HUD elements

Menus and other parts of the game's interface draw images with HUD elements. Each HUD element runs a HudScript, which says which images to show, for how long, and at what size.

Writing a HudScript

Most HudScripts show icons. hs_SetIcon names an icon by its path, with / replaced by _, so icon/key/Gift.png is key_Gift.

This HudScript shows icon/key/Gift.png at 32×32:

#include "hud_element.h"

HudScript HES_Gift = HES_TEMPLATE_ITEM(key_Gift);

To animate an icon, list its frames between hs_Loop and hs_Restart. The first argument of hs_SetIcon is how many frames to show that icon for:

HudScript HES_Pointer = {
    hs_SetVisible
    hs_SetTileSize(HUD_ELEMENT_SIZE_24x24)
    hs_Loop
        hs_SetIcon(8, anim_hand_0)
        hs_SetIcon(8, anim_hand_1)
    hs_Restart
    hs_End
};

Showing a HudScript

To show a HudScript, create a HUD element from it and set where it's drawn. Free the element when you no longer need it:

HudElemID hid = hud_element_create(HES_Pointer);
hud_element_set_render_pos(hid, 160, 120);

// Later:
hud_element_free(hid);

HudScript commands

Command	What it does
`hs_SetVisible`	Draws the images after it as indexed images. Start every HudScript that shows icons with it. Despite its name, it doesn't make the element visible.
`hs_SetTileSize(size)`	Sets the icon's size, such as `HUD_ELEMENT_SIZE_32x32`. `hud_element.h` lists the sizes.
`hs_SetCustomSize(width, height)`	Sets a size that has no `HUD_ELEMENT_SIZE_` value.
`hs_SetIcon(frames, icon)`	Shows `icon` for `frames` frames.
`hs_Loop`	Marks where `hs_Restart` goes back to.
`hs_Restart`	Goes back to `hs_Loop`.
`hs_RandomRestart(max, chance)`	Goes back to `hs_Loop` with a probability of `chance` in `max + 1`, and otherwise carries on.
`hs_RandomDelay(min, max)`	Waits a random number of frames, from `min` to `max`.
`hs_SetTexelOffset(x, y)`	Draws the icon `x` and `y` pixels from the element's position.
`hs_AddTexelOffsetX(x)`, `hs_AddTexelOffsetY(y)`	Adds to the offset.
`hs_SetScale(scale)`	Scales the icon, such as `hs_SetScale(1.5)`.
`hs_SetAlpha(alpha)`	Sets the opacity, from `0` (invisible) to `255` (opaque).
`hs_PlaySound(sound)`	Plays a sound effect, such as `SOUND_MENU_CHANGE_SELECTION`.
`hs_End`	Stops the HudScript, and keeps showing the last icon.
`hs_Delete`	Stops the HudScript, and frees the element.

hud_element.h has more commands, for images that aren't icons and for effects that the game sets up from code.