Author Topic: Zelda Roth Reproduced Intro Help  (Read 270 times)

Tulk

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Zelda Roth Reproduced Intro Help
« on: June 25, 2017, 07:56:34 am »
Hello guys! I tried to reproduce the intro from Zelda Roth and got this error: line 27:31 >


Code: [Select]
Error: In maps/intro: [string:"maps/intro.lua"]:33: attempt to index a nil value
The code:

Code: [Select]
-- Frescos.
local frescos = {}
for i = 1, 5 do
  frescos[i] = sol.surface.create("menus/intro/intro" .. i .. ".png")
  frescos[i]:set_xy(0, 16)
end

It's the same code maked by Christopho's, Just change quantitis on for. What's wrong with it?
« Last Edit: June 25, 2017, 07:58:35 am by Tulk »

Diarandor

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Re: Zelda Roth Reproduced Intro Help
« Reply #1 on: June 25, 2017, 09:56:57 am »
The error is in line 33 of your script (could you post the code of all the script?).
It says that you are trying to index (access an attribute) of a nil variable (the variable has nothing attached so you cannot access the attribute and hence you get an error; you need a list to access an attribute).

Tulk

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Re: Zelda Roth Reproduced Intro Help
« Reply #2 on: June 25, 2017, 10:37:44 am »
Code: [Select]
local map = ...
local game = map:get_game()

-- Intro.

local map_width, map_height = map:get_size()

game:set_hud_enabled(false)
hero:set_enabled(false)

-- Scrolling backgrounds.
local bg1_img = sol.surface.create("menus/intro/bg1.png")
local bg1_width, bg1_height = bg1_img:get_size()
local bg1_xy = {}
local bg1_movement = sol.movement.create("straight")
bg1_movement:set_angle(3 * math.pi / 4)
bg1_movement:set_speed(32)
bg1_movement:start(bg1_xy)

local bg2_img = sol.surface.create("menus/intro/bg2.png")
local bg2_width, bg2_height = bg2_img:get_size()
local bg2_xy = {}
local bg2_movement = sol.movement.create("straight")
bg2_movement:set_angle(math.pi / 4)
bg2_movement:set_speed(32)
bg2_movement:start(bg2_xy)

-- Frescos.

local frescos = {}
for i = 1, 4 do
  frescos[i] = sol.surface.create("menus/intro/intro" .. i .. ".png")
  frescos[i]:set_xy(0, 16)
end
local fresco_index = 0  -- Index of the current fresco.

-- Dialog.
local dialog_background_img = sol.surface.create(256, 64)
dialog_background_img:set_xy(32, 160)
dialog_background_img:fill_color({255, 255, 128, 128})

function bg1_movement:on_position_changed(x, y)

  if y <= -bg1_height then
    bg1_movement:set_xy(0, 0)
  end

end

function bg2_movement:on_position_changed(x, y)

  if y <= -bg2_height then
    bg2_movement:set_xy(0, 0)
  end

end

local function next_fresco()


  if fresco_index < #frescos then
    fresco_index = fresco_index + 1
    game:start_dialog("intro.fresco_" .. fresco_index, next_fresco)
  else
    -- Restore usual settings.
    game:get_dialog_box():set_style("box")
    game:get_dialog_box():set_position("bottom")
    hero:unfreeze()

    -- Go to the first map.
   -- hero:teleport("houses/link_house", "from_intro")
  end
end

function map:on_started()

  game:get_dialog_box():set_style("empty")
  game:get_dialog_box():set_position({ x = 32, y = 160})
  next_fresco()
end

function map:on_opening_transition_finished()

  hero:freeze()
end

function map:on_draw(dst_surface)

  -- Scrolling backgrounds.
  for y = -bg2_height, map_height + bg2_height, bg2_height do
    for x = -bg2_width, map_width + bg2_width, bg2_width do
      bg2_img:draw(dst_surface, bg2_xy.x + x, bg2_xy.y + y)
    end
  end

  for y = -bg1_height, map_height + bg1_height, bg1_height do
    for x = -bg1_width, map_width + bg1_width, bg1_width do
      bg1_img:draw(dst_surface, bg1_xy.x + x, bg1_xy.y + y)
    end
  end

  -- Fresco.
  if fresco_index > 0 and fresco_index <= #frescos then
    frescos[fresco_index]:draw(dst_surface)
  end

  -- Dialog box background.
  dialog_background_img:draw(dst_surface)
end
« Last Edit: June 25, 2017, 10:40:00 am by Tulk »

Diarandor

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Re: Zelda Roth Reproduced Intro Help
« Reply #3 on: June 25, 2017, 11:09:12 am »
Thanks.

Ok, the error is exactly in line:
Code: Lua
  1. frescos[i]:set_xy(0, 16)
which means that
Code: [Select]
frescos[i] is nil, or in other words, your image has not been created in the previous line:
Code: Lua
  1. frescos[i] = sol.surface.create("menus/intro/intro" .. i .. ".png")
which in turn means that the id of the image (this one: "menus/intro/intro" .. i .. ".png") is not correct.
(The image has not been created by the engine since that file does not exist; there is something wrong in that string.)

MetalZelda

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Re: Zelda Roth Reproduced Intro Help
« Reply #4 on: June 25, 2017, 01:03:35 pm »
In most case, if frescos returns nil, this is because your surface isn't created because the file has not been found

Tulk

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Re: Zelda Roth Reproduced Intro Help
« Reply #5 on: June 25, 2017, 08:26:43 pm »
Thank you guys! xD


--------- @Edit:

How can I reproduce something like in this video: 1:34 - 1:38

https://www.youtube.com/watch?v=3Jm8_1zoZtw&list=PLaT85v0g5RS6Lshz4RUNGF8bpNqZHsmuM

The camera approaches on point of image on the screen in game intro. How to make it?
« Last Edit: June 25, 2017, 08:50:59 pm by Tulk »

Diarandor

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Re: Zelda Roth Reproduced Intro Help
« Reply #6 on: June 26, 2017, 02:14:38 am »
To do that zoom with that camera angle we may need something like this: https://en.wikipedia.org/wiki/Mode_7
Or maybe just a normal zoom (maybe this can already be done).

I don't remember if there are already requests for these features in github.


Diarandor

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Re: Zelda Roth Reproduced Intro Help
« Reply #8 on: June 26, 2017, 12:12:51 pm »
Probably, but I am not sure if that is the same thing, and also I don't know which license has that code (it could be incompatible with GPL).

Anyway, you cannot directly add a library without coding something in the engine (the C++ part).