From 7072fe447d09bc01e81795a283dd73587a7a8145 Mon Sep 17 00:00:00 2001
From: Andrei Alexeyev <akari@taisei-project.org>
Date: Sat, 16 May 2020 23:42:22 +0300
Subject: [PATCH] Revamp screen shake system (#225)

---
 src/boss.c                 | 25 ++++++++--------------
 src/global.h               |  3 ---
 src/plrmodes/marisa_a.c    |  6 ++----
 src/plrmodes/marisa_b.c    |  4 +---
 src/plrmodes/reimu_a.c     |  4 +---
 src/plrmodes/reimu_b.c     |  4 ++--
 src/stage.c                | 40 +++++++++++++++++++++++-----------
 src/stage.h                |  3 +++
 src/stagedraw.c            | 42 ++++++++++++++++++++----------------
 src/stages/stage5_events.c |  8 ++-----
 src/stages/stage6_events.c | 44 ++++++++++++++++----------------------
 11 files changed, 88 insertions(+), 95 deletions(-)

diff --git a/src/boss.c b/src/boss.c
index 341193e4..1d8c9e0a 100644
--- a/src/boss.c
+++ b/src/boss.c
@@ -1050,20 +1050,18 @@ void process_boss(Boss **pboss) {
 			float p = (boss->current->endtime - global.frames)/(float)ATTACK_END_DELAY_EXTRA;
 			float a = fmax((base + ampl * s) * p * 0.5, 5 * pow(1 - p, 3));
 			if(a < 2) {
-				global.shake_view = 3 * a;
+				stage_shake_view(3 * a);
 				boss_rule_extra(boss, a);
 				if(a > 1) {
 					boss_rule_extra(boss, a * 0.5);
 					if(a > 1.3) {
-						global.shake_view = 5 * a;
+						stage_shake_view(5 * a);
 						if(a > 1.7)
-							global.shake_view += 2 * a;
+							stage_shake_view(2 * a);
 						boss_rule_extra(boss, 0);
 						boss_rule_extra(boss, 0.1);
 					}
 				}
-			} else {
-				global.shake_view_fade = 0.15;
 			}
 		} else if(time < 0) {
 			boss_rule_extra(boss, 1+time/(float)ATTACK_START_DELAY_EXTRA);
@@ -1074,12 +1072,10 @@ void process_boss(Boss **pboss) {
 			boss_rule_extra(boss, fmax(1-time/300.0, base + ampl * s) * q);
 			if(o) {
 				boss_rule_extra(boss, fmax(1-time/300.0, base + ampl * s) - o);
-				if(!global.shake_view) {
-					global.shake_view = 5;
-					global.shake_view_fade = 0.9;
-				} else if(o > -0.05) {
-					global.shake_view = 10;
-					global.shake_view_fade = 0.5;
+
+				stage_shake_view(5);
+				if(o > -0.05) {
+					stage_shake_view(10);
 				}
 			}
 		}
@@ -1131,11 +1127,7 @@ void process_boss(Boss **pboss) {
 		);
 
 		if(!extra) {
-			if(t == 1) {
-				global.shake_view_fade = 0.2;
-			} else {
-				global.shake_view = 5 * (t + t*t + t*t*t);
-			}
+			stage_shake_view(5 * (t + t*t + t*t*t));
 		}
 
 		if(t == 1) {
@@ -1277,6 +1269,7 @@ void boss_death(Boss **boss) {
 
 	if(!fleed) {
 		stage_clear_hazards(CLEAR_HAZARDS_ALL | CLEAR_HAZARDS_FORCE);
+		stage_shake_view(100);
 
 		PARTICLE(
 			.pos = (*boss)->pos,
diff --git a/src/global.h b/src/global.h
index c842de39..a4c7c7ee 100644
--- a/src/global.h
+++ b/src/global.h
@@ -126,9 +126,6 @@ typedef struct {
 	ReplayMode replaymode;
 	ReplayStage *replay_stage;
 
-	float shake_view;
-	float shake_view_fade;
-
 	uint voltage_threshold;
 
 	RandomState rand_game;
diff --git a/src/plrmodes/marisa_a.c b/src/plrmodes/marisa_a.c
index f76658c7..cf6a6350 100644
--- a/src/plrmodes/marisa_a.c
+++ b/src/plrmodes/marisa_a.c
@@ -533,11 +533,11 @@ TASK(marisa_laser_masterspark, { MarisaAController *ctrl; }) {
 		marisa_laser_masterspark_damage(ms);
 
 		if(bomb_progress >= 3.0/4.0) {
-			global.shake_view = 8 * (1 - bomb_progress * 4 + 3);
+			stage_shake_view(8 * (1 - bomb_progress * 4 + 3));
 			goto skip_particles;
 		}
 
-		global.shake_view = 8;
+		stage_shake_view(8);
 
 		uint pflags = PFLAG_NOREFLECT | PFLAG_MANUALANGLE;
 
@@ -581,8 +581,6 @@ skip_particles:
 		YIELD;
 	} while(player_is_bomb_active(plr));
 
-	global.shake_view = 0;
-
 	while(ms->alpha > 0) {
 		approach_p(&ms->alpha, 0, 0.2);
 		YIELD;
diff --git a/src/plrmodes/marisa_b.c b/src/plrmodes/marisa_b.c
index 37909c14..e26750f6 100644
--- a/src/plrmodes/marisa_b.c
+++ b/src/plrmodes/marisa_b.c
@@ -436,7 +436,7 @@ TASK(marisa_star_bomb_controller, { MarisaBController *ctrl; }) {
 	}
 
 	do {
-		global.shake_view = fmax(8, global.shake_view);
+		stage_shake_view(8);
 		player_placeholder_bomb_logic(plr);
 
 		float tb = player_get_bomb_progress(plr);
@@ -457,8 +457,6 @@ TASK(marisa_star_bomb_controller, { MarisaBController *ctrl; }) {
 		++beams->time;
 		YIELD;
 	} while(player_is_bomb_active(plr));
-
-	global.shake_view = 0;
 }
 
 TASK(marisa_star_bomb_handler, { MarisaBController *ctrl; }) {
diff --git a/src/plrmodes/reimu_a.c b/src/plrmodes/reimu_a.c
index d6d21a1e..a5ff98ed 100644
--- a/src/plrmodes/reimu_a.c
+++ b/src/plrmodes/reimu_a.c
@@ -217,8 +217,7 @@ TASK(reimu_spirit_bomb_orb_impact, { BoxedProjectile orb; }) {
 	play_sound("boom");
 	play_sound("spellend");
 
-	global.shake_view = 20;
-	global.shake_view_fade = 0.6;
+	stage_shake_view(200);
 
 	real damage = 2000;
 	real range = 300;
@@ -429,7 +428,6 @@ TASK(reimu_spirit_bomb_handler, { ReimuAController *ctrl; }) {
 		WAIT_EVENT_OR_DIE(&plr->events.bomb_used);
 		INVOKE_SUBTASK(reimu_spirit_bomb_background, ctrl);
 
-		global.shake_view = 4;
 		play_sound("bomb_reimu_a");
 		play_sound("bomb_marisa_b");
 
diff --git a/src/plrmodes/reimu_b.c b/src/plrmodes/reimu_b.c
index ed24378a..2b8815a5 100644
--- a/src/plrmodes/reimu_b.c
+++ b/src/plrmodes/reimu_b.c
@@ -171,7 +171,7 @@ TASK(reimu_dream_bomb_barrage, { ReimuBController *ctrl; }) {
 			);
 		}
 
-		global.shake_view += 6;
+		stage_shake_view(4);
 		t += WAIT(BOMB_PROJECTILE_FIRE_DELAY);
 	} while(player_is_bomb_active(plr));
 }
@@ -611,7 +611,7 @@ TASK(reimu_dream_controller_tick, { ReimuBController *ctrl; }) {
 
 	for(;;) {
 		if(player_is_bomb_active(plr)) {
-			global.shake_view_fade = fmax(global.shake_view_fade, 2);
+			stage_shake_view(1);
 			approach_p(&ctrl->bomb_alpha, 1.0, 0.1);
 		} else {
 			approach_p(&ctrl->bomb_alpha, 0.0, 0.025);
diff --git a/src/stage.c b/src/stage.c
index 5320d4c4..e2bfb565 100644
--- a/src/stage.c
+++ b/src/stage.c
@@ -31,7 +31,6 @@ static void stage_start(StageInfo *stage) {
 	global.timer = 0;
 	global.frames = 0;
 	global.gameover = 0;
-	global.shake_view = 0;
 	global.voltage_threshold = 0;
 
 	player_stage_pre_init(&global.plr);
@@ -579,8 +578,11 @@ typedef struct StageFrameState {
 	int transition_delay;
 	int logic_calls;
 	uint16_t last_replay_fps;
+	float view_shake;
 } StageFrameState;
 
+static StageFrameState *_current_stage_state;  // TODO remove this shitty hack
+
 static void stage_update_fps(StageFrameState *fstate) {
 	if(global.replaymode == REPLAY_RECORD) {
 		uint16_t replay_fps = (uint16_t)rint(global.fps.logic.fps);
@@ -638,17 +640,8 @@ static LogicFrameAction stage_logic_frame(void *arg) {
 		global.plr.iddqd = true;
 	}
 
-	if(global.shake_view > 30) {
-		global.shake_view = 30;
-	}
-
-	if(global.shake_view_fade) {
-		global.shake_view -= global.shake_view_fade;
-
-		if(global.shake_view <= 0) {
-			global.shake_view = global.shake_view_fade = 0;
-		}
-	}
+	fapproach_p(&fstate->view_shake, 0, 1);
+	fapproach_asymptotic_p(&fstate->view_shake, 0, 0.05, 1e-2);
 
 	((global.replaymode == REPLAY_PLAY) ? replay_input : stage_input)();
 
@@ -688,6 +681,7 @@ static LogicFrameAction stage_logic_frame(void *arg) {
 	}
 
 	if(global.gameover > 0) {
+		log_warn("RESTART");
 		return LFRAME_STOP;
 	}
 
@@ -822,6 +816,8 @@ void stage_enter(StageInfo *stage, CallChain next) {
 	fstate->stage = stage;
 	fstate->cc = next;
 
+	_current_stage_state = fstate;
+
 	#ifdef DEBUG
 	_skip_to_dialog = env_get_int("TAISEI_SKIP_TO_DIALOG", 0);
 	_skip_to_bookmark = env_get_string_nonempty("TAISEI_SKIP_TO_BOOKMARK", NULL);
@@ -840,6 +836,7 @@ void stage_enter(StageInfo *stage, CallChain next) {
 
 void stage_end_loop(void* ctx) {
 	StageFrameState *s = ctx;
+	assert(s == _current_stage_state);
 
 	if(global.replaymode == REPLAY_RECORD) {
 		replay_stage_event(global.replay_stage, global.frames, EV_OVER, 0);
@@ -868,8 +865,12 @@ void stage_end_loop(void* ctx) {
 		global.gameover = GAMEOVER_ABORT;
 	}
 
-	run_call_chain(&s->cc, NULL);
+	_current_stage_state = NULL;
+
+	CallChain cc = s->cc;
 	free(s);
+
+	run_call_chain(&cc, NULL);
 }
 
 void stage_unlock_bgm(const char *bgm) {
@@ -877,3 +878,16 @@ void stage_unlock_bgm(const char *bgm) {
 		progress_unlock_bgm(bgm);
 	}
 }
+
+void stage_shake_view(float strength) {
+	assume(strength >= 0);
+	_current_stage_state->view_shake += strength;
+}
+
+float stage_get_view_shake_strength(void) {
+	if(_current_stage_state) {
+		return _current_stage_state->view_shake;
+	}
+
+	return 0;
+}
diff --git a/src/stage.h b/src/stage.h
index 648c9752..aa8a716e 100644
--- a/src/stage.h
+++ b/src/stage.h
@@ -101,6 +101,9 @@ void stage_unlock_bgm(const char *bgm);
 
 void stage_begin_dialog(Dialog *d) attr_nonnull_all;
 
+void stage_shake_view(float strength);
+float stage_get_view_shake_strength(void);
+
 #ifdef DEBUG
 void _stage_bookmark(const char *name);
 #define STAGE_BOOKMARK(name) _stage_bookmark(#name)
diff --git a/src/stagedraw.c b/src/stagedraw.c
index 4f5c4135..eccbd552 100644
--- a/src/stagedraw.c
+++ b/src/stagedraw.c
@@ -46,23 +46,22 @@ static struct {
 		ShaderProgram *copy_depth;
 	} shaders;
 
-	struct {
-		float alpha;
-		float target_alpha;
-	} clear_screen;
-
 	PostprocessShader *viewport_pp;
 	FBPair fb_pairs[NUM_FBPAIRS];
 	FBPair powersurge_fbpair;
 	FBPair *current_postprocess_fbpair;
 
+	ManagedFramebufferGroup *mfb_group;
+	StageDrawEvents events;
+
+	struct {
+		float alpha;
+		float target_alpha;
+	} clear_screen;
+
 	bool framerate_graphs;
 	bool objpool_stats;
 
-	ManagedFramebufferGroup *mfb_group;
-
-	StageDrawEvents events;
-
 	#ifdef DEBUG
 		Sprite dummy;
 	#endif
@@ -906,28 +905,33 @@ static void postprocess_prepare(Framebuffer *fb, ShaderProgram *s, void *arg) {
 }
 
 static inline void begin_viewport_shake(void) {
-	if(global.shake_view) {
+	float s = stage_get_view_shake_strength();
+
+	if(s > 0) {
+// 		s = log1pf(s);
+		s = sqrtf(s);
+
 		r_mat_mv_push();
 		r_mat_mv_translate(
-			global.shake_view * sin(global.frames),
-			global.shake_view * sin(global.frames * 1.1 + 3),
+			s * sin(global.frames),
+			s * sin(global.frames * 1.1 + 3),
 			0
 		);
 		r_mat_mv_scale(
-			1 + 2 * global.shake_view / VIEWPORT_W,
-			1 + 2 * global.shake_view / VIEWPORT_H,
+			1 + 2 * s / VIEWPORT_W,
+			1 + 2 * s / VIEWPORT_H,
 			1
 		);
 		r_mat_mv_translate(
-			-global.shake_view,
-			-global.shake_view,
+			-s,
+			-s,
 			0
 		);
 	}
 }
 
 static inline void end_viewport_shake(void) {
-	if(global.shake_view) {
+	if(stage_get_view_shake_strength() > 0) {
 		r_mat_mv_pop();
 	}
 }
@@ -942,7 +946,7 @@ void stage_draw_begin_noshake(void) {
 	assert(!shake_suppressed);
 	shake_suppressed = 1;
 
-	if(global.shake_view) {
+	if(stage_get_view_shake_strength() > 0) {
 		shake_suppressed = 2;
 		r_mat_mv_push_identity();
 	}
@@ -951,7 +955,7 @@ void stage_draw_begin_noshake(void) {
 void stage_draw_end_noshake(void) {
 	assert(shake_suppressed);
 
-	if(global.shake_view) {
+	if(stage_get_view_shake_strength() > 0) {
 		// make sure shake_view doesn't change in-between the begin/end calls;
 		// that would've been *really* nasty to debug.
 		assert(shake_suppressed == 2);
diff --git a/src/stages/stage5_events.c b/src/stages/stage5_events.c
index 5519a814..dc81ce3c 100644
--- a/src/stages/stage5_events.c
+++ b/src/stages/stage5_events.c
@@ -1094,8 +1094,7 @@ static int iku_extra_trigger_bullet(Projectile *p, int t) {
 				.args = { dir, 10 },
 			);
 		}
-		global.shake_view += 5;
-		global.shake_view_fade = 0.2;
+		stage_shake_view(40);
 		aniplayer_hard_switch(&global.boss->ani,"main_mirror",0);
 		play_sound("boom");
 		return ACTION_DESTROY;
@@ -1195,9 +1194,6 @@ static int iku_extra_slave(Enemy *e, int t) {
 				Laser *l;
 				int cnt = 6 + 2 * global.diff, i;
 
-				global.shake_view = 0;
-				global.shake_view_fade = 0.2;
-
 				e->args[2] = 1;
 
 				for(o = global.enemies.first; o; o = o->next) {
@@ -1217,7 +1213,7 @@ static int iku_extra_slave(Enemy *e, int t) {
 					o->args[1] = 0;
 					o->args[2] = 0;
 
-					global.shake_view += 1;
+					stage_shake_view(5);
 				}
 
 				for(l = global.lasers.first; l; l = l->next) {
diff --git a/src/stages/stage6_events.c b/src/stages/stage6_events.c
index acbed9f9..ad64cae2 100644
--- a/src/stages/stage6_events.c
+++ b/src/stages/stage6_events.c
@@ -925,7 +925,7 @@ static int scythe_explode(Enemy *e, int t) {
 
 	if(t == 100) {
 		petal_explosion(100, e->pos);
-		global.shake_view = 16;
+		stage_shake_view(16);
 		play_sound("boom");
 
 		scythe_common(e, t);
@@ -990,8 +990,14 @@ static void elly_paradigm_shift(Boss *b, int t) {
 		elly_spawn_baryons(b->pos);
 	}
 
+	/*
 	if(t > 120)
 		global.shake_view = fmax(0, 16-0.26*(t-120));
+	*/
+
+	AT(120) {
+		stage_shake_view(200);
+	}
 }
 
 static void set_baryon_rule(EnemyLogicRule r) {
@@ -1160,8 +1166,7 @@ static int broglie_charge(Projectile *p, int t) {
 		play_sound_ex("laser1", 10, true);
 		play_sound("boom");
 
-		global.shake_view = 5.0;
-		global.shake_view_fade = 0.25;
+		stage_shake_view(20);
 
 		Color clr = p->color;
 		clr.a = 0;
@@ -1747,7 +1752,6 @@ void elly_lhc(Boss *b, int t) {
 		set_baryon_rule(baryon_lhc);
 	AT(EVENT_DEATH) {
 		set_baryon_rule(baryon_reset);
-		global.shake_view_fade=1;
 	}
 
 	FROM_TO(260, 10000, 400) {
@@ -1759,7 +1763,7 @@ void elly_lhc(Boss *b, int t) {
 		int c = 30+10*global.diff;
 		cmplx pos = VIEWPORT_W/2 + 100.0*I+400.0*I*((t/400)&1);
 
-		global.shake_view = 16;
+		stage_shake_view(160);
 		play_sound("boom");
 
 		for(i = 0; i < c; i++) {
@@ -1810,10 +1814,6 @@ void elly_lhc(Boss *b, int t) {
 			.args = { cexp(2.0*I*_i), 3 },
 		);
 	}
-
-	FROM_TO(300, 10000, 400) {
-		global.shake_view = 0;
-	}
 }
 
 static int baryon_explode(Enemy *e, int t) {
@@ -1822,7 +1822,7 @@ static int baryon_explode(Enemy *e, int t) {
 		free_ref(e->args[1]);
 		petal_explosion(24, e->pos);
 		play_sound("boom");
-		global.shake_view = fmaxf(15, global.shake_view);
+		stage_shake_view(15);
 
 		for(uint i = 0; i < 3; ++i) {
 			PARTICLE(
@@ -2071,8 +2071,6 @@ static void elly_baryon_explode(Boss *b, int t) {
 
 	GO_TO(b, BOSS_DEFAULT_GO_POS, 0.05);
 
-	global.shake_view_fade = 0.5;
-
 	AT(20) {
 		set_baryon_rule(baryon_explode);
 	}
@@ -2084,7 +2082,8 @@ static void elly_baryon_explode(Boss *b, int t) {
 	FROM_TO(0, 200, 1) {
 		// tsrand_fill(2);
 		// petal_explosion(1, b->pos + 100*afrand(0)*cexp(2.0*I*M_PI*afrand(1)));
-		global.shake_view = fmaxf(global.shake_view, 5 * _i / 200.0f);
+		// global.shake_view = fmaxf(global.shake_view, 5 * _i / 200.0f);
+		stage_shake_view(_i / 200.0f);
 
 		if(_i > 30) {
 			play_loop("charge_generic");
@@ -2093,8 +2092,7 @@ static void elly_baryon_explode(Boss *b, int t) {
 
 	AT(200) {
 		tsrand_fill(2);
-		global.shake_view += 30;
-		global.shake_view_fade = 0.05;
+		stage_shake_view(40);
 		play_sound("boom");
 		petal_explosion(100, b->pos + 100*afrand(0)*cexp(2.0*I*M_PI*afrand(1)));
 		enemy_kill_all(&global.enemies);
@@ -2635,7 +2633,7 @@ static void elly_toe_laser_logic(Laser *l, int t) {
 //
 void elly_theory(Boss *b, int time) {
 	if(time == EVENT_BIRTH) {
-		global.shake_view = 10;
+		stage_shake_view(50);
 		boss_set_portrait(b, "elly", "beaten", "shouting");
 		return;
 	}
@@ -2650,7 +2648,6 @@ void elly_theory(Boss *b, int time) {
 	AT(0) {
 		assert(cabs(b->pos - ELLY_TOE_TARGET_POS) < 1);
 		b->pos = ELLY_TOE_TARGET_POS;
-		global.shake_view = 0;
 		elly_clap(b,50000);
 	}
 
@@ -2737,16 +2734,14 @@ void elly_theory(Boss *b, int time) {
 
 	AT(fermiontime) {
 		play_sound("charge_generic");
-		global.shake_view=10;
-		global.shake_view_fade=1;
+		stage_shake_view(10);
 	}
 
 	AT(symmetrytime) {
 		play_sound("charge_generic");
 		play_sound("boom");
 		stagetext_add("Symmetry broken!", VIEWPORT_W/2+I*VIEWPORT_H/4, ALIGN_CENTER, get_font("big"), RGB(1,1,1), 0,100,10,20);
-		global.shake_view=10;
-		global.shake_view_fade=1;
+		stage_shake_view(10);
 
 		PARTICLE(
 			.sprite = "blast",
@@ -2774,16 +2769,14 @@ void elly_theory(Boss *b, int time) {
 	AT(yukawatime) {
 		play_sound("charge_generic");
 		stagetext_add("Coupling the Higgs!", VIEWPORT_W/2+I*VIEWPORT_H/4, ALIGN_CENTER, get_font("big"), RGB(1,1,1), 0,100,10,20);
-		global.shake_view=10;
-		global.shake_view_fade=1;
+		stage_shake_view(10);
 	}
 
 	AT(breaktime) {
 		play_sound("charge_generic");
 		stagetext_add("Perturbation theory", VIEWPORT_W/2+I*VIEWPORT_H/4, ALIGN_CENTER, get_font("big"), RGB(1,1,1), 0,100,10,20);
 		stagetext_add("breaking down!", VIEWPORT_W/2+I*VIEWPORT_H/4+30*I, ALIGN_CENTER, get_font("big"), RGB(1,1,1), 0,100,10,20);
-		global.shake_view=10;
-		global.shake_view_fade=1;
+		stage_shake_view(10);
 	}
 
 	FROM_TO(higgstime,yukawatime+100,4+4*(time>symmetrytime)) {
@@ -2962,7 +2955,6 @@ static void elly_begin_toe(Boss *b, int t) {
 		start_fall_over();
 		stage_unlock_bgm("stage6boss_phase2");
 		stage_start_bgm("stage6boss_phase3");
-		global.shake_view_fade = 0;
 	}
 }