Grid values

grid.odin

@@ -0,0 +1,48 @@
+package main
+
+import "core:math/linalg"
+import rl "libraries/raylib"
+
+Grid :: struct {
+	cell_size: v2,
+	zoom_previous, zoom: v2,
+	world_position, world_size, offset: v2,
+}
+
+draw_grid :: proc(grid: Grid, text_draw, text_clip: rect2) {
+	zoom_amount := grid_get_zoom_amount(grid.zoom)
+	world_to_grid_matrix := (
+		mat3 {
+			1, 0, 0,
+			0, 1, 0,
+			grid.offset.x, grid.offset.y, 1,
+		} *
+		linalg.matrix3_scale(v3{**zoom_amount, 1.0}))
+	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
+
+	for x: f32 = grid_tl.x; x < grid_br.x; x += grid.cell_size.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}
+		rl.DrawLineV(p1, p2, grid_color)
+		if p1.x >= text_clip.x && p1.x < text_clip.x + text_clip.width {
+			draw_float_aligned(x, {world_position_x, text_draw.y}, program.font_style, .Middle, .Top, rl.GRAY)
+		}
+	}
+
+	for y: f32 = grid_tl.y; y < grid_br.y; y += grid.cell_size.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}
+		rl.DrawLineV(p1, p2, grid_color)
+		if p1.y >= text_clip.y && p1.y < text_clip.y + text_clip.height {
+			draw_float_aligned(y, {text_draw.x, world_position_y}, program.font_style, .Left, .Center, rl.GRAY)
+		}
+	}
+}