| Microsoft DirectX 8.1 (Visual Basic) |
When illuminated by a light source, matte surfaces display diffuse light reflection. The brightness of diffuse light depends on the distance from the light source and the angle between the surface normal and the light source direction vector. The diffuse lighting effects simulated by lighting calculations produce only general effects.
Your application can simulate more complex diffuse lighting with texture light maps. Do this by adding the diffuse light map to the base texture, as shown in the following Microsoft® Visual Basic® code example.
' This example assumes that d3dDevice is a valid reference to ' a Direct3DDevice7 object. ' texBaseTexture is a valid reference to a texture. ' texDiffuseLightMap is a valid reference to a texture that contains ' RGB diffuse light map data. ' Set the base texture. Call d3dDevice.SetTexture(0, texBaseTexture) ' Set the base texture operation and args. Call d3dDevice.SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_MODULATE) Call d3dDevice.SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_TEXTURE) Call d3dDevice.SetTextureStageState(0, D3DTSS_COLORARG2, D3DTA_DIFFUSE) ' Set the diffuse light map. Call d3dDevice.SetTexture(1, texDiffuseLightMap) ' Set the blend stage. Call d3dDevice.SetTextureStageState(1, D3DTSS_COLOROP, D3DTOP_MODULATE) Call d3dDevice.SetTextureStageState(1, D3DTSS_COLORARG1, D3DTA_TEXTURE) Call d3dDevice.SetTextureStageState(1, D3DTSS_COLORARG2, D3DTA_CURRENT)