SRL Archive - Help and Support

I want to create code where I'm able to generate a TPA from X points (realistic amount of points), but I don't know how to go about doing this.

For example:

TPAFromCircle (Radius, NumberOfTPoints: Integer; Center: TPoint): TPointArray;

For example, NumberOfTPoints would return this:
4:

8:
Image broken

One way I was thinking of it was dividing 2*pi radians by NumberOfTPoints, doing some trigonometry to find out:

Use sine/cosine laws to get the x/y changed, then apply that to the center point.
Is there an easier way to do this? Are there any functions we have that will do this for me?

{.include SRL\SRL.scar}
{.include SRL\SRL\Misc\Debug.scar}

function PolygonCorners(NumberOfPoints, Radius: LongInt; Center: TPoint): TPointArray;
var
  AngleShare, Angle: Extended;
  I: LongInt;
begin
  SetLength(Result, NumberOfPoints);
  AngleShare := 360 / NumberOfPoints;
  for I := 0 to NumberOfPoints - 1 do
  begin
    Angle := AngleShare * I;
    Result[I] := Point(Round(Radius * Sin(Angle * Pi / 180)) + Center.X, Round(Radius * Cos(Angle * Pi / 180)) + Center.Y);
  end;
end;

var
  TPA: TPointArray;

begin
  SetUpSRL;
  TPA := PolygonCorners(8, 100, Point(50, 50));
  DebugTPA(TPA, '');
end.

Plugin would probably be faster.

Looks great :)
When you run that in Simba, does it crash for you at all? If not, just me then.
I have the includes and all set up properly

From: cstrike
Looks great :)
When you run that in Simba, does it crash for you at all? If not, just me then.
I have the includes and all set up properly

Does for me, but only if you call DebugTPA or whatever, not sure..

Edit: Ah, simba can't handle negatives in the bitmap canvas or some shit, change the center from 50, 50 to 150, 150

Don't know if you still want it, but I think this looks better…

function TPAFromCircle (Radius, NumberOfTPoints: Integer; Center: TPoint): TPointArray;
var
  I: Integer;
begin
  SetLength(Result, NumberOfTPoints);
  for I := 0 to NumberOfTPoints - 1 do
    Result[i] := Point(Round(Sin(Radians(360.0 * I / NumberofTPoints)) * Radius) + Center.x, Round(Cos(Radians(360.0 * I / NumberofTPoints)) * Radius) + Center.y);
end;

From: Bad Boy JH
Don't know if you still want it, but I think this looks better…

function TPAFromCircle (Radius, NumberOfTPoints: Integer; Center: TPoint): TPointArray;
var
  I: Integer;
begin
  SetLength(Result, NumberOfTPoints);
  for I := 0 to NumberOfTPoints - 1 do
    Result[i] := Point(Round(Sin(Radians(360.0 * I / NumberofTPoints)) * Radius) + Center.x, Round(Cos(Radians(360.0 * I / NumberofTPoints)) * Radius) + Center.y);
end;

Mind you, the only reason I did not code it like this^ is because mine will be slightly faster as it uses variables instead of multiplying multiple times.

I misread your code the first time, and thought it would stuff up under cetrain conditions, however I was inccorrect, one thing I would change on your code… you could just have the angle as Radians in the first place.

function PolygonCorners(NumberOfPoints, Radius: LongInt; Center: TPoint): TPointArray;
var
  AngleShare, Angle: Extended;
  I: LongInt;
begin
  SetLength(Result, NumberOfPoints);
  AngleShare := 2 * Pi NumberOfPoints;
  for I := 0 to NumberOfPoints - 1 do
  begin
    Angle := AngleShare * I;
    Result[I] := Point(Round(Radius * Sin(Angle)) + Center.X, Round(Radius * Cos(Angle)) + Center.Y);
  end;
end;

From: IceFire908
Edit: Ah, simba can't handle negatives in the bitmap canvas or some shit, change the center from 50, 50 to 150, 150

How does it crash? (Also, you shouldn't ever use a negative point since it's not valid. It's basically just out of bounds. But Simba should catch this.)

E: Nevermind. Simba doesn't crash. It just raises an exception because you're accessing invalid points:

Error: Exception: TMWindow.ReturnData: The parameters passed are wrong; xs,ys -50,-50 width,height 201,201 at line 101

From: Bad Boy JH
I misread your code the first time, and thought it would stuff up under cetrain conditions, however I was inccorrect, one thing I would change on your code… you could just have the angle as Radians in the first place.

Try this:

function PolygonCorners(NumberOfPoints, Radius: LongInt; Center: TPoint): TPointArray;
var
  AngleShare, Angle: Extended;
  i, j: Integer;
begin
  SetLength(Result, NumberOfPoints);
  AngleShare := 2 * Pi / NumberOfPoints;
  j := 0;
  dec(NumberOfPoints);
  try
    for i := 0 to NumberOfPoints do
    begin
      Angle := AngleShare * j;
      Result[i] := Point(Round(Radius * Sin(Angle)) + Center.X, Round(Radius * Cos(Angle)) + Center.Y);
      inc(j);
    end;
  except
    errorFound := True;
  end;
  if (errorFound) then
    setLength(Result, j+1);
end;

It should never allow an exception to pass, if it does then it will adjust and just make the array smaller. So if you have a circle that goes over the needed space, it`ll asjust and fix the array. So, there would be a line of cut off points where the points were invalid, however the function will not crash, and the valid points will remain in an array of the appropriate size.

From: Nava2
Try this:

function PolygonCorners(NumberOfPoints, Radius: LongInt; Center: TPoint): TPointArray;
var
  AngleShare, Angle: Extended;
  i, j: Integer;
begin
  SetLength(Result, NumberOfPoints);
  AngleShare := 2 * Pi / NumberOfPoints;
  j := 0;
  dec(NumberOfPoints);
  try
    for i := 0 to NumberOfPoints do
    begin
      Angle := AngleShare * j;
      Result[i] := Point(Round(Radius * Sin(Angle)) + Center.X, Round(Radius * Cos(Angle)) + Center.Y);
      inc(j);
    end;
  except
    errorFound := True;
  end;
  if (errorFound) then
    setLength(Result, j+1);
end;

It should never allow an exception to pass, if it does then it will adjust and just make the array smaller. So if you have a circle that goes over the needed space, it`ll asjust and fix the array. So, there would be a line of cut off points where the points were invalid, however the function will not crash, and the valid points will remain in an array of the appropriate size.

Those exceptions are generally not to be caught. :p
As you can see it is trying to copy the client starting from -50,-50, which is just plain nonsense. That's why Simba throws this exception.

From: Bad Boy JH
I misread your code the first time, and thought it would stuff up under cetrain conditions, however I was inccorrect, one thing I would change on your code… you could just have the angle as Radians in the first place.

function PolygonCorners(NumberOfPoints, Radius: LongInt; Center: TPoint): TPointArray;
var
  AngleShare, Angle: Extended;
  I: LongInt;
begin
  SetLength(Result, NumberOfPoints);
  AngleShare := 2 * Pi NumberOfPoints;
  for I := 0 to NumberOfPoints - 1 do
  begin
    Angle := AngleShare * I;
    Result[I] := Point(Round(Radius * Sin(Angle)) + Center.X, Round(Radius * Cos(Angle)) + Center.Y);
  end;
end;

Ah I see.

I made some logic errors:

function PolygonCorners(NumberOfPoints, Radius: LongInt; Center: TPoint): TPointArray;
var
  AngleShare, Angle: Extended;
  i, j: Integer;
begin
  SetLength(Result, NumberOfPoints);
  AngleShare := 2 * Pi / NumberOfPoints;
  j := 0; errorFound := False;
  dec(NumberOfPoints);
  for i := 0 to NumberOfPoints do
    try
      Angle := AngleShare * j;
      Result[j] := Point(Round(Radius * Sin(Angle)) + Center.X, Round(Radius * Cos(Angle)) + Center.Y);
      inc(j);
    except
      errorFound := True;
    end;
  if (errorFound) then
    setLength(Result, j+1);
end;