I used NoShell with my 83+BE, that's probably what caused the crash.

I'll try with MirageOS then (DCS is too heavy for my calc)

Thanks for those drawings, but they only show the easy part of the proof.

The interesting part is that B is the center of the drawn circle, which is true if and only if PAC=PCD.
Here are some drawings :


The inscribed angle theorem says that the blue angle remains the same when you move B.
(This is a well-known and useful result)
The corollary of this theorem says that it is the same as the angle with the tangent in C.
(To understand this, keep in mind that the blue angle doesn't change when B is getting close to C)


In this drawing you can notice that the purple angles are acting the same way as mentionned before.
Therefore, you can say that AD is tangent to the circle in A.
Moreover, you can do the same with the blue angles. So CD is tangent to the circle in C.


Since ABCD is a square, CB is perpendicular to CD in C. But CD is tangent to the circle in C.
Therefore CB is a radius of the circle.
You can do the same and find that AB is also a radius.
The two radii meet in B, so B is the center of the circle.

The conclusion is now quite obvious, see SpiroH's drawings
I personnally did it with the inscribed angle theorem :
You can apply this to PAC and PBC and find out that PBC=2*PAC, so PBC=40°

Wow, this looks pretty good !

My question to chokosta is : can i use the lvl and the design of gravity guys nspire for my game if i quote you in my credit ?

Of course.
You don't have to quote me, since my programs are totally free. Anybody could re-use my code and sell it.

IIRC chockosta's version was inspired by mine lol

No, I discovered your gravity guy a few days after starting mine.
My game was more inspired by the android version. (The gravity is linear in my game and the android app, but not in your version)

I don't think that you could switch gravity in mid-air in any version of Gravity Guy. That's what made the game hard to beat.

Indeed, that would make it trivial.

Hey there !
I have stopped programming for a while, and currently I'm into danmaku (Touhou addiction, to be more specific)
I was passing by, and I decided to give your game a try.

Well, I guess I beat it. I'm not sure, because there's no ending scene, just no more enemies.
It wasn't really hard, though. I didn't use any bomb.
The only hard part is when the level 3 boss spawns right on your hitbox.

I'm looking forward to harder levels !
I recommend using more aimed bullets, and streaming-based levels.

There's a new demo, with netplay and a new stage !
(But still only 3 characters)

You can download it on Tasogare frontier official website : http://www.tasofro.net/touhou135/index.html#130412
So, does anybody want to play ?

I never saw this bug, this is very strange.
Which OS are you using ?
And what do you mean by "the document is sometimes just blank" ? Is the document totally empty or is it the Lua script app which is blank ?

Sure ! My programs aren't under any license.

You can use them, and even get all the credit for it. (But I'd appreciate if you mention my name)
The source code is attached to this post.

No, not necessarily.

Actually, they can be as far as you want, if they are in the field of view cone. (The only restriction is that the x-coordinate can't be negative)
That's why if you want to keep a good speed, you should check if vertices are not too far before drawing them.

Here is the function that I use in nCraft :
-vertices* is an 1D array with 3D coordinates of used vertices. (example : {5,0,0,  5,1,0,  5,1,1  5,0,1})
-pos* is an 1D array when I will store the 2D coordinates of projections (example : {50,50  100,50   50,100  100,100})
-size is the number of vertices

void computeVertices(float *vertices,int *pos,int size)
{
  int i=0;
  float temp=0.0;
  for(i=0;i<size;i++)
  {
    if(vertices[i*3+1]>0)
    {
      temp=OFFSET*vertices[i*3]/vertices[i*3+1]*50.0+160.0;  //offset is an arbitrary value. I use 10.
      pos[i*2]=(int)temp; //screen coordinates have to be integers
      temp=-OFFSET*vertices[i*3+2]/vertices[i*3+1]*50.0+120.0;
      pos[i*2+1]=(int)temp;
    }
    else
    {
      //if vertices are behind the camera, I store arbitrary values to remember not to draw them
      pos[i*2]=-10000;
      pos[i*2+1]=-10000;
    }
  }
}