A side-scrolling tactical 2D shooter that sets out to be challenging and to some extent realistic. The goal is to resolve situations where armed suspects and hostages are involved -- with as little bloodshed as possible. Inspiration is taken from the Police Quest and Rainbow Six series, while I add my own touch of blood and gore.

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Blog RSS Feed Report abuse Latest News: In-depth: Blood particles

6 comments by isbeorn on Nov 9th, 2013

So I thought I should write a bit more in-depth about features in my game and engine to give you some more content between the demo releases.

The characters, or bodies as they are named in my code have a number of properties that define their health and to emulate functions of the human body. Mostly in terms of emitting blood:

* Heart rate
* Blood pressure
* Amount of blood
* Number and size of wounds

The body as a whole has a blood pressure. This is simply the ratio of blood left in the body out of how much was in it from the beginning. It will be between 0 and 1 and it drops when the bodies bleed. It is combined with the body's heart rate so that the pressure changes in rythm with the beats. But the blood pressure value is not ready to be used at this point. Next it is passed on to the limbs of the body.

Each body has a set of limbs and each of these has an individual constant or modifier for the blood pressure. They are a bit different. For example the head has a much higher pressure than the feet. I'm no expert on these things but it's meant to be an abstraction of the different pressures in veins and arteries inside the body. The body's pressure is modified by this constant to create a local blood pressure for each limb.

Now on to the wounds. The limbs can have wounds (read bullet holes). These emit blood particles at a rate determined by the limb's local pressure. A wound at a limb with high pressure will squirt out the blood, while at lower pressure it will just drip. Remember that the pressure at the body level is based on the amount of blood left in the body. This means that each wound on the body decreases the blood pressure. In effect, this means that a single wound in the head of a body will pump out more forcefully than two wounds, or if there were many other wounds present on the body already. The size of the wounds also have an effect on how the blood will be emitted.

Low pressure due to loss of blood.

A smaller hole makes the emission more focused and the particles leave with a higher velocity. The size of an entry wound is determined by the diameter of the bullet. The size of the exit hole is more complicated and might be an article by itself.

A single emitter from the head with high pressure. The second one also showing pooling on the floor, and towards the end how the pressure is noticeably dropping.

Each emitted particle represents one milliliter of blood as it stands now, for a total of 4000-5000 milliliters (about one gallon) in a body's total capacity. Every particle has it's own velocity and is affected by gravity. When they spawn they also inherit the velocity of the limb they come from. You can see this in the gif above: when the head flips forward it makes a small bounce which is also makes the blood spawned at that time fly higher.

I hope you enjoyed this article. I will try to drop one once in a while when I feel there might be need for a 'filler episode' between my other updates.

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Demo 3

Demo 3

Jul 5, 2013 Demo 30 comments

The third Blood and Bullet demo adds more game play mechanics. Use concussion grenades to overwhelm the suspects. Restrain them, secure their weapons...

Demo 2

Demo 2

Apr 19, 2013 Demo 2 comments

This demo is more of a taste of game play than the previous one, but still with some obvious parts missing. There are more weapons, a bit of AI, rooms...

Sandbox/tech demo

Sandbox/tech demo

Mar 15, 2013 Demo 4 comments

This is not a game-play demo. I just want to point that out. It's a sandbox/tech demo of the features so far. It's scaled down a bit to keep it simple...

Post comment Comments  (0 - 10 of 208)
Cantalouper Oct 12 2014, 6:50pm says:

Any updates?

+1 vote     reply to comment
isbeorn Creator
isbeorn Oct 20 2014, 3:03pm replied:

Hi, I've had a very long break and haven't really gotten back into it yet. Mostly due to some difficulties with messy code I've created. I'm working on bringing my code under test now which will take some time. After that I can hopefully continue to make progress without breaking stuff.

+2 votes   reply to comment
12mods May 30 2014, 12:32am says:

How's it going isbeorn finnaly get my email confirmed how follow your game and other (well im being patient so..... sugessting time) how about health bars. and how about levels maybe nah... anyway have some rest when your tired (you feeling any better man?

+1 vote     reply to comment
isbeorn Creator
isbeorn Jun 1 2014, 4:46am replied:

Hi, it's summer time where I live now (4 months of the year) with lots of distractions. I have one night each week that I work on the game and that's about what I feel up for now. So it's going quite slow.
I don't plan to have indicators for things like health. A person holding a weapon is a threat and a person lying injured should be patched up. :) I have a few ideas for character progress but that's so far away from where I am now so it's hardly worth mentioning... :P

+1 vote   reply to comment
Torhque Sep 17 2014, 1:48am replied:

I'm looking forward to watch this game together because I've been following it for a long time now. Just keep us updated if you can. There's no rush.

+1 vote     reply to comment
UltimateHeron Jun 2 2014, 5:40am replied:

But what about blood pressure meter? As for me, it suits the game idea well...

+1 vote     reply to comment
isbeorn Creator
isbeorn Jun 2 2014, 11:53am replied:

You are spot on - blood pressure is a critical factor. It is actually one of the parameters determining consciousness of the characters. But can you see on someone what blood pressure they have? I'm going for realism so "extra" info will be sparse. :) I have considered changing the color tone of their skin as blood pressure drops. That would also make dead bodies look more dead.

+2 votes   reply to comment
UltimateHeron Jun 2 2014, 12:07pm replied:

Oh, got it. Well, change of skin color should be great for that matter. So, your idea of is better to my mind.
I can also say, that as i understand it affects only enemy but not the actual player (because if someone get shot he dies quickly) So, after i thought about what i wrote here i realized that any kind of `meter is useless in this game for those reasons.
So, good luck with development!

+1 vote     reply to comment
isbeorn Creator
isbeorn Jun 2 2014, 3:33pm replied:

Thanks :)
Yes for the most part things go from good to bad quite fast in this game!

+1 vote   reply to comment
LaGNeVeRFaiLs May 12 2014, 9:23pm says:

I will wait for This! Even if i have to wait for a Year!

+4 votes     reply to comment
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Blood & Bullet
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Tactical Shooter
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Got solid grounds for animation driven locomotion in place now. Soon the characters will walk around and change directions!

Feb 8 2014, 6:57am

I've made some great progress on the new animation system. It feels solid.

Jan 19 2014, 9:21am

Planning and writing the new Body class. The new animation system will allow characters to turn in either direction and walk around.

Jan 18 2014, 8:56am

Now adding an audio browser to the weapon editor.

Oct 27 2013, 4:02am

I have a title screen background in the workings. I should add a main menu soon. The weapon editor now also imports properly.

Oct 20 2013, 3:32pm

The weapon editor is functional now! Just some minor things remain, then I hope to get some weapons produced for the next demo.

Oct 14 2013, 4:08pm

I made lots of progress on the GUI and weapon editor this weekend. The weapon editor is very close to finished now.

Oct 13 2013, 4:13pm

Had a good run with the new GUI system tonight. Not far away from bringing it into the weapon editor now.

Oct 2 2013, 4:00pm

The weapon editor is more work than I anticipated but it's progressing nicely.

Aug 4 2013, 7:23am

Striving to get the weapon editor done today.

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