GXSetBlendMode

C Specification

#include <revolution/gx.h>

void GXSetBlendMode( 
GXBlendMode    type,
GXBlendFactor  src_factor, 
GXBlendFactor  dst_factor, 
GXLogicOp      op );

Arguments

type

the blend mode
Accepted values are:

Name	Mode
`GX_BM_NONE`	performs neither blending nor logical processing
`GX_BM_BLEND`	blending mode
`GX_BM_LOGIC`	logical processing mode
`GX_BM_SUBTRACT`	subtraction processing mode

src_factor

input coefficient
The pixel color created by the graphics processor is multiplied by this coefficient. Acceptable values are as follows:

Name	Description
`GX_BL_ZERO`	0.0
`GX_BL_ONE`	1.0
`GX_BL_DSTCLR`	the frame buffer color
`GX_BL_INVDSTCLR`	1.0 - (the frame buffer color)
`GX_BL_SRCALPHA`	the source alpha
`GX_BL_INVSRCALPHA`	1.0 - (the source alpha)
`GX_BL_DSTALPHA`	the frame buffer alpha
`GX_BL_INVDSTALPHA`	1.0 - (the frame buffer alpha)

This coefficient works only when type is GX_BM_BLEND.

dst_factor

the output coefficient
The current frame buffer pixel color is multiplied by this coefficient. Acceptable values are as follows:

Name	Description
`GX_BL_ZERO`	0.0
`GX_BL_ONE`	1.0
`GX_BL_SRCCLR`	source color
`GX_BL_INVSRCCLR`	1.0 - (the source color)
`GX_BL_SRCALPHA`	the source alpha
`GX_BL_INVSRCALPHA`	1.0 - (the source alpha)
`GX_BL_DSTALPHA`	the frame buffer alpha
`GX_BL_INVDSTALPHA`	1.0 - (the frame buffer alpha)

This coefficient works only when type is GX_BM_BLEND.

blend processing
The acceptable values and logical operations are as follows:

Name	Bit Operations as Expressed in C
`GX_LO_CLEAR`	dst = 0
`GX_LO_SET`	dst = 1
`GX_LO_COPY`	dst = src
`GX_LO_INVCOPY`	dst = ~src
`GX_LO_NOOP`	dst = dst
`GX_LO_INV`	dst = ~dst
`GX_LO_AND`	dst = src & dst
`GX_LO_NAND`	dst = ~(src & dst)
`GX_LO_OR`	dst = src \| dst
`GX_LO_NOR`	dst = ~(src \| dst)
`GX_LO_XOR`	dst = src ^ dst
`GX_LO_EQUIV`	dst = ~(src ^ dst)
`GX_LO_REVAND`	dst = src & ~dst
`GX_LO_INVAND`	dst = ~src & dst
`GX_LO_REVOR`	dst = src \| ~dst
`GX_LO_INVOR`	dst = ~src \| dest

This coefficient only functions when type is GX_BM_LOGIC.

Return Values

None.

Description

This function determines how the source image, generated by the graphics processor, is blended with the embedded frame buffer (EFB). Be aware that color updates are be enabled by calling GXSetColorUpdate. When type is set to GX_BM_NONE, the source data is written directly to the EFB. When type is set to GX_BM_BLEND, the source and EFB pixels are blended using the following formulae.

dst_pix_clr = src_pix_clr * src_factor + dst_pix_clr * dst_factor

The GX_BL_DSTALPHA / GX_BL_INVDSTALPHA can be used only when the EFB is set to the GX_PF_RGBA6_Z24 pixel format (see GXSetPixelFmt). If the pixel format is GX_PF_RGBA6_Z24 then src_factor and dst_factor are also applied to the alpha channel. To write the alpha channel to the EFB you must call GXSetAlphaUpdate.

When type is set to GX_BM_LOGIC, the source and EFB pixels are blended using logical bitwise operations. You can't use both blending and logic operations at the same time.

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