From c01a01a41717ba31b75edd8fdcb9ff0feb99f538 Mon Sep 17 00:00:00 2001
From: Sollace <sollacea@gmail.com>
Date: Wed, 6 Feb 2019 11:40:58 +0200
Subject: [PATCH] Rainbows now consider the sun's brightness and are less
 visible during the night

---
 .../unicopia/render/RenderRainbow.java        | 25 ++++--
 .../com/minelittlepony/util/WorldHelper.java  | 86 +++++++++++++++++++
 2 files changed, 103 insertions(+), 8 deletions(-)
 create mode 100644 src/main/java/com/minelittlepony/util/WorldHelper.java

diff --git a/src/main/java/com/minelittlepony/unicopia/render/RenderRainbow.java b/src/main/java/com/minelittlepony/unicopia/render/RenderRainbow.java
index 82624b13..5aea9b58 100644
--- a/src/main/java/com/minelittlepony/unicopia/render/RenderRainbow.java
+++ b/src/main/java/com/minelittlepony/unicopia/render/RenderRainbow.java
@@ -3,6 +3,7 @@ package com.minelittlepony.unicopia.render;
 import org.lwjgl.opengl.GL11;
 
 import com.minelittlepony.unicopia.entity.EntityRainbow;
+import com.minelittlepony.util.WorldHelper;
 
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.renderer.BufferBuilder;
@@ -22,6 +23,21 @@ public class RenderRainbow extends Render<EntityRainbow> {
     private static final ResourceLocation TEXTURE = new ResourceLocation("unicopia", "textures/environment/rainbow.png");
 
     public void doRender(EntityRainbow entity, double x, double y, double z, float entityYaw, float partialTicks) {
+
+
+        float distance = Minecraft.getMinecraft().getRenderViewEntity().getDistance(entity);
+        float maxDistance = 16 * Minecraft.getMinecraft().gameSettings.renderDistanceChunks;
+        double r = entity.getRadius();
+        float light = WorldHelper.getDaylightBrightness(entity.getEntityWorld(), partialTicks);
+
+        float opacity = ((maxDistance - distance) / maxDistance);
+
+        opacity *= light;
+
+        if (opacity <= 0) {
+            return;
+        }
+
         bindEntityTexture(entity);
 
         GlStateManager.pushMatrix();
@@ -33,18 +49,11 @@ public class RenderRainbow extends Render<EntityRainbow> {
         GlStateManager.translate(x, y, z);
         GlStateManager.rotate(entityYaw, 0, 1, 0);
 
-        float distance = Minecraft.getMinecraft().getRenderViewEntity().getDistance(entity);
-
-
-        float maxDistance = 16 * Minecraft.getMinecraft().gameSettings.renderDistanceChunks;
-
-        GlStateManager.color(1, 1, 1, ((maxDistance - distance) / maxDistance) * 0.9f);
+        GlStateManager.color(1, 1, 1, opacity);
 
         Tessellator tessellator = Tessellator.getInstance();
         BufferBuilder bufferbuilder = tessellator.getBuffer();
 
-        double r = entity.getRadius();
-
         bufferbuilder.begin(GL11.GL_QUADS, DefaultVertexFormats.POSITION_TEX);
         bufferbuilder.pos(-r, r, 0).tex(1, 0).endVertex();
         bufferbuilder.pos( r, r, 0).tex(0, 0).endVertex();
diff --git a/src/main/java/com/minelittlepony/util/WorldHelper.java b/src/main/java/com/minelittlepony/util/WorldHelper.java
new file mode 100644
index 00000000..a01bd0ed
--- /dev/null
+++ b/src/main/java/com/minelittlepony/util/WorldHelper.java
@@ -0,0 +1,86 @@
+package com.minelittlepony.util;
+
+import net.minecraft.world.World;
+
+public final class WorldHelper {
+
+
+    /**
+     * Gets the daylight brightness value on a scale of 0-1.
+     * Midday = 1
+     * Sunrise/Sunset = 0
+     * Nighttime = 0
+     */
+    public static float getDaylightBrightness(World w, float partialTicks) {
+        float celst = w.getCelestialAngle(partialTicks);
+
+        // ----------------------------
+        // 0 |          0.5      |      1
+        //   |          |        |    midday
+        //   |          midnight |
+        // sunset                |
+        //                       sunrise
+        //---|                   |-------
+   //---//                    |-------|
+        //  /                    \
+        // /                      \
+        //                         \
+        //                          \
+        // midnight = 0.5
+        // sunrise = 0.7
+        // midday = 1
+        // sunset = 0.3
+
+        if (celst >= 0.7F || celst <= 0.3F) {
+            if (celst >= 0.7) {
+                celst -= 0.7;
+            } else {
+                celst = -celst + 0.3F;
+            }
+
+            return celst * (3 + 1/3);
+        } else {
+            celst = 0;
+        }
+
+
+        System.out.println(celst);
+
+        return celst;
+    }
+
+    /**
+     * Gets the brightness of the moon. Works as the inverse of getDaylightBrightness but for the moon.
+     * Midnight = 1
+     * Sunrise/Sunset = 0
+     * Daytime = 0
+     */
+    public static float getLunarBrightness(World w, float partialTicks) {
+        float celst = w.getCelestialAngle(partialTicks);
+
+        // ----------------------------
+        // 0 |          0.5      |      1
+        //   |          |        |    midday
+        //   |          midnight |
+        // sunset                |
+        //                       sunrise
+        //   |-------------------|
+        //   \         |        /
+        //    \        |       /
+        //     \       |      /
+        //      \      |     /
+        //             |
+        // midnight = 0.5
+        // sunrise = 0.7
+        // midday = 1
+        // sunset = 0.3
+
+        if (celst < 0.7F && celst > 0.3F) {
+            return Math.abs(celst - 0.5F) / 0.2F;
+        }
+
+        System.out.println(celst);
+
+        return 0;
+    }
+}