From 3a148d92224a9ab88a9c602b072d85d4b1b1eddd Mon Sep 17 00:00:00 2001
From: John Tsiombikas <nuclear@mutantstargoat.com>
Date: Mon, 22 Aug 2016 05:42:57 +0300
Subject: [PATCH] transitions

---
 src/conscr.c |   38 ++++++++++++++++++++++++++++++++------
 src/main.c   |    2 +-
 src/screen.c |    8 ++++++++
 src/tunnel.c |   44 +++++++++++++++++++++++++++++++++++---------
 4 files changed, 76 insertions(+), 16 deletions(-)

diff --git a/src/conscr.c b/src/conscr.c
index 4c56fb0..51c50f2 100644
--- a/src/conscr.c
+++ b/src/conscr.c
@@ -9,6 +9,7 @@ static void destroy(void);
 static void start(long trans_time);
 static void stop(long trans_time);
 static void draw(void);
+static float smoothstep(float a, float b, float x);
 
 static struct screen scr = {
 	"console",
@@ -21,7 +22,12 @@ static struct screen scr = {
 
 static void *saved_fb;
 static int fbsize;
-static long trans_start, trans_dur;
+static long trans_start = -1, trans_dur;
+
+#define NBLOCKS		32
+#define MAX_DELAY	0.5
+static float delay[NBLOCKS];
+static int blksz;
 
 struct screen *console_screen(void)
 {
@@ -30,13 +36,21 @@ struct screen *console_screen(void)
 
 static int init(void)
 {
+	int i;
 	fbsize = fb_width * fb_height * fb_depth / 8;
 
 	if(!(saved_fb = malloc(fbsize))) {
-		perror("failed to allocate memory");
+		perror("failed to allocate console framebuffer");
 		return -1;
 	}
 	memcpy(saved_fb, fb_pixels, fbsize);
+
+	blksz = fb_height / NBLOCKS;
+
+	for(i=0; i<NBLOCKS; i++) {
+		delay[i] = (float)rand() / (float)RAND_MAX * MAX_DELAY;
+	}
+
 	return 0;
 }
 
@@ -63,16 +77,19 @@ static void draw(void)
 	unsigned char *dptr = fb_pixels;
 	unsigned char *sptr = saved_fb;
 
-	if(!trans_start) {
+	if(trans_start < 0) {
 		return;
 	}
-	printf("console draw\n");
 
 	elapsed = time_msec - trans_start;
-	offs = fb_width * elapsed / trans_dur;
-	rem = fb_width - offs;
 
 	for(i=0; i<fb_height; i++) {
+		int bidx = i / blksz;
+		float t = (float)elapsed / (float)trans_dur;
+		offs = fb_width * smoothstep(0, 1.0 - delay[bidx], t - delay[bidx]);
+		if(offs < 0) offs = 0;
+		rem = fb_width - offs;
+
 		if(offs > 0) {
 			memset(dptr, 0, offs * pixsz);
 		}
@@ -84,3 +101,12 @@ static void draw(void)
 		sptr += fb_width * pixsz;
 	}
 }
+
+static float smoothstep(float a, float b, float x)
+{
+	if(x < a) return 0.0;
+	if(x >= b) return 1.0;
+
+	x = (x - a) / (b - a);
+	return x * x * (3.0 - 2.0 * x);
+}
diff --git a/src/main.c b/src/main.c
index 1cd4950..f18563e 100644
--- a/src/main.c
+++ b/src/main.c
@@ -50,7 +50,7 @@ int main(void)
 		goto end;
 	}
 	scr_change(scr_lookup("console"), 0);
-	scr_change(scr_lookup("tunnel"), 2000);
+	scr_change(scr_lookup("tunnel"), 4000);
 
 	start_msec = get_time_msec();
 	for(;;) {
diff --git a/src/screen.c b/src/screen.c
index 1f1dfbe..ff88268 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -45,6 +45,7 @@ void scr_update(void)
 	if(prev) {	/* we're in the middle of a transition */
 		long interval = time_msec - trans_start;
 		if(interval >= trans_dur) {
+			next->start(trans_dur);
 			prev = 0;
 			cur = next;
 			next = 0;
@@ -70,16 +71,23 @@ struct screen *scr_lookup(const char *name)
 
 int scr_change(struct screen *s, long trans_time)
 {
+	if(!s) return -1;
 	if(s == cur) return 0;
 
 	if(trans_time && cur) {
 		trans_dur = trans_time / 2;	/* half for each part transition out then in */
 		trans_start = time_msec;
 
+		if(cur) cur->stop(trans_dur);
+
 		prev = cur;
 		next = s;
 	} else {
+		if(cur) cur->stop(0);
+		s->start(0);
+
 		cur = s;
+		prev = 0;
 	}
 	return 0;
 }
diff --git a/src/tunnel.c b/src/tunnel.c
index 4707d81..8dec902 100644
--- a/src/tunnel.c
+++ b/src/tunnel.c
@@ -20,10 +20,10 @@ static void start(long trans_time);
 static void stop(long trans_time);
 static void draw(void);
 
-static void (*draw_tunnel_range)(void*, int, int);
+static void (*draw_tunnel_range)(void*, int, int, long);
 
-static void draw_tunnel_range16(void *pixels, int starty, int num_lines);
-static void draw_tunnel_range32(void *pixels, int starty, int num_lines);
+static void draw_tunnel_range16(void *pixels, int starty, int num_lines, long tm);
+static void draw_tunnel_range32(void *pixels, int starty, int num_lines, long tm);
 static int count_bits(unsigned int x);
 static int count_zeros(unsigned int x);
 
@@ -47,6 +47,9 @@ static unsigned int tex_xmask, tex_ymask;
 
 static struct thread_pool *tpool;
 
+static long trans_start, trans_dur;
+static int trans_dir;
+
 
 struct screen *tunnel_screen(void)
 {
@@ -146,10 +149,16 @@ static void destroy(void)
 
 static void start(long trans_time)
 {
+	trans_start = time_msec;
+	trans_dur = trans_time;
+	trans_dir = 1;
 }
 
 static void stop(long trans_time)
 {
+	trans_start = time_msec;
+	trans_dur = trans_time;
+	trans_dir = -1;
 }
 
 #define NUM_WORK_ITEMS	32
@@ -157,21 +166,38 @@ static void stop(long trans_time)
 static struct work {
 	void *pixels;
 	int starty, num_lines;
+	long tm;
 } work[NUM_WORK_ITEMS];
 
 static void work_func(void *cls)
 {
 	struct work *w = (struct work*)cls;
-	draw_tunnel_range(w->pixels, w->starty, w->num_lines);
+	draw_tunnel_range(w->pixels, w->starty, w->num_lines, w->tm);
 }
 
 static void draw(void)
 {
 	int i, num_lines = vysz / NUM_WORK_ITEMS;
+	int draw_lines = num_lines;
+
+	if(trans_dir) {
+		long interval = time_msec - trans_start;
+		int progr = num_lines * interval / trans_dur;
+		if(trans_dir < 0) {
+			draw_lines = num_lines - progr - 1;
+		} else {
+			draw_lines = progr;
+		}
+		if(progr >= num_lines) {
+			trans_dir = 0;
+		}
+	}
+
 	for(i=0; i<NUM_WORK_ITEMS; i++) {
 		work[i].pixels = fb_pixels;
 		work[i].starty = i * num_lines;
-		work[i].num_lines = num_lines;
+		work[i].num_lines = draw_lines;
+		work[i].tm = time_msec;
 
 		tpool_enqueue(tpool, work + i, work_func, 0);
 	}
@@ -205,13 +231,13 @@ static void tunnel_color(int *rp, int *gp, int *bp, long toffs, unsigned int tpa
 #define PACK_RGB32(r, g, b) \
 	((((r) & 0xff) << 16) | (((g) & 0xff) << 8) | ((b) & 0xff))
 
-static void draw_tunnel_range16(void *pix, int starty, int num_lines)
+static void draw_tunnel_range16(void *pix, int starty, int num_lines, long tm)
 {
 	int i, j;
 	unsigned int *tmap = tunnel_map + starty * vxsz;
 	unsigned char *fog = tunnel_fog + starty * vxsz;
 
-	long toffs = time_msec / 4;
+	long toffs = tm / 4;
 	unsigned int *pixels = (unsigned int*)pix + starty * (xsz >> 1);
 
 	for(i=0; i<num_lines; i++) {
@@ -226,13 +252,13 @@ static void draw_tunnel_range16(void *pix, int starty, int num_lines)
 	}
 }
 
-static void draw_tunnel_range32(void *pix, int starty, int num_lines)
+static void draw_tunnel_range32(void *pix, int starty, int num_lines, long tm)
 {
 	int i, j;
 	unsigned int *tmap = tunnel_map + starty * vxsz;
 	unsigned char *fog = tunnel_fog + starty * vxsz;
 
-	long toffs = time_msec / 4;
+	long toffs = tm / 4;
 	unsigned int *pixels = (unsigned int*)pix + starty * xsz * VSCALE;
 
 	for(i=0; i<num_lines; i++) {
-- 
1.7.10.4