Add example code for node colormap generation

This commit is contained in:
Nils Dagsson Moskopp 2022-07-31 00:24:15 +02:00
parent 685bdcb379
commit e9862f5f24
Signed by untrusted user who does not match committer: erlehmann
GPG Key ID: A3BC671C35191080
1 changed files with 32 additions and 0 deletions

32
colormap_generator.lua Normal file
View File

@ -0,0 +1,32 @@
dofile("init.lua")
-- This generates images necessary to colorize 16 Minetest nodes in 4096 colors.
-- It serves as a demonstration of what you can achieve using colormapped nodes.
-- It is be useful for grass or beam or glass nodes that need to blend smoothly.
-- Sample depth rescaling is done according to the algorithm presented in:
-- <https://www.w3.org/TR/2003/REC-PNG-20031110/#13Sample-depth-rescaling>
local max_sample_in = math.pow(2, 4) - 1
local max_sample_out = math.pow(2, 8) - 1
for r = 0,15 do
local pixels = {}
for g = 0,15 do
if nil == pixels[g + 1] then
pixels[g + 1] = {}
end
for b = 0,15 do
local color = {
math.floor((r * max_sample_out / max_sample_in) + 0.5),
math.floor((g * max_sample_out / max_sample_in) + 0.5),
math.floor((b * max_sample_out / max_sample_in) + 0.5),
}
pixels[g + 1][b + 1] = color
end
end
local filename = "colormap_" .. tostring(r) .. ".tga"
tga_encoder.image(pixels):save(
filename,
{ color_format="A1R5G5B5" } -- waste less bits
)
end