imgui part 1

ui.odin

@@ -0,0 +1,121 @@
+package main
+
+import "core:math/linalg"
+import "core:fmt"
+import "core:mem"
+
+UiElementType :: enum {
+	Input,
+	Button,
+	Container,
+}
+
+UiElementData :: union {
+	UiElementData_Button,
+	UiElementData_Input,
+	UiElementData_Container,
+}
+
+UiElementData_Button :: struct {
+	label: cstring,
+}
+
+UiElementData_Container :: struct {
+	label: cstring,
+}
+
+UiElementData_Input :: struct {
+	label: cstring,
+}
+
+UiElement :: struct {
+	area: rect2,
+	type: UiElementType,
+	data: UiElementData,
+}
+
+UiState :: struct {
+	origin, position_left, position: v2,
+	same_line: bool,
+	style: UiStyle,
+	elements: [dynamic]UiElement,
+	container: ^UiElement,
+	group_element_count: int,
+}
+
+UiStyle :: struct {
+	margin, padding: f32,
+}
+
+ui_button :: proc(state: ^UiState, size: v2, data: UiElementData_Button) {
+	area := _ui_advance_element(state, size)
+	append(&state.elements, UiElement{area = area, type = .Button, data = data})
+}
+
+ui_container_begin :: proc(state: ^UiState, data: UiElementData_Container) {
+	assert(state.container == nil)
+	append(&state.elements, UiElement{area = _ui_advance_container(state), type = .Container, data = data})
+	state.container = &state.elements[len(state.elements) - 1]
+}
+
+ui_container_end :: proc(state: ^UiState) {
+	assert(state.container != nil)
+	state.container = nil
+}
+
+_ui_advance_element :: proc(state: ^UiState, size: v2) -> rect2 {
+	if state.group_element_count > 0 {
+		if state.same_line {
+			state.position.x += size.x + state.style.padding
+			state.same_line = false
+		} else {
+			state.position_left.y += size.y + state.style.padding
+			state.position = state.position_left
+		}
+	} else {
+		state.position += state.style.padding
+	}
+	area := rect2{**state.position, **size}
+	if state.container != nil {
+		element_bottom_left := rect_get_br(area)
+		container_bottom_left := rect_get_br(state.container.area)
+		new_br := linalg.max(element_bottom_left + state.style.padding, container_bottom_left)
+		state.container.area.width = new_br.x - state.container.area.x
+		state.container.area.height = new_br.y - state.container.area.y
+	}
+	state.group_element_count += 1
+	return area
+}
+
+_ui_advance_container :: proc(state: ^UiState) -> rect2 {
+	state.position += state.style.margin
+	return {**state.position, 0.0, 0.0}
+}
+
+ui_input :: proc(state: ^UiState, size: v2, data: UiElementData_Input) {
+	area := _ui_advance_element(state, size)
+	append(&state.elements, UiElement{area = area, type = .Input, data = data})
+}
+
+ui_same_line :: proc(state: ^UiState) {
+	state.same_line = true
+}
+
+ui_start :: proc(state: ^UiState) {
+	clear(&state.elements)
+	state.position_left = state.origin
+	state.position = state.position_left
+}
+
+ui_end :: proc(state: UiState) -> []UiElement {
+	return state.elements[:]
+}
+
+ui_init :: proc(state: ^UiState, style: UiStyle, origin: v2, allocator: mem.Allocator) {
+	state^ = {
+		origin = origin,
+		position = origin,
+		style = style,
+		elements = make(type_of(state.elements), 0, 512, allocator)
+	}
+}