examples: add examples/hot_reload/tunnel.v

examples/hot_reload/tunnel.v

@@ -0,0 +1,169 @@
+// Try commenting or changing the drawing functions, that are at the bottom of the file,
+// and that are inside functions marked with @[live] ...
+import gg
+import math
+
+fn main() {
+	mut state := init_state()
+	gg.start(
+		window_title: 'Tunnel'
+		bg_color:     gg.Color{255, 255, 255, 255}
+		width:        1024
+		height:       768
+		frame_fn:     unsafe { state.draw }
+		event_fn:     fn (event &gg.Event, ctx voidptr) {
+			if event.typ == .char && event.char_code == `f` {
+				gg.toggle_fullscreen()
+				return
+			}
+		}
+	)
+}
+
+struct BigRect {
+mut:
+	id     int
+	t      f32
+	x      f32
+	y      f32
+	w      f32
+	bwidth f32
+	c      gg.Color
+}
+
+struct State {
+mut:
+	t       f32
+	real_t  f32
+	tparams gg.DrawTextParams
+	rects   []BigRect
+}
+
+const colors = []gg.Color{len: 1024, init: gg.Color{u8(100 +
+	100 * math.sin(f32(index) / 50) * math.cos(f32(index) / 50)), u8(100 +
+	100 * math.cos(f32(index) / 50)), 100 + u8(index % 50), 255}}
+
+fn init_state() State {
+	mut state := State{
+		real_t:  1300
+		tparams: gg.DrawTextParams{
+			x:     40
+			size:  20
+			color: gg.Color{255, 255, 255, 255}
+		}
+		rects:   [
+			BigRect{
+				x:      350
+				y:      250
+				w:      30
+				bwidth: 10
+				c:      gg.Color{0, 0, 255, 255}
+			},
+		]
+	}
+	for i in 1 .. 50 {
+		state.rects << BigRect{
+			id: i
+		}
+	}
+	return state
+}
+
+fn (mut state State) draw(ctx &gg.Context) {
+	update(mut state)
+	ctx.begin()
+	mut r0 := &state.rects[0]
+	draw_big_rect(ctx, r0)
+	for i in 1 .. state.rects.len {
+		draw_big_rect(ctx, state.rects[i])
+	}
+	ctx.draw_text2(gg.DrawTextParams{
+		...state.tparams
+		y:    0
+		text: 'real_t: ${state.real_t:7.3f}, r: ${state.t:7.3f}, r0.x: ${r0.x:7.3f}, r0.y: ${r0.y:7.3f}'
+	})
+	draw_center_point(ctx, r0, state.t)
+	ctx.show_fps()
+	ctx.end()
+}
+
+@[live]
+fn update(mut state State) {
+	state.real_t += 0.1
+	state.t += 0.5 * math.sinf(state.real_t / 7000)
+	mut r0 := &state.rects[0]
+	r0.t = state.t
+	r0.x = 550 + 450 * math.sinf(state.t / 10) * math.sinf(state.t / 50)
+	r0.y = 350 + 350 * math.cosf(state.t / 20) * math.cosf(-state.t / 50)
+	r0.x += 5 * math.sinf(state.t)
+	r0.y += 5 * math.cosf(state.t)
+	r0.c = colors[int((50000 + state.t) / 200 * (1 + math.sin(state.t / 5))) % colors.len]
+	for i := state.rects.len - 1; i > 0; i-- {
+		state.rects[i] = state.rects[i - 1]
+		state.rects[i].w *= 1.11 + f32(i) / 1000
+		state.rects[i].bwidth *= 1.09
+	}
+}
+
+@[live]
+fn draw_center_point(ctx &gg.Context, br BigRect, t f32) {
+	b := u8(128 + 128 * math.sin(t / 12))
+	c := gg.Color{255 - b, b, b, 55}
+	ctx.draw_circle_filled(br.x, br.y, 8, c)
+}
+
+@[live]
+fn draw_big_rect(ctx &gg.Context, br BigRect) {
+	radius := 20
+	x := br.x
+	y := br.y
+	w := br.w
+	c := br.c
+	bwidth := br.bwidth
+	base := gg.DrawRectParams{
+		radius:     radius
+		is_rounded: true
+		color:      c
+	}
+	rleft := gg.DrawRectParams{
+		...base
+		x: x - (w / 2)
+		y: y - (w / 2)
+		w: bwidth
+		h: w
+	}
+	rright := gg.DrawRectParams{
+		...base
+		x: x + (w / 2) - bwidth
+		y: y - w + (w / 2)
+		w: bwidth
+		h: w
+	}
+	rtop := gg.DrawRectParams{
+		...base
+		x: x - (w / 2)
+		y: y - (w / 2)
+		w: w
+		h: bwidth
+	}
+	rbottom := gg.DrawRectParams{
+		...base
+		x: x + (w / 2) - w
+		y: y + (w / 2) - bwidth
+		w: w
+		h: bwidth
+	}
+	border := gg.DrawRectParams{
+		x:     x - (w / 2) + bwidth + 1
+		y:     y - (w / 2) + bwidth + 2
+		w:     w - 2 * bwidth - 2
+		h:     w - 2 * bwidth - 1
+		color: gg.Color{255, 255, 255, 155}
+		style: .stroke
+	}
+	ctx.draw_rect(rtop)
+	ctx.draw_rect(rleft)
+	ctx.draw_rect(rright)
+	ctx.draw_rect(border)
+	ctx.draw_rect(rbottom)
+}