《directx第8章》PPT课件VIP

第8章Direct3D渲染技巧,主讲：苏振扬,课前回忆,示例程序：g_pd3dDevice-SetTextureStageState(0,D3DTSS_COLOROP,D3DTOP_MODULATE);g_pd3dDevice-SetTextureStageState(0,D3DTSS_COLORARG1,D3DTA_TEXTURE);g_pd3dDevice-SetTextureStageState(0,D3DTSS_COLORARG2,D3DTA_DIFFUSE);g_pd3dDevice-SetTextureStageState(0,D3DTSS_ALPHAOP,D3DTOP_DISABLE);,D3DTSS_SELECTARG2,D3DTSS_SELECTARG1,D3DTSS_SELECTARG1,D3DTSS_MODULATE,主要内容,8.1Alpha混合8.2Direct3d雾化效果8.3模板测试,8.1Alpha混合,8.1Alpha混合,进行Alpha混合操作时，首先绘制那些不需要进行融合的物体，然后将需要进行混合的物体按照相对于摄像机的深度值进行排序；最后，按照自后往前的顺序逐个绘制将要进行融合运算的物体。,8.1Alpha混合,Alpha混合原理Color=(RGBsrc*Ksrc)OP(RGBdst*Kdst)Color:Alpha混合后的颜色RGBsrc：当前计算得到的，要与后台缓存进行混合的像素颜色Ksrc：源混合因子RGBdst：当前处于后台缓存中的像素颜色值Kdst：目标混合因子OP通过D3DBLENDOP枚举常量指定，默认为D3DBLENDOP_ADD。,8.1Alpha混合,RGBsrc=？,RGBdst=？,背景颜色（红色）、漫反射颜色（蓝色）、纹理（颜色）,8.1Alpha混合,Alpha混合公式中的源混合系数和目标混合系数是通过D3DBLEND枚举常量指定。typedefenumD3DBLENDD3DBLEND_ZERO=1,D3DBLEND_ONE=2,D3DBLEND_SRCCOLOR=3,D3DBLEND_INVSRCCOLOR=4,D3DBLEND_SRCALPHA=5,D3DBLEND_INVSRCALPHA=6,D3DBLEND_DESTALPHA=7,D3DBLEND_INVDESTALPHA=8,D3DBLEND_DESTCOLOR=9,D3DBLEND_INVDESTCOLOR=10,D3DBLEND_SRCALPHASAT=11,D3DBLEND_BOTHSRCALPHA=12,D3DBLEND_BOTHINVSRCALPHA=13,D3DBLEND_BLENDFACTOR=14,D3DBLEND_INVBLENDFACTOR=15,D3DBLEND_SRCCOLOR2=16,D3DBLEND_INVSRCCOLOR2=17,D3DBLEND_FORCE_DWORD=0 x7fffffff,D3DBLEND,*LPD3DBLEND;,8.1Alpha混合,g_pd3dDevice-SetRenderState(D3DRS_BLENDOP,D3DBLENDOP_ADD);/设定混合方法g_pd3dDevice-SetRenderState(D3DRS_SRCBLEND,D3DBLEND_SRCALPHA);/设定源混合因子。D3DBLEND_SRCALPHA为当前绘制像素的Alpha值。g_pd3dDevice-SetRenderState(D3DRS_DESTBLEND,D3DBLEND_INVSRCALPHA);/设定目标混合因子，D3DBLEND_INVSRCALPHA为1减去当前绘制像素的Alpha值。Color=(RGBsrc*Alphasrc)+(RGBdst*(1-Alphasrc),8.1Alpha混合,当前像素Alpha值的设定。g_pd3dDevice-SetTextureStageState(0,D3DTSS_ALPHAOP,D3DTOP_SELECTARG1);g_pd3dDevice-SetTextureStageState(0,D3DTSS_ALPHAARG1,D3DTA_DIFFUSE);g_pd3dDevice-SetTextureStageState(0,D3DTSS_ALPHAOP,D3DTOP_SELECTARG1);g_pd3dDevice-SetTextureStageState(0,D3DTSS_ALPHAARG1,D3DTA_TEXTURE);,8.1Alpha混合,g_pd3dDevice-SetTextureStageState(0,D3DTSS_ALPHAOP,D3DTOP_MODULATE);,8.2Direct3d雾化效果,雾化效果原理Color=f*Colorsence+(1-f)*ColorfogColor最终经过雾化处理的颜色Colorsence物体原来的颜色Colorfog程序中定义的雾的颜色f雾化因子,8.2Direct3d雾化效果,雾化因子随距观察点的距离而衰减，其衰减规律取决于雾化模式。D3DFOG_NONED3DFOG_LINEAR，需要设置雾化开始和结束距离D3DFOG_EXP，需要设置雾的浓度D3DFOG_EXP2，需要设置雾的浓度,8.2Direct3d雾化效果,Direct3D采用了两种方法进行雾化处理：顶点雾化和像素雾化。顶点雾化由渲染状态D3DRS_FOGVETREMODE控制。像素雾化，由渲染状态D3DRS_FOGTABLEMODE控制。,8.2Direct3d雾化效果,1.激活雾化效果g_pd3dDevice-SetRenderState(D3DRS_FOGENABLE,true);2.设置雾化模式g_pd3dDevice-SetRenderState(D3DRS_FOGVERTEXMODE,D3DFOG_EXP);3.设置雾化参数g_pd3dDevice-SetRenderState(D3DRS_FOGCOLOR,D3DCOLOR_XRGB(45,50,170);staticfloatfogDensity=0.02f;g_pd3dDevice-SetRenderState(D3DRS_FOGDENSITY,*(DWORD*),8.3模板测试,8.3模板测试,模板测试过程模板测试使用模板参考值、模板掩码、模板比较函数以及当前像素在模板缓存中对应的模板值作为参数。如果通过了模板测试，绘制像素，如果为通过测试，则不绘制该像素，并按未通过模板测试的设定更改模板缓存。,8.3模板测试,模板缓存d3dpp.AutoDepthStencilFormat=D3DFMT_D24S8;D3DFMT_D15S1D3DFMT_D24S8D3DFMT_D24X4S4D3DFMT_D24FS8,8.3模板测试,1.模板参考值我们可用D3DRS_STENCILREF绘制状态改变该值g_pd3dDevice-SetRenderState(D3DRS_STENCILREF,0 x0);2.模板掩码模板掩码用于屏蔽模板参考值或者当前像素模板值g_pd3dDevice-SetRenderState(D3DRS_STENCILMASK,0 xffffffff);3.模板写掩码指定写入模板缓存中的掩码，默认为0 xffffffffg_pd3dDevice-SetRenderState(D3DRS_STENCILWRITEMASK,0 xffffffff);,8.3模板测试,4.模板值我们不能显式地单独设置模板值，但是可以对模板缓存进行清空操作。此外，还可以用模板的绘制状态控制要写入模板缓存的内容。typedefenumD3DSTENCILOPD3DSTENCILOP_KEEP=1,D3DSTENCILOP_ZERO=2,D3DSTENCILOP_REPLACE=3,D3DSTENCILOP_INCRSAT=4,D3DSTENCILOP_DECRSAT=5,D3DSTENCILOP_INVERT=6,D3DSTENCILOP_INCR=7,D3DSTENCILOP_DECR=8,D3DSTENCILOP_FORCE_DWORD=0 x7fffffff,D3DSTENCILOP,*LPD3DSTENCILOP;,8.3模板测试,5.比较运算typedefenumD3DCMPFUNCD3DCMP_NEVER=1,D3DCMP_LESS=2,D3DCMP_EQUAL=3,D3DCMP_LESSEQUAL=4,D3DCMP_GREATER=5,D3DCMP_NOTEQUAL=6,D3DCMP_GREATEREQUAL=7,D3DCMP_ALWAYS=8,D3DCMP_FORCE_DWORD=0 x7fffffff,D3DCMPFUNC,*LPD3DCMPFUNC;,8.3模板测试,7.三种测试状态D3DRS_STENCILFAILD3DRS_STENCILZFAILD3DRS_STENCILPASS,8.3模板测试,示例代码g_pd3dDevice-SetRenderState（D3DRS_STENCILENABLE,true);g_pd3dDevice-SetRenderState(D3DRS_STENCILFUNC,D3DCMP_EQUAL);g_pd3dDevice-SetRenderState(D3DRS_STENCIL