Renders a trail of iron ore behind the render view entity

ClientEventSubscriber.java

package io.github.cadiboo.testmod.client;

import net.minecraft.block.state.IBlockState;
import net.minecraft.client.Minecraft;
import net.minecraft.client.renderer.BlockRendererDispatcher;
import net.minecraft.client.renderer.BufferBuilder;
import net.minecraft.client.renderer.Tessellator;
import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
import net.minecraft.entity.Entity;
import net.minecraft.init.Blocks;
import net.minecraft.util.math.BlockPos;
import net.minecraft.world.IBlockAccess;
import net.minecraftforge.client.event.RenderWorldLastEvent;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;
import net.minecraftforge.fml.common.gameevent.TickEvent;

import java.util.ArrayList;

import static io.github.cadiboo.testmod.util.ModReference.MOD_ID;
import static net.minecraftforge.fml.relauncher.Side.CLIENT;
import static org.lwjgl.opengl.GL11.GL_QUADS;

/**
 * Subscribe to events that should be handled on the PHYSICAL CLIENT in this class
 *
 * @author Cadiboo
 */
@Mod.EventBusSubscriber(modid = MOD_ID, value = CLIENT)
public final class ClientEventSubscriber {

	private static final ArrayList<BlockPos> previousPositions = new ArrayList<>();

	@SubscribeEvent
	public static void onClientTickEvent(final TickEvent.ClientTickEvent event) {
		if (Minecraft.getMinecraft().getRenderViewEntity() == null) {
			return;
		}
		previousPositions.add(Minecraft.getMinecraft().getRenderViewEntity().getPosition());
		while (previousPositions.size() > 25) {
			previousPositions.remove(0);
		}
	}

	@SubscribeEvent
	public static void onRenderWorldLastEvent(final RenderWorldLastEvent event) {
		if (previousPositions.isEmpty()) {
			return;
		}

		final float partialTicks = event.getPartialTicks();

		// Not always the player, is sometimes the mob the player is spectating. Mods that hijack the camera also often do it this way.
		final Minecraft minecraft = Minecraft.getMinecraft();
		final Entity renderViewEntity = minecraft.getRenderViewEntity();
		assert renderViewEntity != null;

		// Interpolating everything back to (0, 0, 0). You can find these transforms in the RenderEntity class
		final double d0 = renderViewEntity.lastTickPosX + ((renderViewEntity.posX - renderViewEntity.lastTickPosX) * partialTicks);
		final double d1 = renderViewEntity.lastTickPosY + ((renderViewEntity.posY - renderViewEntity.lastTickPosY) * partialTicks);
		final double d2 = renderViewEntity.lastTickPosZ + ((renderViewEntity.posZ - renderViewEntity.lastTickPosZ) * partialTicks);

		final Tessellator tessellator = Tessellator.getInstance();
		final BufferBuilder bufferBuilder = tessellator.getBuffer();

		// Transform to BlockPos (0, 0, 0)
		bufferBuilder.setTranslation(-d0, -d1, -d2);

		// Begin drawing quads in the block format
		bufferBuilder.begin(GL_QUADS, DefaultVertexFormats.BLOCK);

		final BlockRendererDispatcher blockRendererDispatcher = minecraft.getBlockRendererDispatcher();
		final IBlockState state = Blocks.IRON_ORE.getDefaultState();

		// Read-only access to the world
		final IBlockAccess blockAccess = minecraft.world;

		for (final BlockPos previousPosition : previousPositions) {
			// Render the block with the dispatcher
			blockRendererDispatcher.renderBlock(state, previousPosition, blockAccess, bufferBuilder);
		}

		// Draw with the tessellator, not the bufferBuilder
		tessellator.draw();

		// Reset translation
		bufferBuilder.setTranslation(0, 0, 0);
	}

}