G2_SetBlendAlpha

Syntax

#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

If the value of ev1 or ev2 is greater than 16, the alpha-blending coefficient is set to 16.

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 Specifies BG0.
GX_BLEND_PLANEMASK_BG1 Specifies BG1.
GX_BLEND_PLANEMASK_BG2 Specifies BG2.
GX_BLEND_PLANEMASK_BG3 Specifies BG3.
GX_BLEND_PLANEMASK_OBJ Specifies OBJs.
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

2008/10/30 Added description of the alpha-blending coefficients.

2006/04/21 Added description.

2004/01/19 Initial version.


CONFIDENTIAL