Makes potion icons fade over time

src/main/java/markil3/immersive_hud/TimerUtils.java

@@ -23,6 +23,8 @@ import net.minecraft.client.network.ClientPlayerEntity;
 import net.minecraft.client.util.math.MatrixStack;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.LivingEntity;
+import net.minecraft.entity.effect.StatusEffect;
+import net.minecraft.entity.effect.StatusEffectInstance;
 import net.minecraft.entity.effect.StatusEffects;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.item.BowItem;
@@ -41,7 +43,13 @@ import net.minecraft.item.TridentItem;
 import net.minecraft.util.Hand;
 import net.minecraft.util.hit.EntityHitResult;
 import net.minecraft.util.hit.HitResult;
+import net.minecraft.util.math.MathHelper;
 
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Optional;
 
@@ -92,6 +100,8 @@ public class TimerUtils
      */
     private static int mapLock;
 
+    private static HashMap<StatusEffect, Integer> effectTime = new HashMap<>();
+
     /**
      * How many more ticks the hotbar will be onscreen. Every tick is 1/20th of
      * a second.
@@ -427,6 +437,75 @@ public class TimerUtils
         return true;
     }
 
+    /**
+     * Updates the timings of some of the potions currently affecting the
+     * player.
+     *
+     * @param player - The player being affected.
+     */
+    public static void updatePotions(ClientPlayerEntity player)
+    {
+        for (StatusEffect effect :
+                new HashSet<>(effectTime.keySet()))
+        {
+            if (!player.hasStatusEffect(effect))
+            {
+                effectTime.remove(effect);
+            }
+        }
+    }
+
+    /**
+     * Updates the timings of some of the potions currently affecting the
+     * player.
+     *
+     * @param effectinstance - The effect to update
+     */
+    public static boolean updatePotion(StatusEffectInstance effectinstance)
+    {
+        Integer time = effectTime.get(effectinstance.getEffectType());
+        if (time == null)
+        {
+            effectTime.put(effectinstance.getEffectType(),
+                    (time = VISUAL_TIME));
+        }
+        else
+        {
+            effectTime.put(effectinstance.getEffectType(), (time -= 1));
+        }
+        return Main.getAlpha(time) > 0;
+    }
+
+    /**
+     * Obtains how transparent
+     *
+     * @param effectinstance
+     *
+     * @return
+     */
+    public static float getPotionAlpha(StatusEffectInstance effectinstance)
+    {
+        final int BLINK_TIME = 200;
+        float effectAlpha = 0.0F;
+        if (effectinstance.getDuration() <= BLINK_TIME)
+        {
+            effectAlpha =
+                    MathHelper.sin(7000F / (effectinstance.getDuration() + 16F * (float) Math.PI)) * 50F / (effectinstance
+                            .getDuration() + 100F) + 0.5F;
+        }
+        else if (effectinstance.getDuration() <= BLINK_TIME + 10)
+        {
+            effectAlpha = -(effectinstance.getDuration() - 200) / 22F + 0.454F;
+        }
+        else
+        {
+            effectAlpha =
+                    Main.getAlpha(effectTime.getOrDefault(effectinstance.getEffectType(),
+                            0));
+        }
+        return effectAlpha;
+    }
+
     /**
      * Determines whether or not to draw the armor bar, adjusting the alpha as
      * needed.

src/main/java/markil3/immersive_hud/mixin/HudHook.java

@@ -16,12 +16,17 @@
  */
 package markil3.immersive_hud.mixin;
 
+import net.minecraft.client.MinecraftClient;
 import net.minecraft.client.gui.hud.InGameHud;
+import net.minecraft.client.network.ClientPlayerEntity;
 import net.minecraft.client.util.math.MatrixStack;
+import net.minecraft.entity.effect.StatusEffectInstance;
 
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.injection.At;
 import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.ModifyVariable;
+import org.spongepowered.asm.mixin.injection.Redirect;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 
 import markil3.immersive_hud.TimerUtils;
@@ -36,6 +41,8 @@ import markil3.immersive_hud.TimerUtils;
 @Mixin(InGameHud.class)
 public class HudHook
 {
+    private StatusEffectInstance currentEffect;
+
     /**
      * Determines whether or not to draw the crosshair.
      *
@@ -83,8 +90,7 @@ public class HudHook
      * @since 0.1-1.16.4-fabric
      */
     @Inject(method = "renderMountJumpBar", at = @At(value = "HEAD"),
-            cancellable =
-            true)
+            cancellable = true)
     public void startJumpbar(MatrixStack stack,
                              int x,
                              CallbackInfo callbackInfo)
@@ -166,8 +172,7 @@ public class HudHook
      * @since 0.1-1.16.4-fabric
      */
     @Inject(method = "renderMountHealth", at = @At(value = "HEAD"),
-            cancellable =
-            true)
+            cancellable = true)
     public void startMountHealth(MatrixStack stack, CallbackInfo callbackInfo)
     {
         if (TimerUtils.drawMountHealth())
@@ -194,6 +199,77 @@ public class HudHook
         TimerUtils.resetAlpha();
     }
 
+    /**
+     * Makes the actual adjustment to the hotbar as needed.
+     *
+     * @version 0.2-1.16.4-fabric
+     * @since 0.1-1.16.4-fabric
+     */
+    @Inject(method = "renderStatusEffectOverlay" +
+            "(Lnet/minecraft/client/util/math/MatrixStack;)V", at =
+    @At(value = "HEAD", shift = At.Shift.AFTER))
+    public void startPotion(MatrixStack effect, CallbackInfo info)
+    {
+        TimerUtils.updatePotions(MinecraftClient.getInstance().cameraEntity instanceof ClientPlayerEntity ?
+                                 ((ClientPlayerEntity) MinecraftClient.getInstance().cameraEntity) :
+                                 null);
+    }
+
+    /**
+     * Makes the actual adjustment to the hotbar as needed.
+     *
+     * @version 0.2-1.16.4-fabric
+     * @since 0.1-1.16.4-fabric
+     */
+    @Redirect(method = "renderStatusEffectOverlay" +
+            "(Lnet/minecraft/client/util/math/MatrixStack;)V", at =
+    @At(value = "INVOKE",
+            target =
+                    "Lnet/minecraft/entity/effect/StatusEffectInstance;" +
+                            "shouldShowIcon()Z"))
+    public boolean shouldRenderPotion(StatusEffectInstance effect)
+    {
+        currentEffect = effect;
+        return TimerUtils.updatePotion(effect);
+    }
+
+    /**
+     * Makes the actual adjustment to the hotbar as needed.
+     *
+     * @param matrices - The matrix drawing stack.
+     * @param callbackInfo
+     *
+     * @version 0.2-1.16.4-fabric
+     * @since 0.1-1.16.4-fabric
+     */
+    @ModifyVariable(method = "renderStatusEffectOverlay" +
+            "(Lnet/minecraft/client/util/math/MatrixStack;)V", at =
+    @At(value = "STORE"), ordinal = 1)
+    public float updatePotion(float f,
+                              MatrixStack stack)
+    {
+        return TimerUtils.getPotionAlpha(currentEffect);
+    }
+
+    /**
+     * Resets any changes from drawing the potion effects.
+     *
+     * @param matrices - The matrix drawing stack.
+     * @param callbackInfo
+     *
+     * @version 0.2-1.16.4-fabric
+     * @since 0.2-1.16.4-fabric
+     */
+    @Inject(method = "renderStatusEffectOverlay", at = @At(value = "TAIL"))
+    public void finishPotion(MatrixStack matrices,
+                             CallbackInfo callbackInfo)
+    {
+        /*
+         * Resets the color so that nothing else is bothered.
+         */
+        TimerUtils.resetAlpha();
+    }
+
     /**
      * Determines whether or not to draw the hotbar.
      *