Demo of Text in Opengl point by point

[TempodiBasic]

Hi
here a adjourned version of Text point by point in Opengl
now with no handy conversions of colors and dimensions from standard SCREEN and Opengl Screen.

Code: QB64: [Select]

1. 'OpenGL text without mapping or font
2. Option _Explicit
3.  
4. Const True = -1, False = 0
5. Const Black = _RGB32(0, 0, 0, 255), White = _RGB32(255)
6. Const Red = _RGB32(230, 0, 0, 255), Green = _RGB32(0, 230, 0, 255)
7. Const Blu = _RGB32(0, 0, 230, 255)
8.  
9. Dim Shared T As _Unsigned Long, S As _Unsigned Long, glRun As Integer
10. Dim Shared sXp As Integer, glXp As Single, sYp As Integer, glYp As Single
11. Dim Shared glInit As Integer, sRc As Integer, sGc As Integer, sBc As Integer, sAc As Integer
12.  
13. Dim txt As String
14. Dim Shared sBkc As _Unsigned Long, sFgc As _Unsigned Long
15.  
16. T = _NewImage(600, 400, 32)
17. S = _NewImage(600, 400, 32)
18. Screen S
19. Do: Loop Until _ScreenExists
20. _Title "Demo2 of Text in OpenGL:point by point"
21. _ScreenMove 1, 1
22.  
23. glRun = False
24. sBkc = White
25. sFgc = Green
26. PrepareTxt "Hello"
27.  
28. ShowSourceTxt
29. Print "Now a text in OpenGL"
30. Sleep 3
31. Cls
32. glInit = True
33. glRun = True
34. Do
35.     _Limit 10
36. Loop Until _KeyHit = 32
37. Cls
38. End
39.  
40. Sub PrepareTxt (txt As String)
41.     _Dest T
42.     Cls , Red
43.     Color sFgc, sBkc
44.     Locate 1, 1: Print txt
45.     _Dest 0
46. End Sub
47.  
48. Sub ShowSourceTxt
49.     Screen T
50.     _Delay 3
51.     Screen S
52. End Sub
53.  
54.  
55.  
56. Sub copyTxt (Xs As Integer, Ys As Integer, glFgc As _Unsigned Long, Size As Integer)
57.     Dim WidhTxt As Integer, HeighTxt As Integer
58.     WidhTxt = 40
59.     HeighTxt = 12
60.     _Source T
61.     _Dest S
62.  
63.     For sXp = 0 To WidhTxt Step 1
64.         For sYp = 1 To HeighTxt Step 1
65.             If Point(sXp, sYp) = sFgc Then
66.                 PaintPoint Xs + (sXp * Size), Ys + (sYp * Size), glFgc, Size
67.             End If
68.         Next sYp
69.     Next sXp
70.  
71. End Sub
72.  
73. ' OpenGl-----------------------------
74. Sub _GL ()
75.     If glRun = False Then Exit Sub
76.     If glInit Then InitGL
77.     _glClear _GL_COLOR_BUFFER_BIT
78.  
79.     ' every time _GL runs it must set values for screen
80.     _glMatrixMode _GL_MODELVIEW
81.     _glTranslatef -1, 1, 0
82.     _glScalef (1 / (_Width / 2)), (-1 / (_Height / 2)), 1
83.  
84.  
85.  
86.     copyTxt 1, 1, Green, 1
87.     copyTxt 100, 200, Red, 2
88.     copyTxt 200, 100, Black, 4
89. End Sub
90.  
91. Sub InitGL
92.     glInit = False
93.     _glViewport 0, _Width, 0, _Height
94.     _glClearColor 0, 0, 0.8, 1
95.     _glDisable _GL_MULTISAMPLE ' disable antialiasing method that hides one pixel
96.     ' in Opengl Anti aliasing method is ON for default
97.     _glFlush
98. End Sub
99.  
100.  
101. Sub PaintPoint (X As Single, Y As Single, glFgc As _Unsigned Long, Sizing As Integer)
102.     Dim gXp As Single, gYp As Single, gRc As Single, gGc As Single, gBc As Single, gAc As Single
103.     _glColor4ub _Red32(glFgc), _Green32(glFgc), _Blue32(glFgc), _Alpha32(glFgc) 'f gRc, gGc, gBc, gAc
104.     _glPointSize Sizing
105.     _glBegin _GL_POINTS
106.     _glVertex2f X, Y
107.     _glEnd
108. End Sub
109.  
110.  

while here a clear example to make text in 3D using a matrix by SMcNeill
https://www.qb64.org/forum/index.php?topic=3254.msg125353#msg125353
Good watching