Shooting

Question 1

Having the weapon follow the player and aim using mouse

Answer 1

(step event)

x = obj_player.x;
y = obj_player.y;

image_angle = point_direction(x, y, mouse_x, mouse_y);

use +/- # after obj_player.x/y to allign where the weapon will be placed

place this code in a Begin Step Event to have a slight delay in the weapon trailing the player; can give a feeling of weightiness

adjusting the origin point can help with the way the object follows the mouse cursor

Question 2

Firing the weapon

Answer 2

In the weapon’s (create event)

firingdelay = 0;
recoil = 0;

In the weapon’s (step event)

firingdelay = firingdelay - 1;
recoil = max(0, recoil - 1);

if (mouse_check_button(mb_left)) && (firingdelay < 0)
{
recoil = 1.5;
firingdelay = 7;
with (instance_create_layer(x, y, “Bullets”, obj_bullet))
{
speed = 5;
direction = other.image_angle + random_range(-3, 3);
image_angle = direction;
}
}

x = x - lengthdir_x(recoil, image_angle);
y = y - lengthdir_y(recoil, image_angle);

a “with” statement is used to apply the code within to a different designated object: (x, y, instance layer name, object name)

using “other.[]” within a “with” statement will refer to the original object you were coding (in this case the weapon)

setting the recoil’s max range as max(0, recoil - 1); is so that if the value ever becomes 0 - 1 = -1, it will instead take the 0, ensuring the recoil value never drops below 0

x/y = x/y - lengthdir_x/y(recoil, image_angle); is used to actually set the recoil movement by moving the weapon by the number of pixels designated in the “recoil = #” statement in the x and y directions

Question 3

Bullet Animation

Answer 3

To utilize a muzzle flash frame, use this code in the bullet’s (animation end event):

image_speed = 0;
image_index = 1;

To have the bullet be destroyed on collision with another object, use this code in the bullet’s (post-draw event):

if (place_meeting(x, y, obj_wall)) instance_destroy();

if using muzzle flash, adjust the origin point of the bullet to better line it up with the front of the weapon

Question 4

If weapon sprite should be flipping at certain angles

Answer 4

In weapon’s (step event):

if (image_angle > 90) && (image_angle < 270)
{
	image_yscale = -1;
}
else
{
	image_yscale = 1;
}

Question 5

Restarting

Answer 5

(Add event -> Key Pressed -> Letters -> R)

game_restart();

good for testing

Question 6

Bullet collision with Enemies

Answer 6

In obj_enemy:

(create event)
hp = [#];
flash = 0;

*flash is the # of frames an enemy will flash white when hit

In obj_bullet

(Add event -> collision -> obj_enemy)

with (other)
{
	hp--;
	flash = 3;
}

instance_destroy():

“with (other)” in a collision event returns the ID of the object hit. Using “obj_enemy” would apply to EVERY enemy, while “other” retreives only the ID of the specific enemy hit.

Question 7

Adding damage flash

Answer 7

Create shader

within .fsh, under “ gl_FragColor = v_vColour * texture2D( gm_BaseTexture, v_vTexcoord );”:

gl_FragColor = vec4(1.0, 1.0, 1.0, gl_FragColor.a);

*this sets R,G, & B to max (255), which makes a white pixel. gl_FragColor.a sets the alpha (the transparency) the the value already set in the previous lines.

within obj_enemy:

(draw event)

draw_self();

if (flash>0)
{
	flash--;
	shader_set(shdr_White);
	draw_self();
	shader_reset();
}

• draw_self(); is necessary because a draw event revokes all automatic process, so the all draw actions must be input manually.
• we earlier set the “collsion obj_enemy” event within obj_bullet to flash = 3; which allows this “if (flash>0)” statement to work upon bullet collision. flash–; will subtract 1 from the flash value each frame until reaching 0, meaning the enemy will be white for 3 frames.

Question 8

Enemy Death

Answer 8

In obj_enemy

(begin step event)

if (hp <= 0)
{
	instance_create_layer(x, y, "Enemies", obj_dead);
	instance_destroy();
}

In obj_dead

(animation end event)

image_speed = 0;
image_index = #;

(post-draw event)

if (image_index = #) instance_destroy();