evmu_icondata.h File Reference

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Data Structures
struct	EvmuIconData

Macros
#define	EVMU_ICONDATA_VMS_FILE_NAME   "ICONDATA_VMS"
Field Sizes
Sizes and dimensions for icons
#define	EVMU_ICONDATA_DESCRIPTION_SIZE   16
#define	EVMU_ICONDATA_ICON_WIDTH   32
#define	EVMU_ICONDATA_ICON_HEIGHT   32
#define	EVMU_ICONDATA_VMU_ICON_BYTES   128
#define	EVMU_ICONDATA_DC_PALETTE_SIZE   16
#define	EVMU_ICONDATA_DC_PALETTE_BYTES   32
#define	EVMU_ICONDATA_DC_ICON_BYTES   512
Secret Bios
Definitions for secret BIOS information
#define	EVMU_ICONDATA_BIOS_SECRET_OFFSET   0x2c0
#define	EVMU_ICONDATA_BIOS_SECRET_BYTE_COUNT   16
Palette Colors
Extracting and packet palette colors
#define	EVMU_ICONDATA_PALETTE_ENTRY_A(c)
#define	EVMU_ICONDATA_PALETTE_ENTRY_R(c)
#define	EVMU_ICONDATA_PALETTE_ENTRY_G(c)
#define	EVMU_ICONDATA_PALETTE_ENTRY_B(c)
#define	EVMU_ICONDATA_PALETTE_ENTRY(a, r, g, b)

Functions
const uint8_t *	EvmuIconData_unlockSecretBiosBytes (void)

Detailed Description

EvmuIconData: Header for the ICONDATA_VMS reserved file.

ICONDATA_VMS is a reserved filename on the VMU filesystem that is treated differently by the Dreamcast's BIOS menu. Rather than having the regular EvmuVms header structure, it has a structure given by EvmuIconData.

An ICONDATA_VMS file provides the following:

• Custom VMU icon which is drawn to the VMU in the DC BIOS
• Custom DC icon which is drawn to the screen in the DC BIOS
• Optional byte sequence for unlocking the secret 3D DC BIOS

The VMU icon is a simple monochrome bitmap of exactly the resolution of the VMU screen while the Dreamcast icon is a 32x32 icon with a 16-bit, 16-entry color palette.

Note

In order to unlock the secret 3D Dreamcast BIOS, a particular byte sequence must appear within the ICONDATA_VMS file. This sequence must appear starting at byte offset 0x2c0 with the following 16 byte values:

Byte	Value	Byte	Value
0	0xda	8	0x18
1	0x69	9	0x92
2	0xd0	10	0x79
3	0xda	11	0x68
4	0xc7	12	0x2d
5	0x4e	13	0xb5
6	0xf8	14	0x30
7	0x36	15	0x86

Todo

• Set icondata icon if there is no game
• data present instead of the ES logo/screensaver
• good description of what IconData is

Bug

• Loading VMU image with both a game and an icondata just shows icon instead of starting game

Author

2023 Falco Girgis

Copyright

MIT License

Definition in file evmu_icondata.h.

Macro Definition Documentation

EVMU_ICONDATA_BIOS_SECRET_BYTE_COUNT

#define EVMU_ICONDATA_BIOS_SECRET_BYTE_COUNT   16

Number of bytes in the secret BIOS byte sequence

Definition at line 74 of file evmu_icondata.h.

EVMU_ICONDATA_BIOS_SECRET_OFFSET

#define EVMU_ICONDATA_BIOS_SECRET_OFFSET   0x2c0

Offset of the secret BIOS byte sequence.

Definition at line 73 of file evmu_icondata.h.

EVMU_ICONDATA_DC_ICON_BYTES

#define EVMU_ICONDATA_DC_ICON_BYTES   512

Total number of bytes for the DC icon

Definition at line 66 of file evmu_icondata.h.

EVMU_ICONDATA_DC_PALETTE_BYTES

#define EVMU_ICONDATA_DC_PALETTE_BYTES   32

Total number of bytes for the DC icon color palette.

Definition at line 65 of file evmu_icondata.h.

EVMU_ICONDATA_DC_PALETTE_SIZE

#define EVMU_ICONDATA_DC_PALETTE_SIZE   16

Number of entries in the DC icon color palette.

Definition at line 64 of file evmu_icondata.h.

EVMU_ICONDATA_DESCRIPTION_SIZE

#define EVMU_ICONDATA_DESCRIPTION_SIZE   16

Number of bytes in the EvmuIconData::description string.

Definition at line 60 of file evmu_icondata.h.

EVMU_ICONDATA_ICON_HEIGHT

#define EVMU_ICONDATA_ICON_HEIGHT   32

Height of the DC icon in pixels.

Definition at line 62 of file evmu_icondata.h.

EVMU_ICONDATA_ICON_WIDTH

#define EVMU_ICONDATA_ICON_WIDTH   32

Width of the DC icon in pixels.

Definition at line 61 of file evmu_icondata.h.

EVMU_ICONDATA_PALETTE_ENTRY

#define EVMU_ICONDATA_PALETTE_ENTRY	(		a,
			r,
			g,
			b )

Value:

            ((uint16_t)(((a & 0xf) << 12) | ((r & 0xf) <<  8) | ((g & 0xf) <<  4) | ((b & 0xf))))

Packs the channels given by a, r, g, b, into a single 16-bit palette entry color.

Definition at line 86 of file evmu_icondata.h.

#define EVMU_ICONDATA_PALETTE_ENTRY(a, r, g, b) \
            ((uint16_t)(((a & 0xf) << 12) | ((r & 0xf) <<  8) | ((g & 0xf) <<  4) | ((b & 0xf))))

EVMU_ICONDATA_PALETTE_ENTRY_A

#define EVMU_ICONDATA_PALETTE_ENTRY_A

(

c

)

Value:

((c >> 12) & 0xf)

Extracts the alpha channel from DC icon a palette entry.

Definition at line 81 of file evmu_icondata.h.

EVMU_ICONDATA_PALETTE_ENTRY_B

#define EVMU_ICONDATA_PALETTE_ENTRY_B

(

c

)

Value:

((c      ) & 0xf)

Extracts the blue channel from a DC icon palette entry

Definition at line 84 of file evmu_icondata.h.

EVMU_ICONDATA_PALETTE_ENTRY_G

#define EVMU_ICONDATA_PALETTE_ENTRY_G

(

c

)

Value:

((c >> 4 ) & 0xf)

Extracts the green channel from a DC icon palette entry.

Definition at line 83 of file evmu_icondata.h.

EVMU_ICONDATA_PALETTE_ENTRY_R

#define EVMU_ICONDATA_PALETTE_ENTRY_R

(

c

)

Value:

((c >> 8 ) & 0xf)

Extracts the red channel from a DC icon palette entry.

Definition at line 82 of file evmu_icondata.h.

EVMU_ICONDATA_VMS_FILE_NAME

#define EVMU_ICONDATA_VMS_FILE_NAME   "ICONDATA_VMS"

Reserved EvmuDirEntry::fileName value for EvmuIconData files.

Definition at line 54 of file evmu_icondata.h.

EVMU_ICONDATA_VMU_ICON_BYTES

#define EVMU_ICONDATA_VMU_ICON_BYTES   128

Total number of bytes for the VMU icon.

Definition at line 63 of file evmu_icondata.h.

Function Documentation

EvmuIconData_unlockSecretBiosBytes()

const uint8_t * EvmuIconData_unlockSecretBiosBytes

(

void

)

Returns the 16-byte ICONDATA sequence for unlocking the secret Dreamcast BIOS.