Alphanauts - Indie Speed Run 2012 & Ludum Dare 25

So, it’s been awhile! A lot happened since my last post. I’ll come back to that later. For now, I wanna talk a bit about the game jam I just did the past weekend. The Neverpants team (Dom2D, Technobeanie and I) assembled for an intense 48 hours game jam combining both the Indie Speed Run and Ludum Dare into one awesome game. We ended up with the themes “loss” and “skeleton” for Indie Speed Run and “You are the villain” for Ludum Dare. You can check out Dom2D’s blog for a great summary about the game. I couldn’t have done better!

Anyhow, here’s my technical post mortem.

Our idea was about controlling a bunch of characters to avoid random obstacles on a screen. By assigning a letter to everyone, you would move them by holding the associated key down and use the arrow keys to direct them. We hit a wall pretty fast. I’m still not sure if it’s either Unity or the OS, but it seems like some keys don’t respond correctly when holding more than one key down. One would say don’t use those “bugged” keys, but it appears that they’re specific to every OS… Our hole idea was kinda based on this particular behavior, so we decided to go ahead anyway and don’t bother about it.

Our first prototype was simple, but sad Keanu in the role of black holes added some style to it. Dom2D, as our game designer and artist, had a very specific idea in mind for the black holes. He wanted them to reveal a sort of outer-space parallel world that was taking over the screen. It didn’t take me long to come up with the way to do it. A shader! Shaders are our best friends. So, we stack a bunch of planes, and then we assign them the same material with a shader converting the UVs to screen space.

Shader "Seventy Sevian/Black Hole" 
{
	Properties 
	{	
		_Color ("Color", Color) = (1.0, 1.0, 1.0, 1.0)
		_MainTex ("Texture", 2D) = "white" {}
		_Detail ("Detail", 2D) = "gray" {}
		_Scale ("Scale", Float) = 2.0 
	}
	
	SubShader 
	{
		Lighting Off
		Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }
		Blend SrcAlpha OneMinusSrcAlpha 
		
		CGPROGRAM
		#pragma surface surf Unlit alpha 
		
		struct Input 
		{
			float2 uv_MainTex;
			float4 screenPos;
		};
		
		sampler2D _MainTex;
		sampler2D _Detail;
		float _Scale;
		uniform float2 _Offset = float2(0.0f, 0.0f);
		
		half4 LightingUnlit(SurfaceOutput s, half3 lightDir, half atten) 
		{
			half4 c;
			c.rgb = s.Albedo;
			c.a = s.Alpha;
			return c;
		}
		
		void surf (Input IN, inout SurfaceOutput o) 
		{
			float2 screenUV = (IN.screenPos.xy / IN.screenPos.w) * _Scale;
			screenUV.x += _Offset.x;
			screenUV.y += _Offset.y;
			
			o.Albedo = tex2D(_Detail, screenUV).rgb;
			o.Alpha = tex2D(_MainTex, IN.uv_MainTex).a;
		}
		ENDCG
	} 
	
	Fallback "Diffuse"
}

It’s fairly simple and not that elegant, but it works. I use _Offset to scroll the UVs with a constant velocity. I update it through Unity with a simple script.

private void Update()
{
	if (m_Velocity != Vector2.zero)
	{
		m_Offset.x += m_Velocity.x * Time.deltaTime;
		m_Offset.y += m_Velocity.y * Time.deltaTime;
		
		if (m_Offset.x > 1.0f)
		{
			m_Offset.x -= 1.0f;
		}
		if (m_Offset.y > 1.0f)
		{
			m_Offset.y -= 1.0f;
		}
		
		if (m_Offset.x < 0.0f)
		{
			m_Offset.x += 1.0f;
		}
		if (m_Offset.y < 0.0f)
		{
			m_Offset.y += 1.0f;
		}

		Shader.SetGlobalVector("_Offset", m_Offset); 
	}
}

At some point during the first 24 hours we hit another wall. We have a custom script that can create polygons and use them as colliders. The meteorites (triangle black holes) were using it through a rigidbody and it wasn’t triggering any collisions. I spent some time playing around with the settings, but in the end I wasn’t able to make it work and it’s a game jam, so I used…mmmm…a bunch of box colliders to form that triangle. Ya I know, not proud of it, but hey it gets the job done!

After a day we were exactly where we wanted to be. We had a fully playable game that just needed polishing.

The next day we integrated all that was left to make it a full game jam game. We added music, SFX, the menus, animations, score system and a cheat when you align the characters to form KEANU. Made that last one up…or did I? We didn’t spend enough time on balancing the difficulty progression. It’s okay. After all, we only had 48 hours, but I feel like it could be better.

In the end, I’m most happy with the result we ended up with. It’s a neat little game and I had lots of fun making it with the guys. It’s a great experience as a first 48 hours game jam. I really like what we came up with for the themes.

Gâtez-vous!
Web (requires Unity Web Player)
Windows 32 bits
Windows 64 bits
Mac OS X