@helvetica @aeiowu It really is amazing how this shit is all playing out just as predicted without net neutrality. (Today)

RT @helvetica: Oh great. Great fucking appointment Obama. God damnit. Look, I’m loving the healthcare, but this is a huge blunder. t… (Today)

RT @MOOMANiBE: If you like learning about interesting, lesser-known games, you really should be following @WarpDoor. (Today)

@twobitart @RayMPerry @pietepiet t.co/cQFOUQC6v3 (Today)

RT @rabbit_nabokov: momo 3 is 95% approved to top 100! please vote and RT to spread the word, minna!! t.co/Aw9zjkSpeZ t.co/Xo… (Today)

@legobutts Its a tool to teach american children that eating a sandwich of marshmallows is a perfectly fine meal. #diabetes (Today)

@twobitart nuuuuuudistu beachu~ (Today)

@djcoreynolan <3 (Today)

RT @djcoreynolan: dammit, life would be so excellent if I didn't have some mysterious autoimmune disease continuously sapping my HP (Today)

The fade away jumper: t.co/qaSLcckISB #TowerFall t.co/1Z1U1YF72t (Yesterday)

@SeeBeeWhitman @NoelFB You challenge Father Time to a cage match with no ref. OOHH YEAAAH #savage (Yesterday)

Hmm so far time boxing is working out a lot better for me if I just accept the fact that my first one or two blocks of the day might suck. (Yesterday)

@Seagaia2 humble avocado bundle (Yesterday)

@initials_games Whoa thanks! (Yesterday)

@mushbuh @theBanov fuck yeah. giant metal holographic slammers! t.co/padUe7h1nL (Yesterday)

@snakepixel @ADAMATOMIC its like you have access to colors that the rest of us don't even know about JEEZ (Yesterday)

RT @snakepixel: Here we go. This is how I would do a new Breath of Fire game.You know, if I was given the option. t.co/k8iPDjBWap (Yesterday)

@infinite_ammo I haven't actually read a game review in years. If people I know like the game I'll research it a little bit then decide. (Yesterday)

@Patashu0 Maybe on Steam but not for awhile yet ;D (Yesterday)

@NorthernlionLP I am laughing with JOY! ;D (Yesterday)

posts tagged with: dev log

2014 - 4 - 22 / 11:53 am / general

Dev Log: Impact Effects

Dev Log: Impact Effects

Whoops, been kinda neglecting my poor blog for a week. I've been making some progress on my fancy game project though! Just have been forgetting to post about it.


One of the things I tackled over the last couple of days was adding more visual effects for stuff like damage impacts. I want damage to feel over the top juicy at all times so that every impact is really felt by the player. The effect I ended up with for damage impacts is an inverted flash combined with some red colored mixing and additive blending.


Right now I'm using one utility shader that has a bunch of parameters on it for various effects. Check it out:

#version 120
uniform sampler2D texture;
uniform sampler2D noiseTexture;
uniform vec4 overlayColor;
uniform vec4 additiveColor;
uniform vec4 subtractiveColor;
uniform float overlayNoise;
uniform float inverted;
uniform float noiseX;
uniform float noiseY;

void main() {
//get color of this pixel
vec2 pixpos = gl_TexCoord[0].xy;
vec4 pixcol = texture2D(texture, pixpos);

vec4 outcol = abs(inverted-pixcol);
outcol.a = pixcol.a;

//mix in the overlay color
outcol = mix(outcol, overlayColor, overlayColor.a);

//add the additive color
outcol += additiveColor * additiveColor.a;

//subtract the subtractive color (DUH)
outcol -= subtractiveColor;

vec4 noiseColor = texture2D(noiseTexture, mod(pixpos, 1) + vec2(noiseX, noiseY));
outcol = mix(outcol, noiseColor, overlayNoise);

//reset alpha to prevent coloring transparent pixels
outcol.a = pixcol.a;

//output the final color
gl_FragColor = outcol;

I'm still learning the ins and outs of shaders so this probably isn't the best way to do this, but for now it seems to be working out fine.

Along with this shader there is some code in my "Combatant" component to control the shader. The Combatant has a timer that is set whenever it takes damage. This timer is then used to control various parameters on the shader. Every 2 frames the image is inverted using the shader. When the image is inverted there's a red additive color blend applied to the image, and when the image is not inverted there is a normal red color mix applied. The intensity of the color mix is determined by the timer. It starts very intense then fades away.

On top of that another texture is blended with the image. The other texture is just a simple image of generated noise. I'm not totally sure why, but for some reason I like the noise texture along with the rest of the effects. It kind of represents a disruption to the target taking damage, or something poetic like that.

Last but not least the image also shakes around a bit. This is something I first noticed a lot while playing Street Fighter 4. An action freeze along with sprite shaking is an incredibly useful way to convey an intense impact.

Here's the little blurb of code that handles the effects for Combatants

//Handle graphics
foreach (var img in Images) {
var overlay = Util.ScaleClamp(StunEffect, 0, StunEffectMax, 0, 0.5f);
var color = new Color(Color.Black) { A = overlay };
var addColor = new Color(StunColor) { A = overlay };

img.Shader.SetParameter("overlayNoise", overlay * 0.5f);
img.Shader.SetParameter("noiseX", Rand.Float(0, 0.25f));
img.Shader.SetParameter("noiseY", Rand.Float(0, 0.25f));

if (StunEffect > StunEffectMax * 0.25f) {
addColor.A = 0.5f;
color = G.Colors.Dark;
color.A = 0.25f;
img.Shader.SetParameter("inverted", StunEffect % 4 > 1 ? 1 : 0);
else {
img.Shader.SetParameter("inverted", 0);

img.Shader.SetParameter("overlayColor", color);
img.Shader.SetParameter("additiveColor", addColor);

img.Shake = Util.ScaleClamp(StunEffect, 0, StunEffectMax, 0, 30);

Along with the impact effects the Bullet entities have an impact effect to help show damage. If bullets hit something and deal damage they spawn a small red and yellow explosion, and if they don't do damage then the particle is blue and cyan. This is something I saw when I played a lot of Thunder Force III as a kid!

1 Comment

2014 - 4 - 16 / 4:58 pm / general

Dev Log: Quick Lighting Test

Dev Log: Quick Lighting Test

As a quick experiment I wanted to see how Otter would be equipped to handle a simple lighting set up. The basic set up is just a big render texture that is filled with a dark color with a blend mode set to multiply. Then light is rendered to the render texture with a blend mode of additive. The result is a layer of shadow that can have light rendered to it.


The code for this set up right now is pretty straight forward as well. I'm using a black and white image for the light. Just a black rectangle with a white radial gradient in the center.

Here's some sample code to show how this effect is achieved with Otter!

//set up the surface
public Surface SurfaceLighting = new Surface(Game.Instance.Width, Game.Instance.Height, new Color("379")) {
Blend = BlendMode.Multiply

//set up the light
public Image ImageLight = new Image(Assets.ImageLight1) {
Blend = BlendMode.Add

//add the surface to an entity to render it
//this happens in an object's initialization

//render light to the surface
//this happens in a Render() function
ImageLight.Color = Color.White;
Draw.Graphic(ImageLight, Input.MouseX, Input.MouseY);
ImageLight.Color = Color.Red;
Draw.Graphic(ImageLight, Input.MouseX + 500, Input.MouseY);
ImageLight.Color = Color.Blue;
Draw.Graphic(ImageLight, Input.MouseX - 500, Input.MouseY);


2014 - 4 - 9 / 4:11 am / general

Dev Log: Pathfinding Fun


Like a cat chasing a laser pointer, I have some basic enemies chasing paths through the skies.

Right now I'm using A* and although I don't really know what is going on that much, I have a system that enemies can use to find paths to their destinations. Normally I wouldn't bother with any sort of path finding, but for this game I want enemies to have to intelligently navigate through obstacles that the player is deploying, so my usual "make up a path finding function that doesn't actually path find but sometimes works out" function wont cut it.

What I have currently is a pretty straight forward set up:
- One PathFinder instance in my Scene. It extends Entity so that it can be updated by the scene automatically.
- Enemies request a path from PathFinder and also register a callback Action with the request.
- The PathFinder instance adds the request to the queue.
- Every update the PathFinder will take the top item of the queue and start the path finding process.
- The actual A* algorithm and calculations are run on a BackgroundThread so that the game can continue while this is going on.
- When the path is done calculating the callback is fired, and the enemy now knows about its path.
- It chases down the nodes that were added to its path.

I made a quick change to the A* algorithm as well under the sage advice of Chevy Ray: I'm using a maximum movement value that will stop the algorithm if the move costs become too high. The result is that the algorithm will return a partial path to the final target instead of the entire path (which could take a long time to calculate in a set of nodes with a lot of open spaces.) So with this in mind the rest of my logic looks like this:

- When the enemy reaches the last node, it checks to see if its close to its intended target.
- If not it requests a new path to its target.
- If it is then it will enter its attack behavior, whatever that is.

So far this seems to be working out pretty well. I have a lot of work to do with how enemies will end up treating their path nodes in regards to their actual movement. Right now they just try to move toward each node, but with a lot of nodes together they end up having some trouble, like that wiggling in the animation above. Something like an averaged out path between a lot of nodes might work better... hmm!


2014 - 4 - 2 / 11:24 am / general

Dev Log: Anti-clumping Made Easy


Starting to get back into a bit of a groove on this game thing. One little fun thing to work on was the enemy anti-clumping code. I don't want any enemies to stack on top of each other (although it would be smart of them to do so in order to conceal their numbers.) With a short bit of code I can have enemies push each other away, similar to how babies and rocks push away from each other in Offspring Fling.

public virtual void PushAway() {
if (Hitbox != null) {
if (Overlap(X, Y, (int)Tags.Enemy)) {
var e = Overlapped as Enemy;
if (e.Mass >= Mass) {
var push = new Vector2(X - Overlapped.X, Y - Overlapped.Y);

if (push.X == 0 && push.Y == 0) {
push = new Vector2(Rand.Float(-1, 1), Rand.Float(-1, 1));

pushAwaySpeed += push;

var length = Util.Approach((float)pushAwaySpeed.Length, 0, pushAwayForce * 0.5f);


X += (float)pushAwaySpeed.X * 0.01f;
Y += (float)pushAwaySpeed.Y * 0.01f;

Pretty neat! This is actually pretty similar to the original code in the prototype many many years ago, except now it's in fancy C# instead of GML. Enemies will call PushAway() every update.

No Comments

2014 - 3 - 12 / 9:22 am / general

Dev Log: Some Shaders

Dev Log: Some Shaders

One of the things I miss about working in FlashPunk and working with a bunch of bitmaps and blitting to the screen is the super easy color overlay blending. FlashPunk had an Image blending mode called Tint and it could be used in place of Multiply and it is amazing for doing effects like fading an entire sprite to a specific color. The world of rendering quads and triangles I don't have such a luxury, but I do have shaders.

I've been working on the building islands animation, and here's a really fast version of it:


At the end of it when the island pops out it's silhouetted with solid white. The white fades to cyan, and also fades back to the normal art at the same time. To get this effect I used a simple shader to handle a color overlay.

uniform sampler2D texture;
uniform vec4 overlayColor;

void main() {
vec4 pixcol = texture2D(texture, gl_TexCoord[0].xy);
vec4 outcol = mix(pixcol, overlayColor, overlayColor.a);
outcol.a = pixcol.a;
gl_FragColor = outcol;

I also use this code for enemies as well. When they get hit they turn red for a brief moment. I use code in the C# end to determine the color and intensity of the overlay and pass it along to the shader.

var overlay = Util.ScaleClamp(Combatant.Stun, 0, Combatant.StunMax, 0, 1);
var color = new Color(1, 0.2f, 0.1f, overlay);

ImageSpineAnim.Shader.SetParameter("overlayColor", color);

Soon I'll probably make some sort of system that allows me to easily add a bunch of color overlays to the shader and automatically figure out the final color for the shader to use. I'll probably also use the shader for a bunch of different effects down the road.

No Comments

2014 - 3 - 11 / 5:03 pm / general

Dev Log: Slow and Steady

Dev Log: Slow and Steady

I've been tinkering with a lot of systems over the past couple of days. Mostly stuff involving enemies, and some other things involving building islands and structures on the islands.

At some point last week I sat down and tried to figure out path finding with moderate success. I have something working, but it's pretty dang laggy when it has to figure out a path. As far as I know I'm just doing straight up A* path finding and I copied the psuedocode from Wikipedia right into the game. I started looking into using different data structures for storing things to hopefully speed it up, but honestly I still have no idea what I'm doing and I don't know how to use some of these fancy things that people suggest (priority heaps, or something?)

I took a break from that to tinker with placing structures on islands, and trying to figure out how I want to animate the building process for building a structure on an island. This is also a tough one to solve, and I'm not sure if frame by frame stuff in Flash would be good, or if structures should be animated with skeletons similar to the enemies using Spine.


Back in the world of enemies I've started experimenting with behavior trees for how they should interact with the world. It seems like a good way to do things, but part of me feels like it's over-engineering. Setting up a whole series of classes for the system to run the behaviors, and then every simple little task then has to be a behavior command... I kind of like systems like this, but I wonder if it will be worth it in the end working on a system that takes a lot of up-front work to get running.

It's definitely a very different way of doing things outside of the game jam environment. I've made a lot of cool stuff in game jams, but it's all been on top of really odd code that doesn't leave a lot of room for expansion. I'm trying not to design or code myself into a corner when it comes to working on this new game, so things are going a little slower than they did for Offspring Fling, but it's also probably due to the fact that I'm in pretty unfamiliar territory. Working on something that's not a platformer can be pretty tough!




Hi there, my name is Kyle, and I'm a 27 year old kid with adult powers. I'm making video games and living the indie game developer life in Tempe, Arizona. Here you will find my thoughts, games, websites, doodles, and other stuff like that. I worked on Snapshot, Offspring Fling, and a whole bunch of other games. I also created and maintain Otter, a 2d game making framework. If you want to get a hold of me use the form on the bottom of the page, leave a comment, or just tweet at me. I try to post three times a week. Thanks for stoppin' by! You're the coolest.



Do you want to make a Let's Play of one of my games, or a just a video featuring footage of my games? You have my full permission to do so! Even if you are monetizing your videos, you still have my full permission to use any footage from any of my games. Go for it!


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