GMS 2 [Solved] How can i set a variable collison mask by code?

RDM

Member
Hey I could really appreciate some help with that problem and please excuse all style problems it's my first post.

Gamemaker Version: 2.1.4.288

How it should work:
I have 2 points that I can move through a grid and when I press a key an object is created at the top left position of an rectangle created by this 2 points.
Then this object/sprite is enlarged to fit the rectangle.
Problem:
The collision mask is not matching the rectangle. I somehow got to change it from it's normal collision mask but i don't know how and it's still too small.

obj_functioncall
Keypress 80(p)
Code:
#region //Creation of 2 marker Points
global.p1 = instance_create_layer(mouse_x,mouse_y,"layer_UI",obj_rooms);
global.p2 = instance_create_layer(mouse_x + 50,mouse_y + 50,"layer_UI",obj_rooms);
#endregion
upload_2018-4-17_17-28-10.png

obj_rooms
keypress 17(STRG)
That part should work but maybe the problem is already here.
Code:
#region //setting variables for roomvar p3x = global.p2.x
var p3x = global.p2.x
var p3y = global.p1.y
var p4x = global.p1.x
var p4y = global.p2.y
var px = 0
var py = 0
#region //setting start and end point
var p1_d = point_distance(0,0,global.p1.x,global.p1.y);
var p2_d = point_distance(0,0,global.p2.x,global.p2.y);
var p3_d = point_distance(0,0,p3x,p3y);
var p4_d = point_distance(0,0,p4x,p4y);
var minpd = min(p1_d,p2_d,p3_d,p4_d);
var maxpd = max(p1_d,p2_d,p3_d,p4_d);
if(minpd = p1_d){
global.rx = global.p1.x - 16
global.ry = global.p1.y - 16
}
if(minpd = p2_d){
global.rx = global.p2.x - 16
global.ry = global.p2.y - 16
}
if(minpd = p3_d){
global.rx = p3x - 16
global.ry = p3y - 16
}
if(minpd = p4_d){
global.rx = p4x - 16
global.ry = p4y - 16
}

if(maxpd = p1_d){
px = global.p1.x
py = global.p1.y
}
if(maxpd = p2_d){
px = global.p2.x
py = global.p2.y
}
if(maxpd = p3_d){
px = p3x 
py = p3y
}
if(maxpd = p4_d){
px = p4x
py = p4y
}
#endregion
#region //setting width and height always positive
global._width = px - global.rx + 16
if global._width < 0{
global._width = global._width * (-1)   
}
global._height = py - global.ry + 16
if global._height < 0{
global._height = global._height * (-1)   
}
#endregion
#endregion
#region //insert vars and create room
var new_room = instance_create_layer(global.rx,global.ry,"layer_rooms",obj_rooms_kitchen)
instance_destroy(obj_rooms)
#endregion
upload_2018-4-17_17-32-48.png
Grid removed to show drawn collision mask

obj_rooms_kitchen
draw
Code:
#region //extending sprite to given width and height and making it transparent
draw_sprite_stretched_ext(sprite_index,image_index,rx,ry,_width,_height,c_white,transparent_alpha)
bb_left = 0
bb_top = 0
bb_right = _width
bb_bot = _height
tolerance = 0
mask_index = sprite_collision_mask(sprite_index, true,2, bb_left, bb_top, bb_right, bb_bot, 1, tolerance);
//draw collision mask
draw_rectangle(bbox_left,bbox_top,bbox_right,bbox_bottom,true)

#endregion
I tried some variants of setting the collision mask and only this got a change of it.
But I don't know why it always stays at 64x64.

Thanks for any help.
 

jo-thijs

Member
Hey I could really appreciate some help with that problem and please excuse all style problems it's my first post.

Gamemaker Version: 2.1.4.288

How it should work:
I have 2 points that I can move through a grid and when I press a key an object is created at the top left position of an rectangle created by this 2 points.
Then this object/sprite is enlarged to fit the rectangle.
Problem:
The collision mask is not matching the rectangle. I somehow got to change it from it's normal collision mask but i don't know how and it's still too small.

obj_functioncall
Keypress 80(p)
Code:
#region //Creation of 2 marker Points
global.p1 = instance_create_layer(mouse_x,mouse_y,"layer_UI",obj_rooms);
global.p2 = instance_create_layer(mouse_x + 50,mouse_y + 50,"layer_UI",obj_rooms);
#endregion
View attachment 17807

obj_rooms
keypress 17(STRG)
That part should work but maybe the problem is already here.
Code:
#region //setting variables for roomvar p3x = global.p2.x
var p3x = global.p2.x
var p3y = global.p1.y
var p4x = global.p1.x
var p4y = global.p2.y
var px = 0
var py = 0
#region //setting start and end point
var p1_d = point_distance(0,0,global.p1.x,global.p1.y);
var p2_d = point_distance(0,0,global.p2.x,global.p2.y);
var p3_d = point_distance(0,0,p3x,p3y);
var p4_d = point_distance(0,0,p4x,p4y);
var minpd = min(p1_d,p2_d,p3_d,p4_d);
var maxpd = max(p1_d,p2_d,p3_d,p4_d);
if(minpd = p1_d){
global.rx = global.p1.x - 16
global.ry = global.p1.y - 16
}
if(minpd = p2_d){
global.rx = global.p2.x - 16
global.ry = global.p2.y - 16
}
if(minpd = p3_d){
global.rx = p3x - 16
global.ry = p3y - 16
}
if(minpd = p4_d){
global.rx = p4x - 16
global.ry = p4y - 16
}

if(maxpd = p1_d){
px = global.p1.x
py = global.p1.y
}
if(maxpd = p2_d){
px = global.p2.x
py = global.p2.y
}
if(maxpd = p3_d){
px = p3x
py = p3y
}
if(maxpd = p4_d){
px = p4x
py = p4y
}
#endregion
#region //setting width and height always positive
global._width = px - global.rx + 16
if global._width < 0{
global._width = global._width * (-1)  
}
global._height = py - global.ry + 16
if global._height < 0{
global._height = global._height * (-1)  
}
#endregion
#endregion
#region //insert vars and create room
var new_room = instance_create_layer(global.rx,global.ry,"layer_rooms",obj_rooms_kitchen)
instance_destroy(obj_rooms)
#endregion
View attachment 17808
Grid removed to show drawn collision mask

obj_rooms_kitchen
draw
Code:
#region //extending sprite to given width and height and making it transparent
draw_sprite_stretched_ext(sprite_index,image_index,rx,ry,_width,_height,c_white,transparent_alpha)
bb_left = 0
bb_top = 0
bb_right = _width
bb_bot = _height
tolerance = 0
mask_index = sprite_collision_mask(sprite_index, true,2, bb_left, bb_top, bb_right, bb_bot, 1, tolerance);
//draw collision mask
draw_rectangle(bbox_left,bbox_top,bbox_right,bbox_bottom,true)

#endregion
I tried some variants of setting the collision mask and only this got a change of it.
But I don't know why it always stays at 64x64.

Thanks for any help.
Hi and welcome to the GMC!

mask_index expects a sprite index.
sprite_collision_mask doesn't return anything, so GameMaker makes it return 0 by default.
When interpreting 0 as a sprite index in GameMaker:Studio, it refers to the first sprite in the resource tree of your project.
So, you're setting the mask to the collision mask of the first sprite in your project.
Instead, you probably wanted to do this:
Code:
mask_index = sprite_index;
Then again, that's probably the mask you alreay had anyway.

What exactly should your mask change to?
A scaled version of itself to match the sprite drawn through draw_sprite_stretched_ext?
 

RDM

Member
Thank you
I wanted another way to set the mask as with a sprite.
And yes it should exactly do this but i can't use a sprite because the points are moveable so the scale is always different.(i think i forgot to mention this)

Is there a way to do this?
 

jo-thijs

Member
Thank you
I wanted another way to set the mask as with a sprite.
And yes it should exactly do this but i can't use a sprite because the points are moveable so the scale is always different.(i think i forgot to mention this)

Is there a way to do this?
You can set the variables "image_xscale" and "image_yscale" to "_width / sprite_get_width(sprite_index)" and "_height / sprite_get_height(sprite_index)" respectively.
These scales will be applied to the collision mask as well.
 
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