OpenGL Blur effect...

[M109uk]

Hi all,

Yet another problem lol

Im trying to get a rubik's cube with a blur effect, how ever i get something else :s Its a nice effect and all, but not what i want...

I looked at the examples from NeHe, sulaco and somewhere else i cant remember..

What im getting is:




My code is as follows:

procedure Box(const Pos: TVector3f);

  procedure renderPoint(Point: TVector3f);
  var
    p,n: TVector3f;
  begin
    p := Point;
    n := VectorNormalize(p);
    glNormal3fv(@n);
    glVertex3fv(@p);
  end;

begin
  If bindEnv Then
  Begin
    glEnable(GL_TEXTURE_GEN_S);
    glEnable(GL_TEXTURE_GEN_T);
    glEnable(GL_BLEND);    
    _XMaterials.Bind(cubEnv, Nil);
  End Else
     _XMaterials.Bind(cubTex, Nil);

  glBegin(GL_QUADS);
  // front
    glTexCoord2f(0, 0); renderPoint(Vector3fMake(Pos[0],      Pos[1],      Pos[2]));
    glTexCoord2f(0, 1); renderPoint(Vector3fMake(Pos[0],      Pos[1]+Size, Pos[2]));
    glTexCoord2f(1, 1); renderPoint(Vector3fMake(Pos[0]+Size, Pos[1]+Size, Pos[2]));
    glTexCoord2f(1, 0); renderPoint(Vector3fMake(Pos[0]+Size, Pos[1],      Pos[2]));

    glTexCoord2f(0, 0); renderPoint(Vector3fMake(Pos[0]+Size, Pos[1],      Pos[2]));
    glTexCoord2f(0, 1); renderPoint(Vector3fMake(Pos[0]+Size, Pos[1]+Size, Pos[2]));
    glTexCoord2f(1, 1); renderPoint(Vector3fMake(Pos[0]+Size, Pos[1]+Size, Pos[2]+Size));
    glTexCoord2f(1, 0); renderPoint(Vector3fMake(Pos[0]+Size, Pos[1],      Pos[2]+Size));

    glTexCoord2f(0, 0); renderPoint(Vector3fMake(Pos[0],      Pos[1],      Pos[2]+Size));
    glTexCoord2f(0, 1); renderPoint(Vector3fMake(Pos[0],      Pos[1]+Size, Pos[2]+Size));
    glTexCoord2f(1, 1); renderPoint(Vector3fMake(Pos[0]+Size, Pos[1]+Size, Pos[2]+Size));
    glTexCoord2f(1, 0); renderPoint(Vector3fMake(Pos[0]+Size, Pos[1],      Pos[2]+Size));

    glTexCoord2f(0, 0); renderPoint(Vector3fMake(Pos[0]     , Pos[1],      Pos[2]));
    glTexCoord2f(0, 1); renderPoint(Vector3fMake(Pos[0]     , Pos[1]+Size, Pos[2]));
    glTexCoord2f(1, 1); renderPoint(Vector3fMake(Pos[0]     , Pos[1]+Size, Pos[2]+Size));
    glTexCoord2f(1, 0); renderPoint(Vector3fMake(Pos[0]     , Pos[1],      Pos[2]+Size));

    glTexCoord2f(0, 0); renderPoint(Vector3fMake(Pos[0]+Size, Pos[1]+Size, Pos[2]));
    glTexCoord2f(0, 1); renderPoint(Vector3fMake(Pos[0]+Size, Pos[1]+Size, Pos[2]+Size));
    glTexCoord2f(1, 1); renderPoint(Vector3fMake(Pos[0]     , Pos[1]+Size, Pos[2]+Size));
    glTexCoord2f(1, 0); renderPoint(Vector3fMake(Pos[0]     , Pos[1]+Size, Pos[2]));

    glTexCoord2f(0, 0); renderPoint(Vector3fMake(Pos[0]+Size, Pos[1]     , Pos[2]));
    glTexCoord2f(0, 1); renderPoint(Vector3fMake(Pos[0]+Size, Pos[1]     , Pos[2]+Size));
    glTexCoord2f(1, 1); renderPoint(Vector3fMake(Pos[0]     , Pos[1]     , Pos[2]+Size));
    glTexCoord2f(1, 0); renderPoint(Vector3fMake(Pos[0]     , Pos[1]     , Pos[2]));
  glEnd;

  If bindEnv Then
  Begin
    _XMaterials.UnBind(cubEnv, Nil);
    glDisable(GL_TEXTURE_GEN_S);
    glDisable(GL_TEXTURE_GEN_T);
  End Else
     _XMaterials.Bind(cubTex, Nil);
end;

procedure DCCube;
begin
  glPushMatrix;
    Box(Vector3fMake(-11,-11,-11)); Box(Vector3fMake(  0,-11,-11)); Box(Vector3fMake( 11,-11,-11));
    Box(Vector3fMake(-11,-11,  0)); Box(Vector3fMake(  0,-11,  0)); Box(Vector3fMake( 11,-11,  0));
    Box(Vector3fMake(-11,-11, 11)); Box(Vector3fMake(  0,-11, 11)); Box(Vector3fMake( 11,-11, 11));

    Box(Vector3fMake(-11,  0,-11)); Box(Vector3fMake(  0,  0,-11)); Box(Vector3fMake( 11,  0,-11));
    Box(Vector3fMake(-11,  0,  0)); Box(Vector3fMake(  0,  0,  0)); Box(Vector3fMake( 11,  0,  0));
    Box(Vector3fMake(-11,  0, 11)); Box(Vector3fMake(  0,  0, 11)); Box(Vector3fMake( 11,  0, 11));

    Box(Vector3fMake(-11, 11,-11)); Box(Vector3fMake(  0, 11,-11)); Box(Vector3fMake( 11, 11,-11));
    Box(Vector3fMake(-11, 11,  0)); Box(Vector3fMake(  0, 11,  0)); Box(Vector3fMake( 11, 11,  0));
    Box(Vector3fMake(-11, 11, 11)); Box(Vector3fMake(  0, 11, 11)); Box(Vector3fMake( 11, 11, 11));
  glPopMatrix;
end;

procedure RenderDCCube_ENV;
begin
  bindEnv := False;
  DCCube;

  glDisable(GL_BLEND);  
  glBlendFunc(GL_SRC_ALPHA, GL_ONE);  

  bindEnv := True;
  DCCube;
end;

procedure createTexture;
var
  rX,rY,rZ: Integer;
begin
  glBlendFunc(GL_SRC_ALPHA, GL_ONE);
  
  glPushAttrib(GL_ALL_ATTRIB_BITS);
  glViewport(0, 0, 128, 128);
  glClear(GL_COLOR_BUFFER_BIT Or GL_DEPTH_BUFFER_BIT);

  _XCameras[_XEngine.Camera].Render;

    glTranslatef(0, 0, Z);
    glRotatef(rot[0], 1, 0, 0);
    glRotatef(rot[1], 0, 1, 0);
    glRotatef(rot[2], 0, 0, 1);

    RenderDCCube_ENV;

    glMatrixMode(GL_PROJECTION);
    glPopMatrix;

    glMatrixMode(GL_MODELVIEW);
    If blrTex > 0 Then
    Begin
      glBindTexture(GL_TEXTURE_2D, blrTex);
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
      glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, 128, 128);
    End Else
    Begin
      glGenTextures(1, @blrTex);
      glBindTexture(GL_TEXTURE_2D, blrTex);
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
      glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 0, 0, 128, 128, 0);
    End;
  glPopAttrib;
end;

procedure InitDCubes;
begin
  glBlendFunc(GL_SRC_ALPHA, GL_ONE);
  cubTex := _XMaterials.Add(BASE_DIR+'data.src\cube.png');
  cubEnv := _XMaterials.Add(BASE_DIR+'data.src\Envmap.bmp');
end;

procedure PreRenderDCubes;
begin
  glEnable(GL_DEPTH_TEST);
  createTexture;
end;

procedure RenderDCubes;
var
  a1,a2: Single;
  i,rX,rY,rZ: Integer;
  aspect: Double;
begin
  glEnable(GL_DEPTH_TEST);
  glTranslatef(0, 0, Z);
  glRotatef(rot[0], 1, 0, 0);
  glRotatef(rot[1], 0, 1, 0);
  glRotatef(rot[2], 0, 0, 1);

  RenderDCCube_ENV;

  glDisable(GL_LIGHTING);
  glDisable(GL_DEPTH_TEST);

  glBindTexture(GL_TEXTURE_2D, blrTex);
  glColor4f(1, 1, 1, 1/numSamples);

  _XEngine.Ortho(True);

  a1 := 1;
  a2 := 1/(numSamples-1)*blrDistance;

  For i := 0 To numSamples Do
  Begin
    a1 := a1+a2;
    glBegin(GL_QUADS);
      glTexCoord2f(0, 0); glVertex2f(-a1,-a1);
      glTexCoord2f(1, 0); glVertex2f( a1,-a1);
      glTexCoord2f(1, 1); glVertex2f( a1, a1);
      glTexCoord2f(0, 1); glVertex2f(-a1, a1);
    glEnd;
  End;

  _XEngine.Ortho(False);

  rot[0] := rot[0]+Sin(50/(_XEngine.Delta/200));
  rot[1] := rot[1]+Sin(60/(_XEngine.Delta/200));
  rot[2] := rot[2]+Sin(70/(_XEngine.Delta/200));

  If rot[0] > 360 Then rot[0] := 0;
  If rot[1] > 360 Then rot[1] := 0;
  If rot[2] > 360 Then rot[2] := 0;

  If rot&#91;0&#93; < 0 Then rot&#91;0&#93; &#58;= 360;
  If rot&#91;1&#93; < 0 Then rot&#91;1&#93; &#58;= 360;
  If rot&#91;2&#93; < 0 Then rot&#91;2&#93; &#58;= 360;
end;

Im guessing that its just rendering the blur as the textures of the cube instead, but i cant for the life of me work out how and why :s im sure i've missed something really dumb..

Thanks

[Robert Kosek]

I haven't touched OpenGL in quite awhile so I'm a bit rusty, but if I recall the most simple way to do a motion blur is to set the clear-scene color (the one you draw before each frame renders) to have an alpha value of about 0.8.

[M109uk]

Thanks for the top

I have managed to get it working after a re-write... and i changed the alpha of the clear colour and all seems to work good

heres a screeny:



Thanks again

[Robert Kosek]

Awesome looking effect. I like it!

You're welcome, I'm just glad I remembered how to do it.

[M109uk]

Thanks

I've updated it so that it looks like it is glowing on the inside of the cube, all i have to do now is think of a way that i can have it rotate throught the colours :?

[Traveler]

Stunning!

[WILL]

Very nice indeed.

[Robert Kosek]

Ooh! I know!

Draw the whole thing in greyscale and then draw an additive color overlay! Voila! Rotating, colorized, blurred cubes!

Though, if you don't want something else beneath/within the cube to be the same color that'd be a mess.

[M109uk]

Thanks for all the comments

heres a few more, i now have it bluring from white to red with a blue flash from with in




It sort of looks like theres lightning with in the cube

[Robert Kosek]

Awesome! If you wanted to get psychedelic with it, you could stretch a dynamic plasma texture over it... but that could make some folks sick. Heh.