Textures & VRAM¶

The PS1 has a fixed 1MB of VRAM (1024x512 pixels at 16-bit). SplashEdit manages VRAM allocation automatically, but understanding the layout helps you optimize.

Texture Size Requirements

All textures must be power-of-two in both width and height. The maximum texture size is 256x256. SplashEdit does NOT validate this for you. Using non-power-of-two or oversized textures will produce broken results.

Valid sizes: 16x16, 32x32, 64x64, 128x128, 256x256 (and non-square like 32x64, 64x128, etc.)

VRAM Layout¶

The PS1 VRAM is 1024x512 pixels. Framebuffers are arranged vertically (stacked), not side-by-side:

  0         320       640       960  1024
  +---------+---------+---------+----+
  |         |                   |Font|
  | Frame-  |                   | Col|
  | buffer  |  Texture Atlas    | (64|
  | 1       |  Space            | px)|
  | 320x240 |                   |    |
  |---------|                   |    |  240
  |         |                   |    |
  | Frame-  |                   |    |
  | buffer  |                   |    |
  | 2       |                   |    |
  | 320x240 |                   |    |
  |         |                   |    |  480
  +---------+-------------------+----+  512

Framebuffers: Two 320x240 buffers stacked vertically for double-buffering (mandatory, uses 320x480 of VRAM)
Font Column: x=960-1023, reserved for system font and up to 3 custom fonts
Texture Atlas Space: Everything else is available for your textures and CLUTs (color palettes)

Bit Depth¶

Each object's texture can use one of three bit depths:

Bit Depth	Colors	VRAM Width Multiplier	Best For
4-bit	16 colors	1/4x	Simple textures, UI, fonts
8-bit	256 colors	1/2x	Most game textures
16-bit	32768 colors	1x	Photos, complex gradients

A 64x64 texture at 4-bit only uses 16x64 pixels of VRAM space. The same texture at 16-bit uses 64x64. Lower bit depth means more textures fit in VRAM.

Texture Quantization¶

SplashEdit automatically quantizes your Unity textures to PS1-compatible formats:

K-Means color clustering finds the optimal palette for the target color count
KD-Tree nearest neighbor maps each pixel to the closest palette entry
Floyd-Steinberg dithering distributes quantization error to neighboring pixels for smoother gradients

The result is a palette-indexed texture (4-bit or 8-bit) or direct-color (16-bit) packed into VRAM.

Color Palettes (CLUTs)¶

4-bit and 8-bit textures each have a CLUT (Color Look-Up Table) stored separately in VRAM. CLUTs are small (16 or 256 entries at 16 bits each) and are packed into available VRAM space.

Deduplication¶

If multiple objects share the same source texture and bit depth, SplashEdit stores it only once. The deduplication check compares the Unity texture asset reference and the bit depth setting. This happens automatically during export.

Tips¶

Use 4-bit aggressively

Many PS1 games used 4-bit textures everywhere. 16 colors with dithering looks surprisingly good on a CRT or low-resolution display. Saves 4x VRAM vs 16-bit.

Keep textures small

Common PS1 texture sizes: 32x32, 64x64, 128x128. Larger textures eat VRAM fast. Remember: max 256x256, power-of-two only.

Share materials

Every unique material creates a separate texture. Two objects with identical materials share one texture. Two objects with different materials pointing to the same image create two separate textures.