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OpenGL Fullscreen in OpenGL...

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I've posted this already on NeHe's Forum, but getting little response (I still apreciate the help giving to me by those who have) but I find that I need more input, so if anybody else can help out It would really be appreciated. The problem is already stated here: Fullscreen in OpenGL... I really need to know how to get this working, otherwise I might be forced to bring back my video card. I really want fullscreen OpenGL w/ acceleration WITHOUT having to change my desktops bit depth to 16bpp. All comments are appreciated! ZaneX Edited by - ZaneX on 10/4/00 7:20:38 AM

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The best way I am aware of with Windows and OpenGL is to create your window with CreateWindowEx and use the WS_EX_TOPMOST flag. Then you set the width and height to that of the screen with GetSytemMetrics();

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The NeHe Tuts explain very well how to set fullscreen mode
I think its the SetDeviceMode or something like that function
It should set the bitdepth for you without worrying about desktop settings. It works for me.

Chris

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TheLabRat... NeHe''s tutorials are great and do explain it well, but I have a problem with his frame work, my Voodoo3 3000 doesn''t want to go to fullscreen mode for some reason, and it should, at least I can''t see why not. Anyways, I should have more time this weekend to fool around with the code and I''m hoping that Win98 will fix the problem (I''m still running 95). If you''re more curious on what is happening, the thread in NeHe''s forum explains more in detail to what I''ve been going through...

ZaneX

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I suppose it''s an obvious piece of advice, but are you running the latest drivers - if you''re running beta drivers this might be a problem.
I have a Voodoo3 as well, and with the original drivers, opengl would not accelerate at all. I downloaded later drivers and all problems were fixed. Unfortunately, 3dfx make very big downloads.
Sorry if this is patronistic

Chris

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There is a Win32 API function to change the color depth of the display without using DirectX, I think. Look at the Resolution Switching Without using DirectX article, although your game will now not work with Win95 before version a because it cannot change color depth without restarting. You might just have to change your desktop color depth.

------------------------------
#pragma twice


sharewaregames.20m.com

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Bringing back your video card would be a perfect idea anyway ! 3Dfx has the worst OpenGL drivers in the history of computer gfx, so you are really out of luck if you are trying to code anything GL for that card...

Tim

--------------------------
glvelocity.gamedev.net
www.gamedev.net/hosted/glvelocity

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Ya I could bring it back, but what am I suppose to get??? I need a PCI card 'cause I don't have the money to upgrade my system. I'm also limited to a 130$(US) price range!

ZaneX

Edited by - ZaneX on October 6, 2000 12:24:46 PM

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I''m not sure if this helps, but I''ve been doing some OpenGL coding for a Voodoo3 and I had some problems that sound similar to yours. The basic problem was that is wasn''t properly changing screen resolution (the scene would be clipped). I fixed this by changing the location of my call to glViewport. When you first bind the OpenGL rendering context to your window it assumes the width and height of the current context (the desktop) as your viewport. Then it would change the screen resolution to 800 by 600 or whatever, so the two values would be misaligned. By adding your call to glViewport after your initial OpenGL setup you can set it right again.

This fixed my problem, but you may be facing something else entirely.

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Jo...

It does sound like I have the same problem... I'll give your solution a try, hopefully it'll work. (If you could spare a framework of your source, it would save me some time)

ZaneX


Edited by - ZaneX on October 6, 2000 2:24:31 PM

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I won''t be able to get home in a little while, but it isn''t too complicated. Just make a call to glViewport after you call all the init stuff but before you set up your projection matrix. The glViewport call should be something like this:

glViewport( 0, 0, width, height );

Check the SDK info to make sure (I may have missed a parameter).

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i recommend getting a tnt2/m64 or a vanta (ive one) not the fastest cards around (though i can still do more than 10000 tris at 20fps+ at 1152x864x16 so not to bad) also they are half the price of a voodoo3, and best of all the drivers are great

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Just wanted to thank everybody for their responses....

I''ve managed to fix my problem, go figure... Win98

I don''t know if the problem was within the Win95 drivers for the Voodoo3 or if it was just the Win95 API that wasn''t supporting the function call properly... I don''t care anymore, everything works fine and how I wan''t it to work. Hence, I''m keeping my Voodoo3 (just don''t feel like going through the hassle of bringing it back and finding another card)

Even GLUT is being accelerated... Just a mistake on my part, I really didn''t think the keyboard handler was that slow... I added a frame rate and noticed it was being accelerated... my mistake...

Thanks again...

ZaneX...

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I''m confused what you want now...but I''ll show you how to go full screen anyway. This code works with Voodoo3s because I had one when I made this code

    

GLint glInitFullScreen(GLuint Width, GLuint Height, GLubyte ColorDepth, HWND* hwnd, HINSTANCE hInstance, WNDPROC WindowProc, char* AppName, char* Title, char* Message)
{
DEVMODE devMode;
GLuint Result;
char sResolution[32];
char sTemp[32];

itoa(Width, sTemp, 10);
strcpy(sResolution, sTemp);
strcat(sResolution, "x");
itoa(Height, sTemp, 10);
strcat(sResolution, sTemp);
strcat(sResolution, "x");
itoa(ColorDepth, sTemp, 10);
strcat(sResolution, sTemp);

memset(&devMode, 0, sizeof(devMode));
devMode.dmSize = sizeof(devMode);
devMode.dmBitsPerPel = ColorDepth;
devMode.dmPelsWidth = Width;
devMode.dmPelsHeight = Height;
devMode.dmFields = DM_PELSWIDTH | DM_PELSHEIGHT | DM_BITSPERPEL;

Result=ChangeDisplaySettings(&devMode, CDS_FULLSCREEN);

switch(Result)
{
case DISP_CHANGE_SUCCESSFUL:
break;

case DISP_CHANGE_RESTART:
strcpy(Message, "You need to manually set the video res to ");
strcat(Message, sResolution);
return false;

case DISP_CHANGE_BADFLAGS:
strcpy(Message, "An invalid set of flags was passed in");
return false;

case DISP_CHANGE_BADPARAM:
strcpy(Message, "An invalid parameter was passed in");
return false;

case DISP_CHANGE_FAILED:
strcpy(Message, "The display driver failed the specified graphics mode ");
strcat(Message, sResolution);
return false;

case DISP_CHANGE_BADMODE:
strcpy(Message, "The graphics mode is not supported");
return false;

case DISP_CHANGE_NOTUPDATED:
strcpy(Message, "Windows NT: Unable to write settings to the registry");
return false;
}

WNDCLASS wc;

wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = WindowProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(hInstance, IDI_APPLICATION);
wc.hCursor = LoadCursor(hInstance, IDC_ARROW);
wc.hbrBackground = NULL;
wc.lpszMenuName = NULL;
wc.lpszClassName = AppName;

RegisterClass(&wc);

*hwnd = CreateWindowEx(
//WS_EX_APPWINDOW,
WS_EX_TOPMOST,
AppName,
Title,
WS_POPUP,
0, 0,
Width,
Height,
NULL,
NULL,
hInstance,
NULL);

if (!*hwnd)
{
strcpy(Message, "Couldn''t create OpenGL window");
return false;
}

ShowWindow(*hwnd, SW_SHOWNORMAL);
UpdateWindow(*hwnd);

if (!glSetPixelFormat(ColorDepth, *hwnd))
{
strcpy(Message, "Couldn''t set the pixel format");
return false;
}

if(!(hGLRC = wglCreateContext(hDC)))
{
strcpy(Message, "Couldn''t create OpenGL context");
return false;
}

wglMakeCurrent(hDC, hGLRC);
return true;
}



If anything is clipped, and you can see the existing windows desktop, it''s because you set your viewport wrong.

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      PipelineStateDesc PSODesc; RasterizerStateDesc &RasterizerDesc = PSODesc.GraphicsPipeline.RasterizerDesc; RasterizerDesc.FillMode = FILL_MODE_SOLID; RasterizerDesc.CullMode = CULL_MODE_NONE; RasterizerDesc.FrontCounterClockwise = True; RasterizerDesc.ScissorEnable = True; RasterizerDesc.AntialiasedLineEnable = False; Depth-stencil and blend states are defined in a similar fashion.
      Another important thing that pipeline state object encompasses is the input layout description that defines how inputs to the vertex shader, which is the very first shader stage, should be read from the memory. Input layout may define several vertex streams that contain values of different formats and sizes:
      // Define input layout InputLayoutDesc &Layout = PSODesc.GraphicsPipeline.InputLayout; LayoutElement TextLayoutElems[] = {     LayoutElement( 0, 0, 3, VT_FLOAT32, False ),     LayoutElement( 1, 0, 4, VT_UINT8, True ),     LayoutElement( 2, 0, 2, VT_FLOAT32, False ), }; Layout.LayoutElements = TextLayoutElems; Layout.NumElements = _countof( TextLayoutElems ); Finally, pipeline state defines primitive topology type. When all required members are initialized, a pipeline state object can be created by IRenderDevice::CreatePipelineState() method:
      // Define shader and primitive topology PSODesc.GraphicsPipeline.PrimitiveTopologyType = PRIMITIVE_TOPOLOGY_TYPE_TRIANGLE; PSODesc.GraphicsPipeline.pVS = pVertexShader; PSODesc.GraphicsPipeline.pPS = pPixelShader; PSODesc.Name = "My pipeline state"; m_pDev->CreatePipelineState(PSODesc, &m_pPSO); When PSO object is bound to the pipeline, the engine invokes all API-specific commands to set all states specified by the object. In case of Direct3D12 this maps directly to setting the D3D12 PSO object. In case of Direct3D11, this involves setting individual state objects (such as rasterizer and blend states), shaders, input layout etc. In case of OpenGL, this requires a number of fine-grain state tweaking calls. Diligent Engine keeps track of currently bound states and only calls functions to update these states that have actually changed.
      Binding Shader Resources
      Direct3D11 and OpenGL utilize fine-grain resource binding models, where an application binds individual buffers and textures to certain shader or program resource binding slots. Direct3D12 uses a very different approach, where resource descriptors are grouped into tables, and an application can bind all resources in the table at once by setting the table in the command list. Resource binding model in Diligent Engine is designed to leverage this new method. It introduces a new object called shader resource binding that encapsulates all resource bindings required for all shaders in a certain pipeline state. It also introduces the classification of shader variables based on the frequency of expected change that helps the engine group them into tables under the hood:
      Static variables (SHADER_VARIABLE_TYPE_STATIC) are variables that are expected to be set only once. They may not be changed once a resource is bound to the variable. Such variables are intended to hold global constants such as camera attributes or global light attributes constant buffers. Mutable variables (SHADER_VARIABLE_TYPE_MUTABLE) define resources that are expected to change on a per-material frequency. Examples may include diffuse textures, normal maps etc. Dynamic variables (SHADER_VARIABLE_TYPE_DYNAMIC) are expected to change frequently and randomly. Shader variable type must be specified during shader creation by populating an array of ShaderVariableDesc structures and initializing ShaderCreationAttribs::Desc::VariableDesc and ShaderCreationAttribs::Desc::NumVariables members (see example of shader creation above).
      Static variables cannot be changed once a resource is bound to the variable. They are bound directly to the shader object. For instance, a shadow map texture is not expected to change after it is created, so it can be bound directly to the shader:
      PixelShader->GetShaderVariable( "g_tex2DShadowMap" )->Set( pShadowMapSRV ); Mutable and dynamic variables are bound via a new Shader Resource Binding object (SRB) that is created by the pipeline state (IPipelineState::CreateShaderResourceBinding()):
      m_pPSO->CreateShaderResourceBinding(&m_pSRB); Note that an SRB is only compatible with the pipeline state it was created from. SRB object inherits all static bindings from shaders in the pipeline, but is not allowed to change them.
      Mutable resources can only be set once for every instance of a shader resource binding. Such resources are intended to define specific material properties. For instance, a diffuse texture for a specific material is not expected to change once the material is defined and can be set right after the SRB object has been created:
      m_pSRB->GetVariable(SHADER_TYPE_PIXEL, "tex2DDiffuse")->Set(pDiffuseTexSRV); In some cases it is necessary to bind a new resource to a variable every time a draw command is invoked. Such variables should be labeled as dynamic, which will allow setting them multiple times through the same SRB object:
      m_pSRB->GetVariable(SHADER_TYPE_VERTEX, "cbRandomAttribs")->Set(pRandomAttrsCB); Under the hood, the engine pre-allocates descriptor tables for static and mutable resources when an SRB objcet is created. Space for dynamic resources is dynamically allocated at run time. Static and mutable resources are thus more efficient and should be used whenever possible.
      As you can see, Diligent Engine does not expose low-level details of how resources are bound to shader variables. One reason for this is that these details are very different for various APIs. The other reason is that using low-level binding methods is extremely error-prone: it is very easy to forget to bind some resource, or bind incorrect resource such as bind a buffer to the variable that is in fact a texture, especially during shader development when everything changes fast. Diligent Engine instead relies on shader reflection system to automatically query the list of all shader variables. Grouping variables based on three types mentioned above allows the engine to create optimized layout and take heavy lifting of matching resources to API-specific resource location, register or descriptor in the table.
      This post gives more details about the resource binding model in Diligent Engine.
      Setting the Pipeline State and Committing Shader Resources
      Before any draw or compute command can be invoked, the pipeline state needs to be bound to the context:
      m_pContext->SetPipelineState(m_pPSO); Under the hood, the engine sets the internal PSO object in the command list or calls all the required native API functions to properly configure all pipeline stages.
      The next step is to bind all required shader resources to the GPU pipeline, which is accomplished by IDeviceContext::CommitShaderResources() method:
      m_pContext->CommitShaderResources(m_pSRB, COMMIT_SHADER_RESOURCES_FLAG_TRANSITION_RESOURCES); The method takes a pointer to the shader resource binding object and makes all resources the object holds available for the shaders. In the case of D3D12, this only requires setting appropriate descriptor tables in the command list. For older APIs, this typically requires setting all resources individually.
      Next-generation APIs require the application to track the state of every resource and explicitly inform the system about all state transitions. For instance, if a texture was used as render target before, while the next draw command is going to use it as shader resource, a transition barrier needs to be executed. Diligent Engine does the heavy lifting of state tracking.  When CommitShaderResources() method is called with COMMIT_SHADER_RESOURCES_FLAG_TRANSITION_RESOURCES flag, the engine commits and transitions resources to correct states at the same time. Note that transitioning resources does introduce some overhead. The engine tracks state of every resource and it will not issue the barrier if the state is already correct. But checking resource state is an overhead that can sometimes be avoided. The engine provides IDeviceContext::TransitionShaderResources() method that only transitions resources:
      m_pContext->TransitionShaderResources(m_pPSO, m_pSRB); In some scenarios it is more efficient to transition resources once and then only commit them.
      Invoking Draw Command
      The final step is to set states that are not part of the PSO, such as render targets, vertex and index buffers. Diligent Engine uses Direct3D11-syle API that is translated to other native API calls under the hood:
      ITextureView *pRTVs[] = {m_pRTV}; m_pContext->SetRenderTargets(_countof( pRTVs ), pRTVs, m_pDSV); // Clear render target and depth buffer const float zero[4] = {0, 0, 0, 0}; m_pContext->ClearRenderTarget(nullptr, zero); m_pContext->ClearDepthStencil(nullptr, CLEAR_DEPTH_FLAG, 1.f); // Set vertex and index buffers IBuffer *buffer[] = {m_pVertexBuffer}; Uint32 offsets[] = {0}; Uint32 strides[] = {sizeof(MyVertex)}; m_pContext->SetVertexBuffers(0, 1, buffer, strides, offsets, SET_VERTEX_BUFFERS_FLAG_RESET); m_pContext->SetIndexBuffer(m_pIndexBuffer, 0); Different native APIs use various set of function to execute draw commands depending on command details (if the command is indexed, instanced or both, what offsets in the source buffers are used etc.). For instance, there are 5 draw commands in Direct3D11 and more than 9 commands in OpenGL with something like glDrawElementsInstancedBaseVertexBaseInstance not uncommon. Diligent Engine hides all details with single IDeviceContext::Draw() method that takes takes DrawAttribs structure as an argument. The structure members define all attributes required to perform the command (primitive topology, number of vertices or indices, if draw call is indexed or not, if draw call is instanced or not, if draw call is indirect or not, etc.). For example:
      DrawAttribs attrs; attrs.IsIndexed = true; attrs.IndexType = VT_UINT16; attrs.NumIndices = 36; attrs.Topology = PRIMITIVE_TOPOLOGY_TRIANGLE_LIST; pContext->Draw(attrs); For compute commands, there is IDeviceContext::DispatchCompute() method that takes DispatchComputeAttribs structure that defines compute grid dimension.
      Source Code
      Full engine source code is available on GitHub and is free to use. The repository contains two samples, asteroids performance benchmark and example Unity project that uses Diligent Engine in native plugin.
      AntTweakBar sample is Diligent Engine’s “Hello World” example.

       
      Atmospheric scattering sample is a more advanced example. It demonstrates how Diligent Engine can be used to implement various rendering tasks: loading textures from files, using complex shaders, rendering to multiple render targets, using compute shaders and unordered access views, etc.

      Asteroids performance benchmark is based on this demo developed by Intel. It renders 50,000 unique textured asteroids and allows comparing performance of Direct3D11 and Direct3D12 implementations. Every asteroid is a combination of one of 1000 unique meshes and one of 10 unique textures.

      Finally, there is an example project that shows how Diligent Engine can be integrated with Unity.

      Future Work
      The engine is under active development. It currently supports Windows desktop, Universal Windows and Android platforms. Direct3D11, Direct3D12, OpenGL/GLES backends are now feature complete. Vulkan backend is coming next, and support for more platforms is planned.
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