vertex buffer objects for OpenGl 1.5

[primo]

Hi Petr, DirectuX
i remember Petr said that GBuffer is created using glDrawArrays, but it is not known that its coupled with glVertexPointer/glColorPointer/... without VBO context, or created with VBO Context and buffered to GPU with glBufferData, something like that. it is said glInterleavedArrays can speed the execution.
but there is a problem :
the arrays presented to Gbuffer is either VertexArray() [, ColorArray(), NormalArray(), TexCoordArray() ])
but i can't use the data type like this

Type Point3D
x As Single
y As Single
z As Single
r As Byte
g As Byte
b As Byte
End Type

i am restricted to something like :
Type PointPosition
x As Single
y As Single
z As Single
End Type
Type PointColor
r As Byte
g As Byte
b As Byte
End Type

this works while the later does not work

Uses "TBGL"
Uses "math"

Type PointPosition
  x As Single
  y As Single
  z As Single 
End Type 
Type PointColor
  r As Byte
  g As Byte
  b As Byte
End Type 
 
Function TBMain()

  Local hWnd      As DWord
  Local FrameRate As Double
   
  ' -- Create and show window
  hWnd = TBGL_CreateWindowEx("Plotting 3D Data in an array using GBuffers - press ESC to quit", 600, 600, 32, %TBGL_WS_WINDOWED Or %TBGL_WS_CLOSEBOX) 
  TBGL_ShowWindow  
   
  TBGL_BackColor 255,255,255 
  TBGL_SetDrawDistance 250
 
  ' -- Create 3D points buffer
  'Dim  gbPoints As DWord = TBGL_GBufferCreate(%TBGL_POINTS, %TBGL_3D)
  Dim  gbPoints As DWord = TBGL_GBufferCreate(%TBGL_TRIANGLES, %TBGL_3D)
  
  Global Nb As DWord = 3 
  
  ' -- Define data for it
  Global VertexA(Nb) As PointPosition 'TBGL_TVECTOR3F
  Global ColorA(Nb)  As PointColor 'TBGL_TRGB
  
VertexA(1).x = 0: VertexA(1).y = 1: VertexA(1).z = 0
VertexA(2).x = -1: VertexA(2).y = -1: VertexA(2).z = 0 
VertexA(3).x = 1: VertexA(3).y = -1: VertexA(3).z = 0

ColorA(1).r = 255: ColorA(1).g = 0: ColorA(1).b=0
ColorA(2).r = 0: ColorA(2).g = 255: ColorA(2).b=0
ColorA(3).r = 0: ColorA(3).g = 0: ColorA(3).b=255
 
  ' -- Create buffer dynamically linked to the arrays above
  TBGL_GBufferDefineFromArray(gbPoints, %TBGL_DYNAMIC, CountOf(VertexA), VertexA(1), ColorA(1))
  
  ' -- Resets status of all keys 
  TBGL_ResetKeyState()
  'TBGL_PointSize 2
  
  ' -- Main loop
  While TBGL_IsWindow(hWnd)
  'init 
    FrameRate = TBGL_GetFrameRate
    
    TBGL_ClearFrame
      TBGL_Camera(0, 0, 5, 0, 0, 0)
       
      ' -- Turn triangle
      TBGL_Rotate GetTickCount/50, 0, 1, 0
      'TBGL_Scale 0.6, 0.6, 0.6
                                     
      ' -- Render it                              
      TBGL_GBufferRender(gbPoints)   
        
    TBGL_DrawFrame
 
    ' -- ESCAPE key to exit application
    If TBGL_GetWindowKeyState(hWnd, %VK_ESCAPE) Then Exit While
 
  Wend        
  ' -- Destroying the buffer is not necessary,
  ' -- the garbage collector will take care of it
 
  ' -- Destroy window
  TBGL_DestroyWindow
End Function

this does not work:

Uses "TBGL"
Uses "math"

Type Point3D
  x As Single
  y As Single
  z As Single
  r As Byte
  g As Byte
  b As Byte 
End Type 
 
Function TBMain()

  Local hWnd      As DWord
  Local FrameRate As Double
   
  ' -- Create and show window
  hWnd = TBGL_CreateWindowEx("Plotting 3D Data in an array using GBuffers - press ESC to quit", 600, 600, 32, %TBGL_WS_WINDOWED Or %TBGL_WS_CLOSEBOX) 
  TBGL_ShowWindow  
   
  TBGL_BackColor 255,255,255 
  TBGL_SetDrawDistance 250
 
  ' -- Create 3D points buffer
  'Dim  gbPoints As DWord = TBGL_GBufferCreate(%TBGL_POINTS, %TBGL_3D)
  Dim  gbPoints As DWord = TBGL_GBufferCreate(%TBGL_TRIANGLES, %TBGL_3D)
  
  Global Nb As DWord = 3 
  
  ' -- Define data for it
  Global data(Nb) As Point3D 'TBGL_TVECTOR3F
  'Global ColorA(Nb)  As PointColor 'TBGL_TRGB
  
data(1).x = 0: data(1).y = 1: data(1).z = 0
data(2).x = -1: data(2).y = -1: data(2).z = 0 
data(3).x = 1: data(3).y = -1: data(3).z = 0

data(1).r = 255: data(1).g = 0:   data(1).b=0
data(2).r = 0:   data(2).g = 255: data(2).b=0
data(3).r = 0:   data(3).g = 0:   data(3).b=255
'MsgBox(0, Str$(CountOf(data)))
  ' -- Create buffer dynamically linked to the arrays above
  TBGL_GBufferDefineFromArray(gbPoints, %TBGL_DYNAMIC, CountOf(data), data(1).x, data(1).r)
  
  ' -- Resets status of all keys 
  TBGL_ResetKeyState()
  'TBGL_PointSize 2
  
  ' -- Main loop
  While TBGL_IsWindow(hWnd)
  'init 
    FrameRate = TBGL_GetFrameRate
    
    TBGL_ClearFrame
      TBGL_Camera(0, 0, 5, 0, 0, 0)
       
      ' -- Turn triangle
      TBGL_Rotate GetTickCount/50, 0, 1, 0
      'TBGL_Scale 0.6, 0.6, 0.6
                                     
      ' -- Render it                              
      TBGL_GBufferRender(gbPoints)   
        
    TBGL_DrawFrame
 
    ' -- ESCAPE key to exit application
    If TBGL_GetWindowKeyState(hWnd, %VK_ESCAPE) Then Exit While
 
  Wend        
  ' -- Destroying the buffer is not necessary,
  ' -- the garbage collector will take care of it
 
  ' -- Destroy window
  TBGL_DestroyWindow
End Function

also i suggest to let the color type Single , since it is hard coded as byte.

[Petr Schreiber]

Hi Primo,

GBuffers are "abstraction for geometry definition and rendering". The fact they use Vertex Arrays internally now is an implementation detail which might or might not change anytime on the future.

With that I want to say - let's not restrict our vision with what we have. It can be expanded, improved, reworked.

Of course it does not work now, because the documentation indicates this is not one of the valid uses - now.

I could keep the current TBGL_GBufferDefineFromArray, and add different TBGL_GBufferDefine* function to work with interleaved format, for example. Just thinking out loud.

Just let me know if you see any benefit in this.

DirectuX - I think it is important to collect inspiration from users continuously, not just once all issues are resolved. I see no harm with adding them to the issue list as they come.


Petr

[Petr Schreiber]

Primo,

could you please explain more what do you mean by "also i suggest to let the color type Single , since it is hard coded as byte."?

Do you mean you would like to specify color channels in range 0.0 - 1.0 as a 32bit floating point?


Thank you,
Petr

[primo]

Hi Petr, yes TBGL_GBufferDefine will be appropriate
regarding the single versus Byte,
this works:

Type PointColor
  r As Byte
  g As Byte
  b As Byte
End Type

while this:

Type PointColor
  r As Single
  g As Single
  b As Single 
End Type

does not work

so it is hard coded.

Do you mean you would like to specify color channels in range 0.0 - 1.0 as a 32bit floating point?

Yes, the reason is what if we need more than the eye can see, also with single we have more freedom .
i remember the perlin noise example posted 2 years ago using byte for color channels in a gbuffer example gives different results than when we use single for color in an opengl example

[DirectuX]

Hi Primo,

GBuffers are "abstraction for geometry definition and rendering". The fact they use Vertex Arrays internally now is an implementation detail which might or might not change anytime on the future.

With that I want to say - let's not restrict our vision with what we have. It can be expanded, improved, reworked.

Of course it does not work now, because the documentation indicates this is not one of the valid uses - now.

I could keep the current TBGL_GBufferDefineFromArray, and add different TBGL_GBufferDefine* function to work with interleaved format, for example. Just thinking out loud.

Just let me know if you see any benefit in this.

DirectuX - I think it is important to collect inspiration from users continuously, not just once all issues are resolved. I see no harm with adding them to the issue list as they come.


Petr

indeed Petr, I've just entierly left the choice to Primo, it is his code example after all

[Petr Schreiber]

Primo,

well, it is documented behaviour. If you want, I can add TBGL_tRGB_f32 and TBGL_tRGBA_f32 for 32bit floating point colors. Deal?


Petr

[primo]

Thanks Petr,

TBGL_tRGB_f32 and TBGL_tRGBA_f32 for 32bit floating point colors.

this is a nice suggestion. Deal.

[Petr Schreiber]

Hi primo,

I added the support for single color, you can grab new TBGL here:
https://github.com/ThinBASIC/thinBas...s/tag/1.11.2.3

Will be present in next release

The interleaved arrays need deeper thought, so I will switch now to another issue we discussed with DirectuX and then will get back to interleaved.


Petr