void SetBlendMode(int blendmode)

                Set the texture behavior with alpha channel.

blendmode:

See texture blend modes in DirectX documentation.

  BLEND_NONE         1

  BLEND_DISABLE   1

  BLEND_MODULATE       4

  BLEND_MODULATE2X  5

  BLEND_MODULATE4X  6

  BLEND_ADD           7

  BLEND_ADDSIGNED       8

  BLEND_ADDSIGNED2X  9

  BLEND_SUBTRACT        10

  BLEND_ADDSMOOTH    11