an_editor/src/ui.h

324 lines
10 KiB
C

// A naive implementation of an immediate mode gui.
#ifndef ED_UI_INCLUDED
#define ED_UI_INCLUDED
#define MAX_UI_ELEMENTS 2048
// TODO: replace this with functions
#define _FONT_WIDTH 16
#define _FONT_HEIGHT 32
#define _elm(index) (&cx->frame_elements.data[index])
#define _flags(index, flgs) ((_elm(index)->flags & (flgs)) == (flgs))
#define _first(index) (_elm(index)->first)
#define _last(index) (_elm(index)->last)
#define _next(index) (_elm(index)->next)
#define _prev(index) (_elm(index)->prev)
#define _parent(index) (_elm(index)->parent)
#define _first_ref(index) (_elm(_first(index)))
#define _last_ref(index) (_elm(_last(index)))
#define _next_ref(index) (_elm(_next(index)))
#define _prev_ref(index) (_elm(_prev(index)))
#define _parent_ref(index) (_elm(_parent(index)))
#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
#include "ht.h"
#include "ed_array.h"
typedef enum {
UI_AXIS_HORIZONTAL,
UI_AXIS_VERTICAL,
} ui_axis;
typedef enum {
UI_SEMANTIC_SIZE_FIT_TEXT,
UI_SEMANTIC_SIZE_CHILDREN_SUM,
UI_SEMANTIC_SIZE_FILL,
UI_SEMANTIC_SIZE_EXACT,
UI_SEMANTIC_SIZE_PERCENT_OF_PARENT,
} ui_semantic_size_t;
typedef struct {
ui_semantic_size_t type;
union {
uint32_t integer;
};
} ui_semantic_size;
typedef struct {
ui_axis axis;
ui_semantic_size semantic_size[2];
uint32_t computed_size[2];
uint32_t computed_pos[2];
} ui_size;
// UI Element data persisted across frames
typedef struct {
string label;
ui_size size;
size_t last_instantiated_index;
} ui_element_cache_data;
typedef enum {
UI_FLAG_CLICKABLE = 0b000000001,
UI_FLAG_HOVERABLE = 0b000000010,
UI_FLAG_SCROLLABLE = 0b000000100,
UI_FLAG_DRAW_TEXT = 0b000001000,
UI_FLAG_DRAW_BORDER = 0b000010000,
UI_FLAG_DRAW_BACKGROUND = 0b000100000,
UI_FLAG_ROUNDED_BORDER = 0b001000000,
UI_FLAG_FLOATING = 0b010000000,
UI_FLAG_CUSTOM_DRAW_FUNC = 0b100000000,
} ui_flags;
// Ephemeral frame only UI Element data
typedef struct {
size_t index;
string key;
string label;
ui_size size;
ui_flags flags;
// optional types
size_t first;
size_t last;
size_t next;
size_t prev;
size_t parent;
} ui_element_frame_data;
arrayTemplate(ui_element_frame_data);
typedef struct {
ed_ht cached_elements;
array(ui_element_frame_data) frame_elements;
array(ui_element_frame_data) frame_floating_elements;
size_t frame_index;
uint32_t canvas_size[2];
size_t current_parent;
} ui_context;
void ui_compute_layout(ui_context *cx, size_t element_index);
#ifdef ED_UI_IMPLEMENTATION
ui_context init_ui_context() {
ed_ht cached_elements = ht_create(MAX_UI_ELEMENTS, sizeof(ui_element_cache_data));
array(ui_element_frame_data) frame_elements = newArray(ui_element_frame_data, MAX_UI_ELEMENTS);
array(ui_element_frame_data) frame_floating_elements = newArray(ui_element_frame_data, MAX_UI_ELEMENTS);
return (ui_context) {
.cached_elements = cached_elements,
.frame_elements = frame_elements,
.frame_floating_elements = frame_floating_elements,
.frame_index = 0,
};
}
size_t ui_element(ui_context *cx, string label) {
ui_element_frame_data frame_data = (ui_element_frame_data) {
.index = cx->frame_elements.size,
// TODO: don't just set this to label, because then elements
// with the same label can't be created together
.key = label,
.label = label,
.first = -1,
.last = -1,
.next = -1,
.prev = cx->frame_elements.data[cx->current_parent].last,
.parent = cx->current_parent,
};
// Get cached element data
ui_element_cache_data *cache_data = ht_get(&cx->cached_elements, label);
if (cache_data) {
cache_data->last_instantiated_index = cx->frame_index;
frame_data.size = cache_data->size;
} else {
assert("couldn't insert into ui element cache" && ht_set(&cx->cached_elements, label, &(ui_element_cache_data) {
.label = label,
.size = { 0 },
.last_instantiated_index = cx->frame_index,
}));
}
pushArray(ui_element_frame_data, &cx->frame_elements, frame_data);
if (frame_data.prev >= 0) {
_prev_ref(frame_data.index)->next = frame_data.index;
}
if (_elm(cx->current_parent)->first < 0) {
_elm(cx->current_parent)->first = frame_data.index;
}
_elm(cx->current_parent)->last = frame_data.index;
return frame_data.index;
}
static uint32_t _ui_ancestor_size(ui_context *cx, size_t element_index, ui_axis axis) {
if (element_index < 0 || _parent(element_index) < 0) return 0;
switch (_parent_ref(element_index)->size.semantic_size[axis].type) {
case UI_SEMANTIC_SIZE_FIT_TEXT:
case UI_SEMANTIC_SIZE_FILL:
case UI_SEMANTIC_SIZE_EXACT:
case UI_SEMANTIC_SIZE_PERCENT_OF_PARENT:
return _parent_ref(element_index)->size.computed_size[axis];
break;
case UI_SEMANTIC_SIZE_CHILDREN_SUM:
return _ui_ancestor_size(cx, _parent(element_index), axis);
break;
}
}
static void _ui_compute_simple_layout(ui_context *cx, ui_element_frame_data *elm, ui_axis axis, bool *post_compute) {
switch (elm->size.semantic_size[axis].type) {
case UI_SEMANTIC_SIZE_FIT_TEXT:
if (axis == UI_AXIS_HORIZONTAL) {
elm->size.computed_size[axis] = elm->label.len * _FONT_WIDTH;
} else if (axis == UI_AXIS_VERTICAL) {
elm->size.computed_size[axis] = _FONT_WIDTH;
}
break;
case UI_SEMANTIC_SIZE_CHILDREN_SUM:
post_compute[axis] = true;
break;
case UI_SEMANTIC_SIZE_FILL:
// TODO: set to ancestor size for floating
break;
case UI_SEMANTIC_SIZE_EXACT:
elm->size.computed_size[axis] = elm->size.semantic_size[axis].integer;
break;
case UI_SEMANTIC_SIZE_PERCENT_OF_PARENT:
{
float semantic_value = (float)elm->size.semantic_size[axis].integer;
elm->size.computed_size[axis] = (uint32_t)((float)(_ui_ancestor_size(cx, elm->index, axis)) * (semantic_value/100.0));
}
break;
}
}
static void _ui_compute_children_layout(ui_context *cx, ui_element_frame_data *elm) {
uint32_t child_size[2] = { 0 };
// NOTE: the number of fills for the opposite axis of this box needs to be 1
// because it will never get incremented in the loop below and cause a divide by zero
// and the number of fills for the axis of the box needs to start at zero or else it will
// be n+1 causing incorrect sizes
uint32_t num_fills[2] = { 1 };
num_fills[elm->size.axis] = 0;
// TODO: maybe just use the actual data instead of copying?
uint32_t elm_size[2] = { elm->size.computed_size[0], elm->size.computed_size[1] };
size_t child_index = elm->first;
do {
ui_compute_layout(cx, child_index);
if (_elm(child_index)->size.semantic_size[elm->size.axis].type == UI_SEMANTIC_SIZE_FILL) {
num_fills[elm->size.axis] += 1;
} else {
child_size[elm->size.axis] += _elm(child_index)->size.computed_size[elm->size.axis];
}
} while ((child_index = _next(child_index)) >= 0);
child_index = elm->first;
do {
for (size_t axis = UI_AXIS_HORIZONTAL; axis < UI_AXIS_VERTICAL; ++axis) {
if (_elm(child_index)->size.semantic_size[axis].type == UI_SEMANTIC_SIZE_FILL) {
_elm(child_index)->size.computed_pos[axis] = (elm_size[axis] - child_size[axis]) / num_fills[axis];
}
}
ui_compute_layout(cx, child_index);
} while ((child_index = _next(child_index)) >= 0);
}
void ui_compute_layout(ui_context *cx, size_t element_index) {
if (element_index <= 0) return;
ui_axis axis = UI_AXIS_HORIZONTAL;
__auto_type elm = _elm(element_index);
if (_parent(element_index) >= 0 && (_elm(element_index)->flags & UI_FLAG_FLOATING) > 0) {
__auto_type parent = _parent_ref(element_index);
axis = parent->size.axis;
elm->size.computed_pos[0] = parent->size.computed_pos[0];
elm->size.computed_pos[1] = parent->size.computed_pos[1];
// TODO: implement scrolling
// elm->size.computed_pos[axis] += parent.scroll_offset;
}
if (!_flags(element_index, UI_FLAG_FLOATING) && _prev(element_index) >= 0) {
__auto_type prev = _prev_ref(element_index);
if (prev>= 0) {
elm->size.computed_pos[axis] = prev->size.computed_pos[axis] + prev->size.computed_size[axis];
}
}
bool post_compute[2] = { false, false };
_ui_compute_simple_layout(cx, elm, UI_AXIS_HORIZONTAL, post_compute);
_ui_compute_children_layout(cx, elm);
// NOTE(pcleavelin): the only difference between these two blocks is the ordering of the switch block
// they can probably be merged
if (post_compute[UI_AXIS_HORIZONTAL]) {
elm->size.computed_size[UI_AXIS_HORIZONTAL] = 0;
size_t child_index = elm->first;
do {
__auto_type child = _elm(child_index);
switch (elm->size.axis) {
case UI_AXIS_HORIZONTAL:
elm->size.computed_size[UI_AXIS_HORIZONTAL] += child->size.computed_size[UI_AXIS_HORIZONTAL];
break;
case UI_AXIS_VERTICAL:
if (child->size.computed_size[UI_AXIS_HORIZONTAL] > elm->size.computed_size[UI_AXIS_HORIZONTAL]) {
elm->size.computed_size[UI_AXIS_HORIZONTAL] = child->size.computed_size[UI_AXIS_HORIZONTAL];
}
break;
}
} while ((child_index = _next(child_index)) >= 0);
}
if (post_compute[UI_AXIS_VERTICAL]) {
elm->size.computed_size[UI_AXIS_VERTICAL] = 0;
size_t child_index = elm->first;
do {
__auto_type child = _elm(child_index);
switch (elm->size.axis) {
case UI_AXIS_HORIZONTAL:
if (child->size.computed_size[UI_AXIS_VERTICAL] > elm->size.computed_size[UI_AXIS_VERTICAL]) {
elm->size.computed_size[UI_AXIS_VERTICAL] = child->size.computed_size[UI_AXIS_VERTICAL];
}
break;
case UI_AXIS_VERTICAL:
elm->size.computed_size[UI_AXIS_VERTICAL] += child->size.computed_size[UI_AXIS_VERTICAL];
break;
}
} while ((child_index = _next(child_index)) >= 0);
}
}
#endif
#endif