dx11 入门 Tutorial 06: 明白context->updateSubsource和setConstantBuffers DirectXSampleBrowser(June 2010)

cb1.vOutputColor = XMFLOAT4(0, 0, 0, 0);
	g_pImmediateContext->UpdateSubresource( g_pConstantBuffer, 0, NULL, &cb1, 0, 0 );
        //更新cube的数据
	//
	// Render the cube
	//
	g_pImmediateContext->VSSetShader( g_pVertexShader, NULL, 0 );
	g_pImmediateContext->VSSetConstantBuffers( 0, 1, &g_pConstantBuffer );
        //VS shader里需要constant数据
	g_pImmediateContext->PSSetShader( g_pPixelShader, NULL, 0 );
	g_pImmediateContext->PSSetConstantBuffers( 0, 1, &g_pConstantBuffer );
        //PS shader里传入constant数据
	g_pImmediateContext->DrawIndexed( 36, 0, 0 );
	//
	// Render each light
	//
	for( int m = 0; m < 2; m++ )
	{
		XMMATRIX mLight = XMMatrixTranslationFromVector( 5.0f * XMLoadFloat4( &vLightDirs[m] ) );
		XMMATRIX mLightScale = XMMatrixScaling( 0.2f, 0.2f, 0.2f );
        mLight = mLightScale * mLight;
		// Update the world variable to reflect the current light
		cb1.mWorld = XMMatrixTranspose( mLight );
		cb1.vOutputColor = vLightColors[m];
		g_pImmediateContext->UpdateSubresource( g_pConstantBuffer, 0, NULL, &cb1, 0, 0 );
                //更新lightCube的位置
		g_pImmediateContext->PSSetShader( g_pPixelShaderSolid, NULL, 0 );
                //由于light没有使用constant数据，所以不需要PSSetConstantBuffers

g_pImmediateContext->DrawIndexed( 36, 0, 0 ); }