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<pre class="prettyprint // include the basic windows header files and the Direct3D header file
#include <windows.h>
#include <windowsx.h>
#include <d3d9.h>

// define the screen resolution
#define SCREEN_WIDTH 800
#define SCREEN_HEIGHT 600

// include the Direct3D Library file
#pragma comment (lib, "d3d9.lib")

// global declarations
LPDIRECT3D9 d3d; // the pointer to our Direct3D interface
LPDIRECT3DDEVICE9 d3ddev; // the pointer to the device class

// function prototypes
void initD3D(HWND hWnd); // sets up and initializes Direct3D
void display_core(void); // renders a single frame
void cleanD3D(void); // closes Direct3D and releases memory
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);

struct CUSTOMVERTEX {FLOAT X, Y, Z,RHW; DWORD COLOR;};
#define CUSTOMFVF (D3DFVF_XYZRHW | D3DFVF_DIFFUSE)

//Handle the program loop
int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int nCmdShow)
{
HWND hWnd;
WNDCLASSEX wc;

ZeroMemory(&wc, sizeof(WNDCLASSEX));

wc.cbSize = sizeof(WNDCLASSEX);
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = WindowProc;
wc.hInstance = hInstance;
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.lpszClassName = "WindowClass";

RegisterClassEx(&wc);

hWnd = CreateWindowEx(NULL,
"WindowClass",
"Triangle Display",
WS_OVERLAPPEDWINDOW,
0, 0,
SCREEN_WIDTH, SCREEN_HEIGHT,
NULL,
NULL,
hInstance,
NULL);

ShowWindow(hWnd, nCmdShow);

// set up and initialize Direct3D
initD3D(hWnd);

// enter the main loop:

MSG msg;

while(TRUE)
{
while(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
if(msg.message == WM_QUIT)
break;
display_core();
}
cleanD3D();
return msg.wParam;
}


//Handle the Event Messages
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch(message)
{
case WM_DESTROY:
{
PostQuitMessage(0);
return 0;
} break;
}

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


//Create the DirectX Object
void initD3D(HWND hWnd)
{
d3d = Direct3DCreate9(D3D_SDK_VERSION);

D3DPRESENT_PARAMETERS d3dpp;

ZeroMemory(&d3dpp, sizeof(d3dpp));
d3dpp.Windowed = TRUE;
d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
d3dpp.hDeviceWindow = hWnd;
d3dpp.BackBufferFormat = D3DFMT_X8R8G8B8;
d3dpp.BackBufferWidth = SCREEN_WIDTH;
d3dpp.BackBufferHeight = SCREEN_HEIGHT;

// create a device class using this information and the info from the d3dpp stuct
d3d->CreateDevice(D3DADAPTER_DEFAULT,
D3DDEVTYPE_HAL,
hWnd,
D3DCREATE_SOFTWARE_VERTEXPROCESSING,
&d3dpp,
&d3ddev);
}


// this is the function that cleans up Direct3D and COM
void cleanD3D(void)
{
d3ddev->Release(); // close and release the 3D device
d3d->Release(); // close and release Direct3D
}
LPDIRECT3DVERTEXBUFFER9 generateTriangle(CUSTOMVERTEX vertices[])
{
LPDIRECT3DVERTEXBUFFER9 buffer;
d3ddev->CreateVertexBuffer(sizeof(vertices)*sizeof(CUSTOMVERTEX),0,CUSTOMFVF,D3DPOOL_MANAGED,&buffer,NULL);
d3ddev->SetStreamSource(0, buffer, 0, sizeof(CUSTOMVERTEX));
VOID* pVoid; // a void pointer
buffer->Lock(0, 0, (void**)&pVoid, 0);
memcpy(pVoid, vertices, sizeof(vertices));
buffer->Unlock();
d3ddev->DrawPrimitive(D3DPT_LINESTRIP, 0,1);
return buffer;
}
// this is the function used to render a single frame
void display_core(void)
{
d3ddev->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0, 0, 40), 1.0f, 0);
d3ddev->BeginScene();
d3ddev->SetFVF(CUSTOMFVF);
//Generate 1 triangle
CUSTOMVERTEX vertex[] = {
{0,0,0,1,D3DCOLOR_XRGB(255,0,0)},
{100,200,0,1,D3DCOLOR_XRGB(255,0,0)},
{0,100,0,1,D3DCOLOR_XRGB(255,0,0)},
};
generateTriangle(vertex)->Release();
d3ddev->EndScene();
d3ddev->Present(NULL, NULL, NULL, NULL);
}
[/code]
<br/>
<span style="font-family:verdana,arial,helvetica,sans-serif; line-height:normal Hello, I have recently been looking into DirectX. Ive been reading up on a tutorial and i decided to improvise and manipulate around with the tutorial code. Can someone explain
to me why this doesnt work so I have a better understanding?

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