Do you _MAPTRIANGLE?

[dbox]

I've been working on adding _MapTriangle to QBJS and it's got me curious about usage of this method by the community.  _MapTriangle is an interesting and powerful function... it's really two different functions in one.  There is a 2D version which takes (x, y) points and a 3d version which takes true 3d (x, y, z) coordinates which are relative to the screen size.

So, do you _MapTriangle?

[bplus]

My 2 main uses:
1. Yes for RotoZoom 2D
2. But even before that I used for Filled Triangles

I am not seeing my category.

[dbox]

Sounds like you are option 2 since you use the 2d version for more than RotoZoom.

[James D Jarvis]

It's darn handy in rotozoom but I also use it to fill areas without using paint. It's pretty quick and I don't have to worry about bleeding outside a boundary by accident.

[dbox]

Based on his recent post it looks like Petr would be in the 3d version camp.  Nice example Petr!

[dbox]

It's darn handy in rotozoom but I also use it to fill areas without using paint. It's pretty quick and I don't have to worry about bleeding outside a boundary by accident.

Thanks for the feedback James.  Do you have any sample code where you've used it for filling areas instead of Paint?

[James D Jarvis]

It's darn handy in rotozoom but I also use it to fill areas without using paint. It's pretty quick and I don't have to worry about bleeding outside a boundary by accident.

Thanks for the feedback James.  Do you have any sample code where you've used it for filling areas instead of Paint?

sure, here's an example:

Code: (Select All)

'imperfect false grid, doesn't work perfectly but it's an example of using _maptriangle to "paint"
Screen _NewImage(800, 500, 32)
'prepare the fill triangle
t& = _NewImage(9, 9, 32)
_Dest t&
Paint (2, 2), _RGB32(200, 200) 'i use paint here because it only gets called once and I wouldn't remember what is going on otherwise
_Dest 0
_DontBlend 0
'get the maze ready
maxx = 61
maxy = 41
Dim grid(0 To maxx + 1, 0 To maxy + 1, 1 To 2)
Dim map(0 To maxx + 1, 0 To maxy + 1)
Do
    Cls
    'make flasegrid
    ybias = 0
    trend = Int(-1 + Rnd * 3)
    For y = 0 To maxy + 1
        trend = Int(-2 + Rnd * 5)

        For x = 0 To maxx + 1
            ybias = ybias + ((trend * (Rnd * 6)) / 30)
            grid(x, y, 1) = x * 10 + Int(Rnd * 4) - Int(Rnd * 4)
            grid(x, y, 2) = Int(y * 10 + Int(Rnd * 4) - Int(Rnd * 4) + ybias)
            map(x, y) = 1
        Next x
    Next y
    'drunk wandering maze
    sx = 4 + Int(Rnd * (maxx - 4))
    sy = 4 + Int(Rnd * (maxy - 4))
    lastgo = Int(1 + Rnd * 4)
    drun = Int(1 + Rnd * 4)
    For c = 1 To 1800
        dgo = Int(1 + Rnd * 6)
        If dgo = 6 Then drun = Int(1 + Rnd * 4)
        If dgo > 4 Then dgo = lastgo
        Select Case dgo
            Case 1
                If sy - drun > 1 Then
                    For ny = sy To sy - drun Step -1
                        map(sx, ny) = 0
                        sy = ny
                    Next ny
                End If
                c = c + drun
            Case 2
                If sx + drun < maxx - 1 Then
                    For nx = sx To sx + drun
                        map(nx, sy) = 0
                        sx = nx
                    Next nx
                End If
                c = c + drun
            Case 3
                If sy + drun < maxy - 1 Then
                    For ny = sy To sy + drun
                        map(sx, ny) = 0
                        sy = ny
                    Next ny
                End If
                c = c + drun
            Case 4
                If sx - drun > 1 Then
                    For nx = sx To sx - drun Step -1
                        map(nx, sy) = 0
                        sx = nx
                    Next nx
                End If
                c = c + drun
        End Select
        lastgo = dgo
    Next c

    'show maze
    For y = 0 To maxy - 1
        For x = 0 To maxx - 1
            If map(x, y) > 0 Then
                x1 = grid(x, y, 1)
                x2 = grid(x + 1, y, 1)
                x3 = grid(x + 1, y + 1, 1)
                x4 = grid(x, y + 1, 1)

                y1 = grid(x, y, 2)
                y2 = grid(x + 1, y, 2)
                y3 = grid(x + 1, y + 1, 2)
                y4 = grid(x, y + 1, 2)
'filling the irregular cells with _maptriangle instead of paint so there is no need to worry about "leaking"
                _MapTriangle (0, 0)-(0, 8)-(8, 8), t& To(x1, y1)-(x2, y2)-(x3, y3)
                _MapTriangle (0, 0)-(0, 8)-(8, 0), t& To(x1, y1)-(x3, y3)-(x4, y4)
            End If
        Next x
    Next y


    For y = 0 To maxy - 1
        For x = 0 To maxx - 1
            If map(x, y) = 0 Then
                cx = (grid(x, y, 1) + grid(x + 1, y, 1) + grid(x, y + 1, 1) + grid(x + 1, y + 1, 1)) / 4
                cy = (grid(x, y, 2) + grid(x + 1, y, 2) + grid(x, y + 1, 2) + grid(x + 1, y + 1, 2)) / 4
                ' Circle (cx, cy), 1, _RGB32(250, 0, 0)
                'not really doing anything right now... it was earlier, it might do so again
            End If
        Next x
    Next y
    Do
        _Limit 60
        kk$ = InKey$
    Loop Until kk$ <> ""
Loop Until kk$ = Chr$(27)

[Gets]

I mainly use it for scaling, since it was faster than PUTIMAGE, and for the tiling effect.

[mnrvovrfc]

_MAPTRIANGLE is a command in QB64(PE) that I've never cared about. After coming across some of MasterGy's programs I feel very small having a lot to learn about graphics programming. I just don't have the patience. I could barely fire up GIMP to create the silly-looking avatars that you keep seeing from me on this site, and other things like the "derpface" GIF file.

[dbox]

I mainly use it for scaling, since it was faster than PUTIMAGE, and for the tiling effect.

Thanks for the feedback @Gets!  I'm collecting samples for testing purposes.  Do you have an example program you could share that uses the tiling effect?