D3D中的光照（3）

D3D中的光照（3）

平行光示例：

The GetAsyncKeyState function determines whether a key is up or down at the time the function is called, and whether the key was pressed after a previous call to GetAsyncKeyState.

Syntax

SHORT GetAsyncKeyState(      
    int vKey
);

Parameters

vKey

[in] Specifies one of 256 possible virtual-key codes. For more information, see Virtual-Key Codes.

Return Value

If the function succeeds, the return value specifies whether the key was pressed since the last call to GetAsyncKeyState, and whether the key is currently up or down. If the most significant bit is set, the key is down, and if the least significant bit is set, the key was pressed after the previous call to GetAsyncKeyState. However, you should not rely on this last behavior; for more information, see the Remarks.

截图：

源代码：

/* *************************************************************************************
  Demonstrates using a directional light with D3DX objects.  
  You can orbit the scene using the left and right arrow keys.  
  In addition you can elevate the camera with the up and down arrow keys.  
 ************************************************************************************* */

#include  " d3dUtility.h "

#pragma warning(disable :  4100 )

#define  MESH_TEAPOT        0
#define  MESH_SPHERE        1
#define  MESH_TORUS        2
#define  MESH_CYLINDER    3
#define  NUM_MESH        4

const   int  WIDTH   =   640 ;
const   int  HEIGHT  =   480 ;

IDirect3DDevice9 *         g_d3d_device   =  NULL;
ID3DXMesh *                 g_object_meshes[NUM_MESH];
D3DXMATRIX                g_world_matrices[NUM_MESH];
D3DMATERIAL9            g_materials[NUM_MESH];

/////////////////////////////////////////////////////////////////////////////////////////////////// /

bool  setup()
{    
     //  create objects
    D3DXCreateTeapot(g_d3d_device,  & g_object_meshes[MESH_TEAPOT], NULL);
    D3DXCreateSphere(g_d3d_device,  1.0f ,  20 ,  20 ,  & g_object_meshes[MESH_SPHERE], NULL);
    D3DXCreateTorus(g_d3d_device,  0.5f ,  1.0f ,  20 ,  20 ,  & g_object_meshes[MESH_TORUS], NULL);
    D3DXCreateCylinder(g_d3d_device,  0.5f ,  1.0f ,  2.0f ,  20 ,  20 ,  & g_object_meshes[MESH_CYLINDER], NULL);

     //  build world matrices - position the objects in world space
    D3DXMatrixTranslation( & g_world_matrices[MESH_TEAPOT],      0.0f ,   2.0f ,  0.0f );
    D3DXMatrixTranslation( & g_world_matrices[MESH_SPHERE],      0.0f ,  - 2.0f ,  0.0f );
    D3DXMatrixTranslation( & g_world_matrices[MESH_TORUS],     - 3.0f ,   0.0f ,  0.0f );
    D3DXMatrixTranslation( & g_world_matrices[MESH_CYLINDER],      3.0f ,   0.0f ,  0.0f );

     //  setup the object's materials
    g_materials[MESH_TEAPOT]    =  RED_MATERIAL;
    g_materials[MESH_SPHERE]    =  BLUE_MATERIAL;
    g_materials[MESH_TORUS]     =  GREEN_MATERIAL;
    g_materials[MESH_CYLINDER]  =  YELLOW_MATERIAL;

     //  setup a directional light
    D3DXVECTOR3 light_direction( 1.0f ,  - 0.0f ,  0.25f );
    D3DXCOLOR   color  =  WHITE;
    D3DLIGHT9   dir_light  =  init_directional_light( & light_direction,  & color);

     //  set and enable the light
    g_d3d_device -> SetLight( 0 ,  & dir_light);
    g_d3d_device -> LightEnable( 0 , TRUE);

     //  turn off specular lighting and instruct Direct3D to renormalize normals
    g_d3d_device -> SetRenderState(D3DRS_NORMALIZENORMALS, TRUE);
    g_d3d_device -> SetRenderState(D3DRS_SPECULARENABLE, FALSE);

     //  set the projection matrix
    D3DXMATRIX proj;
    D3DXMatrixPerspectiveFovLH( & proj, D3DX_PI  *   0.25f , ( float )WIDTH / HEIGHT,  1.0f ,  1000.0f );
    g_d3d_device -> SetTransform(D3DTS_PROJECTION,  & proj);
    
     return   true ;
}

void  cleanup()
{
     for ( int  i  =   0 ; i  <  NUM_MESH; i ++ )
        safe_release < ID3DXMesh *> (g_object_meshes[i]);
}

bool  display( float  time_delta)
{
     //  update the scene: update camera position

     static   float  angle  =  ( 3.0f   *  D3DX_PI)  /   2.0f ;
     static   float  height  =   5.0f ;

     if (GetAsyncKeyState(VK_LEFT)  &   0x8000f )
        angle  -=   0.5f   *  time_delta;

     if (GetAsyncKeyState(VK_RIGHT)  &   0x8000f )
        angle  +=   0.5f   *  time_delta;

     if (GetAsyncKeyState(VK_UP)  &   0x8000f )
        height  +=   5.0f   *  time_delta;

     if (GetAsyncKeyState(VK_DOWN)  &   0x8000f )
        height  -=   5.0f   *  time_delta;

    D3DXVECTOR3 position(cosf(angle)  *   7.0f , height, sinf(angle)  *   7.0f );
    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);

     //  draw the scene

    g_d3d_device -> Clear( 0 , NULL, D3DCLEAR_TARGET  |  D3DCLEAR_ZBUFFER,  0x00000000 ,  1.0f ,  0 );

    g_d3d_device -> BeginScene();

     for ( int  i  =   0 ; i  <  NUM_MESH; i ++ )
    {
         //  set material and world matrix for ith object, then render the ith object.
        g_d3d_device -> SetMaterial( & g_materials[i]);
        g_d3d_device -> SetTransform(D3DTS_WORLD,  & g_world_matrices[i]);
        g_object_meshes[i] -> DrawSubset( 0 );
    }
    
    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 ;
}

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