The last few weeks have been crazy. I've started work on several projects in addition to what I'm doing for school, and a lot of stuff has been going on besides that... But, things are still progressing with the game, and I think I'm in the home stretch now.
The current state of the game is that most of the "required" things are there. The controls work, there's enough feedback from the HUD to be able to finish the game(As soon as the game can be finished, anyways), and I've got a working way to detect when I hit the ground.
All that's left(I think) is to do the game logic for when I hit the ground, a few graphics tweaks(Have it show something when the engine is firing, an explosion when you crash), some kind of options thing when you start it up, so you can change difficulty stuff... And I think that's it.
Of those, the only one that seems even remotely difficult at the moment is the options thing. Mostly because I have no idea how to work with multiple forms. We'll see if that happens.
Thursday, May 31, 2012
Sunday, May 13, 2012
Game Design Log - Entry #11
Today, so far, has been spent playing with GraphicsPaths. I've got my Lander designed, and all the points plotted, and put into an array of points, which then gets added to a GraphicsPath. I can draw this path, and as far as I can tell looks correct. The only problem is, it's tiny. Oh, and I haven't figured out how to move it around the screen yet.
There's functions of the GraphicsPath class that lets you apply transformations to the path, but I haven't quite figured out how they work yet. Once I get that going, I should be able to resize it to be more easily visible. It might also let me move it around the screen.
Attached is a scan of me sketching the lander, and plotting out the path to draw it.
There's functions of the GraphicsPath class that lets you apply transformations to the path, but I haven't quite figured out how they work yet. Once I get that going, I should be able to resize it to be more easily visible. It might also let me move it around the screen.
Attached is a scan of me sketching the lander, and plotting out the path to draw it.
Friday, May 11, 2012
Game Design Log - Entry #10
Right, supposed to be doing a log thing...
So, motion is pretty much done now. I've got gravity as you'd have on the moon, and the lander itself is using numbers from the Apollo lander for it's mass and engine power. The only thing I don't have is limited fuel, because I couldn't wrap my head around that particular equation...
Using the numbers from the Apollo is interesting, because the engine is throttle-able to a point where(at least as I'm using it), you're at 40% throttle before you can even push the mass of the lander. I'm not sure if this is something I'm doing wrong or if that's actually how it's supposed to be, but I need to work on other things. It's workable, and as long as I include something on the HUD to show the the amount of thrust you'll actually be producing, it should be fine...
Speaking of HUDs! I realized that I can just draw strings on top of the game, and it'll work. I'm actually using this for debug purposes, currently showing the lander's rotation, throttle level, and potential delta-V with the throttle at that level.
Next up is graphics. I've taken to calling this "rocketbox" for now, as that's basically what it is. I'm just drawing a box on the screen showing where the rocket is at the moment. Doesn't rotate or anything(Hence why I have the rotation shown in the debug HUD)... So yeah. That's what I'm looking into at the moment. Currently looking into an array of points, and what can be done with that... If my thinking's right, I can do vector-like graphics, and get graphics and collisions with the same array of points. We'll see how that goes.
So, motion is pretty much done now. I've got gravity as you'd have on the moon, and the lander itself is using numbers from the Apollo lander for it's mass and engine power. The only thing I don't have is limited fuel, because I couldn't wrap my head around that particular equation...
Using the numbers from the Apollo is interesting, because the engine is throttle-able to a point where(at least as I'm using it), you're at 40% throttle before you can even push the mass of the lander. I'm not sure if this is something I'm doing wrong or if that's actually how it's supposed to be, but I need to work on other things. It's workable, and as long as I include something on the HUD to show the the amount of thrust you'll actually be producing, it should be fine...
Speaking of HUDs! I realized that I can just draw strings on top of the game, and it'll work. I'm actually using this for debug purposes, currently showing the lander's rotation, throttle level, and potential delta-V with the throttle at that level.
Next up is graphics. I've taken to calling this "rocketbox" for now, as that's basically what it is. I'm just drawing a box on the screen showing where the rocket is at the moment. Doesn't rotate or anything(Hence why I have the rotation shown in the debug HUD)... So yeah. That's what I'm looking into at the moment. Currently looking into an array of points, and what can be done with that... If my thinking's right, I can do vector-like graphics, and get graphics and collisions with the same array of points. We'll see how that goes.
Wednesday, May 2, 2012
Game Design Log - Entry #9
AHAHAHAHAHA! SUCCESS!
I took a break from Thrust calculations for the last day or two, and skipped ahead a bit to actually adjusting the trajectory with the results from the thrust calculations... Kinda backwards, but I wasn't getting anywhere with the thrust stuff.
After spending a day and a half going in circles trying to figure out what I was doing wrong(Believe it or not, all the references I could find online were wrong in some way...), I finally asked a friend, and we found two problems. One, I had the wrong operation in one place(I needed ArcTan/Atan/Tan-1, and I had Tan), and two, I was putting it into my calculator wrong.
In my LanderMotion structure, which contains just about everything relating to the motion of my Lander(How about that name, eh?), I'm storing things as polar coordinates. I didn't know that they were polar coordinates when I was setting up my structure, but now I do and that's what they are. Now, I had never worked with polar coordinates before, just cartesian. Polar coordinates, to me, seem better suited for things like this, as you're applying force in specific directions and amounts, which is exactly what polar coordinates are, direction and magnitude.
The fun part came when I got to adding multiples of these forces together. There's three forces acting on the course of the lander -- momentum, gravity, and the engine. Gravity is always in the same direction, down, and for this game will stay constant through one "game". The engine is variable -- You can change your rotation, and the throttle of the engine. Momentum is variable -- It's the result of your previous motion, and is also what the result of your trajectory calculation is calculating.
Now, to get the net result of these forces, you simply add them together. "Simply". Anyways, to add these vectors together, you have to convert each one to cartesian coordinates, add all the cartesian coordinates together, and then convert it back to polar coordinates. Converting polar coordinates to rectangular coordinates is easy, and I had actually already been doing it in my ballistic trajectory stuff(Which I just realized is horrible misnamed in my game as it stands... It's not gravity at all...). Let's walk through it real quick.
For a given vector, there's two components to the polar coordinates for it, the radius and the polar angle. The vector we're going to work with has a radius of 15 and a polar angle of 180. To convert this to Cartesian coordinates takes two calculations, one for each the X and Y axis.
To calculate the X axis, take the cosine of your polar angle, and multiply it by the radius.
To calculate the Y axis, take the sine of your polar angle, and multiple it by the radius.
Easy, no? The part I had problems with was going the other way, cartesian to polar. This is more difficult, and the best way that I can think of to show it is to link to the code that I ended up with.
See here, starting at line 69.
Rtheta is the polar angle, Rmag is the radius, Rx is the cartesian X coordinate of the rectangular coordinates you're converting, and Ry is the cartesian Y coordinate.
Quite a bit more complicated, no? After I got help and figured out what was going wrong with my calculations, this got cranked out in less than half an hour, but I spent just about two days going 'round in circles on the 'net.
So things are moving along. Next up's back to thrust calculations. Also, I should have mentioned before now... My code's being put in a Git repository, accessible at http://code.meldaire.net/lunarlander. Not much to look at yet, but it's very much a work in progress.
I took a break from Thrust calculations for the last day or two, and skipped ahead a bit to actually adjusting the trajectory with the results from the thrust calculations... Kinda backwards, but I wasn't getting anywhere with the thrust stuff.
After spending a day and a half going in circles trying to figure out what I was doing wrong(Believe it or not, all the references I could find online were wrong in some way...), I finally asked a friend, and we found two problems. One, I had the wrong operation in one place(I needed ArcTan/Atan/Tan-1, and I had Tan), and two, I was putting it into my calculator wrong.
In my LanderMotion structure, which contains just about everything relating to the motion of my Lander(How about that name, eh?), I'm storing things as polar coordinates. I didn't know that they were polar coordinates when I was setting up my structure, but now I do and that's what they are. Now, I had never worked with polar coordinates before, just cartesian. Polar coordinates, to me, seem better suited for things like this, as you're applying force in specific directions and amounts, which is exactly what polar coordinates are, direction and magnitude.
The fun part came when I got to adding multiples of these forces together. There's three forces acting on the course of the lander -- momentum, gravity, and the engine. Gravity is always in the same direction, down, and for this game will stay constant through one "game". The engine is variable -- You can change your rotation, and the throttle of the engine. Momentum is variable -- It's the result of your previous motion, and is also what the result of your trajectory calculation is calculating.
Now, to get the net result of these forces, you simply add them together. "Simply". Anyways, to add these vectors together, you have to convert each one to cartesian coordinates, add all the cartesian coordinates together, and then convert it back to polar coordinates. Converting polar coordinates to rectangular coordinates is easy, and I had actually already been doing it in my ballistic trajectory stuff(Which I just realized is horrible misnamed in my game as it stands... It's not gravity at all...). Let's walk through it real quick.
For a given vector, there's two components to the polar coordinates for it, the radius and the polar angle. The vector we're going to work with has a radius of 15 and a polar angle of 180. To convert this to Cartesian coordinates takes two calculations, one for each the X and Y axis.
To calculate the X axis, take the cosine of your polar angle, and multiply it by the radius.
To calculate the Y axis, take the sine of your polar angle, and multiple it by the radius.
Easy, no? The part I had problems with was going the other way, cartesian to polar. This is more difficult, and the best way that I can think of to show it is to link to the code that I ended up with.
See here, starting at line 69.
Rtheta is the polar angle, Rmag is the radius, Rx is the cartesian X coordinate of the rectangular coordinates you're converting, and Ry is the cartesian Y coordinate.
Quite a bit more complicated, no? After I got help and figured out what was going wrong with my calculations, this got cranked out in less than half an hour, but I spent just about two days going 'round in circles on the 'net.
So things are moving along. Next up's back to thrust calculations. Also, I should have mentioned before now... My code's being put in a Git repository, accessible at http://code.meldaire.net/lunarlander. Not much to look at yet, but it's very much a work in progress.
Subscribe to:
Posts (Atom)