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toggling render of triangle and updating screen

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hi guys i am stuck as to how i would toggle the rendering of a triangle. i have a bool value to represent whether the triangle is rendered or not and it seems to work but it will not let me determine whethere this bool value is true or false using the VK_UP and VK_DOWN keys. I think it has to do with the fact i can see no update screen function. but now that i have entered the code if(wParam = VK_ESCAPE) { PostQuitMessage(0); } whenever a key is pressed the window not gets destroyed. here is my full source code
//--------------------------------------------------------------------------------------
// File: Tutorial02.cpp
//
// This application displays a triangle using Direct3D 10
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//--------------------------------------------------------------------------------------
#include <windows.h>
#include <d3d10.h>
#include <d3dx10.h>
#include "resource.h"


//--------------------------------------------------------------------------------------
// Structures
//--------------------------------------------------------------------------------------
struct SimpleVertex
{
    D3DXVECTOR3 Pos;
};


//--------------------------------------------------------------------------------------
// Global Variables
//--------------------------------------------------------------------------------------
HINSTANCE               g_hInst = NULL;
HWND                    g_hWnd = NULL;
D3D10_DRIVER_TYPE       g_driverType = D3D10_DRIVER_TYPE_NULL;
ID3D10Device*           g_pd3dDevice = NULL;
IDXGISwapChain*         g_pSwapChain = NULL;
ID3D10RenderTargetView* g_pRenderTargetView = NULL;
ID3D10Effect*           g_pEffect = NULL;
ID3D10EffectTechnique*  g_pTechnique = NULL;
ID3D10InputLayout*      g_pVertexLayout = NULL;
ID3D10Buffer*           g_pVertexBuffer = NULL;
bool mToggleRender;


//--------------------------------------------------------------------------------------
// Forward declarations
//--------------------------------------------------------------------------------------
HRESULT InitWindow( HINSTANCE hInstance, int nCmdShow );
HRESULT InitDevice();
void CleanupDevice();
LRESULT CALLBACK    WndProc( HWND, UINT, WPARAM, LPARAM );
void Render();



//--------------------------------------------------------------------------------------
// Entry point to the program. Initializes everything and goes into a message processing 
// loop. Idle time is used to render the scene.
//--------------------------------------------------------------------------------------
int WINAPI wWinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPWSTR lpCmdLine, int nCmdShow )
{
    if( FAILED( InitWindow( hInstance, nCmdShow ) ) )
        return 0;

    if( FAILED( InitDevice() ) )
    {
        CleanupDevice();
        return 0;
    }

    // Main message loop
    MSG msg = {0};
    while( WM_QUIT != msg.message )
    {
        if( PeekMessage( &msg, NULL, 0, 0, PM_REMOVE ) )
        {
            TranslateMessage( &msg );
            DispatchMessage( &msg );
        }
        else
        {
            Render();
        }
    }

    CleanupDevice();

    return ( int )msg.wParam;
}


//--------------------------------------------------------------------------------------
// Register class and create window
//--------------------------------------------------------------------------------------
HRESULT InitWindow( HINSTANCE hInstance, int nCmdShow )
{
    // Register class
    WNDCLASSEX wcex;
    wcex.cbSize = sizeof( WNDCLASSEX );
    wcex.style = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc = WndProc;
    wcex.cbClsExtra = 0;
    wcex.cbWndExtra = 0;
    wcex.hInstance = hInstance;
    wcex.hIcon = LoadIcon( hInstance, ( LPCTSTR )107 );
    wcex.hCursor = LoadCursor( NULL, IDC_ARROW );
    wcex.hbrBackground = ( HBRUSH )( 5 + 1 );
    wcex.lpszMenuName = NULL;
    wcex.lpszClassName = L"TutorialWindowClass";
    wcex.hIconSm = LoadIcon( wcex.hInstance, ( LPCTSTR )IDI_TUTORIAL1 );
    if( !RegisterClassEx( &wcex ) )
        return E_FAIL;

    // Create window
    g_hInst = hInstance;
    RECT rc = { 0, 0, 640, 480 };
    AdjustWindowRect( &rc, WS_OVERLAPPEDWINDOW, FALSE );
    g_hWnd = CreateWindow( L"TutorialWindowClass", L"Direct3D 10 Tutorial 2: Rendering a Triangle",
                           WS_OVERLAPPEDWINDOW,
                           CW_USEDEFAULT, CW_USEDEFAULT, rc.right - rc.left, rc.bottom - rc.top, NULL, NULL, hInstance,
                           NULL );
    if( !g_hWnd )
        return E_FAIL;

    ShowWindow( g_hWnd, nCmdShow );

    return S_OK;
}


//--------------------------------------------------------------------------------------
// Create Direct3D device and swap chain
//--------------------------------------------------------------------------------------
HRESULT InitDevice()
{
    HRESULT hr = S_OK;

    RECT rc;
    GetClientRect( g_hWnd, &rc );
    UINT width = rc.right - rc.left;
    UINT height = rc.bottom - rc.top;

    UINT createDeviceFlags = 0;
#ifdef _DEBUG
    createDeviceFlags |= D3D10_CREATE_DEVICE_DEBUG;
#endif

    D3D10_DRIVER_TYPE driverTypes[] =
    {
        D3D10_DRIVER_TYPE_HARDWARE,
        D3D10_DRIVER_TYPE_REFERENCE,
    };
    UINT numDriverTypes = sizeof( driverTypes ) / sizeof( driverTypes[0] );

    DXGI_SWAP_CHAIN_DESC sd;
    ZeroMemory( &sd, sizeof( sd ) );
    sd.BufferCount = 1;
    sd.BufferDesc.Width = width;
    sd.BufferDesc.Height = height;
    sd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
    sd.BufferDesc.RefreshRate.Numerator = 60;
    sd.BufferDesc.RefreshRate.Denominator = 1;
    sd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
    sd.OutputWindow = g_hWnd;
    sd.SampleDesc.Count = 1;
    sd.SampleDesc.Quality = 0;
    sd.Windowed = TRUE;

    for( UINT driverTypeIndex = 0; driverTypeIndex < numDriverTypes; driverTypeIndex++ )
    {
        g_driverType = driverTypes[driverTypeIndex];
        hr = D3D10CreateDeviceAndSwapChain( NULL, g_driverType, NULL, createDeviceFlags,
                                            D3D10_SDK_VERSION, &sd, &g_pSwapChain, &g_pd3dDevice );
        if( SUCCEEDED( hr ) )
            break;
    }
    if( FAILED( hr ) )
        return hr;

    // Create a render target view
    ID3D10Texture2D* pBuffer;
    hr = g_pSwapChain->GetBuffer( 0, __uuidof( ID3D10Texture2D ), ( LPVOID* )&pBuffer );
    if( FAILED( hr ) )
        return hr;

    hr = g_pd3dDevice->CreateRenderTargetView( pBuffer, NULL, &g_pRenderTargetView );
    pBuffer->Release();
    if( FAILED( hr ) )
        return hr;

    g_pd3dDevice->OMSetRenderTargets( 1, &g_pRenderTargetView, NULL );

    // Setup the viewport
    D3D10_VIEWPORT vp;
    vp.Width = width;
    vp.Height = height;
    vp.MinDepth = 0.0f;
    vp.MaxDepth = 1.0f;
    vp.TopLeftX = 0;
    vp.TopLeftY = 0;
    g_pd3dDevice->RSSetViewports( 1, &vp );

    // Create the effect
    DWORD dwShaderFlags = D3D10_SHADER_ENABLE_STRICTNESS;
#if defined( DEBUG ) || defined( _DEBUG )
    // Set the D3D10_SHADER_DEBUG flag to embed debug information in the shaders.
    // Setting this flag improves the shader debugging experience, but still allows 
    // the shaders to be optimized and to run exactly the way they will run in 
    // the release configuration of this program.
    dwShaderFlags |= D3D10_SHADER_DEBUG;
    #endif
    hr = D3DX10CreateEffectFromFile( L"Tutorial02.fx", NULL, NULL, "fx_4_0", dwShaderFlags, 0,
                                         g_pd3dDevice, NULL, NULL, &g_pEffect, NULL, NULL );
    if( FAILED( hr ) )
    {
        MessageBox( NULL,
                    L"The FX file cannot be located.  Please run this executable from the directory that contains the FX file.", L"Error", MB_OK );
        return hr;
    }

    // Obtain the technique
    g_pTechnique = g_pEffect->GetTechniqueByName( "Render" );

    // Define the input layout
    D3D10_INPUT_ELEMENT_DESC layout[] =
    {
        { "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D10_INPUT_PER_VERTEX_DATA, 0 },
    };
    UINT numElements = sizeof( layout ) / sizeof( layout[0] );

    // Create the input layout
    D3D10_PASS_DESC PassDesc;
    g_pTechnique->GetPassByIndex( 0 )->GetDesc( &PassDesc );
    hr = g_pd3dDevice->CreateInputLayout( layout, numElements, PassDesc.pIAInputSignature,
                                          PassDesc.IAInputSignatureSize, &g_pVertexLayout );
    if( FAILED( hr ) )
        return hr;

    // Set the input layout
    g_pd3dDevice->IASetInputLayout( g_pVertexLayout );

    // Create vertex buffer
    SimpleVertex vertices[] =
    {
        D3DXVECTOR3( 0.0f, 0.5f, 0.5f ),
        D3DXVECTOR3( 0.5f, -0.5f, 0.5f ),
        D3DXVECTOR3( -0.5f, -0.5f, 0.5f ),
    };
    D3D10_BUFFER_DESC bd;
    bd.Usage = D3D10_USAGE_DEFAULT;
    bd.ByteWidth = sizeof( SimpleVertex ) * 3;
    bd.BindFlags = D3D10_BIND_VERTEX_BUFFER;
    bd.CPUAccessFlags = 0;
    bd.MiscFlags = 0;
    D3D10_SUBRESOURCE_DATA InitData;
    InitData.pSysMem = vertices;
    hr = g_pd3dDevice->CreateBuffer( &bd, &InitData, &g_pVertexBuffer );
    if( FAILED( hr ) )
        return hr;

    // Set vertex buffer
    UINT stride = sizeof( SimpleVertex );
    UINT offset = 0;
    g_pd3dDevice->IASetVertexBuffers( 0, 1, &g_pVertexBuffer, &stride, &offset );

    // Set primitive topology
    g_pd3dDevice->IASetPrimitiveTopology( D3D10_PRIMITIVE_TOPOLOGY_TRIANGLELIST );

    return S_OK;
}


//--------------------------------------------------------------------------------------
// Clean up the objects we've created
//--------------------------------------------------------------------------------------
void CleanupDevice()
{
    if( g_pd3dDevice ) g_pd3dDevice->ClearState();

    if( g_pVertexBuffer ) g_pVertexBuffer->Release();
    if( g_pVertexLayout ) g_pVertexLayout->Release();
    if( g_pEffect ) g_pEffect->Release();
    if( g_pRenderTargetView ) g_pRenderTargetView->Release();
    if( g_pSwapChain ) g_pSwapChain->Release();
    if( g_pd3dDevice ) g_pd3dDevice->Release();
}


//--------------------------------------------------------------------------------------
// Called every time the application receives a message
//--------------------------------------------------------------------------------------
LRESULT CALLBACK WndProc( HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam )
{
    PAINTSTRUCT ps;
    HDC hdc;
	

    switch( message )
    {

		case WM_KEYDOWN:
			
				if(wParam = VK_UP)
				{
					mToggleRender = true;
				}
				if(wParam = VK_DOWN)
				{
					mToggleRender = false;
				}
				if(wParam = VK_ESCAPE)
				{
					PostQuitMessage(0);
				}

				break;

        case WM_PAINT:
            hdc = BeginPaint( hWnd, &ps );
            EndPaint( hWnd, &ps );
            break;

		
			

        case WM_DESTROY:
            PostQuitMessage( 0 );
            break;

        default:
            return DefWindowProc( hWnd, message, wParam, lParam );
    }

    return DefWindowProc(hWnd, message, wParam, lParam);
}


//--------------------------------------------------------------------------------------
// Render a frame
//--------------------------------------------------------------------------------------
void Render()
{
    // Clear the back buffer 
    float ClearColor[4] = { 0.0f, 0.125f, 0.3f, 1.0f }; // red,green,blue,alpha
    g_pd3dDevice->ClearRenderTargetView( g_pRenderTargetView, ClearColor );

	
	if(mToggleRender != true)
	{
    // Render a triangle
    D3D10_TECHNIQUE_DESC techDesc;
    g_pTechnique->GetDesc( &techDesc );
    for( UINT p = 0; p < techDesc.Passes; ++p )
    {
        g_pTechnique->GetPassByIndex( p )->Apply( 0 );
        g_pd3dDevice->Draw( 3, 0 );
    }
	}
    // Present the information rendered to the back buffer to the front buffer (the screen)
    g_pSwapChain->Present( 0, 0 );
	
}



so how would i basically toggle the triangle on and off? would i need to put in an updatescene function? or what? please help :D

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You are doing assignments instead of comparisons.

wParam = VK_UP

should be

wParam == VK_UP

And by the way, wParam = VK_UP is bool(wParam = VK_UP) is bool(wParam). So unless wParam is zero, it will always pass. I suggest you use a switch statemanet for the wParam checks as well.

If this is a problem too often, write the constant first, VK_UP == wParam, that way the compiler will throw an error if you accidentally write an assignment.

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I'd recommend putting your compilers warning level up to maximum, and setting the "Treat warnings as errors" setting too - VC2005 and VC2008 certainly warn about a possible unwanted assignment on warning level 4 (And they may do on level 3, but I always use level 4).

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