Collission detection on level ( source Travels doc + some other examples)

[robert83]

Hi,

I was playing a bit further with my program, and modified so I do the movement in the SpriteEngine.DoMove procedure , and it works fine regardles if velocity is 80, 95, or whatever... what I modified compared to my older source is :

TForm1.OnIDLE

Here is one obvious problem, which I did not even tried to solve... for now, somehow my Figure moves faster then the
screen is scroll. ( I was hoping the speed would be the same...but there is a slight difference... will play with it later... was not
the object here to solve that ... but rather to implement the movement more properly)

    ActTime := ActTime + AdPerCounter.TimeGap;
    if ActTime > 25 then
    begin
      Blurp.vx:=0;
      Blurp.vy:=0;
          if GetKeyState(VK_LEFT) < 0 then
            begin
                  Blurp.vx:=-95;
                  AdSpriteEngine.X:=AdSpriteEngine.X-Blurp.vx*(AdPerCounter.TimeGap/1000);
            end;
          if GetKeyState(VK_RIGHT) < 0 then
            begin
                  Blurp.vx:=95;
                  AdSpriteEngine.X:=AdSpriteEngine.X-Blurp.vx*(AdPerCounter.TimeGap/1000);
            end;
          if GetKeyState(VK_UP) < 0 then
            begin
                  Blurp.vy:=-95;
                  AdSpriteEngine.Y:=AdSpriteEngine.Y-Blurp.vy*(AdPerCounter.TimeGap/1000);
            end;
          if GetKeyState(VK_DOWN) < 0 then
            begin
                  Blurp.vy:=95;
                  AdSpriteEngine.Y:=AdSpriteEngine.Y-Blurp.vy*(AdPerCounter.TimeGap/1000);
            end;
      ActTime := 0;
    end;

Here Is my modified DoMove , for now works great, been playing with it , using different velocity... always stops where it should yippeee

procedure TBlurp.DoMove(TimeGap: Double);
begin
  inherited;
  // left
  if vx < 0 then
    begin
      if not testForWall(X+vx*TimeGap,Y,Image.Width,Image.Height-1,'left') then
        begin
          X:=X+round(vx*TimeGap) ;
        end;
    end;
  // right
  if vx > 0 then
    begin
     if not testForWall(X,Y,Image.Width,Image.Height-1,'right') then
       begin
         X:=X+round(vx*TimeGap);
       end;
    end;
  // up
  if vy < 0 then
    begin
      if not testForWall(X,Y+vy*TimeGap,Image.Width-1,Image.Height,'up') then
        begin
          Y:=Y+round(vy*TimeGap);
        end;
    end;
  // down
  if vy > 0 then
    begin
      if not testForWall(X,Y,Image.Width-1,Image.Height,'down') then
        begin
          Y:=Y+round(vy*TimeGap);
        end;
    end;

  Collision;
end;

Also one unexpected sidefect is ... before it was important where my Start position for my character was... now it's not , X can be 128,139,131 ... it works the same.

Anyway I'll continue now with implementing gravity And checking the scrolling part.

Greetings
Rob

[robert83]

    if ActTime > 10 then
    begin
      Blurp.vx:=0;
      Blurp.vy:=0;
          if GetKeyState(VK_LEFT) < 0 then
            begin
                  Blurp.vx:=-80;
                  if (Blurp.X > 320) and (Blurp.X < (40*64)-320) then
                    begin
                      AdSpriteEngine.X:=(Blurp.X*-1)+320;
                    end;
            end;
          if GetKeyState(VK_RIGHT) < 0 then
            begin
                  Blurp.vx:=80;
                  if (Blurp.X > 320) and (Blurp.X < (40*64)-320) then
                    begin
                      AdSpriteEngine.X:=(Blurp.X*-1)+320;
                    end;
            end;
          if GetKeyState(VK_UP) < 0 then
            begin
                  Blurp.vy:=-80;
                  if (Blurp.Y > 240) and (Blurp.Y < (29*64)-240) then
                    begin
                      AdSpriteEngine.Y:=(Blurp.Y*-1)+240;
                    end;
            end;
          if GetKeyState(VK_DOWN) < 0 then
            begin
                  Blurp.vy:=80;
                  if (Blurp.Y > 240) and (Blurp.Y < (29*64)-240) then
                    begin
                      AdSpriteEngine.Y:=(Blurp.Y*-1)+240;
                    end;
            end;
      ActTime := 0;
    end;

Due to the fact that I use 60 FPS limit... had to decrease ACT TIME to 10... I don't know what to call this effect but when ACT TIME was 60... the screen was moving... I dunnot a bit erm... tear effect ... the outer lines of my character seemed to be jumping in and out of the character when it was redrawn...

Anyway now it works great , and was pretty simple to do to. Only thing, gravity...tomorrow.

Greetings
Rob

ps. : once I'm finished with my experiments...I'll use const and more variables instead of manually putting in numbers....

[paul_nicholls]

Hi Rob, glad to hear that it is now working for you

cheers,
Paul