   Multiple viewports
  HiWhat I want to do is drawing to two different parts of the same window. Which is the best method, using viewports, the present parameters. I want to draw different studd to both areas and drawing them at the same time. So how should I set this up? Something like this doesnt work, why?clear()beginScene();SetViewport(&v); // v set to one of the partsdrawSomePart1();SetViewport(&v); // v set to the other partdrawSomePart2();endScene();present();   
Quote:Original post by ProblemBabySomething like this doesnt work, why?I believe you have to wrap each viewport in its own BeginScene / EndScene pair. So something like this:clear()beginScene();SetViewport(&v); // v set to one of the partsdrawSomePart1();endScene();beginScene();SetViewport(&v); // v set to the other partdrawSomePart2();endScene();present();;  For multiple areas of the same back buffer surface in the same window, multiple viewports is indeed the way to go.You'd use multiple swap chains if you had multiple windows; but since it's the same window, viewports are fine.Quote:Something like this doesnt work, why?It should work. What problems are you experiencing with using multiple viewports?I just modified the source of the Vertices tutorial from the SDK to illustrate this for you:The relevent modifications are in bold; the other modifications are just for creating a second, different coloured triangle to render.[edit]Aaargh, the board software seems to want to eat my bold tags (GD.NET or HTML style) when they're inside a source block. Search the source for <B> to find the bits that should be bold.[/edit]//-----------------------------------------------------------------------------// File: Vertices.cpp//// Desc: In this tutorial, we are rendering some vertices. This introduces the//  concept of the vertex buffer, a Direct3D object used to store//  vertices. Vertices can be defined any way we want by defining a//  custom structure and a custom FVF (flexible vertex format). In this//  tutorial, we are using vertices that are transformed (meaning they//  are already in 2D window coordinates) and lit (meaning we are not//  using Direct3D lighting, but are supplying our own colors).//// Copyright (c) Microsoft Corporation. All rights reserved.//-----------------------------------------------------------------------------#include <d3d9.h>#pragma warning( disable : 4996 ) // disable deprecated warning #include <strsafe.h>#pragma warning( default : 4996 ) //-----------------------------------------------------------------------------// Global variables//-----------------------------------------------------------------------------LPDIRECT3D9   g_pD3D  = NULL; // Used to create the D3DDeviceLPDIRECT3DDEVICE9  g_pd3dDevice = NULL; // Our rendering deviceLPDIRECT3DVERTEXBUFFER9 g_pVB   = NULL; // Buffer to hold verticesLPDIRECT3DVERTEXBUFFER9 g_pVB2  = NULL; // Buffer to hold verticesD3DVIEWPORT9g_VP;// A structure for our custom vertex typestruct CUSTOMVERTEX{    FLOAT x, y, z, rhw; // The transformed position for the vertex    DWORD color;   // The vertex color};// Our custom FVF, which describes our custom vertex structure#define D3DFVF_CUSTOMVERTEX (D3DFVF_XYZRHW|D3DFVF_DIFFUSE)//-----------------------------------------------------------------------------// Name: InitD3D()// Desc: Initializes Direct3D//-----------------------------------------------------------------------------HRESULT InitD3D( HWND hWnd ){    // Create the D3D object.    if( NULL == ( g_pD3D = Direct3DCreate9( D3D_SDK_VERSION ) ) )   return E_FAIL;    // Set up the structure used to create the D3DDevice    D3DPRESENT_PARAMETERS d3dpp;    ZeroMemory( &d3dpp, sizeof(d3dpp) );    d3dpp.Windowed = TRUE;d3dpp.BackBufferCount = 1;    d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;    d3dpp.BackBufferFormat = D3DFMT_UNKNOWN;    // Create the D3DDevice    if( FAILED( g_pD3D->CreateDevice( D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hWnd,   D3DCREATE_SOFTWARE_VERTEXPROCESSING,   &d3dpp, &g_pd3dDevice ) ) )    {   return E_FAIL;    }<B>    // fetch the default viewport. This is the one D3D creates automatically    // for you when you create the IDirect3DDevice    g_pd3dDevice->GetViewport(&g_VP);</B>    return S_OK;}//-----------------------------------------------------------------------------// Name: InitVB()// Desc: Creates a vertex buffer and fills it with our vertices. The vertex//  buffer is basically just a chuck of memory that holds vertices. After//  creating it, we must Lock()/Unlock() it to fill it. For indices, D3D//  also uses index buffers. The special thing about vertex and index//  buffers is that they can be created in device memory, allowing some//  cards to process them in hardware, resulting in a dramatic//  performance gain.//-----------------------------------------------------------------------------HRESULT InitVB(){    // Initialize three vertices for rendering a triangle    CUSTOMVERTEX vertices[] =    {   { 150.0f,  50.0f, 0.5f, 1.0f, 0xffff0000, }, // x, y, z, rhw, color   { 250.0f, 250.0f, 0.5f, 1.0f, 0xffff0000, },   {  50.0f, 250.0f, 0.5f, 1.0f, 0xffff0000, },    };    CUSTOMVERTEX vertices2[] =    {   { 150.0f,  50.0f, 0.5f, 1.0f, 0xff00ff00, }, // x, y, z, rhw, color   { 250.0f, 250.0f, 0.5f, 1.0f, 0xff00ff00, },   {  50.0f, 250.0f, 0.5f, 1.0f, 0xff00ff00, },    };    // Create the vertex buffer. Here we are allocating enough memory    // (from the default pool) to hold all our 3 custom vertices. We also    // specify the FVF, so the vertex buffer knows what data it contains.    if( FAILED( g_pd3dDevice->CreateVertexBuffer( 3*sizeof(CUSTOMVERTEX),0, D3DFVF_CUSTOMVERTEX,D3DPOOL_DEFAULT, &g_pVB, NULL ) ) )    {   return E_FAIL;    }    if( FAILED( g_pd3dDevice->CreateVertexBuffer( 3*sizeof(CUSTOMVERTEX),0, D3DFVF_CUSTOMVERTEX,D3DPOOL_DEFAULT, &g_pVB2, NULL ) ) )    {   return E_FAIL;    }    // Now we fill the vertex buffer. To do this, we need to Lock() the VB to    // gain access to the vertices. This mechanism is required becuase vertex    // buffers may be in device memory.    VOID* pVertices;    if( FAILED( g_pVB->Lock( 0, sizeof(vertices), (void**)&pVertices, 0 ) ) )   return E_FAIL;    memcpy( pVertices, vertices, sizeof(vertices) );    g_pVB->Unlock();    if( FAILED( g_pVB2->Lock( 0, sizeof(vertices2), (void**)&pVertices, 0 ) ) )   return E_FAIL;    memcpy( pVertices, vertices2, sizeof(vertices2) );    g_pVB2->Unlock();    return S_OK;}//-----------------------------------------------------------------------------// Name: Cleanup()// Desc: Releases all previously initialized objects//-----------------------------------------------------------------------------VOID Cleanup(){    if( g_pVB != NULL ) g_pVB->Release();    if( g_pd3dDevice != NULL )    g_pd3dDevice->Release();    if( g_pD3D != NULL )g_pD3D->Release();}//-----------------------------------------------------------------------------// Name: Render()// Desc: Draws the scene//-----------------------------------------------------------------------------VOID Render(){    // Clear the backbuffer to a blue color    g_pd3dDevice->Clear( 0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0,0,255), 1.0f, 0 );    // Begin the scene    if( SUCCEEDED( g_pd3dDevice->BeginScene() ) )    {<B>// left hand side viewportD3DVIEWPORT9 a = g_VP;a.Width = a.Width / 2;// half the widthg_pd3dDevice->SetViewport(&a);</B>// draw stuff   g_pd3dDevice->SetStreamSource( 0, g_pVB, 0, sizeof(CUSTOMVERTEX) );   g_pd3dDevice->SetFVF( D3DFVF_CUSTOMVERTEX );   g_pd3dDevice->DrawPrimitive( D3DPT_TRIANGLELIST, 0, 1 );<B>// right hand side viewportD3DVIEWPORT9 b = g_VP;b.X = b.Width / 2;// starts to the right of the left hand viewportb.Width = b.Width / 2;// half the widthg_pd3dDevice->SetViewport(&b);</B>// draw stuffg_pd3dDevice->SetStreamSource( 0, g_pVB2, 0, sizeof(CUSTOMVERTEX) );   g_pd3dDevice->SetFVF( D3DFVF_CUSTOMVERTEX );   g_pd3dDevice->DrawPrimitive( D3DPT_TRIANGLELIST, 0, 1 );   // End the scene   g_pd3dDevice->EndScene();    }    // Present the backbuffer contents to the display    g_pd3dDevice->Present( NULL, NULL, NULL, NULL );}//-----------------------------------------------------------------------------// Name: MsgProc()// Desc: The window's message handler//-----------------------------------------------------------------------------LRESULT WINAPI MsgProc( HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam ){    switch( msg )    {   case WM_DESTROY:  Cleanup();  PostQuitMessage( 0 );  return 0;    }    return DefWindowProc( hWnd, msg, wParam, lParam );}//-----------------------------------------------------------------------------// Name: WinMain()// Desc: The application's entry point//-----------------------------------------------------------------------------INT WINAPI WinMain( HINSTANCE hInst, HINSTANCE, LPSTR, INT ){    // Register the window class    WNDCLASSEX wc = { sizeof(WNDCLASSEX), CS_CLASSDC, MsgProc, 0L, 0L,  GetModuleHandle(NULL), NULL, NULL, NULL, NULL,  "D3D Tutorial", NULL };    RegisterClassEx( &wc );RECT rc = {100,100, 100+300,100+300};AdjustWindowRect( &rc, WS_OVERLAPPEDWINDOW, FALSE );    // Create the application's window    HWND hWnd = CreateWindow( "D3D Tutorial", "D3D Tutorial 02: Vertices",WS_OVERLAPPEDWINDOW, rc.left, rc.top, rc.right-rc.left, rc.bottom-rc.top,NULL, NULL, wc.hInstance, NULL );    // Initialize Direct3D    if( SUCCEEDED( InitD3D( hWnd ) ) )    {   // Create the vertex buffer   if( SUCCEEDED( InitVB() ) )   {  // Show the window  ShowWindow( hWnd, SW_SHOWDEFAULT );  UpdateWindow( hWnd );  // Enter the message loop  MSG msg;  ZeroMemory( &msg, sizeof(msg) );  while( msg.message!=WM_QUIT )  { if( PeekMessage( &msg, NULL, 0U, 0U, PM_REMOVE ) ) {TranslateMessage( &msg );DispatchMessage( &msg ); } elseRender();  }   }    }    UnregisterClass( "D3D Tutorial", wc.hInstance );    return 0;};  Thanks it works, but Ive to set the viewport to the whole area before calling clear else it doesnt clear everything.   ;Quote:Original post by ProblemBabyThanks it works, but Ive to set the viewport to the whole area before calling clear else it doesnt clear everything.Ah yes, forgot about that! The last viewport you set can affect the subsequent Clear() call(s), so you should set the viewport back to the original size before any call to Clear().BEWARE: the device drivers for some older graphics cards don't honour the current viewport rectangle for their Clear() calls, some didn't even honour the rectangle you pass to Clear(). Newer drivers/cards are ok, but it's something to remember if you're targetting older h/w.   