GXPokeBlendMode

C Specification

#include <revolution/gx.h>

void GXPokeBlendMode( 
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 blend nor logical processing
`GX_BM_BLEND`	the blend mode
`GX_BM_LOGIC`	logical operation mode
`GX_BM_SUBTRACT`	subtraction processing mode

src_factor

source coefficient
The pixel color generated by the GP is multiplied by this coefficient. Applicable values are indicated in the table below.

Name	Coefficient 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)

dst_factor

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

Name	Coefficient 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)

blend processing
Applicable values and logical operations are indicated in the table below.

Name	Logical Bit Operations 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

Return Values

None.

Description

This function determines how the source image, written with the GXPoke* function, is blended with the current embedded frame buffer (EFB). No color data is written to the EFB when type is set to GX_CM_NONE. When type is set to GX_CM_BLEND, the source and EFB pixels are blended using the following equation:

dst_pix_clr = src_pix_clr * src_factor + dst_pix_clr * dst_factor

dst_factor can be used only when the frame buffer has a GX_PF_RGBA6_Z24 pixel format (see GXSetPixelFmt).

When type is set to GX_CM_LOGIC, the source and EFB pixels are blended using logical bitwise operations.

This function does not affect the normal rendering state, GXSetBlendMode.

When GX_BM_SUBTRACT is used for type, the destination pixel is calculated as follows:

dst_pix_clr = dst_pix_clr - src_pix_clr [clamped to zero]

Be aware that src_factor and dst_factor are not part of the equation.

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