Create a mirror in DirectX

最新推荐文章于 2020-07-28 14:53:28 发布

arhaiyun

最新推荐文章于 2020-07-28 14:53:28 发布

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分类专栏： DirectX

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本文介绍如何使用DirectX创建镜面效果，包括设置渲染状态、绘制镜面对象、启用和禁用Z缓冲区写入等步骤，并通过计算反射矩阵来显示镜像。

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【I】.SetMirrorParameters
//[1].Create a mesh use it as a mirror
D3DXCreateMeshFVF(2, 4, D3DXMESH_MANAGED, D3DFVF_CUSTOMVERTEX, g_pd3dDevice, &g_pMirrorMesh);
//[2].fill the verts data
CUSTOMVERTEX *pVertices = NULL;
g_pMirrorMesh->LockVertexBuffer(0, (void**)&pVertices);
pVertices[0] = CUSTOMVERTEX( -10.0f, 10.0f, 20.0f, 0.0f, 0.0f);
pVertices[1] = CUSTOMVERTEX( 10.0f, 10.0f, 20.0f, 1.0f, 0.0f);
pVertices[2] = CUSTOMVERTEX( 10.0f, -10.0f, 20.0f, 1.0f, 1.0f);
pVertices[3] = CUSTOMVERTEX(-10.0f, -10.0f, 20.0f, 0.0f, 1.0f);
g_pMirrorMesh->UnlockVertexBuffer();

//[3].fill the index data
WORD *pIndices = NULL;
g_pMirrorMesh->LockIndexBuffer(0, (void**)&pIndices);
pIndices[0] = 0; pIndices[1] = 1; pIndices[2] = 2;
pIndices[3] = 0; pIndices[4] = 2; pIndices[5] = 3;
g_pMirrorMesh->UnlockIndexBuffer();

//[4].attribute data
DWORD* pAttrib = NULL;
g_pMirrorMesh->LockAttributeBuffer(0, &pAttrib);
//for(int a = 0; a < 4; a++) pAttrib[a] = 0;
g_pMirrorMesh->UnlockAttributeBuffer();

//[5].Create a texture
D3DXCreateTextureFromFile(g_pd3dDevice, L"skin.jpg", &g_mirrorTexture);
D3DXCreateTextureFromFile(g_pd3dDevice, L"boy.jpg", &g_projectTexture);

【II】SetRenderState and TextureState then Draw the mirror
g_pd3dDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);
g_pd3dDevice->SetTextureStageState(0, D3DTSS_TEXCOORDINDEX, D3DTSS_TCI_PASSTHRU);
g_pd3dDevice->SetTexture(0, NULL);
g_pd3dDevice->SetMaterial(&g_Materials[0]);
g_pMirrorMesh->DrawSubset(0);

【III】Enable Stencil buffer
g_pd3dDevice->SetRenderState(D3DRS_STENCILENABLE,    true);
g_pd3dDevice->SetRenderState(D3DRS_STENCILFUNC,      D3DCMP_ALWAYS);
g_pd3dDevice->SetRenderState(D3DRS_STENCILREF,       0x1);
g_pd3dDevice->SetRenderState(D3DRS_STENCILMASK,      0xffffffff);
g_pd3dDevice->SetRenderState(D3DRS_STENCILWRITEMASK, 0xffffffff);
g_pd3dDevice->SetRenderState(D3DRS_STENCILPASS,      D3DSTENCILOP_REPLACE);

【IV】Disable Zbuffer writer
g_pd3dDevice->SetRenderState(D3DRS_ZWRITEENABLE,     false);
g_pd3dDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, true);
g_pd3dDevice->SetRenderState(D3DRS_SRCBLEND,         D3DBLEND_ZERO);
g_pd3dDevice->SetRenderState(D3DRS_DESTBLEND,        D3DBLEND_ONE);
g_pd3dDevice->SetRenderState(D3DRS_CULLMODE,         D3DCULL_CCW);

【V】Draw the mirror into the Stencil buffer
g_pd3dDevice->SetMaterial(&g_Materials[0]);
g_pMirrorMesh->DrawSubset(0);

【VI】Enable Zbuffer writer and stencil function succeed when the mirror image in the mirror
g_pd3dDevice->SetRenderState(D3DRS_ZWRITEENABLE,     true);
g_pd3dDevice->SetRenderState(D3DRS_STENCILFUNC,      D3DCMP_EQUAL);
g_pd3dDevice->SetRenderState(D3DRS_STENCILPASS,      D3DSTENCILOP_KEEP);

【VII】Clear Zbuffer and blend the mirror image with the mirror
g_pd3dDevice->Clear(0, 0, D3DCLEAR_ZBUFFER, 0, 1.0f, 0);
g_pd3dDevice->SetRenderState(D3DRS_SRCBLEND,         D3DBLEND_DESTCOLOR);
g_pd3dDevice->SetRenderState(D3DRS_DESTBLEND,        D3DBLEND_ZERO);
g_pd3dDevice->SetRenderState(D3DRS_CULLMODE,         D3DCULL_CW);

【VIII】Calculate the reflect matrix
D3DXMATRIX matProjector;
D3DXPLANE planeXY(0.0f, 0.0f, -10.0f, 0.0f); //ax+by+cz+d=0
D3DXMatrixReflect(&matProjector, &planeXY);

//draw the project mirror image
matWorld = matWorld * matProjector;
g_pd3dDevice->SetTransform(D3DTS_WORLD, &matWorld);
for (DWORD i = 0; i < g_dwNumMtrls; i++)
{
g_pd3dDevice->SetMaterial(&g_pMaterials[i]);
g_pd3dDevice->SetTexture(0, g_pTextures[i]);
g_pMeshTiny->DrawSubset(i);
}

【IX】recover the render state
g_pd3dDevice->SetRenderState( D3DRS_STENCILENABLE,   false);
g_pd3dDevice->SetRenderState(D3DRS_CULLMODE,         D3DCULL_CCW);
g_pd3dDevice->SetRenderState(D3DRS_ZWRITEENABLE,     true);
g_pd3dDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, false);