ugui/src/ugui_core.c3

338 lines
7.5 KiB

module ugui;
import vtree;
import cache;
import fifo;
import std::io;
import std::core::string;
// element ids are just long ints
def Id = usz;
enum ElemType {
ETYPE_NONE,
ETYPE_DIV,
ETYPE_BUTTON,
ETYPE_SLIDER,
ETYPE_TEXT,
}
bitstruct ElemFlags : uint {
bool updated : 0;
bool is_new : 1;
}
bitstruct ElemEvents : uint {
bool key_press : 0;
bool key_release : 1;
bool key_hold : 2;
bool mouse_hover : 3;
bool mouse_press : 4;
bool mouse_release : 5;
bool mouse_hold : 6;
bool update : 7;
}
// element structure
struct Elem {
Id id;
ElemFlags flags;
ElemEvents events;
Rect bounds;
ElemType type;
union {
ElemDiv div;
ElemButton button;
ElemSlider slider;
ElemText text;
}
}
// relationships between elements are stored in a tree, it stores just the ids
def IdTree = vtree::VTree(<Id>) @private;
// elements themselves are kept in a cache
const uint MAX_ELEMENTS = 1024;
def ElemCache = cache::Cache(<Id, Elem, MAX_ELEMENTS>) @private;
def CmdQueue = fifo::Fifo(<Cmd>);
fault UgError {
INVALID_SIZE,
EVENT_UNSUPPORTED,
UNEXPECTED_ELEMENT,
WRONG_ELEMENT_TYPE,
}
const Rect DIV_FILL = { .x = 0, .y = 0, .w = 0, .h = 0 };
const uint STACK_STEP = 10;
const uint MAX_ELEMS = 128;
const uint MAX_CMDS = 256;
const uint ROOT_ID = 1;
const uint TEXT_MAX = 64;
// global style, similar to the css box model
struct Style { // css box model
Rect padding;
Rect border;
Rect margin;
Color bgcolor; // background color
Color fgcolor; // foreground color
Color brcolor; // border color
ushort radius;
}
struct Ctx {
IdTree tree;
ElemCache cache;
CmdQueue cmd_queue;
// total size in pixels of the context
ushort width, height;
Style style;
Font font;
bool has_focus;
struct input {
InputEvents events;
struct mouse {
Point pos, delta;
// mouse_down: bitmap of mouse buttons that are held
// mouse_updated: bitmap of mouse buttons that have been updated
// mouse_released = mouse_updated & ~mouse_down
// mouse_pressed = mouse_updated & mouse_down
MouseButtons down;
MouseButtons updated;
// scroll wheel
Point scroll;
}
struct keyboard {
char[TEXT_MAX] text;
usz text_len;
ModKeys down;
}
}
Id hover_id;
Id focus_id;
Rect div_scissor; // the current div bounds used for scissor test
isz active_div; // tree node indicating the current active div
}
// return a pointer to the parent of the current active div
fn Elem*! Ctx.get_parent(&ctx)
{
Id parent_id = ctx.tree.get(ctx.active_div)!;
return ctx.cache.search(parent_id);
}
macro @bits(#a) => $typeof(#a).sizeof*8;
macro Id.rotate_left(id, uint $n) => (id << $n) | (id >> (@bits(id) - $n));
const uint GOLDEN_RATIO = 0x9E3779B9;
// generate an id combining the hashes of the parent id and the label
// with the Cantor pairing function
macro Id! Ctx.gen_id(&ctx, String label)
{
Id id1 = ctx.tree.get(ctx.active_div)!;
Id id2 = label.hash();
// Mix the two IDs non-linearly
Id mixed = id1 ^ id2.rotate_left(13);
mixed ^= id1.rotate_left(7);
mixed += GOLDEN_RATIO;
return mixed;
}
// get or push an element from the cache, return a pointer to it
// resets all flags except is_new which is set accordingly
fn Elem*! Ctx.get_elem(&ctx, Id id)
{
Elem empty_elem;
bool is_new;
Elem* elem;
elem = ctx.cache.get_or_insert(&empty_elem, id, &is_new)!;
elem.flags = (ElemFlags)0;
elem.flags.is_new = is_new;
// FIXME: should this be here? or is it better to have the elements set the id?
elem.id = id;
return elem;
}
// find an element, does not allocate a new one in cache
// THIS HAS TO BE A MACRO SINCE IT RETURNS A POINTER TO A TEMPORARY VALUE
macro Elem* Ctx.find_elem(&ctx, Id id)
{
Elem*! elem;
elem = ctx.cache.search(id);
if (catch elem) {
return &&Elem{};
}
return elem;
}
// FIXME: Since ids are now keyed with the element's parent id, this function does not work
// outside of the element's div block.
// this searches an element in the cache by label, it does not create a new element
// if it does't find one
//macro Ctx.get_elem_by_label(&ctx, String label)
//{
// Id id = ctx.get_id(label);
// return ctx.cache.search(id);
//}
macro Ctx.get_elem_by_tree_idx(&ctx, isz idx) @private
{
Id id = ctx.tree.get(ctx.active_div)!;
return ctx.cache.search(id);
}
fn void! Ctx.init(&ctx)
{
ctx.tree.init(MAX_ELEMENTS)!;
defer catch { (void)ctx.tree.free(); }
ctx.cache.init()!;
defer catch { (void)ctx.cache.free(); }
ctx.cmd_queue.init(MAX_ELEMENTS)!;
defer catch { (void)ctx.cmd_queue.free(); }
ctx.active_div = 0;
// TODO: add style config
ctx.style.margin = Rect{2, 2, 2, 2};
ctx.style.border = Rect{2, 2, 2, 2};
ctx.style.padding = Rect{1, 1, 1, 1};
ctx.style.radius = 5;
ctx.style.bgcolor = 0x282828ffu.to_rgba();
ctx.style.fgcolor = 0xfbf1c7ffu.to_rgba();
ctx.style.brcolor = 0xd79921ffu.to_rgba();
}
fn void Ctx.free(&ctx)
{
(void)ctx.tree.free();
(void)ctx.cache.free();
(void)ctx.cmd_queue.free();
(void)ctx.font.free();
}
fn void! Ctx.frame_begin(&ctx)
{
// 2. Get the root element from the cache and update it
Elem* elem = ctx.get_elem(ROOT_ID)!;
// The root should have the updated flag only if the size of the window
// was changed between frames, this propagates an element size recalculation
// down the element tree
elem.flags.updated = ctx.input.events.resize;
// if the window has focus then the root element also has focus, no other
// computation needed, child elements need to check the mouse positon and
// other stuff
//elem.flags.has_focus = ctx.has_focus;
Elem def_root = {
.id = ROOT_ID,
.type = ETYPE_DIV,
.bounds = {
.w = ctx.width,
.h = ctx.height,
},
.div = {
.layout = LAYOUT_ROW,
.children_bounds = {
.w = ctx.width,
.h = ctx.height,
}
},
.flags = elem.flags,
};
*elem = def_root;
// 3. Push the root element into the element tree
ctx.active_div = ctx.tree.add(ROOT_ID, 0)!;
ctx.div_scissor = {0, 0, ctx.width, ctx.height};
// The root element does not push anything to the stack
// TODO: add a background color taken from a theme or config
}
fn void! Ctx.frame_end(&ctx)
{
Elem* root = ctx.get_elem_by_tree_idx(0)!;
root.div.layout = LAYOUT_ROW;
// 1. clear the tree
ctx.tree.nuke();
// 2. clear input fields
ctx.input.events = (InputEvents)0;
ctx.input.keyboard.text_len = 0;
// send atlas updates
if (ctx.font.should_update) {
ctx.push_update_atlas(&ctx.font.atlas)!;
ctx.font.should_update = false;
}
$if 1:
// draw mouse position
Cmd cmd = {
.type = CMD_RECT,
.rect.rect = {
.x = ctx.input.mouse.pos.x - 2,
.y = ctx.input.mouse.pos.y - 2,
.w = 4,
.h = 4,
},
.rect.color = 0xff00ffffu.to_rgba()
};
ctx.cmd_queue.enqueue(&cmd)!;
$endif
}
<*
* @ensure elem != null
*>
macro bool Ctx.is_hovered(&ctx, Elem *elem)
{
return ctx.input.mouse.pos.in_rect(elem.bounds);
}
macro bool Ctx.elem_focus(&ctx, Elem *elem)
{
return ctx.focus_id == elem.id;
}
// TODO: add other events
// FIXME: this does not work with touch
// FIXME: hacked together, please do better
fn ElemEvents Ctx.get_elem_events(&ctx, Elem *elem)
{
bool hover = ctx.is_hovered(elem);
bool focus = ctx.focus_id == elem.id || (hover && ctx.is_mouse_pressed(BTN_LEFT));
if (ctx.is_mouse_pressed(BTN_ANY) && !hover){
focus = false;
if (ctx.focus_id == elem.id) ctx.focus_id = 0;
}
if (hover) { ctx.hover_id = elem.id; }
if (focus) { ctx.focus_id = elem.id; }
ElemEvents ev = {
.mouse_hover = hover,
.mouse_press = hover && focus && ctx.is_mouse_pressed(BTN_ANY),
.mouse_release = hover && focus && ctx.is_mouse_released(BTN_ANY),
.mouse_hold = hover && focus && ctx.is_mouse_down(BTN_ANY),
};
return ev;
}