立方體——只比三角形稍微復(fù)雜一點(diǎn)，這個程序渲染一個線框立方體。
這個簡單的繪制和渲染立方體的程序的運(yùn)行結(jié)果如下圖所示：
源程序：
/**************************************************************************************
Renders a spinning cube in wireframe mode. Demonstrates vertex and index buffers,
world and view transformations, render states and drawing commands.
**************************************************************************************/
#include "d3dUtility.h"
#pragma warning(disable : 4100)
const int WIDTH = 640;
const int HEIGHT = 480;
IDirect3DDevice9* g_d3d_device = NULL;
IDirect3DVertexBuffer9* g_vertex_buffer = NULL;
IDirect3DIndexBuffer9* g_index_buffer = NULL;
class cVertex
{
public:
float m_x, m_y, m_z;
cVertex() {}
cVertex(float x, float y, float z)
{
m_x = x;
m_y = y;
m_z = z;
}
};
const DWORD VERTEX_FVF = D3DFVF_XYZ;
////////////////////////////////////////////////////////////////////////////////////////////////////
bool setup()
{
g_d3d_device->CreateVertexBuffer(8 * sizeof(cVertex), D3DUSAGE_WRITEONLY, VERTEX_FVF,
D3DPOOL_MANAGED, &g_vertex_buffer, NULL);
g_d3d_device->CreateIndexBuffer(36 * sizeof(WORD), D3DUSAGE_WRITEONLY, D3DFMT_INDEX16,
D3DPOOL_MANAGED, &g_index_buffer, NULL);
// fill the buffers with the cube data
cVertex* vertices;
g_vertex_buffer->Lock(0, 0, (void**)&vertices, 0);
// vertices of a unit cube
vertices[0] = cVertex(-1.0f, -1.0f, -1.0f);
vertices[1] = cVertex(-1.0f, 1.0f, -1.0f);
vertices[2] = cVertex( 1.0f, 1.0f, -1.0f);
vertices[3] = cVertex( 1.0f, -1.0f, -1.0f);
vertices[4] = cVertex(-1.0f, -1.0f, 1.0f);
vertices[5] = cVertex(-1.0f, 1.0f, 1.0f);
vertices[6] = cVertex( 1.0f, 1.0f, 1.0f);
vertices[7] = cVertex( 1.0f, -1.0f, 1.0f);
g_vertex_buffer->Unlock();
// define the triangles of the cube
WORD* indices = NULL;
g_index_buffer->Lock(0, 0, (void**)&indices, 0);
// front side
indices[0] = 0; indices[1] = 1; indices[2] = 2;
indices[3] = 0; indices[4] = 2; indices[5] = 3;
// back side
indices[6] = 4; indices[7] = 6; indices[8] = 5;
indices[9] = 4; indices[10] = 7; indices[11] = 6;
// left side
indices[12] = 4; indices[13] = 5; indices[14] = 1;
indices[15] = 4; indices[16] = 1; indices[17] = 0;
// right side
indices[18] = 3; indices[19] = 2; indices[20] = 6;
indices[21] = 3; indices[22] = 6; indices[23] = 7;
// top
indices[24] = 1; indices[25] = 5; indices[26] = 6;
indices[27] = 1; indices[28] = 6; indices[29] = 2;
// bottom
indices[30] = 4; indices[31] = 0; indices[32] = 3;
indices[33] = 4; indices[34] = 3; indices[35] = 7;
g_index_buffer->Unlock();
// position and aim the camera
D3DXVECTOR3 position(0.0f, 0.0f, -5.0f);
D3DXVECTOR3 target(0.0f, 0.0f, 0.0f);
D3DXVECTOR3 up(0.0f, 1.0f, 0.0f);
D3DXMATRIX view_matrix;
D3DXMatrixLookAtLH(&view_matrix, &position, &target, &up);
g_d3d_device->SetTransform(D3DTS_VIEW, &view_matrix);
// set the projection matrix
D3DXMATRIX proj;
D3DXMatrixPerspectiveFovLH(&proj, D3DX_PI * 0.5f, (float)WIDTH/HEIGHT, 1.0f, 1000.0f);
g_d3d_device->SetTransform(D3DTS_PROJECTION, &proj);
// set wireframe mode render state
g_d3d_device->SetRenderState(D3DRS_FILLMODE, D3DFILL_WIREFRAME);
return true;
}
void cleanup()
{
safe_release<IDirect3DVertexBuffer9*>(g_vertex_buffer);
safe_release<IDirect3DIndexBuffer9*>(g_index_buffer);
}
bool display(float time_delta)
{
// spin the cube
D3DXMATRIX rx, ry;
// rotate 45 degree on x-axis
D3DXMatrixRotationX(&rx, 3.14f/4.0f);
// increment y-rotation angle each frame
static float y = 0.0f;
D3DXMatrixRotationY(&ry, y);
y += time_delta;
// reset angle to zero when angle reaches 2*PI
if(y >= 6.28f)
y = 0.0f;
// combine x and y axis ratation transformations
D3DXMATRIX rxy = rx * ry;
g_d3d_device->SetTransform(D3DTS_WORLD, &rxy);
// draw the scene
g_d3d_device->Clear(0, NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0xffffffff, 1.0f, 0);
g_d3d_device->BeginScene();
g_d3d_device->SetStreamSource(0, g_vertex_buffer, 0, sizeof(cVertex));
g_d3d_device->SetIndices(g_index_buffer);
g_d3d_device->SetFVF(VERTEX_FVF);
// draw cube
g_d3d_device->DrawIndexedPrimitive(D3DPT_TRIANGLELIST, 0, 0, 8, 0, 12);
g_d3d_device->EndScene();
g_d3d_device->Present(NULL, NULL, NULL, NULL);
return true;
}
LRESULT CALLBACK wnd_proc(HWND hwnd, UINT msg, WPARAM word_param, LPARAM long_param)
{
switch(msg)
{
case WM_DESTROY:
PostQuitMessage(0);
break;
case WM_KEYDOWN:
if(word_param == VK_ESCAPE)
DestroyWindow(hwnd);
break;
}
return DefWindowProc(hwnd, msg, word_param, long_param);
}
int WINAPI WinMain(HINSTANCE inst, HINSTANCE, PSTR cmd_line, int cmd_show)
{
if(! init_d3d(inst, WIDTH, HEIGHT, true, D3DDEVTYPE_HAL, &g_d3d_device))
{
MessageBox(NULL, "init_d3d() - failed.", 0, MB_OK);
return 0;
}
if(! setup())
{
MessageBox(NULL, "Steup() - failed.", 0, MB_OK);
return 0;
}
enter_msg_loop(display);
cleanup();
g_d3d_device->Release();
return 0;
}
setup函數(shù)創(chuàng)建頂點(diǎn)和索引緩存，鎖定它們，把構(gòu)成立方體的頂點(diǎn)寫入頂點(diǎn)緩存，以及把定義立方體的三角形的索引寫入索引緩存。然后把攝象機(jī)向后移動幾個單位以便我們能夠看見在世界坐標(biāo)系中原點(diǎn)處被渲染的立方體。
display方法有兩個任務(wù)；它必須更新場景并且緊接著渲染它。既然想旋轉(zhuǎn)立方體，那么我們將對每一幀增加一個角度使立方體能在這一幀旋轉(zhuǎn)。對于這每一幀，立方體將被旋轉(zhuǎn)一個很小的角度，這樣我們看起來旋轉(zhuǎn)就會更平滑。接著我們使用IDirect3DDevice9::DrawIndexedPrimitive方法來繪制立方體。
最后，我們釋放使用過的所有內(nèi)存。這意味著釋放頂點(diǎn)和索引緩存接口。
下載立方體演示程序