Author: digm520admin

February 15, 2019

Tower Defense Tutorial

Episode 15 – Laser Beamer

Youtube – How to make a Tower Defense Game (E15 LASER EFFECTS) – Unity Tutorial

By: Brackeys

Ep. 15

This tutorial will focus on creating extra effects for our laser. We’re adding a LaserImpact particle system, starting as a duplicate of the BulletImpact particles.

We started by making it a new material, LaserImpact material, and making this green with some emission. As many other particle effect parameters, this is setup differently in newer versions of unity. The intensity is in the color selector palette after turning on “Emission” for the material. Since we have so many particle systems now, we’re narrowing down what they collide with. We put all the nodes and ground planes on an “Environment” layer and made sure the particle system only collided with that.

Instead of making this particle effect its own prefab like the others, we attached it as a child to the Laser Beamer object. This would then just be an object we enable/disable when needed. For the particle system, we actually use Play() and Stop(), instead of enable/disable. This makes sure you aren’t creating multiple instances of the particle effect, and also makes it so that when you turn off the particle system, it doesn’t immediately go away. The residual particles will still do their thing.

To position the particle system, we just started by making its position that of the target. This however puts it directly in the middle of the target, where we would prefer having it on the surface where the object is hit. To do this, we created a vector that is the difference between our turret’s firepoint and the target to get the direction. Then we rotated the particle system to match this direction, and added/subtracted a small amount from the target position to place it slightly closer to our turret (so hopefully closer to the surface of the object). There might be a cleaner and more consistent way to do this with rays.

We wanted to add more effects to this laser, so we added a child particle system to this original laser ImpactEffect. Play()/Stop() will also apply to any children particle systems of an object. The material they used for this wanted to use the shader Particles -> Additive, which is only a Legacy option now. The new Particles -> Standard Surface shader has a rendering mode blending option that has an additive option, so I tried to see if that was similar. It seemed to give a similar effect, as long as I put the material (we were using the default particle material) in the Albedo map.

We gave the particle a blinking effect by editing the “Color Over Lifetime” to have 0 alpha at the end. So as it would loop, it basically faded in and out very quickly. Finally we added a green light to this particle system as an extra glowing effect. This however, would leave the light at its last position when an object got out of range.

When we went to fix the light (enable/disable it), they mention we could use animations instead to control all of these particle system events as opposed to scripting all of them. The light was just another reference in the Turret script that we enabled/disabled with all the other laser effects.

SUMMARY

• I really need to look into tutorials for the new particle system editor to help find equivalent options for these older tutorials
• Use Play(), Stop() with particle effects instead of enable = true or false for normal use
• Create blinking effect in particle system with looping, short lifetime, and setting “Color over lifetime” final alpha value to 0

February 13, 2019

Tower Defense Tutorial

Episode 14 – Laser Beamer

Youtube – How to make a Tower Defense Game (E14 LASER BEAMER) – Unity Tutorial

By: Brackeys

Ep. 14

This tutorial creates the Laser Beamer, yes beamer, object prefab. Something I’ve done when importing these to make it more similar to the tutorial, under the Materials tab for this imported model, I use “Extract Materials” to make sure all of the materials become easily available to alter and move around in the Unity editor. Before making it into a prefab, we did the same steps we did with the other turrets: add partToRotate empty object, add firePoint empty object, child turret head and firepoint to partToRotate empty so they rotate properly/easily with a forward facing z-axis object.

Everything else was also updated similarly to the other turrets. We added another TurretBluePrint public class to the Shop script so we can inform it of the new prefab to use for the LaserBeamer and its cost. We then added the LaserBeamer shop button (sprite image on UI) and added its new click event for selecting the LaserBeamer.

The laser beamer is different in that its projectile will use a Line Renderer component to simulate a laster. This has clearly received a lot of updates over the several iterations of Unity between now and this tutorial. The “Positions” section has more of a table setup. The “Width” parameter section is now actually a small line graph instead of just values (assuming this allows for more variation with curves, etc.).

The line renderer material gave me some issues, which I cover in PROBLEMS below. However, it seems the material I chose doesn’t allow for variation of the alpha value in the line renderer color component. Another difference here is the suggested shader for the line renderer material was “Particles – Alpha Blended”, which no longer exists. I used “Particles – Standard Unlit” which worked for me. The colors are also different now. Instead of just a start and end color option, it is now a full gradient preview bar with colors on the bottom and alpha values on the top.

Then we edited the Turret script to deal with this new type of weapon. We separated out the variable headers from Attributes into General, Use Bullets (default), and Use Laser to keep everything organized. Then we moved on to dealing with the line renderer in a method, Laser.

We started scripting the line renderer by setting its positions (values in its position array that determine the points to connect with a line). Since we only have two points, those are the start and end point of our line. It’s as easy as:

lineRenderer.SetPosition(0, firePoint.position);
lineRenderer.SetPosition(1, target.position);

Where the first input in SetPosition is the element number in the position array of the line renderer, and the second input is what that position is. So this example draws a line between our firePoint (shooting location) and whatever the target is.

Our laser worked, but it would stay in its last position if the target moved out of range (since it no longer needed to update its location). Since we already had a return happening for the check when there is no target, we just added a laser specific check to also enable = false for the line renderer when there is no target.

PROBLEM

SOLVED: My line renderer was not displaying properly after applying a basic material to it in the prefab editor (it was just solid black, when the material was white). At first I thought this was a lighting issue in the new prefab editor, so I found out that you can create a scene to use as the prefab editor scene and add it in your Project Settings. So I did that and it was still black, but I noticed if I rotate around it was white for about 180 degrees of viewing rotation. I then noticed the next part of the tutorial mentioned changing the shader for the material, and this directly solved the issue. Line renderers might deal with materials strangely, and may often use non-default shaders.

BONUS OBJECTIVES

Add particle effect to the end of the laser line renderer for that sparking impact effect a lot of lasers have.

To set up the Turret variables/editor even better, have a variable called UseBullets, or an enumerator to select either Bullets or Laser, then show fields depending on what you selected. Create an editor script for this. Look up “Unity Custom Editor”.

SUMMARY

• When importing models, use “Extract Materials” to specifically pull out all of the materials to make them easier to edit.
• Check the shader for the material you apply to line renderers since they seem to act uniquely
• Look into “Unity Custom Editor” to learn about editor scripts

February 12 2019

Tower Defense Tutorial

Episode 12 – User Interface

Youtube – How to make a Tower Defense Game (E12 USER INTERFACE) – Unity Tutorial

By: Brackeys

Ep. 12

We created another bool property in BuildManager called HasMoney, which checks if the playerstats has enough money to build what the player is trying to build. This was then used as a check to determine what color a node should be when the player hovers over it.

Next we moved on to creating UI. We moved the timer and money into a canvas in world space, below the main play area. There are weird interactions between UI element scaling and font size. They multiply together so you can get the same size by raising one and lowering the other, but even though the give the same multiplicative size, the resolution can be different.

We updated the wave spawner timer. We added a clamp to it so it never goes below 0. We also edited the formatting of the countdown timer text so that it showed 2 digits before the decimal point and 2 after (the hundredths place). This was done with string.Format(“{0:00.00}”, countdown).

We also added a script, MoneyUI, to the money UI element. This solely references the playerstats money variable and updates to that as text. This definitely does not need to be done in Update, and would be more efficient to happen when the money value changes only.

We added cost UI elements to the turret buttons. These were just simple panel and text UI elements, with the cost hard coded (hard typed) in. You could add functionality to tie this to their true values in script.

Finally we added some particle effects on building a turret. This started by creating an empty game object slightly raised vertically, then adding the particle system as a child to this. This was with the intention of rotating the parent empty object without moving the anchor of the particle system.

PROBLEMS

My UI elements were acting strange between the Horizontal Layout Group on the Canvas and the Layout Elements on the UI buttons (turret images). I was not getting the expected results with the preferred height and width of the Layout Elements (they would not change to those values even though they had room), but I could just manually change them just fine (so the horizontal layout group wasn’t restricting them from being those values). This is extra strange as there was an Editor note specifically stating “Some Values driven by HorizontalLayoutGroup”.

SUMMARY

• Scaling UI Element to fit that around it: Under anchor presets, hold “Alt” and select the bottom right corner option
• Font size multiplies with the UI element scaling, and you can get weird results sometimes. i.e. I had to change my UI scaling down from 1 to 0.1 because even though I could just use one tenth the font size to fit the same space, this gave the text poor resolution.
• Use string.Format to determine number of decimal places to show in number strings. The amount before the decimal point appears to also be important. (i.e. We used 0:00.00, which indicated which element to have two digits before and after the decimal point)