateManager.enableBlend();
			GlStateManager.blendFunc(1, 1);
			GlStateManager.color(brightness, brightness, brightness, 1.0F);
			break;

		case 5:
			GlStateManager.disableAlpha();
			GlStateManager.enableBlend();
			GlStateManager.blendFunc(0, 769);
			GlStateManager.color(brightness, brightness, brightness, 1.0F);
			break;

		case 6:
			GlStateManager.disableAlpha();
			GlStateManager.enableBlend();
			GlStateManager.blendFunc(1, 769);
			GlStateManager.color(brightness, brightness, brightness, 1.0F);
			break;

		case 7:
			GlStateManager.disableAlpha();
			GlStateManager.enableBlend();
			GlStateManager.blendFunc(774, 768);
			GlStateManager.color(brightness, brightness, brightness, 1.0F);
			break;

		case 8:
			GlStateManager.enableAlpha();
			GlStateManager.disableBlend();
			GlStateManager.color(1.0F, 1.0F, 1.0F, brightness);
		}

		GlStateManager.enableTexture2D();
	}

	public static void clearBlend(float rainBrightness) {
		GlStateManager.disableAlpha();
		GlStateManager.enableBlend();
		GlStateManager.blendFunc(770, 1);
		GlStateManager.color(1.0F, 1.0F, 1.0F, rainBrightness);
	}
}