4.1 KiB
TIM files
Standard bitmap images that can be transferred directly to the PSX VRAM.
Can be 4bit or 8bit with a CLUT (Colour Look Up Table), 16bit or 24 bit in direct color.
See this page for further information on how information is stored in the 16/24bpp modes.
You can access the TIM mode through TIM_IMAGE->mode. Mode can be :
- 0: 4bits b0
- 1: 8 bits b1
- 2: 16 bits b10
- 3: 24bits b11
- 4: mixed b100
See FileFormat47.pdf, p.179
Transparency
In 16bpp mode, only 15b are used for colors (R 5, G 5, B 5). The 15th bit is defined as the STP or Semi-Transparency flag.
A primitive transparency is set with SetSemiTrans().
The only case where a primitive with unset (=0) STP is transparent is when all values are 0. i.e ; using STP 0, B 0, G 0, R 0
will result in a transparent pixel wether the primitive is set to semi-tranparent or not.
Here are the transparency modes for various values on semi-transparent and opaque primitives :
| STP, B, G, R | (0, 0, 0, 0) | (1, 0, 0, 0) | (0, n, n, n) | (1, n, n, n) |
|---|---|---|---|---|
| Non-transparent primitive | Transparent | Black | Non-transparent | Non-transparent |
| Semi-transparent primitive | Transparent | Semi-transparent | Non-transparent black | Semi-transparent |
See FileFormat47.pdf, p.56, p.192,
LibOver47.pdf, p.107
img2tim semi-transparency options
img2tim has several options related to pixel transparency :
-t: Set semi-transparent bit (STP) on non fully black pixels. This will set the STP to 1 on pixels with RGB values different from B0,G0,R0.-usealpha: Use alpha channel (if available) as transparency mask. This will use the converted image's alpha channel (PNG, TGA, TIFF, GIF)-alpt <value>: Threshold value when alpha channel is used as transparency mask (Default: 127). Transparency values above this wil be treated as opaque.-tindex <col>: Specify color index to be treated as transparent (ignored on non palletized images). When using 4bpp/8bpp, specified color to be used as transparent.-tcol <r g b>: Specify RGB color value to be treated as transparent. Same as above for 16bpp.
Tools
You can use open source tools : Gimp, Aseprite
To convert your image files to TIM, use IMG2TIM :
4bpp and 8bpp specificities
If you want to generate 4bpp and 8bpp TIMs, your original image must be in indexed mode with a palette.
-
For 8bpp, < 256 colors , and dimensions must be a multiple of 2
-
For 4bpp, < 16 colors, and dimensions must be a multiple of 4
See FileFormat47.pdf, p.182
You can use TIMTOOL.EXE from legacy PsyQ to check your TIM files, or use Lameguy64's TIMedit
Reproducing the TIM in this example
Image > 4bpp, 8bpp
To convert your images to palettized 4bpp and 8bpp pngs, you can use pngquant :
4bpp (16 colors) image :
pngquant 16 input.png -o output.png --force
8bpp (256 colors) image :
pngquant 256 input.png -o output.png --force
Alternatively, you can use imagemagick :
4bpp (16 colors) image :
convert input.png -colors 16 output.png
8bpp (256 colors) image :
convert input.png -colors 256 output.png
PNG > Tim
img2tim -bpp 4 -org 512 0 -plt 0 481 -usealpha -o TIM4.tim TIM4.png
img2tim -bpp 8 -org 512 256 -plt 0 480 -usealpha -o TIM8.tim TIM8.png
img2tim -bpp 16 -org 768 0 -usealpha -o TIM16.tim TIM16.png
Content of Makefile :
SRCS = hello_sprt.c \
../common/crt0/crt0.s \
TIM/TIM16.tim \
TIM/TIM8.tim \
TIM/TIM4.tim \