Respect color.alpha by rendering.draw_something

[darkfrei]

You can try the code (note that a=0.5):

Code: Select all

/c  local p = game.player 
rendering.draw_rectangle{
  color={r=0, g=1, b=1, a=0.5}, 
  filled=true, 
  left_top={x=p.position.x-1.5, y=p.position.y-1.5}, 
  right_bottom={x=p.position.x+1.5, y=p.position.y+1.5}, 
  surface=p.surface}

Expected:

2019-06-04T19_53_05-Window.png (87.01 KiB) Viewed 2030 times

Got:

2019-06-04T19_51_07-Window.png (39.13 KiB) Viewed 2030 times

https://lua-api.factorio.com/latest/Lua ... _rectangle

[eradicator]

Code: Select all

/c  local p = game.player
 rendering.draw_rectangle{
 color = {r=1,g=0,b=0,a=0},
 filled=true, 
 left_top={x=p.position.x-1.5, y=p.position.y-1.5},
 right_bottom={x=p.position.x+1.5, y=p.position.y+1.5},
 surface=p.surface}

It's not completely ignored. It's just not applied correctly. Looks like (r+a)/2 instead of (r*a) to me.

[posila]

Factorio uses (and expects) colors in alpha-premultiplied format. https://factorio.com/blog/post/fff-172

if you want tint with {r=0, g=1, b=1} and alpha blend with alpha = 0.5, tint/color you need to pass in is {r=0, g=0.5, b=0.5, a=0.5}

[eradicator]

Factorio uses (and expects) colors in alpha-premultiplied format. https://factorio.com/blog/post/fff-172

if you want tint with {r=0, g=1, b=1} and alpha blend with alpha = 0.5, tint/color you need to pass in is {r=0, g=0.5, b=0.5, a=0.5}

/me goes to fix my color function... :oops:

[darkfrei]

It's not completely ignored. It's just not applied correctly. Looks like (r+a)/2 instead of (r*a) to me.

You are right, it works correct for gray black images only:

Code: Select all

/c  local p = game.player 
rendering.draw_rectangle{
color={r=0, g=0, b=0, a=0.5}, 
filled=true, 
left_top={x=p.position.x-1.5, y=p.position.y-1.5}, 
right_bottom={x=p.position.x+1.5, y=p.position.y+1.5}, 
surface=p.surface}

2019-06-04T20_41_18-Window.png (178.59 KiB) Viewed 2015 times

upd: rendering rectangles with all grayscales and alphas:

Code: Select all

/c 
local p = game.player
for x = 0, 10 do
  for y = 0, 10 do
    local color = x/10
    local alpha = y/10
    rendering.draw_rectangle{
      color={r=color, g=color, b=color, a=alpha}, 
      filled=true, 
      left_top =   {x=p.position.x   + x, y=p.position.y   + y}, 
      right_bottom={x=p.position.x+1 + x, y=p.position.y+1 + y}, 
      surface=p.surface}
  end
end

day and night results:

2019-06-04T21_20_20-Window.png (238.78 KiB) Viewed 2005 times

2019-06-04T21_21_34-Window.png (131.76 KiB) Viewed 2005 times

fog

upd2, fog emulation:

Code: Select all

/c 
local p = game.player
local y = 0
for x = 0, 10 do
  local color = x/10 * 0.4
  local alpha = x/10
  rendering.draw_rectangle{
    color={r=color, g=color, b=color, a=alpha}, 
    filled=true, 
    left_top =   {x=p.position.x   + x, y=p.position.y   + y}, 
    right_bottom={x=p.position.x+1 + x, y=p.position.y+1 + y}, 
    surface=p.surface}
end

day and night results:

2019-06-04T21_31_17-Window.png (72.33 KiB) Viewed 2005 times

2019-06-04T21_31_10-Window.png (85.37 KiB) Viewed 2005 times

upd3: another for simulation, darker for the middle:

Code: Select all

/c 
local p = game.player
local y = 0
for x = 0, 10 do
  local color = (x/10)^2 * 0.4
  local alpha = x/10
  rendering.draw_rectangle{
    color={r=color, g=color, b=color, a=alpha}, 
    filled=true, 
    left_top =   {x=p.position.x   + x, y=p.position.y   + y}, 
    right_bottom={x=p.position.x+1 + x, y=p.position.y+1 + y}, 
    surface=p.surface}
end

day and night results:

2019-06-04T21_35_02-Window.png (65.37 KiB) Viewed 2002 times

2019-06-04T21_35_14-Window.png (81.4 KiB) Viewed 2002 times

upd4: another fog simulation, bigger area

Code: Select all

/c  local p = game.player 
local amount =128 
for x = 0, amount do   
  local color = (x/amount) * 0.3   
  local alpha = (x/amount) * 0.8   
  rendering.draw_rectangle{
    color={r=color, g=color, b=color, a=alpha},      
    filled=true,      
    left_top =   {x=p.position.x   + x, y=p.position.y},      
    right_bottom={x=p.position.x+1 + x, y=p.position.y+32},      
    surface=p.surface} 
end

day and night results:

2019-06-04T22_24_52-Window.png (802.46 KiB) Viewed 2001 times

2019-06-04T22_25_40-Window.png (344.38 KiB) Viewed 2001 times