該示例演示了如何利用D3D中的模板緩存技術(shù)同時顯示物體的鏡像和陰影。
主程序：
/**************************************************************************************
Demonstrates mirrors and shadows with stencils.
Use the arrow keys and the 'A' and 'S' key to navigate the scene and translate the teapot.
**************************************************************************************/
#include "d3dUtility.h"
#pragma warning(disable : 4100)
class cTextureVertex
{
public:
float _x, _y, _z;
float _nx, _ny, _nz;
float _u, _v;
cTextureVertex() { }
cTextureVertex(float x, float y, float z,
float nx, float ny, float nz,
float u, float v)
{
_x = x; _y = y; _z = z;
_nx = nx; _ny = ny; _nz = nz;
_u = u; _v = v;
}
};
const DWORD TEXTURE_VERTEX_FVF = D3DFVF_XYZ | D3DFVF_NORMAL | D3DFVF_TEX1;
const int WIDTH = 640;
const int HEIGHT = 480;
IDirect3DDevice9* g_d3d_device;
IDirect3DVertexBuffer9* g_vertex_buffer;
IDirect3DTexture9* g_floor_texture;
IDirect3DTexture9* g_wall_texture;
IDirect3DTexture9* g_mirror_texture;
D3DMATERIAL9 g_floor_material = WHITE_MATERIAL;
D3DMATERIAL9 g_wall_material = WHITE_MATERIAL;
D3DMATERIAL9 g_mirror_material = WHITE_MATERIAL;
ID3DXMesh* g_teapot_mesh;
D3DXVECTOR3 g_teapot_pos(0.0f, 3.0f, -7.5f);
D3DMATERIAL9 g_teapot_material = YELLOW_MATERIAL;
void render_scene();
void render_mirror();
void render_shadow();
////////////////////////////////////////////////////////////////////////////////////////////////////
bool setup()
{
// make walls have low specular reflectance - 20%
g_wall_material.Specular = WHITE * 0.2f;
D3DXCreateTeapot(g_d3d_device, &g_teapot_mesh, NULL);
// Create and specify geometry. For this sample we draw a floor and a wall with a mirror on it.
// We put the floor, wall, and mirror geometry in one vertex buffer.
//
// |----|----|----|
// |Wall|Mirr|Wall|
// | | or | |
// /--------------/
// / Floor /
// /--------------/
g_d3d_device->CreateVertexBuffer(24 * sizeof(cTextureVertex), 0, TEXTURE_VERTEX_FVF, D3DPOOL_MANAGED,
&g_vertex_buffer, NULL);
cTextureVertex* v;
g_vertex_buffer->Lock(0, 0, (void**)&v, 0);
// floor
v[0] = cTextureVertex(-7.5f, 0.0f, -10.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f);
v[1] = cTextureVertex(-7.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f);
v[2] = cTextureVertex( 7.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f);
v[3] = cTextureVertex(-7.5f, 0.0f, -10.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f);
v[4] = cTextureVertex( 7.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f);
v[5] = cTextureVertex( 7.5f, 0.0f, -10.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f);
// wall
v[6] = cTextureVertex(-7.5f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f);
v[7] = cTextureVertex(-7.5f, 5.0f, 0.0f, 0.0f, 0.0f, -1.0f, 0.0f, 0.0f);
v[8] = cTextureVertex(-2.5f, 5.0f, 0.0f, 0.0f, 0.0f, -1.0f, 1.0f, 0.0f);
v[9] = cTextureVertex(-7.5f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f);
v[10] = cTextureVertex(-2.5f, 5.0f, 0.0f, 0.0f, 0.0f, -1.0f, 1.0f, 0.0f);
v[11] = cTextureVertex(-2.5f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f, 1.0f, 1.0f);
// Note: We leave gap in middle of walls for mirror
v[12] = cTextureVertex(2.5f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f);
v[13] = cTextureVertex(2.5f, 5.0f, 0.0f, 0.0f, 0.0f, -1.0f, 0.0f, 0.0f);
v[14] = cTextureVertex(7.5f, 5.0f, 0.0f, 0.0f, 0.0f, -1.0f, 1.0f, 0.0f);
v[15] = cTextureVertex(2.5f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f);
v[16] = cTextureVertex(7.5f, 5.0f, 0.0f, 0.0f, 0.0f, -1.0f, 1.0f, 0.0f);
v[17] = cTextureVertex(7.5f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f, 1.0f, 1.0f);
// mirror
v[18] = cTextureVertex(-2.5f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f);
v[19] = cTextureVertex(-2.5f, 5.0f, 0.0f, 0.0f, 0.0f, -1.0f, 0.0f, 0.0f);
v[20] = cTextureVertex( 2.5f, 5.0f, 0.0f, 0.0f, 0.0f, -1.0f, 1.0f, 0.0f);
v[21] = cTextureVertex(-2.5f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f);
v[22] = cTextureVertex( 2.5f, 5.0f, 0.0f, 0.0f, 0.0f, -1.0f, 1.0f, 0.0f);
v[23] = cTextureVertex( 2.5f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f, 1.0f, 1.0f);
g_vertex_buffer->Unlock();
// create the texture and set filters
D3DXCreateTextureFromFile(g_d3d_device, "checker.jpg", &g_floor_texture);
D3DXCreateTextureFromFile(g_d3d_device, "brick0.jpg", &g_wall_texture);
D3DXCreateTextureFromFile(g_d3d_device, "ice.bmp", &g_mirror_texture);
g_d3d_device->SetSamplerState(0, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR);
g_d3d_device->SetSamplerState(0, D3DSAMP_MINFILTER, D3DTEXF_LINEAR);
g_d3d_device->SetSamplerState(0, D3DSAMP_MIPFILTER, D3DTEXF_LINEAR);
// lights
D3DXVECTOR3 light_dir(0.707f, -0.707f, 0.707f);
D3DXCOLOR color(1.0f, 1.0f, 1.0f, 1.0f);
D3DLIGHT9 light = init_directional_light(&light_dir, &color);
g_d3d_device->SetLight(0, &light);
g_d3d_device->LightEnable(0, TRUE);
g_d3d_device->SetRenderState(D3DRS_NORMALIZENORMALS, TRUE);
g_d3d_device->SetRenderState(D3DRS_SPECULARENABLE, TRUE);
// set the projection matrix
D3DXMATRIX proj;
D3DXMatrixPerspectiveFovLH(&proj, D3DX_PI/4.0f, (float)WIDTH/HEIGHT, 1.0f, 1000.0f);
g_d3d_device->SetTransform(D3DTS_PROJECTION, &proj);
return true;
}
///////////////////////////////////////////////////////////////////////////////////////////////////////
void cleanup()
{
safe_release<IDirect3DVertexBuffer9*>(g_vertex_buffer);
safe_release<IDirect3DTexture9*>(g_floor_texture);
safe_release<IDirect3DTexture9*>(g_wall_texture);
safe_release<IDirect3DTexture9*>(g_mirror_texture);
safe_release<ID3DXMesh*>(g_teapot_mesh);
}
///////////////////////////////////////////////////////////////////////////////////////////////////////
bool display(float time_delta)
{
// update the scene
if(GetAsyncKeyState(VK_LEFT) & 0x80000f)
g_teapot_pos.x -= 3.0f * time_delta;
if(GetAsyncKeyState(VK_RIGHT) & 0x80000f)
g_teapot_pos.x += 3.0f * time_delta;
static float radius = 20.0f;
if(GetAsyncKeyState(VK_UP) & 0x80000f)
radius -= 2.0f * time_delta;
if(GetAsyncKeyState(VK_DOWN) & 0x80000f)
radius += 2.0f * time_delta;
static float angle = (3.0f * D3DX_PI) / 2.0f;
if(GetAsyncKeyState('A') & 0x80000f)
angle -= 0.5f * time_delta;
if(GetAsyncKeyState('S') & 0x80000f)
angle += 0.5f * time_delta;
D3DXVECTOR3 position(cosf(angle) * radius, 3.0f, sinf(angle) * radius);
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);
// render now
g_d3d_device->Clear(0, NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER | D3DCLEAR_STENCIL, 0xff000000, 1.0f, 0);
g_d3d_device->BeginScene();
render_scene();
render_mirror();
render_shadow();
g_d3d_device->EndScene();
g_d3d_device->Present(NULL, NULL, NULL, NULL);
return true;
}
///////////////////////////////////////////////////////////////////////////////////////////////////////
void render_scene()
{
// draw teapot
g_d3d_device->SetMaterial(&g_teapot_material);
g_d3d_device->SetTexture(0, NULL);
D3DXMATRIX world_matrix;
D3DXMatrixTranslation(&world_matrix, g_teapot_pos.x, g_teapot_pos.y, g_teapot_pos.z);
g_d3d_device->SetTransform(D3DTS_WORLD, &world_matrix);
g_teapot_mesh->DrawSubset(0);
D3DXMATRIX identity_matrix;
D3DXMatrixIdentity(&identity_matrix);
g_d3d_device->SetTransform(D3DTS_WORLD, &identity_matrix);
g_d3d_device->SetStreamSource(0, g_vertex_buffer, 0, sizeof(cTextureVertex));
g_d3d_device->SetFVF(TEXTURE_VERTEX_FVF);
// draw the floor
g_d3d_device->SetMaterial(&g_floor_material);
g_d3d_device->SetTexture(0, g_floor_texture);
g_d3d_device->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 2);
// draw the walls
g_d3d_device->SetMaterial(&g_wall_material);
g_d3d_device->SetTexture(0, g_wall_texture);
g_d3d_device->DrawPrimitive(D3DPT_TRIANGLELIST, 6, 4);
// draw the mirror
g_d3d_device->SetMaterial(&g_mirror_material);
g_d3d_device->SetTexture(0, g_mirror_texture);
g_d3d_device->DrawPrimitive(D3DPT_TRIANGLELIST, 18, 2);
}
///////////////////////////////////////////////////////////////////////////////////////////////////////
void render_mirror()
{
// Draw Mirror quad to stencil buffer ONLY. In this way only the stencil bits that
// correspond to the mirror will be on. Therefore, the reflected teapot can only be
// rendered where the stencil bits are turned on, and thus on the mirror only.
g_d3d_device->SetRenderState(D3DRS_STENCILENABLE, TRUE);
g_d3d_device->SetRenderState(D3DRS_STENCILFUNC, D3DCMP_ALWAYS);
g_d3d_device->SetRenderState(D3DRS_STENCILREF, 0x1);
g_d3d_device->SetRenderState(D3DRS_STENCILMASK, 0xffffffff);
g_d3d_device->SetRenderState(D3DRS_STENCILWRITEMASK, 0xffffffff);
g_d3d_device->SetRenderState(D3DRS_STENCILZFAIL, D3DSTENCILOP_KEEP);
g_d3d_device->SetRenderState(D3DRS_STENCILFAIL, D3DSTENCILOP_KEEP);
g_d3d_device->SetRenderState(D3DRS_STENCILPASS, D3DSTENCILOP_REPLACE);
// draw the mirror to the stencil buffer
g_d3d_device->SetStreamSource(0, g_vertex_buffer, 0, sizeof(cTextureVertex));
g_d3d_device->SetFVF(TEXTURE_VERTEX_FVF);
g_d3d_device->SetMaterial(&g_mirror_material);
g_d3d_device->SetTexture(0, g_mirror_texture);
D3DXMATRIX identity_matrix;
D3DXMatrixIdentity(&identity_matrix);
g_d3d_device->SetTransform(D3DTS_WORLD, &identity_matrix);
g_d3d_device->DrawPrimitive(D3DPT_TRIANGLELIST, 18, 2);
// only draw reflected teapot to the pixels where the mirror was drawn to
g_d3d_device->SetRenderState(D3DRS_STENCILFUNC, D3DCMP_EQUAL);
// clear depth buffer and blend the reflected teapot with the mirror
g_d3d_device->Clear(0, NULL, D3DCLEAR_ZBUFFER, 0, 1.0f, 0);
g_d3d_device->SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);
g_d3d_device->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_DESTCOLOR);
g_d3d_device->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_ZERO);
// position reflection
D3DXMATRIX world_matrix, translation_matrix, reflect_matrix;
D3DXPLANE plane(0.0f, 0.0f, 1.0f, 0.0f); // xy plane
D3DXMatrixReflect(&reflect_matrix, &plane);
D3DXMatrixTranslation(&translation_matrix, g_teapot_pos.x, g_teapot_pos.y, g_teapot_pos.z);
world_matrix = translation_matrix * reflect_matrix;
// Finally, draw the reflected teapot.
g_d3d_device->SetTransform(D3DTS_WORLD, &world_matrix);
g_d3d_device->SetMaterial(&g_teapot_material);
g_d3d_device->SetTexture(0, NULL);
// reverse cull mode
g_d3d_device->SetRenderState(D3DRS_CULLMODE, D3DCULL_CW);
g_teapot_mesh->DrawSubset(0);
// restore render states
g_d3d_device->SetRenderState(D3DRS_ALPHABLENDENABLE, FALSE);
g_d3d_device->SetRenderState(D3DRS_STENCILENABLE, FALSE);
g_d3d_device->SetRenderState(D3DRS_CULLMODE, D3DCULL_CCW);
}
///////////////////////////////////////////////////////////////////////////////////////////////////////
void render_shadow()
{
g_d3d_device->SetRenderState(D3DRS_STENCILENABLE, TRUE);
g_d3d_device->SetRenderState(D3DRS_STENCILFUNC, D3DCMP_EQUAL);
g_d3d_device->SetRenderState(D3DRS_STENCILREF, 0x0);
g_d3d_device->SetRenderState(D3DRS_STENCILMASK, 0xffffffff);
g_d3d_device->SetRenderState(D3DRS_STENCILWRITEMASK, 0xffffffff);
g_d3d_device->SetRenderState(D3DRS_STENCILZFAIL, D3DSTENCILOP_KEEP);
g_d3d_device->SetRenderState(D3DRS_STENCILFAIL, D3DSTENCILOP_KEEP);
g_d3d_device->SetRenderState(D3DRS_STENCILPASS, D3DSTENCILOP_INCR); // increment to 1
// position shadow
D3DXVECTOR4 light_dir(0.707f, -0.707f, 0.707f, 0.0f);
D3DXPLANE ground_plane(0.0f, -1.0f, 0.0f, 0.0f); // xz plane
D3DXMATRIX shadow_matrix;
D3DXMatrixShadow(&shadow_matrix, &light_dir, &ground_plane);
D3DXMATRIX tran_matrix;
D3DXMatrixTranslation(&tran_matrix, g_teapot_pos.x, g_teapot_pos.y, g_teapot_pos.z);
D3DXMATRIX world_matrix = tran_matrix * shadow_matrix;
g_d3d_device->SetTransform(D3DTS_WORLD, &world_matrix);
// alpha blend the shadow
g_d3d_device->SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);
g_d3d_device->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
g_d3d_device->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);
D3DMATERIAL9 material = init_material(BLACK, BLACK, BLACK, BLACK, 0.0f);
material.Diffuse.a = 0.5f; // 50% transparancy
// disable depth buffer so that z-fighting doesn't occur when we render the shadow
// on top of the floor.
g_d3d_device->SetRenderState(D3DRS_ZENABLE, FALSE);
g_d3d_device->SetMaterial(&material);
g_d3d_device->SetTexture(0, NULL);
g_teapot_mesh->DrawSubset(0);
// restore render states
g_d3d_device->SetRenderState(D3DRS_ZENABLE, TRUE);
g_d3d_device->SetRenderState(D3DRS_ALPHABLENDENABLE, FALSE);
g_d3d_device->SetRenderState(D3DRS_STENCILENABLE, FALSE);
}
///////////////////////////////////////////////////////////////////////////////////////////////////////
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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