View source for GameCube and Wii Image Formats

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There are different image formats supported on [[GameCube]] and [[Wii]]. Textures are generally large and requires a lot of memory. Choosing the correct texture format is important in order to maximize performance, save memory and recieving best quality contra size. This articles describes the different image formats supported on both GameCube and Wii.

== Blocks ==
For optimization, all images are encoded into blocks instead of storing the image data row by row. The block width and height depends on the format.

== Image Formats ==
{| class="textbox grid alt center sortable"
|+ Image Formats
|-
! ID !! Name !! Bits Per Pixel (BPP) !! Block Width !! Block Height !! Block Size !! Type
|-
| 0x00 || [[#I4|I4]] || 4 || 8 || 8 || 32 bytes || Luminance
|-
| 0x01 || [[#I8|I8]] || 8 || 8 || 4 || 32 bytes || Luminance
|-
| 0x02 || [[#IA4|IA4]] || 8 || 8 || 4 || 32 bytes || Luminance + Alpha
|-
| 0x03 || [[#IA8|IA8]] || 16 || 4 || 4 || 32 bytes || Luminance + Alpha
|-
| 0x04 || [[#RGB565|RGB565]] || 16 || 4 || 4 || 32 bytes || Color
|-
| 0x05 || [[#RGB5A3|RGB5A3]] || 16 || 4 || 4 || 32 bytes || Color + Alpha
|-
| 0x06 || [[#RGBA8|RGBA8]] || 32 || 4 || 4 || 64 bytes || Color + Alpha
|-
| 0x08 || [[#C4|C4]] || 4 || 8 || 8 || 32 bytes || Palette (IA8, RGB565, RGB5A3)
|-
| 0x09 || [[#C8|C8]] || 8 || 8 || 4 || 32 bytes || Palette (IA8, RGB565, RGB5A3)
|-
| 0x0A || [[#C14X2|C14X2]] || 16 || 4 || 4 || 32 bytes || Palette (IA8, RGB565, RGB5A3)
|-
| 0x0E || [[#CMPR|CMPR]] || 4 || 8 || 8 || 32 bytes || Compressed Color + Alpha
|}

=== I4 ===
'''I4''' is an intensity format which uses 4-bit luminance. Since the BPP is lower than 8, 1 byte is actually used for two pixels. The upper nibble stores the first pixel and the lower one stores the second pixel.

=== I8 ===
'''I8''' is an intensity format which uses 8-bit luminance.

=== IA4 ===
'''IA4''' is a format which uses 4-bit luminance and 4-bit alpha. The upper nibble stores the luminance value, and the lower nibble stores the alpha.

=== IA8 ===
'''IA8''' is a format which uses 8-bit luminance and 8-bit alpha. The luminance byte is stored before the alpha byte.

=== RGB565 ===
'''RGB565''' is a format which uses 5-bit red, 6-bit green and 5-bit blue. A pixel is stored in the following layout:<br>
<font color="red">RRRR R</font><font color="green">GGG GGG</font><font color="blue">B BBBB</font>

=== RGB5A3 ===
'''RGB565''' is a format which can either store 4-bit red, 4-bit green, 4-bit blue and 3 bit alpha, or 5-bit red, 5 bit green and 5-bit blue. The top bit decides this. A pixel is stored in the following layout:<br>
RGB5: 1<font color="red">RRR RR</font><font color="green">GG GGG</font><font color="blue">B BBBB</font><br>
RGB4A3: 0<font color="gray">AAA</font> <font color="red">RRRR</font> <font color="green">GGGG</font> <font color="blue">BBBB</font>

=== RGBA8 ===
'''RGBA8''' is a format which uses 8-bit red, 8-bit green, 8-bit blue and 8-bit alpha. It is not recommended to use as it uses lots of memory. The components are stored in a special way. First all alpha and red components in a block is stored, and then comes the green and blue components of the same block after.

=== C4 ===
'''C4''' is a palette format used to specify 4-bit indices into a color array. The colors are stored in a palette, and the colors are encoded into a [[#Palette Formats|palette format]]. The maximum amount of colors that can be stored is 16.

=== C8 ===
'''C8''' is a palette format used to specify 8-bit indices into a color array. The colors are stored in a palette, and the colors are encoded into a [[#Palette Formats|palette format]]. The maximum amount of colors that can be stored is 256.

=== C14X2 ===
'''C8''' is a palette format used to specify 14-bit indices into a color array. The two top-most bits are ignored. The colors are stored in a palette, and the colors are encoded into a [[#Palette Formats|palette format]]. The maximum amount of colors that can be stored is 16384.

=== CMPR ===
The CMPR format is a compressed image format. It uses the [https://en.wikipedia.org/wiki/S3_Texture_Compression#DXT1 DXT1 algorithm] (also known as BC1). It's a lossy compression to achieve a 4-bit BPP. It has also the possibility for a 1 bit alpha channel.

== Palette Formats ==
{| class="textbox grid alt center sortable"
|+ Image Formats
|-
! ID !! Name !! Bits Per Palette Color !! Type
|-
| 0x00 || IA8 || 16 || Luminance + Alpha
|-
| 0x01 || RGB565 || 16 || Color
|-
| 0x02 || RGB5A3 || 16 || Color + Alpha
|}

== File Formats ==
The following file formats support all image formats:
* [[BMD]]
* [[BREFT]]
* [[BRFNT]]
* [[BRRES]]
* [[BTI]]
* [[TPL]]

[[Category:Wii]]
[[Category:GameCube]]