Infinitely scrolling grid

TODO.MD

@@ -1,3 +1,6 @@
+- Grid line changing
+- Zoom sensitivity
+- Playback slider
 - Save grid and animation data to file
 - Load project
 - Fix focus on submenu

grid.odin

@@ -10,7 +10,27 @@ Grid :: struct {
 }
 
 grid_get_zoom :: proc(zoom: v2) -> v2 {
-	return linalg.pow(v2{2.0, 2.0}, zoom) - 1.0
+	return linalg.pow(v2(2.0), zoom)
+}
+
+grid_get_line_separation :: proc(zoom: v2, min_line_distance: f32) -> v2 {
+	zoom_factor := grid_get_zoom(zoom)
+	sep := linalg.pow(v2(10.0), linalg.floor(linalg.log10(min_line_distance * zoom_factor)))
+	for {
+		if sep.x / zoom_factor.x >= min_line_distance {
+			break
+		}
+		if sep.x * 2.5 / zoom_factor.x >= min_line_distance {
+			sep *= 2.5
+			break
+		}
+		if sep.x * 5.0 / zoom_factor.x >= min_line_distance {
+			sep *= 5.0
+			break
+		}
+		sep *= 10.0
+	}
+	return sep
 }
 
 grid_world_to_grid_matrix :: proc(zoom, offset: v2) -> mat3 {
@@ -24,17 +44,20 @@ grid_world_to_grid_matrix :: proc(zoom, offset: v2) -> mat3 {
 		linalg.matrix3_scale(v3{**zoom_amount, 1.0}))
 }
 
+import "core:fmt"
+
 draw_grid :: proc(grid: Grid, text_draw, text_clip: rect2) {
 	world_to_grid_matrix := grid_world_to_grid_matrix(grid.zoom, grid.offset)
 	grid_to_world_matrix := linalg.inverse(world_to_grid_matrix)
 	grid_world_br := grid.world_position + grid.world_size
 	grid_color := rl.Color{64, 64, 64, 255}
 
-	grid_tl := (v3{**grid.world_position, 1.0} * world_to_grid_matrix).xy
-	grid_tl = linalg.floor(grid_tl / grid.cell_size) * grid.cell_size
-	grid_br := (v3{**grid_world_br, 1.0} * world_to_grid_matrix).xy
+	sep := grid_get_line_separation(grid.zoom, 32.0)
+	tl := (v3{**grid.world_position, 1.0} * world_to_grid_matrix).xy
+	tl = linalg.floor(tl / sep) * sep
+	br := (v3{**grid_world_br, 1.0} * world_to_grid_matrix).xy
 
-	for x: f32 = grid_tl.x; x < grid_br.x; x += grid.cell_size.x {
+	for x: f32 = tl.x; x < br.x; x += sep.x {
 		world_position_x := (v3{x, 0.0, 1.0} * grid_to_world_matrix).x
 		p1 := v2{world_position_x, grid.world_position.y}
 		p2 := v2{world_position_x, grid_world_br.y}
@@ -44,7 +67,7 @@ draw_grid :: proc(grid: Grid, text_draw, text_clip: rect2) {
 		}
 	}
 
-	for y: f32 = grid_tl.y; y < grid_br.y; y += grid.cell_size.y {
+	for y: f32 = tl.y; y < br.y; y += sep.y {
 		world_position_y := (v3{0.0, y, 1.0} * grid_to_world_matrix).y
 		p1 := v2{grid.world_position.x, world_position_y}
 		p2 := v2{grid_world_br.x, world_position_y}

program.odin

@@ -229,6 +229,7 @@ Program :: struct {
 	grid: Grid,
 	grid_zoom_x_only: bool,
 	grid_zoom_y_only: bool,
+	grid_zoom_speed: f32,
 	font_style: FontStyle,
 	state: ProgramState,
 	message_type: ProgramMessageType,
@@ -301,6 +302,7 @@ program_init :: proc(allocator := context.allocator) {
 		world_position = 0.0,
 		world_size = program_screen_size()
 	}
+	program.grid_zoom_speed = 1.0
 	program.mouse_draggable_radius = 6.0
 
 	ui.init(&program.ui_context, 4000, ui_measure_text, &program.font_style, allocator)
@@ -429,7 +431,6 @@ program_update :: proc() {
 
 	top_bar_container_br := rect_get_br(rect2(top_bar_container.area))
 	matrix_container_br := rect_get_br(rect2(matrix_container.area))
-
 	program.grid.world_size = program_screen_size()
 	grid_text_clip := rect_from_area(v2{matrix_container_br.x, top_bar_container_br.y}, program_screen_size())
 	draw_grid(program.grid, rect_grow(grid_text_clip, -4.0), rect_grow(grid_text_clip, -32.0))
@@ -710,7 +711,7 @@ program_handle_mouse :: proc(mouse_state: MouseState, top_bar_container, matrix_
 		}
 		program.grid.zoom_previous = program.grid.zoom
 		grid_zoom_dimension_lock := v2{1.0 - f32(int(program.grid_zoom_y_only)), 1.0 - f32(int(program.grid_zoom_x_only))}
-		program.grid.zoom += grid_zoom_dimension_lock * mouse_wheel.y * 0.01
+		program.grid.zoom += grid_zoom_dimension_lock * mouse_wheel.y * 0.2 * program.grid_zoom_speed
 	case .DraggingDraggable:
 		if !rl.IsMouseButtonDown(.LEFT) {
 			mouse_state = .Hover