DirectX8 Gamma Correction (Resolved and works!)
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I'm having a difficult time working with gamma correction in DirectX8 for VB. All I get is a black screen no matter what the values are, which means I have done something wrong. Yes, my video card supports it and yes, I'm already looping through all 255 colors of Red Green, and Blue. Anyone know how to do this correctly. A small clip of source code would help, whether it is in VB or C++, doesn't matter just as long as I get the general idea of the solution to my problem. Thanx.
[Edited by - Jacob Roman on October 13, 2004 10:46:25 PM]
Author
Ok I've fixed my code a little bit and now it just displays the gamma color which fills the screen, but not what I'm blitting, which would be the FPS, the Mouse Coordinates, and the game(not shown in the example code). Here is some, but not all of my code. It will not be the same as my program since I have a lot more written, but all of that is not needed in this example code.
So what am I doing wrong. How come it is not blitting the other things I want drawn. I already tried putting Update_Gamma before the Direct3D_Device.Present statement too. Something is missing.
Public Gamma_Ramp As D3DGAMMARAMPPublic Original_Ramp As D3DGAMMARAMPPublic Function Signed(Value As Long) As Integer If Value <= 32767 Then Signed = CInt(Value) Exit Function End If Signed = CInt(Value - 65535) End FunctionPublic Function Unsigned(Value As Integer) As Long If Value >= 0 Then Unsigned = Value Exit Function End If Unsigned = Value + 65535 End FunctionPublic Sub Update_Gamma(Red As Integer, Green As Integer, Blue As Integer) On Error GoTo Error_Handler: Dim Current_Color As Long For Current_Color = 0 To 255 If Red < 0 Then Gamma_Ramp.Red(Current_Color) = Signed(Unsigned(Original_Ramp.Red(Current_Color)) * (100 - Abs(Red)) / 100) If Red = 0 Then Gamma_Ramp.Red(Current_Color) = Original_Ramp.Red(Current_Color) If Red > 0 Then Gamma_Ramp.Red(Current_Color) = Signed(65535 - ((65535 - Unsigned(Original_Ramp.Red(Current_Color))) * (100 - Red) / 100)) If Green < 0 Then Gamma_Ramp.Green(Current_Color) = Signed(Unsigned(Original_Ramp.Green(Current_Color)) * (100 - Abs(Green)) / 100) If Green = 0 Then Gamma_Ramp.Green(Current_Color) = Original_Ramp.Green(Current_Color) If Green > 0 Then Gamma_Ramp.Green(Current_Color) = Signed(65535 - ((65535 - Unsigned(Original_Ramp.Green(Current_Color))) * (100 - Green) / 100)) If Blue < 0 Then Gamma_Ramp.Blue(Current_Color) = Signed(Unsigned(Original_Ramp.Blue(Current_Color)) * (100 - Abs(Blue)) / 100) If Blue = 0 Then Gamma_Ramp.Blue(Current_Color) = Original_Ramp.Blue(Current_Color) If Blue > 0 Then Gamma_Ramp.Blue(Current_Color) = Signed(65535 - ((65535 - Unsigned(Original_Ramp.Blue(Current_Color))) * (100 - Blue) / 100)) Next Direct3D_Device.SetGammaRamp D3DSGR_CALIBRATE, Gamma_Ramp Exit SubError_Handler:End SubPublic Sub Game_Loop() Direct3D_Device.GetGammaRamp Original_Ramp While Game_Active = True If GetQueueStatus(QS_HOTKEY Or QS_KEY Or QS_MOUSEBUTTON Or QS_POSTMESSAGE Or QS_PAINT) Then DoEvents Direct3D_Device.Clear 0, ByVal 0, D3DCLEAR_TARGET, RGB(0, 0, 0), 1#, 0 Direct3D_Device.BeginScene Draw_FPS Draw_Mouse_Coodinates Direct3D_Device.EndScene Direct3D_Device.Present ByVal 0, ByVal 0, frmMain.hWnd, ByVal 0 Update_Gamma 50, 50, 50 'So it's 50% brighter. WendEnd Sub So what am I doing wrong. How come it is not blitting the other things I want drawn. I already tried putting Update_Gamma before the Direct3D_Device.Present statement too. Something is missing.
Author
I don't understand why noone is answering my question. Maybe it's too advanced for some people, I don't know.
Author
AH HA. I just found the rarest article out there on doing Gamma Correction for VB using DirectX8. And it works! DO NOT PASS THIS UP!!! THIS IS RARE. Here is the URL:
http://www.mvps.org/vbdx/articles/gamma/index.html
And here is the code:
I changed the code a little bit. The D3DDevice is the most commonly named variable for the Direct3DDevice8 data type. The guy had g_oDevice. I myself don't like to abreviate variables. My code actually looks like real english and is easy to read that way, so I call mine Direct3D_Device. Some beginner can look at D3DDevice and go "Huh? what's the 'D' in D3DDevice?" or something like that. Anyways, that's not that important. back to the subject. In the GammaFactor, it's default value is 1. I prefere 3 or maybe 5 as an example to where you can actually see it working.
"Where do I use it in a loop?" I asked myself the same question. I just put it one line before the Direct3D_Device.Clear statement.
http://www.mvps.org/vbdx/articles/gamma/index.html
And here is the code:
Public Sub SetGamma(Optional ByVal GammaFactor As Single = 1!) Dim d3dCaps As D3DCAPS8 Dim NewRamp As D3DGAMMARAMP Dim NewValue As Long Dim ui As Long Dim i As Long 'see if this device can do fullscreen gamma Call D3DDevice.GetDeviceCaps(d3dCaps) If (d3dCaps.Caps2 And D3DCAPS2_FULLSCREENGAMMA) _ <> D3DCAPS2_FULLSCREENGAMMA Then 'device does not support gamma correction Exit Sub End If 'create linear gamma ramp For i = 0 To 255 NewValue = i * GammaFactor * 255: ui = 0 If NewValue > 32767 Then NewValue = NewValue - 32767: ui = 1 If NewValue > 32767 Then NewValue = 32767 'manipulate bits to handle unsigned integers NewRamp.red(i) = NewValue Or (&H8000 * ui) NewRamp.green(i) = NewValue Or (&H8000 * ui) NewRamp.blue(i) = NewValue Or (&H8000 * ui) Next i 'send gamma ramp to device Call D3DDevice.SetGammaRamp(D3DSGR_NO_CALIBRATION, NewRamp)End SubI changed the code a little bit. The D3DDevice is the most commonly named variable for the Direct3DDevice8 data type. The guy had g_oDevice. I myself don't like to abreviate variables. My code actually looks like real english and is easy to read that way, so I call mine Direct3D_Device. Some beginner can look at D3DDevice and go "Huh? what's the 'D' in D3DDevice?" or something like that. Anyways, that's not that important. back to the subject. In the GammaFactor, it's default value is 1. I prefere 3 or maybe 5 as an example to where you can actually see it working.
"Where do I use it in a loop?" I asked myself the same question. I just put it one line before the Direct3D_Device.Clear statement.
While Game_Active = True DoEvents '------------------------ SetGamma 3 'HERE IT IS <---------------- '------------------------ Direct3D_Device.Clear 0, ByVal 0, D3DCLEAR_TARGET Or D3DCLEAR_ZBUFFER, RGB(0, 0, 0), 1#, 0 Direct3D_Device.BeginScene Draw_FPS Draw_Mouse_Coodinates Direct3D_Device.DrawPrimitiveUP D3DPT_TRIANGLESTRIP, 2, Polygon(0), Len(Polygon(0)) Direct3D_Device.EndScene Direct3D_Device.Present ByVal 0, ByVal 0, 0, ByVal 0WendThis topic is closed to new replies.
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