OpenGL examples
#28
I finally broke down and above all understood how the little piece of _glLists works. It is important to note that when creating displaylists it is not enough to just place a texture on an object. It is also necessary to set the graphic position to the place where the next DisplayList will start to be rendered (using the glTranslatef command) - look to sub BuildFont.
This is not the program that didn't work for me, but a different one with the same command. And here was the breakthrough. I tried to comment everything in the program, there were a few things that gave me trouble (because I'm working with OpenGL only now, because there are many things with a question mark regarding implantation in QB64, for example calling the sub with the transfer of the field from QB64 to OpenGL caused me compilation error and it took me an hour to figure out why the compiler doesn't like it).

Like this. Its my bug, if I did it more often I would know, right? Smile God Save QB64!


ZIP file contains: source code (mnrvovrfc will surely appreciate) and two textures. EXE file is not included. The letter sizes in the file names match  Big Grin

Code: (Select All)
Declare CustomType Library
    Sub gluBuild2DMipmaps (BYVAL Target As _Unsigned Long, BYVAL iFormat As Long, BYVAL Wdth As Long, BYVAL Hght As Long, BYVAL format As _Unsigned Long, BYVAL typ As _Unsigned Long, BYVAL dat As _Offset)
End Declare
_Title "_glLists and 2D & 3D in one"

Type GL_Loader
    PointerGL As Long
    TextureName As String
    Filtering As _Unsigned _Byte
End Type
ReDim Shared GLL(0) As GL_Loader, t As Long
Dim Shared GL_InitInfo As _Byte
Dim Shared ExitSignal As _Byte, Blend As _Byte
'---------------------------------------------------
image$ = "font.gif"
Dim Shared Img(255) As Long
Dim Shared Textures(255) As Long
Dim Shared Baze, PreInit
Dim Shared Diamond As Long
Screen _NewImage(1024, 768, 32)

Do
    _Limit 20
Loop

Sub _GL
    Static cnt1, cnt2
    Init2 'load images and create displaylists and textures
    'drawing

    _glClear _GL_COLOR_BUFFER_BIT And _GL_DEPTH_BUFFER_BIT 'clear screen and depth buffer
    _glLoadIdentity 'matrix reset
    'We'll select the texture created from bumps.bmp, move it five units inward, and rotate it by 45 on the Z axis. This clockwise rotation will give the appearance of a diamond instead of two squares.




    _glMatrixMode _GL_PROJECTION '                          Set projection matrix  - TRY comment this five rows and then run it. Black screen occur. For view just something then must be depth set to -1 (Z parameter in _glTranslateF)
    _glLoadIdentity ' Reset matrix

    _gluPerspective 45.0F, _Width / _Height, 0.1F, 100.0F ' Perspective calculation
    _glMatrixMode _GL_MODELVIEW '                           set modelview matrix




    _glBindTexture _GL_TEXTURE_2D, Diamond 'diamond texture select

    _glTranslatef 0.0F, 0.0F, -5.0F ') shift to screen
    _glRotatef 45.0F, 0.0F, 0.0F, 1.0F

    'We will perform another rotation on the X and Y axes, which is dependent on the variable cnt1*30. It has the effect of rotating the object around, just as a diamond rotates in one place.
    _glRotatef cnt1 * 30.0F, 1.0F, 1.0F, 0.0F ' Rotation in axis X and Y

    'Since we want it to appear solid, we'll turn off blending and set the color to white. We will render a texture-mapped quadrilateral.
    _glDisable _GL_BLEND 'disable blending
    _glColor3f 1.0F, 1.0F, 1.0F 'white color

    _glBegin _GL_QUADS 'quad drawing

    _glTexCoord2d 0.0F, 0.0F
    _glVertex2f -1.0F, 1.0F
    _glTexCoord2d 1.0F, 0.0F
    _glVertex2f 1.0F, 1.0F
    _glTexCoord2d 1.0F, 1.0F
    _glVertex2f 1.0F, -1.0F
    _glTexCoord2d 0.0F, 1.0F
    _glVertex2f -1.0F, -1.0F
    _glEnd 'quad end

    'Next, we rotate it by 90 degrees on the X and Y axes. We draw a quadrilateral again. This new one intersects the first drawn in the middle and is perpendicular to it (90 degrees). Nice symmetrical shape..

    _glRotatef 90.0F, 1.0F, 1.0F, 0.0F 'rotation in axcis X and Y up to 90 degrees
    _glBegin _GL_QUADS 'quad drawing
    _glTexCoord2d 0.0F, 0.0F
    _glVertex2f -1.0F, 1.0F
    _glTexCoord2d 1.0F, 0.0F
    _glVertex2f 1.0F, 1.0F
    _glTexCoord2d 1.0F, 1.0F
    _glVertex2f 1.0F, -1.0F
    _glTexCoord2d 0.0F, 1.0F
    _glVertex2f -1.0F, -1.0F
    _glEnd 'quad end

    'Let's turn on the blending and start writing the text.

    _glEnable _GL_BLEND 'enable blending
    _glLoadIdentity 'matrix reset




    _glColor3f 1.0 * Cos(cnt1), 1.0 * Sin(cnt2), 1.0 - 0.5 * Cos(cnt1 + cnt2)
    glPrint (280 + (250 * Cos(cnt1))), (235 + (200 * Sin(cnt2))), "NeHe", 0 'print text
    _glColor3f 1.0 * Sin(cnt2), 1.0 - 0.5 * (Cos(cnt1 + cnt2)), 1.0 * Cos(cnt1)
    glPrint (280 + (230 * Cos(cnt2))), (235 + (200 * Sin(cnt1))), "OpenGL", 1 'print text

    _glColor3f .2 + Cos(cnt1), 0.7 * Sin(cnt2), Sin(cnt1 - cnt2)
    glPrint (280 + (200 * Sin(cnt2))), (235 + (200 * Cos(cnt1))), "To QB64 rewrited Petr", 0 'print text

    _glColor3f 0.0F, 0.0F, 1.0F 'blue color


    glPrint (240 + (200 * Cos(cnt2 + cnt1) / 5)), 2, "Giuseppe D'Agata", 0 'first author this program
    _glColor3f 1.0F, 1.0F, 1.0F 'white color
    glPrint (242 + (200 * Cos(cnt2 + cnt1) / 5)), 2, "Giuseppe D'Agata", 0
    cnt1 = cnt1 + 0.01
    cnt2 = cnt2 + 0.0081
End Sub

Sub Init2
    If GL_InitInfo = 0 Then
        LoadCharactersFromImage "font.gif", 16, 16, Img&()
        GL_InitInfo = 1

        For MakeTexture = 0 To 255
            Textures(MakeTexture) = LoadTexture_Array(Img&(MakeTexture), 2)
        Next
        BuildFont

        Dim d(0) As Long
        d(0) = _LoadImage("diam.png", 32)

        Diamond = LoadTexture_Array(d(0), 1) 'this is how get around it so that don't have to add a loader from a file like in previous programs
        _FreeImage d(0)
        ' u nej init GL
        Exit Sub
    End If


    _glClearColor 0.0F, 0.0F, 0.0F, 0.0F 'black background
    _glClearDepth 1.0 'depth buffer settings
    _glDepthFunc _GL_LEQUAL 'depth testing type
    _glBlendFunc _GL_SRC_ALPHA, _GL_ONE 'set blending type
    _glShadeModel _GL_SMOOTH 'allow smooth shading
    _glEnable _GL_TEXTURE_2D 'enable texture mapping
    '---------------------






End Sub

Sub BuildFont
    '  Static Baze
    Baze = _glGenLists(255) ' 256 display lists
    For i& = 0 To 255
        _glNewList Baze + i&, _GL_COMPILE
        _glBindTexture _GL_TEXTURE_2D, Textures(i&)

        _glBegin _GL_QUADS
        a = -1: b = 0 'if is texture bad set, characters are then viewed more than 1x. (try rewrite b to 1)
        c = 16

        _glTexCoord2f a, b: _glVertex2i 0, c ' 0,15  levy horni <--- _glVertex2i use standard coordinates as in QB64
        ' dest                source

        'in case you want to map textures directly from one file, without them being pre-loaded as in this program, the procedure is as follows:
        '1) you load the entire texture as one texture, let it be converted to a texture.
        '2) then the _glTexCoord2f coordinates are calculated as: width of the image / number of pixels that are mapped to the rectangle - so in this case it is 16/256
        '(the width of the image with letters is 256, the width of the letter is 16)


        _glTexCoord2f b, b: _glVertex2i c, c '15,15  pravy horni 'glTexCoord2f cte takto: chces namapovat 16 pixelu z obrazku o width = 256 pixelu, tedy: 16/256 = 0.625
        _glTexCoord2f b, a: _glVertex2i c, 0 '15, 0 pravy dolni
        _glTexCoord2f a, a: _glVertex2i 0, 0 '0, 0 levy dolni
        _glEnd
        _glTranslatef 16, 0, 0 'shift to the place from where the next displaylist will be painted!
        'you are here in RELATIVE coordinate system, therefore _glTranslatef here is for setting place from where is next display list draw. If you comment it, all characters comming to the same place.
        _glEndList
    Next i&
End Sub

Sub KillFont
    _glDeleteLists Baze, 256
End Sub

Sub glPrint (Xpos, Ypos, S As String, set As _Unsigned _Byte)
    If set > 0 Then set = 1 Else set = 0

    _glBindTexture _GL_TEXTURE_2D, Textures(0) 'texture select
    _glDisable _GL_DEPTH_TEST
    _glMatrixMode _GL_PROJECTION 'matrix select
    _glPushMatrix 'save projection matrix
    _glLoadIdentity 'matrix reset
    _glOrtho 0, _Width, 0, _Height, -1, 1 'Vertical projection settings
    _glMatrixMode _GL_MODELVIEW 'matrix select
    _glPushMatrix 'save matrix
    _glLoadIdentity 'reset matrix

    'shift to print position
    _glTranslated Xpos, Ypos, 0 '
    _glListBase (Baze - 32 + (128 * set)) 'set - set normal or italic characters

    _glCallLists Len(S$), _GL_BYTE, _Offset(S$) 'so this little scum works as expected!

    _glMatrixMode _GL_PROJECTION 'select projection matrix
    _glPopMatrix 'Restoring a saved projection matrix

    _glMatrixMode _GL_MODELVIEW 'select matrix modelview
    _glPopMatrix 'restoring saved modelview matrix
    _glEnable _GL_DEPTH_TEST 'enable depth testing

End Sub






Sub LoadCharactersFromImage (filename As String, xstep As Integer, ystep As Integer, img() As Long) 'standard QB64 - load small 16x16 icons from image font.gif and place it to img() array as images
    If _FileExists(filename$) Then
        I& = _LoadImage(filename$, 32)
        If I& < -1 Then 'is supported image format

            For y = 0 To _Height(I&) - ystep Step ystep
                For x = 0 To _Width(I&) - xstep Step xstep
                    img&(imi) = _NewImage(xstep, ystep, 32)
                    _PutImage (0, 0)-(xstep, ystep), I&, img&(imi), (x, y)-(x + xstep, y + ystep)
                    imi = imi + 1
                Next x
            Next y
        Else Print "This image file "; filename$; "is not in suported format.": System
        End If
    Else
        Print "Error: File "; filename$; "not found.": System
    End If
End Sub

Function LoadTexture_Array& (image As Long, filter) 'create textures from images
    D = _Dest
    S = _Source
    texinv& = _NewImage(_Width(image&), _Height(image&), 32)
    _PutImage (0, _Height(image&))-(_Width(image&), 0), image&, texinv&
    ni& = _CopyImage(texinv&, 32)

    Dim Texture As Long
    _glGenTextures 1, _Offset(Texture) 'generate our texture handle    (reserve place in memory for new texture)
    _glBindTexture _GL_TEXTURE_2D, Texture 'select our texture handle  (set this texture for use)

    Dim m As _MEM
    m = _MemImage(texinv&)

    Dim n As _MEM
    n = _MemImage(ni&)

    Select Case filter
        Case -1
            'set our texture wrapping
            _glTexParameteri _GL_TEXTURE_2D, _GL_TEXTURE_WRAP_S, _GL_REPEAT
            _glTexParameteri _GL_TEXTURE_2D, _GL_TEXTURE_WRAP_T, _GL_REPEAT
        Case 0
            'set out texture filtering
            _glTexParameteri _GL_TEXTURE_2D, _GL_TEXTURE_MAG_FILTER, _GL_NEAREST 'for scaling up
            _glTexParameteri _GL_TEXTURE_2D, _GL_TEXTURE_MIN_FILTER, _GL_NEAREST 'for scaling down
        Case 1
            _glTexParameteri _GL_TEXTURE_2D, _GL_TEXTURE_MAG_FILTER, _GL_LINEAR 'for scaling up
            _glTexParameteri _GL_TEXTURE_2D, _GL_TEXTURE_MIN_FILTER, _GL_LINEAR 'for scaling down
        Case 2 'works....not sure, if this output is correct

            'gluBuild2DMipmaps(GL_TEXTURE_2D, pic->bpp/8, pic->width, pic->height, textureType, GL_UNSIGNED_BYTE, pic->data);

            gluBuild2DMipmaps _GL_TEXTURE_2D, 4, 16, 16, _GL_BGRA_EXT, _GL_UNSIGNED_BYTE, _Offset(Texture) 'need own memory block (n - MEM) in combination with m - MEM program crash... why?   ? ? ? ? ?
            _glTexParameteri _GL_TEXTURE_2D, _GL_TEXTURE_MAG_FILTER, _GL_LINEAR_MIPMAP_NEAREST 'for scaling up
            _glTexParameteri _GL_TEXTURE_2D, _GL_TEXTURE_MIN_FILTER, _GL_LINEAR '  IF IS USED _GL_LINEAR_MIMAP_NEAREST here, texture is white. Is it correct?    -?-     just God know...
            '
            _glTexImage2D _GL_TEXTURE_2D, 0, _GL_RGB, _Width(ni&), _Height(ni&), 0, _GL_BGRA_EXT, _GL_UNSIGNED_BYTE, n.OFFSET


            _MemFree n
            _FreeImage ni&
            GoTo saveit
    End Select


    _glTexImage2D _GL_TEXTURE_2D, 0, _GL_RGB, _Width(texinv&), _Height(texinv&), 0, _GL_BGRA_EXT, _GL_UNSIGNED_BYTE, m.OFFSET

    saveit:
    U = UBound(GLL)
    GLL(U).PointerGL = Texture
    GLL(U).TextureName = "ARRAY!"
    GLL(U).Filtering = filter
    ReDim _Preserve GLL(U + 1) As GL_Loader
    _MemFree m
    LoadTexture_Array& = Texture
    _Dest D
    _Source S
End Function


   


Attached Files
.zip   gllists2D3D.zip (Size: 68.27 KB / Downloads: 20)


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Messages In This Thread
OpenGL examples - by Petr - 03-25-2023, 04:01 PM
RE: OpenGL examples - by AshishKingdom - 03-25-2023, 09:46 PM
RE: OpenGL examples - by mnrvovrfc - 03-25-2023, 10:15 PM
RE: OpenGL examples - by Petr - 03-26-2023, 12:26 PM
RE: OpenGL examples - by Petr - 03-29-2023, 01:58 PM
RE: OpenGL examples - by dcromley - 03-29-2023, 03:35 PM
RE: OpenGL examples - by TerryRitchie - 03-29-2023, 04:19 PM
RE: OpenGL examples - by AshishKingdom - 03-31-2023, 11:25 AM
RE: OpenGL examples - by Petr - 03-31-2023, 02:31 PM
RE: OpenGL examples - by Petr - 03-31-2023, 03:12 PM
RE: OpenGL examples - by Petr - 03-31-2023, 06:24 PM
RE: OpenGL examples - by Petr - 03-31-2023, 06:59 PM
RE: OpenGL examples - by TempodiBasic - 04-13-2023, 10:53 PM
RE: OpenGL examples - by Petr - 04-01-2023, 12:56 PM
RE: OpenGL examples - by Petr - 04-01-2023, 01:19 PM
RE: OpenGL examples - by MasterGy - 04-01-2023, 05:20 PM
RE: OpenGL examples - by Petr - 04-01-2023, 06:56 PM
RE: OpenGL examples - by Petr - 04-01-2023, 07:25 PM
RE: OpenGL examples - by Petr - 04-02-2023, 06:36 PM
RE: OpenGL examples - by mnrvovrfc - 04-02-2023, 09:48 PM
RE: OpenGL examples - by Petr - 04-02-2023, 09:03 PM
RE: OpenGL examples - by MasterGy - 04-03-2023, 12:21 PM
RE: OpenGL examples - by Petr - 04-03-2023, 02:12 PM
RE: OpenGL examples - by mnrvovrfc - 04-03-2023, 03:59 PM
RE: OpenGL examples - by Petr - 04-03-2023, 02:23 PM
RE: OpenGL examples - by Petr - 04-03-2023, 07:44 PM
RE: OpenGL examples - by Petr - 04-03-2023, 09:02 PM
RE: OpenGL examples - by Petr - 04-08-2023, 08:40 PM
RE: OpenGL examples - by Petr - 04-09-2023, 07:12 PM
RE: OpenGL examples - by mnrvovrfc - 04-10-2023, 12:42 PM
RE: OpenGL examples - by Petr - 04-12-2023, 08:05 PM
RE: OpenGL examples - by Petr - 04-13-2023, 09:11 PM
RE: OpenGL examples - by mnrvovrfc - 04-14-2023, 01:46 AM
RE: OpenGL examples - by TerryRitchie - 04-14-2023, 03:10 AM
RE: OpenGL examples - by TempodiBasic - 04-14-2023, 08:52 AM
RE: OpenGL examples - by bplus - 04-14-2023, 09:17 AM
RE: OpenGL examples - by MasterGy - 04-14-2023, 10:19 AM
RE: OpenGL examples - by Petr - 04-14-2023, 02:00 PM
RE: OpenGL examples - by Petr - 04-14-2023, 04:23 PM
RE: OpenGL examples - by Petr - 04-14-2023, 08:04 PM
RE: OpenGL examples - by Petr - 04-14-2023, 09:22 PM
RE: OpenGL examples - by Petr - 04-15-2023, 03:08 PM
RE: OpenGL examples - by bplus - 04-15-2023, 05:09 PM
RE: OpenGL examples - by Petr - 04-15-2023, 09:05 PM
RE: OpenGL examples - by Petr - 04-15-2023, 09:27 PM
RE: OpenGL examples - by bplus - 04-15-2023, 10:01 PM
RE: OpenGL examples - by Petr - 04-16-2023, 05:40 AM
RE: OpenGL examples - by bplus - 04-16-2023, 02:22 PM
RE: OpenGL examples - by Petr - 04-17-2023, 06:46 PM
RE: OpenGL examples - by MasterGy - 04-19-2023, 02:43 PM
RE: OpenGL examples - by Petr - 04-19-2023, 02:49 PM
RE: OpenGL examples - by MasterGy - 04-26-2023, 10:12 AM
RE: OpenGL examples - by Petr - 04-26-2023, 02:11 PM



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