求助:怎么理解SetTextureStageState第二个参数为D3DTSS_TEXCOORDIND

skirock

下面的程序摘之DX文档中的一段,它是用于bump map的实现的
这里面理解不了d3dDevice->SetTextureStageState( *, D3DTSS_TEXCOORDINDEX, * )中间的参数为D3DTSS_TEXCOORDINDEX,为什么在base texture 那里设为1,而在bump map与
environment map中分别设为1,0; 请教:如何解释这个参数及其的设定值; 谢谢!

// Set the color operations and arguments to prepare for
//   bump mapping.

// Stage 0: The base texture
d3dDevice->SetTextureStageState( 0, D3DTSS_COLOROP, D3DTOP_MODULATE );
d3dDevice->SetTextureStageState( 0, D3DTSS_COLORARG1, D3DTA_TEXTURE );
d3dDevice->SetTextureStageState( 0, D3DTSS_COLORARG2, D3DTA_DIFFUSE );
d3dDevice->SetTextureStageState( 0, D3DTSS_ALPHAOP, D3DTOP_SELECTARG1 );
d3dDevice->SetTextureStageState( 0, D3DTSS_ALPHAARG1, D3DTA_TEXTURE );

d3dDevice->SetTextureStageState( 0, D3DTSS_TEXCOORDINDEX, 1 );//这里不懂

// Stage 1: The bump map - Use luminance for this example.

d3dDevice->SetTextureStageState( 1, D3DTSS_TEXCOORDINDEX, 1 ););//这里不懂

d3dDevice->SetTextureStageState( 1, D3DTSS_COLOROP, D3DTOP_BUMPENVMAPLUMINANCE);
d3dDevice->SetTextureStageState( 1, D3DTSS_COLORARG1, D3DTA_TEXTURE );
d3dDevice->SetTextureStageState( 1, D3DTSS_COLORARG2, D3DTA_CURRENT );

// Stage 2: A specular environment map

d3dDevice->SetTextureStageState( 2, D3DTSS_TEXCOORDINDEX, 0 ););//这里不懂

d3dDevice->SetTextureStageState( 2, D3DTSS_COLOROP, D3DTOP_ADD );
d3dDevice->SetTextureStageState( 2, D3DTSS_COLORARG1, D3DTA_TEXTURE );
d3dDevice->SetTextureStageState( 2, D3DTSS_COLORARG2, D3DTA_CURRENT );

hdm2968

你看不懂的地方是设置实用哪一套纹理坐标！
例如：
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d3dDevice->SetTextureStageState( 2, D3DTSS_TEXCOORDINDEX, 0 ););//这里不懂
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就是设置第3层纹理使用第1套纹理坐标！

skirock

嗯,的确
厉害,一句话就指出症结所在
谢谢!