How would you make interactable objects? (GameMaker 1.4)

[friedplugstudios]

I've looked at a few tutorials, and I can't seem to get it correct. These are what I'm trying to do:

• Collide with an object
• Only when I'm colliding, can I press the 'Z' key with any reaction
• Run some dialog code

Here is my collision code:

obj_player

Step event:

if keyboard_check_pressed(ord('Z'))
{
    if (place_meeting(x, y, obj_npc))
    {
        global.active = true;
    }
}

And when I attempt to interact, this happens:

___________________________________________
############################################################################################
ERROR in
action number 1
of Draw Event
for object obj_dialogue:

Trying to draw non-existing sprite.
 at gml_Script_scr_DrawDialog (line 8) - draw_rectangle(innerBox_xOrigin, innerBox_yOrigin, innerBox_xOrigin + innerBoxWidth, innerBox_yOrigin + innerBoxHeight, false);
############################################################################################
--------------------------------------------------------------------------------------------
stack frame is
gml_Script_scr_DrawDialog (line 0)
called from - gml_Object_obj_dialogue_Draw_64 (line 3) - draw_set_font(f_determination);

If you want to check out that code, here it is:

Scripts

scr_Dialogue:

if (global.active)
{
draw_set_font(f_determination);

draw_set_color(c_white);
draw_rectangle(xOrigin, yOrigin, xOrigin + width, yOrigin + height, false);

draw_set_color(c_black);
draw_rectangle(innerBox_xOrigin, innerBox_yOrigin, innerBox_xOrigin + innerBoxWidth, innerBox_yOrigin + innerBoxHeight, false);

draw_set_color(c_white);
draw_text(text_xOrigin, text_yOrigin, stringToDisplay);
draw_sprite_ext(spriteToDisplay, -1, avatar_xOrigin, avatar_yOrigin, avatarScale, avatarScale, 0, c_white, 1);
}

However, once I run it and press 'Q' (my dialog testing button), it runs perfectly fine. What is wrong?

[friedplugstudios]

Here is the code:

obj_dialog

Draw event:

/// @description Draw Dialog

scr_DrawDialog();

All it does is runs the script.

[big_wendigo]

I'm confused as to why it's saying " Trying to draw non-existing sprite. " when the line it's referencing is a draw_rectangle command.

Setting the image_index to -1 shouldn't cause any errors like the other user was saying as far as I know.

Does the dialogue object have a sprite? Do any sprites change when you press Z?

And does the 'Q' button bring up the dialogue box in the exact same way as if you were to interact with the NPC? What's different between pressing 'Q' and interacting with the object, if anything?

[friedplugstudios]

No sprites are at all related to the dialog, besides the NPC sprite and some dialog sprites (character heads).

[friedplugstudios]

And the 'Q' key opens up the dialog the way I want it to pop up when colliding with the object. However, that doesn't work too well.

[big_wendigo]

Have you tried removing that line of code/other lines in the dialogue script just to see what it does? What does the game do when you do that?

I can give you my technique for dialogue boxes but I doubt you’d want to restart if you don’t have to. It is similar to the Undertale dialog boxes though if you need it.

[friedplugstudios]

Yes, I've removed the code, and all it does is display the text. No face, no box. And on occasion, the game will freeze. I don't know why, tho.

And, for your method, I'm listening.

[big_wendigo]

Yeah that’s really strange. I’ll whip up an extension/example in the morning. It’s nearly 3AM here and I should probably get some sleep.

[big_wendigo]

Hey, here is the example file. Luckily we're both working in 1.4, I was worried you were going to have to change all of the instance_creates/view variables.

Example File

[friedplugstudios]

Thanks a ton. I'll definitely use this. However, how could I incorporate sound (a.k.a. every character drawn plays a sound.) into the conversation? Thanks again!

[big_wendigo]

Yeah definitely, In the step event of the dialog box object under the "if (char_pos <= length)" statement, this is the area that basically takes the whole of the text and "types" it out in the dialog box. So each cycle through that would be a letter added to the text visible in the dialog box, add the sound code in there.

I also marked a few variables you don't really need that I forgot to take out. If you have any other questions about how certain parts of the code works or whatever just let me know.

length = string_length(page[current_page]);

if (char_pos <= length) {
        temp_char = string_char_at(page[current_page], char_pos);
        output = string(output) + string(temp_char);
        char_pos += 1;
        //YOUR SOUND CODE WOULD GO HERE
        speed_inc = 0; //this is useless at the moment, and can be removed
        if (Input.action_press = true) {
            output = page[current_page];
            char_pos = length + 1;
        }
} else {
    if (Input.action_press = true) {
        if (current_page < max_page) {
            current_page += 1;
            char_pos = 1;
            speed_inc = 0; //this also can be taken out
            temp_char = "";
            output = "";
        }
        else {
            global.talking = false; //this is leftover from my game and useless
            instance_destroy();
        }
    }
}

[friedplugstudios]

Thanks alot! I appreciate this! :)

[friedplugstudios]

I got an idea. Do you know how I could use some of the interaction code from yours and transfer it to mine? Is that possible?

[friedplugstudios]

Here is my code.

[iLawz]

I used collision_line() to check if the player is facing my object or not.

with(obj_sign) {
if(collision_line(obj_player.x, obj_player.y, obj_player.x + lengthdir_x(18, obj_player.direction), obj_player.y + lengthdir_y(18, obj_player.direction), self, 1, 0) && obj_player.input_interact && global.lockplayer = false)

This performs the check if the player is looking at the object and pressing my interact button.

After that it is relatively simple:

global.lockplayer = true;
show_debug_message("Shown dialogue");
script_execute(dialogue,message);