By Melonslise

    public static void drawLine(Vec3d start, Vec3d end, int red, int green, int blue, int alpha, float width, float partialTick)
    {
        Vec3d camera = Minecraft.getMinecraft().player.getPositionEyes(partialTick);

        Vec3d direction = end.subtract(start).normalize();
        Vec3d startUp = direction.crossProduct(start.subtract(camera)).normalize().scale(0.0625);
        Vec3d endUp = direction.crossProduct(end.subtract(camera)).normalize().scale(0.0625);

        Tessellator tessellator = Tessellator.getInstance();
        BufferBuilder buffer = tessellator.getBuffer();

        // Enable bit ?
        GlStateManager.pushMatrix();

        GlStateManager.disableCull(); // Cullface
        GlStateManager.enableBlend();
        GlStateManager.depthMask(false);
        GlStateManager.blendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA);

        buffer.begin(GL11.GL_QUADS, DefaultVertexFormats.POSITION_COLOR);
        buffer.pos(start.x + startUp.x, start.y + startUp.y, start.z + startUp.z).color(red, green, blue, alpha).endVertex();
        buffer.pos(start.x - startUp.x, start.y - startUp.y, start.z - startUp.z).color(red, green, blue, alpha).endVertex();
        buffer.pos(end.x - endUp.x, end.y - endUp.y, end.z - endUp.z).color(red, green, blue, alpha).endVertex();
        buffer.pos(end.x + endUp.x, end.y + endUp.y, end.z + endUp.z).color(red, green, blue, alpha).endVertex();
        tessellator.draw();

        GlStateManager.depthMask(true);
        GlStateManager.disableBlend(); // Cullface
        GlStateManager.enableCull(); // Blend

        GlStateManager.popMatrix();
    }