Andy Pike - DirectX 8 Programming Tutorial

A Vertex Buffer is a memory buffer for storing vertices. A vertex buffer can stored vertices of any format. Once your vertices are stored in a vertex buffer you can perform operations such as: rendering, transforming and clipping.

To represent colours in Direct X, we use the D3DCOLOR_XRGB macro. There are three parameters: Red, Green and Blue. These parameters are integer values between 0 and 255. By specifying different red, green and blue values (mixing colours) you can make any colour you need.

For example:

D3DCOLOR_XRGB(0, 0, 0) is black (no colour)

D3DCOLOR_XRGB(255, 255, 255) is white (full colour)

D3DCOLOR_XRGB(0, 255, 0) is bright green (no red, full green, no blue)

D3DCOLOR_XRGB(100, 20, 100) is dark purple (100 red, 20 green, 100 blue)

Here is the code for this tutorial. It's just the same as the code from the first tutorial, except for a few modifications:

#include

LPDIRECT3D8 g_pD3D = NULL;

LPDIRECT3DDEVICE8 g_pD3DDevice = NULL;

LPDIRECT3DVERTEXBUFFER8 g_pVertexBuffer = NULL; // Buffer to hold vertices

struct CUSTOMVERTEX {

FLOAT x, y, z, rhw; // The transformed position for the vertex.

DWORD colour; // The vertex colour.

};

#define D3DFVF_CUSTOMVERTEX (D3DFVF_XYZRHW|D3DFVF_DIFFUSE)

#define SafeRelease(pObject) if(pObject != NULL) {pObject->Release(); pObject=NULL;}

HRESULT InitialiseD3D(HWND hWnd) {

//First of all, create the main D3D object. If it is created successfully we

//should get a pointer to an IDirect3D8 interface.

g_pD3D = Direct3DCreate8(D3D_SDK_VERSION);

if (g_pD3D == NULL) {

return E_FAIL;

}

//Get the current display mode

D3DDISPLAYMODE d3ddm;

if (FAILED(g_pD3D->GetAdapterDisplayMode(D3DADAPTER_DEFAULT, &d3ddm))) {

return E_FAIL;

}

//Create a structure to hold the settings for our device

D3DPRESENT_PARAMETERS d3dpp;

ZeroMemory(&d3dpp, sizeof(d3dpp));

//Fill the structure.

//We want our program to be windowed, and set the back buffer to a format

//that matches our current display mode

d3dpp.Windowed = TRUE;

d3dpp.SwapEffect = D3DSWAPEFFECT_COPY_VSYNC;

d3dpp.BackBufferFormat = d3ddm.Format;

//Create a Direct3D device.

if (FAILED(g_pD3D->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hWnd, D3DCREATE_SOFTWARE_VERTEXPROCESSING, &d3dpp, &g_pD3DDevice))) {

return E_FAIL;

}

return S_OK;

}

HRESULT InitialiseVertexBuffer() {

VOID* pVertices;

//Store each point of the triangle together with it's colour

CUSTOMVERTEX cvVertices[] = {

{250.0f, 100.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(255, 0, 0),}, //Vertex 1 – Red (250, 100)

{400.0f, 350.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 255, 0),}, //Vertex 2 – Green (400, 350)

{100.0f, 350.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 0, 255),}, //Vertex 3 – Blue (100, 350)

};

//Create the vertex buffer from our device

if (FAILED(g_pD3DDevice->CreateVertexBuffer(3 * sizeof(CUSTOMVERTEX), 0, D3DFVF_CUSTOMVERTEX, D3DPOOL_DEFAULT, &g_pVertexBuffer))) {

return E_FAIL;

}

//Get a pointer to the vertex buffer vertices and lock the vertex buffer

if (FAILED(g_pVertexBuffer->Lock(0, sizeof(cvVertices), (BYTE**)&pVertices, 0))) {

return E_FAIL;

}

//Copy our stored vertices values into the vertex buffer

memcpy(pVertices, cvVertices, sizeof(cvVertices));

//Unlock the vertex buffer

g_pVertexBuffer->Unlock();

return S_OK;

}

void Render() {

if (g_pD3DDevice == NULL) {

return;

}

//Clear the backbuffer to black

g_pD3DDevice->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0, 0, 0), 1.0f, 0);

//Begin the scene

g_pD3DDevice->BeginScene();

//Rendering our triangle

g_pD3DDevice->SetStreamSource(0, g_pVertexBuffer, sizeof(CUSTOMVERTEX));

g_pD3DDevice->SetVertexShader(D3DFVF_CUSTOMVERTEX);

g_pD3DDevice->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 1);

//End the scene

g_pD3DDevice->EndScene();

//Filp the back and front buffers so that whatever has been rendered on the back buffer

//will now be visible on screen (front buffer).

g_pD3DDevice->Present(NULL, NULL, NULL, NULL);

}

void CleanUp() {

SafeRelease(g_pVertexBuffer);

SafeRelease(g_pD3DDevice);

SafeRelease(g_pD3D);

}

void GameLoop() {

//Enter the game loop

MSG msg;

BOOL fMessage;

PeekMessage(&msg, NULL, 0U, 0U, PM_NOREMOVE);

while (msg.message != WM_QUIT) {

fMessage = PeekMessage(&msg, NULL, 0U, 0U, PM_REMOVE);

if (fMessage) {

//Process message

TranslateMessage(&msg);

DispatchMessage(&msg);

} else {

//No message to process, so render the current scene

Render();

}

}

}

//The windows message handler

LRESULT WINAPI WinProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam) {

switch(msg) {

case WM_DESTROY:

PostQuitMessage(0);

return 0;

break;

case WM_KEYUP:

switch (wParam) {

case VK_ESCAPE:

//User has pressed the escape key, so quit

DestroyWindow(hWnd);

return 0;

break;

}

break;

}

return DefWindowProc(hWnd, msg, wParam, lParam);

}

//Application entry point

INT WINAPI WinMain(HINSTANCE hInst, HINSTANCE, LPSTR, INT) {

//Register the window class

WNDCLASSEX wc = {

sizeof(WNDCLASSEX), CS_CLASSDC, WinProc, 0L, 0L, GetModuleHandle(NULL), NULL, NULL, NULL, NULL, "DX Project 2", NULL

};

RegisterClassEx(&wc);

//Create the application's window

HWND hWnd = CreateWindow("DX Project 2", "www.andypike.com: Tutorial 2", WS_OVERLAPPEDWINDOW, 50, 50, 500, 500, GetDesktopWindow(), NULL, wc.hInstance, NULL);

//Initialize Direct3D

if (SUCCEEDED(InitialiseD3D(hWnd))) {

//Show our window

ShowWindow(hWnd, SW_SHOWDEFAULT);

UpdateWindow(hWnd);

//Initialize Vertex Buffer

if (SUCCEEDED(InitialiseVertexBuffer())) {