Allows custom blocks to define if they should use the fluid overlay instead of the flowing texture when in a fluid (#6493)

src/main/java/net/minecraftforge/common/extensions/IForgeBlock.java

@@ -35,6 +35,7 @@ import net.minecraft.block.HorizontalBlock;
 import net.minecraft.block.IBeaconBeamColorProvider;
 import net.minecraft.block.ITileEntityProvider;
 import net.minecraft.block.SoundType;
+import net.minecraft.block.StainedGlassBlock;
 import net.minecraft.block.material.Material;
 import net.minecraft.block.BlockState;
 import net.minecraft.client.particle.ParticleManager;
@@ -1054,4 +1055,18 @@ public interface IForgeBlock
     {
         return getBlock().isIn(BlockTags.FENCES) || getBlock().isIn(BlockTags.WALLS) || getBlock() instanceof FenceGateBlock;
     }
+
+    /**
+     * Called to determine whether this block should use the fluid overlay texture or flowing texture when it is placed under the fluid.
+     *
+     * @param state The current state
+     * @param world The world
+     * @param pos Block position in world
+     * @param fluidState The state of the fluid
+     * @return Whether the fluid overlay texture should be used
+     */
+    default boolean shouldDisplayFluidOverlay(BlockState state, ILightReader world, BlockPos pos, IFluidState fluidState)
+    {
+        return state.getBlock() == Blocks.GLASS || state.getBlock() instanceof StainedGlassBlock;
+    }
 }

src/main/java/net/minecraftforge/common/extensions/IForgeBlockState.java

@@ -898,4 +898,17 @@ public interface IForgeBlockState
     {
         return getBlockState().getBlock().collisionExtendsVertically(getBlockState(), world, pos, collidingEntity);
     }
+
+    /**
+     * Called to determine whether this block should use the fluid overlay texture or flowing texture when it is placed under the fluid.
+     *
+     * @param world The world
+     * @param pos Block position in world
+     * @param fluidState The state of the fluid
+     * @return Whether the fluid overlay texture should be used
+     */
+    default boolean shouldDisplayFluidOverlay(ILightReader world, BlockPos pos, IFluidState fluidState)
+    {
+        return getBlockState().getBlock().shouldDisplayFluidOverlay(getBlockState(), world, pos, fluidState);
+    }
 }