# G2_SetBlendAlpha

## C Specification

      #include <nitro/gx/g2.h>

      void G2_SetBlendAlpha(
          int plane1 /* GXBlendPlaneMask */,
          int plane2 /* GXBlendPlaneMask */,
          int ev1,
          int ev2
      );

## Arguments

plane1 | Selects the first target plane for blending (result of logical OR with `GXBlendPlaneMask` type values)
plane2 | Selects the second target plane for blending (result of logical OR with `GXBlendPlaneMask` type values)
`ev1` | alpha-blending coefficient for the first target screen (0 ≤ `ev1` ≤ 31)
`ev2` | alpha-blending coefficient for the second target screen (0 ≤ `ev2` ≤ 31)

## Return Values

None.

## Description

This function performs alpha-blending when the second target screen immediately follows the first target screen. You cannot specify a backdrop screen for the first target screen. Even if no OBJ is specified in the first target screen, alpha-blending is performed on the translucent OBJ, bitmap OBJ, and 3D screen.

`GX_BLEND_PLANEMASK_NONE` | No plane is specified.
`GX_BLEND_PLANEMASK_BG0` | Indicates that BG0 is visible.
`GX_BLEND_PLANEMASK_BG1` | Indicates that BG1 is visible.
`GX_BLEND_PLANEMASK_BG2` | Indicates that BG2 is visible.
`GX_BLEND_PLANEMASK_BG3` | Indicates that BG3 is visible.
`GX_BLEND_PLANEMASK_OBJ` | Indicates that OBJs are visible.
`GX_BLEND_PLANEMASK_BD` | Specifies the backdrop plane.

The following indicates the type definition for `GXBlendPlaneMask` types.

    typedef enum
    {
        GX_BLEND_PLANEMASK_NONE = 0x0000,
        GX_BLEND_PLANEMASK_BG0 = 0x0001,
        GX_BLEND_PLANEMASK_BG1 = 0x0002,
        GX_BLEND_PLANEMASK_BG2 = 0x0004,
        GX_BLEND_PLANEMASK_BG3 = 0x0008,
        GX_BLEND_PLANEMASK_OBJ = 0x0010,
        GX_BLEND_PLANEMASK_BD = 0x0020
    }
    GXBlendPlaneMask;

## See Also

`G2_BlendNone, G2_SetBlendBrightness, G2_SetBlendBrightnessExt, G2_ChangeBlendAlpha, G2_ChangeBlendBrightness`

## Revision History

Ver. 04/21/2006 Added description.

01/19/2004 Initial version.

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