Direct3D 光照和材质

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今天我们来学习下Direct3D里面的光源和材质.

四大光照类型:

环境光	Ambient Light	一个物体没有被光照直接照射,通过每一些物体反射的光线到达这个物体,它也有可能被看到.这种称为环境光
漫反射光	Diffuse Light	这种类型光沿着特定的方向传播,当达到某一个表面,它会向四周方向均匀反射(重点考虑反射光的空间位置和方向)
镜面反射光	Specular Light	当此类光到达一个表面时,严格地沿着一个方向反射。
自发光	Emissive Light	自发光就是对象自己发光

环境光的开启:

Device->SetRenderState(D3DRS_AMBIENT,D3DCOLOR_XRGB(50,50,36));

镜面反射光开启:

Device->SetRenderState(D3DRS_SPECULARENABLE,true);

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三大光源类型:

点光源(Point Light)具有颜色和位置,但是没有方向,它向所有方向发射光都一样,光源不会因为距离而衰减

方向光源(direction Light) 在场景中以相同的方向传播,具有颜色和方向,不受到衰减和范围的影响.

聚光灯源, 在我们生活中有手电筒由一个内圆柱体和外圆柱体组成,光从最中心位置到外围逐渐衰减. Phi和Theta分别是两个圆锥体的里面夹角大小

创建点光源:

D3DLIGHT9 light;
::ZeroMemory(&light,sizeof(light));
light.Type = D3DLIGHT_POINT;                               //各种光源类型,现在是点光源
light.Ambient = D3DXCOLOR(0.8f,0.8f,0.8f,1.0f);            //下面三个参数是环境光,漫反射光,镜面反射光的颜色值
light.Diffuse = D3DXCOLOR(1.0f,1.0f,1.0f,1.0f);
light.Specular = D3DXCOLOR(0.3f,0.3f,0.3f,1.0f);
light.Position = D3DXVECTOR3(0.0f,200.0f,0.0f);            //坐标位置
light.Attenuation0 = 1.0f;                                 //下面三个参数是光随着距离衰减的系数
light.Attenuation1 = 0.0f;                                
light.Attenuation2 = 0.0f;                                
light.Range = 300.0f;                                      //光照的范围,在某些光源中才有效果
Device->SetLight(0,&light);                                //设置光源
Device->LightEnable(0,true);                               //开启光源

创建方向光源:

//创建方向光源
D3DLIGHT9 light;
::ZeroMemory(&light,sizeof(light));
light.Type = D3DLIGHT_DIRECTIONAL; //方向光源
light.Ambient = D3DXCOLOR(0.5f,0.5f,0.5f,1.0f);
light.Diffuse = D3DXCOLOR(1.0f,1.0f,1.0f,1.0f);
light.Specular = D3DXCOLOR(0.3f,0.3f,0.3f,1.0f);
light.Direction = D3DXVECTOR3(0.0f,0.0f,1.0f);
Device->SetLight(0,&light);
Device->LightEnable(0,true);

创建聚光灯:

D3DLIGHT9 light;
::ZeroMemory(&light,sizeof(light));
light.Type = D3DLIGHT_SPOT;
light.Position = D3DXVECTOR3(100.0f,100.0f,100.0f);
light.Direction = D3DXVECTOR3(-1.0f,-1.0f,-1.0f);
light.Ambient = D3DXCOLOR(0.3f,0.3f,0.3f,1.0f);
light.Diffuse = D3DXCOLOR(1.0f,1.0f,1.0f,1.0f);
light.Specular = D3DXCOLOR(0.3f,0.3f,0.3f,0.3f);
light.Attenuation0 = 1.0f;
light.Attenuation1 = 0.0f;
light.Attenuation2 = 0.0f;
light.Range = 300.0f;
light.Falloff = 0.1f;
light.Phi = D3DX_PI / 3.0f;
light.Theta = D3DX_PI / 6.0f;
Device->SetLight(0,&light);
Device->LightEnable(0,true);

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材质:

光照和材质就像两个好基友,物体表面的材质属性决定了它能反射什么颜色的光线,以及能反射多少, 材质是属于某一个物体的,

来学习下如何创建材质

//创建材质:
D3DMATERIAL9 mtrl;
::ZeroMemory(&mtrl,sizeof(mtrl));
mtrl.Ambient = D3DXCOLOR(0.5f,0.5f,0.7f,1.0f);            //表示物体表面对环境光的反射率,填写一个颜色,ARGB值在0-1之间
mtrl.Diffuse = D3DXCOLOR(0.6f,0.6f,0.6f,1.0f);            //对漫反射光的反射率
mtrl.Specular = D3DXCOLOR(0.3f,0.3f,0.3f,0.3f);            //对镜面反射光的反射率
mtrl.Emissive = D3DXCOLOR(0.0f,0.0f,0.0f,1.0f);            //对自发光颜色的反射率
mtrl.Power = 0.1f;
Device->SetMaterial(&mtrl);    //设置材质

物体的顶点颜色的亮度总和有一个公式:

颜色总和 = 环境光 + 漫反射光 + 镜面反射光 + 自发光