minetest/games/devtest/mods/testnodes/textures.lua
HybridDog cda112493a
Faster blit_with_alpha() (#14448)
* Add test nodes for alpha compositing and the fill texture modifier

Texture test nodes can be helpful to test if `blit_with_alpha` works correctly.

The alpha compositing test node covers different cases where pixel colors are mixed with each other.
The test currently fails because `blitPixel` does not work correctly if a semi-transparent color
is drawn on top of another semi-transparent color.
The test nodes for the fill texture modifier show if the size and position arguments of the modifier work correctly.
They do not cover special cases such as very large or negative position or size values.

* Faster blit_with_alpha()

The `blit_with_alpha` function has a noticeable effect on the time it takes to join a game.

To reduce the join times, I replace the `blit_with_alpha` function with a new one:
* It does not uses floating-point numbers.
* It directly operates on the raw pixel data instead of using the comparatively
  slow `setPixel` and `getPixel` functions from Irrlicht.
  Only ECF_A8R8G8B8 base images are supported now.
  If the top image does not have the ECF_A8R8G8B8 color format, it is converted;
  I assume that this happens rarely.
* There are case distinctions for fully opaque, fully transparent and semi-transparent pixels.
  This empirically increases the performance since the mixing between two semi-transparent happens rarely.
* The new function no longer has the `src_pos` argument since it was always the zero vector.
* The function is only documented once where it is declared.

For backwards compatibility, `blit_with_alpha` still mixes colors without gamma correction.
`blit_with_alpha` nonetheless behaves slightly different than before:
If a semi-transparent pixel is drawn on top of another semi-transparent pixel,
the color is mixed in a way which we can consider to be more correct now.
2024-03-19 19:56:47 +01:00

370 lines
11 KiB
Lua

-- Node texture tests
local S = minetest.get_translator("testnodes")
minetest.register_node("testnodes:6sides", {
description = S("Six Textures Test Node").."\n"..
S("Has 1 texture per face"),
tiles = {
"testnodes_normal1.png",
"testnodes_normal2.png",
"testnodes_normal3.png",
"testnodes_normal4.png",
"testnodes_normal5.png",
"testnodes_normal6.png",
},
groups = { dig_immediate = 2 },
})
minetest.register_node("testnodes:anim", {
description = S("Animated Test Node").."\n"..
S("Tiles animate from A to D in 4s cycle"),
tiles = {
{ name = "testnodes_anim.png",
animation = {
type = "vertical_frames",
aspect_w = 16,
aspect_h = 16,
length = 4.0,
}, },
},
groups = { dig_immediate = 2 },
})
minetest.register_node("testnodes:fill_positioning", {
description = S("Fill Modifier Test Node") .. "\n" ..
S("The node should have the same look as " ..
"testnodes:fill_positioning_reference."),
drawtype = "glasslike",
paramtype = "light",
tiles = {"[fill:16x16:#ffffff^[fill:6x6:1,1:#00ffdc" ..
"^[fill:6x6:1,9:#00ffdc^[fill:6x6:9,1:#00ffdc^[fill:6x6:9,9:#00ffdc"},
groups = {dig_immediate = 3},
})
minetest.register_node("testnodes:fill_positioning_reference", {
description = S("Fill Modifier Test Node Reference"),
drawtype = "glasslike",
paramtype = "light",
tiles = {"testnodes_fill_positioning_reference.png"},
groups = {dig_immediate = 3},
})
-- Node texture transparency test
local alphas = { 64, 128, 191 }
for a=1,#alphas do
local alpha = alphas[a]
-- Transparency taken from texture
minetest.register_node("testnodes:alpha_texture_"..alpha, {
description = S("Texture Alpha Test Node (@1)", alpha).."\n"..
S("Semi-transparent"),
drawtype = "glasslike",
paramtype = "light",
tiles = {
"testnodes_alpha"..alpha..".png",
},
use_texture_alpha = "blend",
groups = { dig_immediate = 3 },
})
-- Transparency set via texture modifier
minetest.register_node("testnodes:alpha_"..alpha, {
description = S("Alpha Test Node (@1)", alpha).."\n"..
S("Semi-transparent"),
drawtype = "glasslike",
paramtype = "light",
tiles = {
"testnodes_alpha.png^[opacity:" .. alpha,
},
use_texture_alpha = "blend",
groups = { dig_immediate = 3 },
})
end
minetest.register_node("testnodes:alpha_compositing", {
description = S("Alpha Compositing Test Node") .. "\n" ..
S("A regular grid should be visible where each cell contains two " ..
"texels with the same colour.") .. "\n" ..
S("Alpha compositing is gamma-incorrect for backwards compatibility."),
drawtype = "glasslike",
paramtype = "light",
tiles = {"testnodes_alpha_compositing_bottom.png^" ..
"testnodes_alpha_compositing_top.png"},
use_texture_alpha = "blend",
groups = {dig_immediate = 3},
})
-- Generate PNG textures
local function mandelbrot(w, h, iterations)
local r = {}
for y=0, h-1 do
for x=0, w-1 do
local re = (x - w/2) * 4/w
local im = (y - h/2) * 4/h
-- zoom in on a nice view
re = re / 128 - 0.23
im = im / 128 - 0.82
local px, py = 0, 0
local i = 0
while px*px + py*py <= 4 and i < iterations do
px, py = px*px - py*py + re, 2 * px * py + im
i = i + 1
end
r[w*y+x+1] = i / iterations
end
end
return r
end
local function gen_checkers(w, h, tile)
local r = {}
for y=0, h-1 do
for x=0, w-1 do
local hori = math.floor(x / tile) % 2 == 0
local vert = math.floor(y / tile) % 2 == 0
r[w*y+x+1] = hori ~= vert and 1 or 0
end
end
return r
end
-- The engine should perform color reduction of the generated PNG in certain
-- cases, so we have this helper to check the result
local function encode_and_check(w, h, ctype, data)
local ret = core.encode_png(w, h, data)
assert(ret:sub(1, 8) == "\137PNG\r\n\026\n", "missing png signature")
assert(ret:sub(9, 16) == "\000\000\000\rIHDR", "didn't find ihdr chunk")
local ctype_actual = ret:byte(26) -- Color Type (1 byte)
ctype = ({rgba=6, rgb=2, gray=0})[ctype]
assert(ctype_actual == ctype, "png should have color type " .. ctype ..
" but actually has " .. ctype_actual)
return ret
end
local fractal = mandelbrot(512, 512, 128)
local frac_emb = mandelbrot(64, 64, 64)
local checker = gen_checkers(512, 512, 32)
local floor = math.floor
local abs = math.abs
local data_emb = {}
local data_mb = {}
local data_ck = {}
for i=1, #frac_emb do
data_emb[i] = {
r = floor(abs(frac_emb[i] * 2 - 1) * 255),
g = floor(abs(1 - frac_emb[i]) * 255),
b = floor(frac_emb[i] * 255),
a = frac_emb[i] < 0.95 and 255 or 0,
}
end
for i=1, #fractal do
data_mb[i] = {
r = floor(fractal[i] * 255),
g = floor(abs(fractal[i] * 2 - 1) * 255),
b = floor(abs(1 - fractal[i]) * 255),
a = 255,
}
data_ck[i] = checker[i] > 0 and "#888" or "#000"
end
fractal = nil
frac_emb = nil
checker = nil
do
-- we used to write the textures to our mod folder. in order to avoid
-- duplication errors delete them if they still exist.
local path = core.get_modpath(core.get_current_modname()) .. "/textures/"
os.remove(path .. "testnodes_generated_mb.png")
os.remove(path .. "testnodes_generated_ck.png")
end
local textures_path = core.get_worldpath() .. "/"
core.safe_file_write(
textures_path .. "testnodes1.png",
encode_and_check(512, 512, "rgb", data_mb)
)
local png_ck = encode_and_check(512, 512, "gray", data_ck)
core.dynamic_add_media({
filename = "testnodes_generated_mb.png",
filepath = textures_path .. "testnodes1.png"
})
core.dynamic_add_media({
filename = "testnodes_generated_ck.png",
filedata = png_ck,
})
minetest.register_node("testnodes:generated_png_mb", {
description = S("Generated Mandelbrot PNG Test Node"),
tiles = { "testnodes_generated_mb.png" },
groups = { dig_immediate = 2 },
})
minetest.register_node("testnodes:generated_png_ck", {
description = S("Generated Checker PNG Test Node"),
tiles = { "testnodes_generated_ck.png" },
groups = { dig_immediate = 2 },
})
local png_emb = "[png:" .. minetest.encode_base64(
encode_and_check(64, 64, "rgba", data_emb))
minetest.register_node("testnodes:generated_png_emb", {
description = S("Generated In-Band Mandelbrot PNG Test Node"),
tiles = { png_emb },
drawtype = "allfaces", -- required because of transparent pixels
use_texture_alpha = "clip",
paramtype = "light",
groups = { dig_immediate = 2 },
})
minetest.register_node("testnodes:generated_png_src_emb", {
description = S("Generated In-Band Source Blit Mandelbrot PNG Test Node"),
tiles = { png_emb .. "^testnodes_damage_neg.png" },
drawtype = "allfaces", -- required because of transparent pixels
use_texture_alpha = "clip",
paramtype = "light",
groups = { dig_immediate = 2 },
})
minetest.register_node("testnodes:generated_png_dst_emb", {
description = S("Generated In-Band Dest Blit Mandelbrot PNG Test Node"),
tiles = { "testnodes_generated_ck.png^" .. png_emb },
groups = { dig_immediate = 2 },
})
png_ck = nil
png_emb = nil
data_emb = nil
data_mb = nil
data_ck = nil
--[[
The following nodes can be used to demonstrate the TGA format support.
Minetest supports TGA types 1, 2, 3 & 10. While adding the support for
TGA type 9 (RLE-compressed, color-mapped) is easy, it is not advisable
to do so, as it is not backwards compatible with any Minetest pre-5.5;
content creators should therefore either use TGA type 1 or 10, or PNG.
TODO: Types 1, 2 & 10 should have two test nodes each (i.e. bottom-top
and top-bottom) for 16bpp (A1R5G5B5), 24bpp (B8G8R8), 32bpp (B8G8R8A8)
colors.
Note: Minetest requires the optional TGA footer for a texture to load.
If a TGA image does not load in Minetest, append eight (8) null bytes,
then the string “TRUEVISION-XFILE.”, then another null byte.
]]--
minetest.register_node("testnodes:tga_type1_24bpp_bt", {
description = S("TGA Type 1 (color-mapped RGB) 24bpp bottom-top Test Node"),
drawtype = "glasslike",
paramtype = "light",
sunlight_propagates = true,
tiles = { "testnodes_tga_type1_24bpp_bt.tga" },
groups = { dig_immediate = 2 },
})
minetest.register_node("testnodes:tga_type1_24bpp_tb", {
description = S("TGA Type 1 (color-mapped RGB) 24bpp top-bottom Test Node"),
drawtype = "glasslike",
paramtype = "light",
sunlight_propagates = true,
tiles = { "testnodes_tga_type1_24bpp_tb.tga" },
groups = { dig_immediate = 2 },
})
minetest.register_node("testnodes:tga_type2_16bpp_bt", {
description = S("TGA Type 2 (uncompressed RGB) 16bpp bottom-top Test Node"),
drawtype = "glasslike",
paramtype = "light",
sunlight_propagates = true,
tiles = { "testnodes_tga_type2_16bpp_bt.tga" },
use_texture_alpha = "clip",
groups = { dig_immediate = 2 },
})
minetest.register_node("testnodes:tga_type2_16bpp_tb", {
description = S("TGA Type 2 (uncompressed RGB) 16bpp top-bottom Test Node"),
drawtype = "glasslike",
paramtype = "light",
sunlight_propagates = true,
tiles = { "testnodes_tga_type2_16bpp_tb.tga" },
use_texture_alpha = "clip",
groups = { dig_immediate = 2 },
})
minetest.register_node("testnodes:tga_type2_32bpp_bt", {
description = S("TGA Type 2 (uncompressed RGB) 32bpp bottom-top Test Node"),
drawtype = "glasslike",
paramtype = "light",
sunlight_propagates = true,
tiles = { "testnodes_tga_type2_32bpp_bt.tga" },
use_texture_alpha = "blend",
groups = { dig_immediate = 2 },
})
minetest.register_node("testnodes:tga_type2_32bpp_tb", {
description = S("TGA Type 2 (uncompressed RGB) 32bpp top-bottom Test Node"),
drawtype = "glasslike",
paramtype = "light",
sunlight_propagates = true,
tiles = { "testnodes_tga_type2_32bpp_tb.tga" },
use_texture_alpha = "blend",
groups = { dig_immediate = 2 },
})
minetest.register_node("testnodes:tga_type3_16bpp_bt", {
description = S("TGA Type 3 (uncompressed grayscale) 16bpp bottom-top Test Node"),
drawtype = "glasslike",
paramtype = "light",
sunlight_propagates = true,
tiles = { "testnodes_tga_type3_16bpp_bt.tga" },
use_texture_alpha = "blend",
groups = { dig_immediate = 2 },
})
minetest.register_node("testnodes:tga_type3_16bpp_tb", {
description = S("TGA Type 3 (uncompressed grayscale) 16bpp top-bottom Test Node"),
drawtype = "glasslike",
paramtype = "light",
sunlight_propagates = true,
tiles = { "testnodes_tga_type3_16bpp_tb.tga" },
use_texture_alpha = "blend",
groups = { dig_immediate = 2 },
})
minetest.register_node("testnodes:tga_type10_32bpp_bt", {
description = S("TGA Type 10 (RLE-compressed RGB) 32bpp bottom-top Test Node"),
tiles = { "testnodes_tga_type10_32bpp_bt.tga" },
drawtype = "glasslike",
paramtype = "light",
sunlight_propagates = true,
use_texture_alpha = "blend",
groups = { dig_immediate = 2 },
})
minetest.register_node("testnodes:tga_type10_32bpp_tb", {
description = S("TGA Type 10 (RLE-compressed RGB) 32bpp top-bottom Test Node"),
drawtype = "glasslike",
paramtype = "light",
sunlight_propagates = true,
tiles = { "testnodes_tga_type10_32bpp_tb.tga" },
use_texture_alpha = "blend",
groups = { dig_immediate = 2 },
})