Grid part 1

program.odin

@@ -36,6 +36,12 @@ ProgramState :: enum {
 	Message,
 }
 
+MouseState :: enum {
+	Hover,
+	DraggingGrid,
+	HoverMatrices,
+}
+
 ProgramMessageType :: enum {
 	ChangeMatrixTypeClearData,
 }
@@ -65,6 +71,7 @@ Program :: struct {
 	matrix_count: int,
 	matrix_scroll: f32,
 	matrix_scroll_speed: f32,
+	mouse_state: MouseState,
 	grid: Grid,
 	font_style: FontStyle,
 	state: ProgramState,
@@ -99,24 +106,69 @@ program_init :: proc(allocator := context.allocator) {
 	}
 	program.grid = {
 		area = {0, 0, WINDOW_WIDTH, WINDOW_HEIGHT},
-		inner_area = {-1, -1, 2, 2},
+		inner_area = {0, 0, WINDOW_WIDTH, WINDOW_HEIGHT},
 		zoom = 1.0,
 	}
 	ui.init(&program.ui_context, 4000, allocator)
 }
 
+world_to_grid_matrix :: proc(grid: Grid) -> mat3 {
+	return matrix3_translate2(-rect_get_tl(grid.inner_area))
+}
+
+grid_to_world_matrix :: proc(grid: Grid) -> mat3 {
+	return {}
+}
+
 program_update :: proc() {
 	if rl.IsKeyPressed(.ENTER) {
 		matrix_pool_get_mat3()
 	}
-	ui_elements := program_build_ui()
+
+	ui_elements, matrix_container := program_build_ui()
+
+	mouse := rl.GetMousePosition()
+	switch program.mouse_state {
+	case .Hover:
+		if rl.IsMouseButtonPressed(.LEFT) {
+			program.mouse_state = .DraggingGrid
+		} else if rect_has_point(rect2(matrix_container.area), mouse) {
+			program.mouse_state = .HoverMatrices
+		}
+	case .DraggingGrid:
+		program.grid.inner_area = rect_translate(program.grid.inner_area, rl.GetMouseDelta())
+		if !rl.IsMouseButtonDown(.LEFT) {
+			program.mouse_state = .Hover
+		}
+	case .HoverMatrices:
+		program.matrix_scroll = max(0, program.matrix_scroll - rl.GetMouseWheelMove() * program.matrix_scroll_speed)
+		if !rect_has_point(rect2(matrix_container.area), mouse) {
+			program.mouse_state = .Hover
+		}
+	}
+
 	if rl.IsKeyPressed(.TAB) {
 		ui.focus_next_element(&program.ui_context)
 	}
+
+	grid := program.grid
+	grid_inner_position := rect_get_tl(grid.inner_area)
+	draw_grid(grid.area, {50.0, 50.0}, rl.GRAY)
+
 	program_render_ui(&program.ui_context, ui_elements)
 }
 
-program_build_ui :: proc() -> []ui.Element {
+draw_grid :: proc(area: rect2, line_interval: v2, color: rl.Color) {
+	br := rect_get_br(area)
+	for x := area.x; x < br.x; x += line_interval.x {
+		rl.DrawLineV({x, area.y}, {x, br.y}, color)
+	}
+	for y := area.y; y < br.y; y += line_interval.y {
+		rl.DrawLineV({area.x, y}, {br.x, y}, color)
+	}
+}
+
+program_build_ui :: proc() -> (elements: []ui.Element, matrix_container: ^ui.Element) {
 	ui.start(&program.ui_context, {0, 0}, {WINDOW_WIDTH, WINDOW_HEIGHT})
 	top_bar_container_config := ui.ElementConfiguration {margin = V2_ONE * 4.0}
 	top_bar_container := ui.container_begin({ui.Size_Percentage(1.0), ui.Size_Pixels(48.0)}, top_bar_container_config)
@@ -136,7 +188,7 @@ program_build_ui :: proc() -> []ui.Element {
 	side_bar_container_config := ui.ElementConfiguration {margin = V2_ONE * 4.0}
 	side_bar_container_data := new(UiElementData_Container, context.temp_allocator)
 	side_bar_container_data^ = {type = .Scroll, scroll = program.matrix_scroll}
-	matrix_container := ui.container_begin({ui.Size_Percentage(0.2), ui.Size_PercentageRemainder(1.0)}, side_bar_container_config, side_bar_container_data)
+	matrix_container = ui.container_begin({ui.Size_Percentage(0.2), ui.Size_PercentageRemainder(1.0)}, side_bar_container_config, side_bar_container_data)
 	for i in 0..<program.matrix_count {
 		container_config := ui.ElementConfiguration{margin = V2_ONE * 8.0, label = fmt.ctprintf("Matrix %d", i)}
 		container_dimensions := ui.Dimensions {ui.Size_Percentage(1.0), ui.Size_Pixels(112.0)}
@@ -145,14 +197,8 @@ program_build_ui :: proc() -> []ui.Element {
 		ui_mat3(mat, value_strings, container_dimensions, container_config)
 	}
 	ui.container_end()
-	elements := ui.end()
+	elements = ui.end()
-
+	return
-	mouse := rl.GetMousePosition()
-	if rect_has_point(rect2(matrix_container.area), mouse) {
-		program.matrix_scroll = max(0, program.matrix_scroll - rl.GetMouseWheelMove() * program.matrix_scroll_speed)
-	}
-
-	return elements
 }
 
 ui_mat3 :: proc(mat: []f32, value_strings: []InputFloatField, dimensions: ui.Dimensions, config: ui.ElementConfiguration, allocator := context.temp_allocator) {