InstantBulletRenderer.java

package com.flansmod.client.model;

import java.util.ArrayList;

import org.lwjgl.opengl.GL11;

import com.flansmod.client.FlansModResourceHandler;
import com.flansmod.common.guns.BulletType;
import com.flansmod.common.vector.Vector3f;

import net.minecraft.client.Minecraft;
import net.minecraft.client.renderer.GlStateManager;
import net.minecraft.client.renderer.Tessellator;
import net.minecraft.client.renderer.WorldRenderer;
import net.minecraft.client.renderer.texture.TextureManager;
import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
import net.minecraft.entity.Entity;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.util.ResourceLocation;

public class InstantBulletRenderer
{
	private static TextureManager textureManager;
	private static ArrayList<InstantShotTrail> trails = new ArrayList<InstantShotTrail>();

	public static void AddTrail(InstantShotTrail trail) 
	{ 
		trails.add(trail);
	}
	
	public static void RenderAllTrails(float partialTicks) 
	{
		for(InstantShotTrail trail : trails)
		{
			trail.Render(partialTicks);
		}
	}
	
	public static void UpdateAllTrails()
	{
		for(int i = trails.size() - 1; i >= 0; i--)
		{
			if(trails.get(i).Update())
			{
				trails.remove(i);
			}
		}
	}
	
	public static class InstantShotTrail
	{
		private Vector3f origin;
		private Vector3f hitPos;
		private float width;
		private float length;
		private float distanceToTarget;
		private float bulletSpeed;
		private int ticksExisted;
		
		private ResourceLocation texture;
		
		public InstantShotTrail(Vector3f origin, Vector3f hitPos, BulletType type)
		{
			this.ticksExisted = 0;
			this.bulletSpeed = 10.0f;
			this.origin = origin;
			this.hitPos = hitPos;
			this.width = 0.05f; // type.trailWidth
			this.length = 10.0f;
			this.texture = FlansModResourceHandler.getTrailTexture(type);
			
	        Vector3f dPos = Vector3f.sub(hitPos, origin, null);
	        this.distanceToTarget = dPos.length();
		}
		
		// Return true if this needs deleting
		public boolean Update()
		{
			ticksExisted++;
			return (ticksExisted) * bulletSpeed >= distanceToTarget - length;
		}
		
		public void Render(float partialTicks)
		{
			//Make sure we actually have the renderEngine
			if(textureManager == null)
				textureManager = Minecraft.getMinecraft().renderEngine;
			
			textureManager.bindTexture(texture);
			
	        GlStateManager.color(1.0F, 1.0F, 1.0F, 1.0F);
	        
	        GlStateManager.pushMatrix();

	        //Get the camera frustrum for clipping
	        Entity camera = Minecraft.getMinecraft().getRenderViewEntity();
	        double x = camera.lastTickPosX + (camera.posX - camera.lastTickPosX) * partialTicks;
	        double y = camera.lastTickPosY + (camera.posY - camera.lastTickPosY) * partialTicks;
	        double z = camera.lastTickPosZ + (camera.posZ - camera.lastTickPosZ) * partialTicks;
	        	        
	        GL11.glTranslatef(-(float)x, -(float)y, -(float)z);
	        
	        float parametric = ((float)(ticksExisted) + partialTicks) * bulletSpeed;
	        
	        Vector3f dPos = Vector3f.sub(hitPos, origin, null);
	        dPos.normalise();
	        
	        float startParametric = parametric - length * 0.5f;
	        Vector3f startPos = new Vector3f(origin.x + dPos.x * startParametric,  origin.y + dPos.y * startParametric, origin.z + dPos.z * startParametric);
	        float endParametric = parametric + length * 0.5f;
	        Vector3f endPos = new Vector3f(origin.x + dPos.x * endParametric,  origin.y + dPos.y * endParametric, origin.z + dPos.z * endParametric);
	        
	        Tessellator tessellator = Tessellator.getInstance();
	        WorldRenderer worldrenderer = tessellator.getWorldRenderer();

	        dPos.normalise();
	        
	        EntityPlayer thePlayer = Minecraft.getMinecraft().thePlayer;
	        Vector3f vectorToPlayer = new Vector3f(thePlayer.posX - hitPos.x, thePlayer.posY - hitPos.y, thePlayer.posZ - hitPos.z);
	        
	        vectorToPlayer.normalise();
	        
	        Vector3f trailTangent = Vector3f.cross(dPos, vectorToPlayer, null);
	        trailTangent.normalise();
	        trailTangent.scale(-width * 0.5f);
	        
	        Vector3f normal = Vector3f.cross(trailTangent, dPos, null);
	        normal.normalise();
	           
	        GlStateManager.enableRescaleNormal();
	        GL11.glNormal3f(normal.x, normal.y, normal.z);
	        
	        worldrenderer.begin(7, DefaultVertexFormats.POSITION_TEX);
	        worldrenderer.pos(startPos.x + trailTangent.x, startPos.y + trailTangent.y, startPos.z + trailTangent.z).tex(0.0f, 0.0f).endVertex();
	        worldrenderer.pos(startPos.x - trailTangent.x, startPos.y - trailTangent.y, startPos.z - trailTangent.z).tex(0.0f, 1.0f).endVertex();
	        worldrenderer.pos(endPos.x - trailTangent.x, endPos.y - trailTangent.y, endPos.z - trailTangent.z).tex(1.0f, 1.0f).endVertex();
	        worldrenderer.pos(endPos.x + trailTangent.x, endPos.y + trailTangent.y, endPos.z + trailTangent.z).tex(1.0f, 0.0f).endVertex();
	        tessellator.draw();
	        	
	        GlStateManager.disableRescaleNormal();
	        
	        GlStateManager.popMatrix();
		}
	}
}