git-subtree-dir: mods/CORE/tga_encoder git-subtree-mainline: a5740f8edf894395605ce936272452cb84f1cd7f git-subtree-split: aad231f5e406a7c1eaafe6595a64b9c55f230692 |
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.. | ||
tools | ||
colormap_generator.lua | ||
donut.lua | ||
examples.lua | ||
init.lua | ||
LICENSE | ||
logo.lua | ||
mod.conf | ||
README.md |
tga_encoder
A TGA Encoder written in Lua without the use of external Libraries.
Created by fleckenstein for MineClone2, then improved by erlehmann.
May be used as a Minetest mod.
See examples.lua
for example code and usage hints.
Use Cases for tga_encoder
Encoding Textures for Editing
TGA images of types 1/2/3 consist of header data followed by a pixel array.
This makes it trivial to parse TGA files – and even edit pixels in-place.
No checksums need to be updated on any kind of in-place texture editing.
Tip: When storing an editable image in item meta, use zlib compression.
Legacy Minetest Texture Encoding
Minetest 5.4 did not include minetest.encode_png()
(or any equvivalent).
Since tga_encoder
is written in pure Lua, it does not need engine support.
Tip: Look at examples.lua
and the Minetest mod mcl_maps
for guidance.
Advanced Texture Format Control
The function minetest.encode_png()
always encodes images as 32bpp RGBA.
tga_encoder
allows saving images as grayscale, 16bpp RGBA and 24bpp RGB.
For generating maps from terrain, color-mapped formats can be more useful.
Encoding Very Small Textures
Images of size 8×8 or below are often smaller than an equivalent PNG file.
Note that on many filesystems files use at least 4096 bytes (i.e. 64×64).
Therefore, saving bytes on files up to a few 100 bytes is often useless.
Encoding Reference Textures
TGA is a simple format, which makes it easy to create reference textures.
Using a hex editor, one can trivially see how all the pixels are stored.
Supported Image Types
For all types, images are encoded in a fast single pass (i.e. append-only).
Color-Mapped Images (Type 1)
These images contain a palette, followed by pixel data.
A1R5G5B5
(8bpp RGB)B8G8R8
(8bpp RGB)B8G8R8A8
(8bpp RGBA)
True-Color Images (Type 2)
These images contain uncompressed RGB(A) pixel data.
A1R5G5B5
(16bpp RGBA)B8G8R8
(24bpp RGB)B8G8R8A8
(32bpp RGBA)
Grayscale Images (Type 3)
Y8
(8bpp grayscale)
Run-Length Encoded (RLE), True-Color Images (Type 10)
These images contain compressed RGB(A) pixel data.
A1R5G5B5
(16bpp RGBA)B8G8R8
(24bpp RGB)B8G8R8A8
(32bpp RGBA)
TODO
- Actually support
R8G8B8A8
input forA1R5G5B5
output - Add both zoomable and explorable maps to
mcl_maps
.