D3D中的网格模型（6）
11.4 外接体（Bounding Volumes）
有时我们需要计算mesh的外接体（边界范围），常用的有两种类型：立方体和球。也有使用其它方法的，如圆柱体，椭球体，菱形体，胶囊形。图11.4演示了对同一个mesh分别使用立方体和球体类型。
边界盒/球常常被用来加速可见性测试，碰撞检测等。假如一个mesh的边界盒/球不可见，那么我们就说mesh不可见。一个盒/球可见性测试是比分别测试 mesh中的每个三角形要廉价的多。对于一个碰撞检测例子，如果一枚导弹点火起飞，我们需要检测它是否击中了同一场景中的目标。由于这些物体都是由大量三角形构成，我们可以依次检测每个对象的每个三角形，来测试导弹（可以用射线数学模型）是否碰撞到了这些三角形。这个方法需要进行多次的射线/三角形交点的运算。一个更好的方法是使用边界盒或边界球，计算射线与场景中的每个对象的边界盒/边界球的交点。如果射线与对象的边界范围相交，可以认为该对象被击中了。这是一个公平的近似方法，如果需要更高的精度，可以用边界范围法先去除那些明显不会相撞的对象，然后用更精确地方法检测很可能相撞的对象。如果边界范围检测发现相撞，则该对象就很有可能相撞。
D3DX库提供了计算mesh的边界盒和边界球的函数。这些函数使用顶点数组作为输入计算边界盒/球。这些函数本来就是设计的很灵活的，它们可以使用各种顶点格式：
| HRESULT D3DXComputeBoundingSphere( LPD3DXVECTOR3 pFirstPosition, DWORD NumVertices, DWORD dwStride, D3DXVECTOR3* pCenter, FLOAT* pRadius ); |
pFirstPosition——指向在顶点数组中第一个顶点的向量，描述顶点位置。
NumVertices——在顶点数组中的的顶点数。
dwStride——每个顶点的字节大小。这很重要，因为顶点结构可能有一些额外信息如法向量和纹理坐标，函数需要知道应该跳过多少字节来得到下一个顶点的位置。
pCenter——返回边界球的中心。
pRadius——返回边界球的半径。
| HRESULT D3DXComputeBoundingBox( LPD3DXVECTOR3 pFirstPosition, DWORD NumVertices, DWORD dwStride, D3DXVECTOR3* pMin, D3DXVECTOR3* pMax ); |
前三个参数和D3DXComputeBoundingSphere的前三个参数是完全一样的。最后两个参数分别用来返回边界盒的最小和最大点。< /p>
11.4.1一些新的特殊常量
const float INFINITY = FLT_MAX;
const float EPSILON = 0.001f;
常量INFINITY是用来表示一个浮点数所能存储的最大数。因为我们找不到一个比FLT_MAX还要大的浮点数，我们可以将它视为无穷大。常量 EPSILON是一个很小的值，我们这样定义它，凡是比它小的数就视为0。这也是很有必要的，因为得到的浮点是不精确的。因此，让它和0比较相等肯定会失败。我们因此可以通过把该值与0的差值与EPSILON比较来确定是否相等：
| bool Equals(float lhs, float rhs) { // if lhs == rhs their difference should be zero return fabs(lhs - rhs) < EPSILON ? true : false; } |
11.4.2外接体类型
为了更容易的使用边界盒和边界球，我们将它们分别封装到两个类中。
class
cBoundingBox
{
public :
D3DXVECTOR3 m_min, m_max;
cBoundingBox();
bool is_point_inside(D3DXVECTOR3 & point);
};
class cBoundingSphere
{
public :
D3DXVECTOR3 m_center;
float m_radius;
cBoundingSphere();
};
cBoundingBox::cBoundingBox()
{
m_min.x = INFINITY;
m_min.y = INFINITY;
m_min.z = INFINITY;
m_max.x = - INFINITY;
m_max.y = - INFINITY;
m_max.z = - INFINITY;
}
bool cBoundingBox::is_point_inside(D3DXVECTOR3 & point)
{
return (point.x >= m_min.x && point.y >= m_min.y && point.z >= m_min.z &&
point.x <= m_max.x && point.y <= m_max.y && point.z <= m_max.z);
}
cBoundingSphere::cBoundingSphere()
{
m_radius = 0.0f ;
}
{
public :
D3DXVECTOR3 m_min, m_max;
cBoundingBox();
bool is_point_inside(D3DXVECTOR3 & point);
};
class cBoundingSphere
{
public :
D3DXVECTOR3 m_center;
float m_radius;
cBoundingSphere();
};
cBoundingBox::cBoundingBox()
{
m_min.x = INFINITY;
m_min.y = INFINITY;
m_min.z = INFINITY;
m_max.x = - INFINITY;
m_max.y = - INFINITY;
m_max.z = - INFINITY;
}
bool cBoundingBox::is_point_inside(D3DXVECTOR3 & point)
{
return (point.x >= m_min.x && point.y >= m_min.y && point.z >= m_min.z &&
point.x <= m_max.x && point.y <= m_max.y && point.z <= m_max.z);
}
cBoundingSphere::cBoundingSphere()
{
m_radius = 0.0f ;
}
11.4.3实例程序：外接体
该实例程序主要演示使用D3DXComputeBoundingSphere和 D3DXComputeBoundingBox。程序读取一个X文件并且计算该mesh的边界球，它创建两个ID3DXMesh对象，一个用来作为边界球模型一个用来作为边界盒模型（如下图所示）。你能够通过敲空格键在边界球和边界盒之间切换。
主程序：
/*
*************************************************************************************
Demonstrates how to use D3DXComputeBoundingSphere and D3DXComputeBoundingBox.
The spacebar key switches between rendering the mesh's bounding sphere and box.
************************************************************************************* */
#include < vector >
#include " d3dUtility.h "
#pragma warning(disable : 4100 )
using namespace std;
const int WIDTH = 640 ;
const int HEIGHT = 480 ;
IDirect3DDevice9 * g_device;
ID3DXMesh * g_mesh;
ID3DXMesh * g_sphere_mesh;
ID3DXMesh * g_box_mesh;
vector < D3DMATERIAL9 > g_materials;
vector < IDirect3DTexture9 *> g_textures;
bool g_is_render_bounding_sphere = true ;
bool compute_bounding_sphere(ID3DXMesh * mesh, cBoundingSphere * sphere);
bool compute_bounding_box(ID3DXMesh * mesh, cBoundingBox * box);
/////////////////////////////////////////////////////////////////////////////////////////////////// /
bool setup()
{
// load the XFile data
ID3DXBuffer * adjacency_buffer = NULL;
ID3DXBuffer * material_buffer = NULL;
DWORD num_material = 0 ;
HRESULT hr = D3DXLoadMeshFromX( " bigship1.x " , D3DXMESH_MANAGED, g_device, & adjacency_buffer, & material_buffer,
NULL, & num_material, & g_mesh);
if (FAILED(hr))
{
MessageBox(NULL, " D3DXLoadMeshFromX() - FAILED " , " ERROR " , MB_OK);
return false ;
}
// extract the materials, and load textures.
if (material_buffer != NULL && num_material != 0 )
{
D3DXMATERIAL * materials = (D3DXMATERIAL * ) material_buffer -> GetBufferPointer();
for (DWORD i = 0 ; i < num_material; i ++ )
{
// the MatD3D property doesn't have an ambient value set when it load, so set it now.
materials[i].MatD3D.Ambient = materials[i].MatD3D.Diffuse;
// save the ith material
g_materials.push_back(materials[i].MatD3D);
// check if the ith material has an associative texture
if (materials[i].pTextureFilename != NULL)
{
// yes, load the texture for the ith subset.
IDirect3DTexture9 * texture;
D3DXCreateTextureFromFile(g_device, materials[i].pTextureFilename, & texture);
// save the loaded texture
g_textures.push_back(texture);
}
else
{
// no texture for the ith subset
g_textures.push_back(NULL);
}
}
}
safe_release < ID3DXBuffer *> (material_buffer);
// optimize the mesh
hr = g_mesh -> OptimizeInplace(D3DXMESHOPT_ATTRSORT | D3DXMESHOPT_COMPACT | D3DXMESHOPT_VERTEXCACHE,
(DWORD * ) adjacency_buffer -> GetBufferPointer(), NULL, NULL, NULL);
safe_release < ID3DXBuffer *> (adjacency_buffer);
if (FAILED(hr))
{
MessageBox(NULL, " OptimizeInplace() - FAILED " , " ERROR " , MB_OK);
return false ;
}
// compute bounding sphere and bounding box
cBoundingSphere bounding_sphere;
cBoundingBox bounding_box;
compute_bounding_sphere(g_mesh, & bounding_sphere);
compute_bounding_box(g_mesh, & bounding_box);
D3DXCreateSphere(g_device, bounding_sphere.m_radius, 20 , 20 , & g_sphere_mesh, NULL);
float width = bounding_box.m_max.x - bounding_box.m_min.x;
float height = bounding_box.m_max.y - bounding_box.m_min.y;
float depth = bounding_box.m_max.z - bounding_box.m_min.z;
D3DXCreateBox(g_device, width, height, depth, & g_box_mesh, NULL);
// set texture filters
g_device -> SetSamplerState( 0 , D3DSAMP_MAGFILTER, D3DTEXF_LINEAR);
g_device -> SetSamplerState( 0 , D3DSAMP_MINFILTER, D3DTEXF_LINEAR);
g_device -> SetSamplerState( 0 , D3DSAMP_MIPFILTER, D3DTEXF_LINEAR);
// set lights
D3DXVECTOR3 dir( 1.0f , - 1.0f , 1.0f );
D3DXCOLOR color( 1.0f , 1.0f , 1.0f , 1.0f );
D3DLIGHT9 light = init_directional_light( & dir, & color);
g_device -> SetLight( 0 , & light);
g_device -> LightEnable( 0 , TRUE);
g_device -> SetRenderState(D3DRS_NORMALIZENORMALS, TRUE);
g_device -> SetRenderState(D3DRS_SPECULARENABLE, TRUE);
// set camera
D3DXVECTOR3 pos( 4.0f , 12.0f , - 20.0f );
D3DXVECTOR3 target( 0.0f , 0.0f , 0.0f );
D3DXVECTOR3 up( 0.0f , 1.0f , 0.0f );
D3DXMATRIX view_matrix;
D3DXMatrixLookAtLH( & view_matrix, & pos, & target, & up);
g_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_device -> SetTransform(D3DTS_PROJECTION, & proj);
return true ;
}
////////////////////////////////////////////////////////////////////////////////////////////////////// /
void cleanup()
{
safe_release < ID3DXMesh *> (g_mesh);
safe_release < ID3DXMesh *> (g_sphere_mesh);
safe_release < ID3DXMesh *> (g_box_mesh);
for (DWORD i = 0 ; i < g_textures.size(); i ++ )
safe_release < IDirect3DTexture9 *> (g_textures[i]);
}
////////////////////////////////////////////////////////////////////////////////////////////////////// /
bool display( float time_delta)
{
// update: rotate the mesh
static float y = 0.0f ;
D3DXMATRIX y_rot_matrix;
D3DXMatrixRotationY( & y_rot_matrix, y);
g_device -> SetTransform(D3DTS_WORLD, & y_rot_matrix);
y += time_delta;
if (y >= 6.28f )
y = 0.0f ;
// render now
g_device -> Clear( 0 , NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0x00000000 , 1.0f , 0 );
g_device -> BeginScene();
for (DWORD i = 0 ; i < g_materials.size(); i ++ )
{
g_device -> SetMaterial( & g_materials[i]);
g_device -> SetTexture( 0 , g_textures[i]);
g_mesh -> DrawSubset(i);
}
// draw bounding volume in yellow and at 30% opacity
D3DMATERIAL9 blue_material = YELLOW_MATERIAL;
blue_material.Diffuse.a = 0.30f ; // 30% opacity
g_device -> SetMaterial( & blue_material);
g_device -> SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);
g_device -> SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
g_device -> SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);
if (g_is_render_bounding_sphere)
g_sphere_mesh -> DrawSubset( 0 );
else
g_box_mesh -> DrawSubset( 0 );
g_device -> SetRenderState(D3DRS_ALPHABLENDENABLE, FALSE);
g_device -> EndScene();
g_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);
if (word_param == VK_SPACE)
g_is_render_bounding_sphere = ! g_is_render_bounding_sphere;
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_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_device -> Release();
return 0 ;
}
////////////////////////////////////////////////////////////////////////////////////////////////////// /
bool compute_bounding_sphere(ID3DXMesh * mesh, cBoundingSphere * sphere)
{
BYTE * v;
mesh -> LockVertexBuffer( 0 , ( void ** ) & v);
HRESULT hr = D3DXComputeBoundingSphere((D3DXVECTOR3 * )v, mesh -> GetNumVertices(),
D3DXGetFVFVertexSize(mesh -> GetFVF()), & sphere -> m_center, & sphere -> m_radius);
mesh -> UnlockVertexBuffer();
if (FAILED(hr))
return false ;
return true ;
}
bool compute_bounding_box(ID3DXMesh * mesh, cBoundingBox * box)
{
BYTE * v;
mesh -> LockVertexBuffer( 0 , ( void ** ) & v);
HRESULT hr = D3DXComputeBoundingBox((D3DXVECTOR3 * )v, mesh -> GetNumVertices(),
D3DXGetFVFVertexSize(mesh -> GetFVF()), & box -> m_min, & box -> m_max);
mesh -> UnlockVertexBuffer();
if (FAILED(hr))
return false ;
return true ;
}
Demonstrates how to use D3DXComputeBoundingSphere and D3DXComputeBoundingBox.
The spacebar key switches between rendering the mesh's bounding sphere and box.
************************************************************************************* */
#include < vector >
#include " d3dUtility.h "
#pragma warning(disable : 4100 )
using namespace std;
const int WIDTH = 640 ;
const int HEIGHT = 480 ;
IDirect3DDevice9 * g_device;
ID3DXMesh * g_mesh;
ID3DXMesh * g_sphere_mesh;
ID3DXMesh * g_box_mesh;
vector < D3DMATERIAL9 > g_materials;
vector < IDirect3DTexture9 *> g_textures;
bool g_is_render_bounding_sphere = true ;
bool compute_bounding_sphere(ID3DXMesh * mesh, cBoundingSphere * sphere);
bool compute_bounding_box(ID3DXMesh * mesh, cBoundingBox * box);
/////////////////////////////////////////////////////////////////////////////////////////////////// /
bool setup()
{
// load the XFile data
ID3DXBuffer * adjacency_buffer = NULL;
ID3DXBuffer * material_buffer = NULL;
DWORD num_material = 0 ;
HRESULT hr = D3DXLoadMeshFromX( " bigship1.x " , D3DXMESH_MANAGED, g_device, & adjacency_buffer, & material_buffer,
NULL, & num_material, & g_mesh);
if (FAILED(hr))
{
MessageBox(NULL, " D3DXLoadMeshFromX() - FAILED " , " ERROR " , MB_OK);
return false ;
}
// extract the materials, and load textures.
if (material_buffer != NULL && num_material != 0 )
{
D3DXMATERIAL * materials = (D3DXMATERIAL * ) material_buffer -> GetBufferPointer();
for (DWORD i = 0 ; i < num_material; i ++ )
{
// the MatD3D property doesn't have an ambient value set when it load, so set it now.
materials[i].MatD3D.Ambient = materials[i].MatD3D.Diffuse;
// save the ith material
g_materials.push_back(materials[i].MatD3D);
// check if the ith material has an associative texture
if (materials[i].pTextureFilename != NULL)
{
// yes, load the texture for the ith subset.
IDirect3DTexture9 * texture;
D3DXCreateTextureFromFile(g_device, materials[i].pTextureFilename, & texture);
// save the loaded texture
g_textures.push_back(texture);
}
else
{
// no texture for the ith subset
g_textures.push_back(NULL);
}
}
}
safe_release < ID3DXBuffer *> (material_buffer);
// optimize the mesh
hr = g_mesh -> OptimizeInplace(D3DXMESHOPT_ATTRSORT | D3DXMESHOPT_COMPACT | D3DXMESHOPT_VERTEXCACHE,
(DWORD * ) adjacency_buffer -> GetBufferPointer(), NULL, NULL, NULL);
safe_release < ID3DXBuffer *> (adjacency_buffer);
if (FAILED(hr))
{
MessageBox(NULL, " OptimizeInplace() - FAILED " , " ERROR " , MB_OK);
return false ;
}
// compute bounding sphere and bounding box
cBoundingSphere bounding_sphere;
cBoundingBox bounding_box;
compute_bounding_sphere(g_mesh, & bounding_sphere);
compute_bounding_box(g_mesh, & bounding_box);
D3DXCreateSphere(g_device, bounding_sphere.m_radius, 20 , 20 , & g_sphere_mesh, NULL);
float width = bounding_box.m_max.x - bounding_box.m_min.x;
float height = bounding_box.m_max.y - bounding_box.m_min.y;
float depth = bounding_box.m_max.z - bounding_box.m_min.z;
D3DXCreateBox(g_device, width, height, depth, & g_box_mesh, NULL);
// set texture filters
g_device -> SetSamplerState( 0 , D3DSAMP_MAGFILTER, D3DTEXF_LINEAR);
g_device -> SetSamplerState( 0 , D3DSAMP_MINFILTER, D3DTEXF_LINEAR);
g_device -> SetSamplerState( 0 , D3DSAMP_MIPFILTER, D3DTEXF_LINEAR);
// set lights
D3DXVECTOR3 dir( 1.0f , - 1.0f , 1.0f );
D3DXCOLOR color( 1.0f , 1.0f , 1.0f , 1.0f );
D3DLIGHT9 light = init_directional_light( & dir, & color);
g_device -> SetLight( 0 , & light);
g_device -> LightEnable( 0 , TRUE);
g_device -> SetRenderState(D3DRS_NORMALIZENORMALS, TRUE);
g_device -> SetRenderState(D3DRS_SPECULARENABLE, TRUE);
// set camera
D3DXVECTOR3 pos( 4.0f , 12.0f , - 20.0f );
D3DXVECTOR3 target( 0.0f , 0.0f , 0.0f );
D3DXVECTOR3 up( 0.0f , 1.0f , 0.0f );
D3DXMATRIX view_matrix;
D3DXMatrixLookAtLH( & view_matrix, & pos, & target, & up);
g_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_device -> SetTransform(D3DTS_PROJECTION, & proj);
return true ;
}
////////////////////////////////////////////////////////////////////////////////////////////////////// /
void cleanup()
{
safe_release < ID3DXMesh *> (g_mesh);
safe_release < ID3DXMesh *> (g_sphere_mesh);
safe_release < ID3DXMesh *> (g_box_mesh);
for (DWORD i = 0 ; i < g_textures.size(); i ++ )
safe_release < IDirect3DTexture9 *> (g_textures[i]);
}
////////////////////////////////////////////////////////////////////////////////////////////////////// /
bool display( float time_delta)
{
// update: rotate the mesh
static float y = 0.0f ;
D3DXMATRIX y_rot_matrix;
D3DXMatrixRotationY( & y_rot_matrix, y);
g_device -> SetTransform(D3DTS_WORLD, & y_rot_matrix);
y += time_delta;
if (y >= 6.28f )
y = 0.0f ;
// render now
g_device -> Clear( 0 , NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0x00000000 , 1.0f , 0 );
g_device -> BeginScene();
for (DWORD i = 0 ; i < g_materials.size(); i ++ )
{
g_device -> SetMaterial( & g_materials[i]);
g_device -> SetTexture( 0 , g_textures[i]);
g_mesh -> DrawSubset(i);
}
// draw bounding volume in yellow and at 30% opacity
D3DMATERIAL9 blue_material = YELLOW_MATERIAL;
blue_material.Diffuse.a = 0.30f ; // 30% opacity
g_device -> SetMaterial( & blue_material);
g_device -> SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);
g_device -> SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
g_device -> SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);
if (g_is_render_bounding_sphere)
g_sphere_mesh -> DrawSubset( 0 );
else
g_box_mesh -> DrawSubset( 0 );
g_device -> SetRenderState(D3DRS_ALPHABLENDENABLE, FALSE);
g_device -> EndScene();
g_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);
if (word_param == VK_SPACE)
g_is_render_bounding_sphere = ! g_is_render_bounding_sphere;
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_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_device -> Release();
return 0 ;
}
////////////////////////////////////////////////////////////////////////////////////////////////////// /
bool compute_bounding_sphere(ID3DXMesh * mesh, cBoundingSphere * sphere)
{
BYTE * v;
mesh -> LockVertexBuffer( 0 , ( void ** ) & v);
HRESULT hr = D3DXComputeBoundingSphere((D3DXVECTOR3 * )v, mesh -> GetNumVertices(),
D3DXGetFVFVertexSize(mesh -> GetFVF()), & sphere -> m_center, & sphere -> m_radius);
mesh -> UnlockVertexBuffer();
if (FAILED(hr))
return false ;
return true ;
}
bool compute_bounding_box(ID3DXMesh * mesh, cBoundingBox * box)
{
BYTE * v;
mesh -> LockVertexBuffer( 0 , ( void ** ) & v);
HRESULT hr = D3DXComputeBoundingBox((D3DXVECTOR3 * )v, mesh -> GetNumVertices(),
D3DXGetFVFVertexSize(mesh -> GetFVF()), & box -> m_min, & box -> m_max);
mesh -> UnlockVertexBuffer();
if (FAILED(hr))
return false ;
return true ;
}
下载源代码