示例程序
运行截图：
为了让物体运动起来，需要不断改变相应的世界矩阵，而投影矩阵和观察矩阵通常不变，特别是投影矩阵在设置好之后基本上不需要重新设置。
在默认情况下，对于窗口显示模式的应用程序，视口的大小就是当前窗口的客户区的大小，对于全屏模式的应用程序，视口的大小就是屏幕的分辨率。除非特殊需要，绝大多数程序都采用这一默认设置，所以在以后的示例程序中都将略过视口设置，而采用其默认设置。
Direct3D中的一个面有前面和背面两部分，默认情况下，在渲染时只画前面，而剔除背面，而在本例中，因为圆筒在不断地旋转，剔除背面会使得圆筒表面不可见，所以需要指定不剔除背面。
完整源程序：
#include <d3dx9.h>
#define CLASS_NAME "GameApp"
#define release_com(p) do { if(p) { (p)->Release(); (p) = NULL; } } while(0)
IDirect3D9* g_d3d;
IDirect3DDevice9* g_device;
IDirect3DVertexBuffer9* g_vertex_buffer;
HWND g_hwnd;
struct sCustomVertex
{
D3DXVECTOR3 position;
DWORD color;
};
#define D3DFVF_CUSTOM_VERTEX (D3DFVF_XYZ | D3DFVF_DIFFUSE)
void setup_world_matrix()
{
// build a world matrix which rotated around x-axis
DWORD time = timeGetTime() % 1000;
float angle = time * (2.0f * D3DX_PI) / 1000.0f;
D3DXMATRIX mat_world;
D3DXMatrixIdentity(&mat_world);
D3DXMatrixRotationX(&mat_world, angle);
g_device->SetTransform(D3DTS_WORLD, &mat_world);
}
void setup_view_proj_matrix()
{
D3DXVECTOR3 eye(0.0f, 3.0f, -5.0f);
D3DXVECTOR3 at(0.0f, 0.0f, 0.0f);
D3DXVECTOR3 up(0.0f, 1.0f, 0.0f);
D3DXMATRIX mat_view;
D3DXMatrixLookAtLH(&mat_view, &eye, &at, &up);
g_device->SetTransform(D3DTS_VIEW, &mat_view);
D3DXMATRIX mat_proj;
D3DXMatrixPerspectiveFovLH(&mat_proj, D3DX_PI/4, 1.0f, 1.0f, 100.0f);
g_device->SetTransform(D3DTS_PROJECTION, &mat_proj);
}
void setup_viewport()
{
RECT rect;
GetClientRect(g_hwnd, &rect);
D3DVIEWPORT9 viewport;
viewport.X = 0;
viewport.Y = 0;
viewport.Width = rect.right;
viewport.Height = rect.bottom;
viewport.MinZ = 0.0f;
viewport.MaxZ = 1.0f;
g_device->SetViewport(&viewport);
}
void init_geometry()
{
g_device->CreateVertexBuffer(50 * 2 * sizeof(sCustomVertex), 0, D3DFVF_CUSTOM_VERTEX, D3DPOOL_DEFAULT,
&g_vertex_buffer, NULL);
sCustomVertex* vertices;
g_vertex_buffer->Lock(0, 0, (void**)&vertices, 0);
for(int i = 0; i < 50; i++)
{
float theta = (2 * D3DX_PI * i) / (50 - 1);
vertices[2 * i + 0].position = D3DXVECTOR3(sin(theta), -1.0f, cos(theta));
vertices[2 * i + 0].color = 0xffffffff;
vertices[2 * i + 1].position = D3DXVECTOR3(sin(theta), 1.0f, cos(theta));
vertices[2 * i + 1].color = 0xff888888;
}
g_vertex_buffer->Unlock();
}
bool init_d3d(HWND hwnd)
{
g_d3d = Direct3DCreate9(D3D_SDK_VERSION);
if(g_d3d == NULL)
return false;
D3DPRESENT_PARAMETERS d3dpp;
ZeroMemory(&d3dpp, sizeof(d3dpp));
d3dpp.Windowed = TRUE;
d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
d3dpp.BackBufferFormat = D3DFMT_UNKNOWN;
if(FAILED(g_d3d->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hwnd, D3DCREATE_SOFTWARE_VERTEXPROCESSING,
&d3dpp, &g_device)))
{
return false;
}
init_geometry();
g_device->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);
g_device->SetRenderState(D3DRS_LIGHTING, FALSE); // disable light, light default state is enable.
setup_view_proj_matrix();
setup_viewport();
return true;
}
void cleanup()
{
release_com(g_vertex_buffer);
release_com(g_device);
release_com(g_d3d);
}
void render()
{
g_device->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(5, 5, 5), 1.0f, 0);
g_device->BeginScene();
setup_world_matrix();
g_device->SetStreamSource(0, g_vertex_buffer, 0, sizeof(sCustomVertex));
g_device->SetFVF(D3DFVF_CUSTOM_VERTEX);
g_device->DrawPrimitive(D3DPT_TRIANGLESTRIP, 0, 2 * 50 - 2);
g_device->EndScene();
g_device->Present(NULL, NULL, NULL, NULL);
}
LRESULT WINAPI WinProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch(msg)
{
case WM_KEYDOWN:
if(wParam == VK_ESCAPE)
DestroyWindow(hwnd);
break;
case WM_DESTROY:
PostQuitMessage(0);
return 0;
}
return DefWindowProc(hwnd, msg, wParam, lParam);
}
int WINAPI WinMain(HINSTANCE inst, HINSTANCE, LPSTR, INT)
{
WNDCLASSEX wc;
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = CS_CLASSDC;
wc.lpfnWndProc = WinProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = inst;
wc.hIcon = NULL;
wc.hCursor = NULL;
wc.hbrBackground = NULL;
wc.lpszMenuName = NULL;
wc.lpszClassName = CLASS_NAME;
wc.hIconSm = NULL;
if(! RegisterClassEx(&wc))
return -1;
HWND hwnd = CreateWindow(CLASS_NAME, "Direct3D App", WS_OVERLAPPEDWINDOW, 200, 100, 600, 500,
NULL, NULL, wc.hInstance, NULL);
if(hwnd == NULL)
return -1;
g_hwnd = hwnd;
if(init_d3d(hwnd))
{
ShowWindow(hwnd, SW_SHOWDEFAULT);
UpdateWindow(hwnd);
MSG msg;
ZeroMemory(&msg, sizeof(msg));
while(msg.message != WM_QUIT)
{
if(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
render();
}
}
cleanup();
UnregisterClass(CLASS_NAME, wc.hInstance);
return 0;
}