Disjointed scroll and selection

* You can be at most 3*16 pixels away from the centerline.
* Bonus polish: during unlock sequence, movement is smooth and zips back and forth.

src/k_menu.h

@@ -1085,6 +1085,8 @@ void M_DrawAddons(void);
 // Challenges menu:
 #define UNLOCKTIME 5
 #define MAXUNLOCKTIME TICRATE
+#define RIGHTUNLOCKSCROLL 3
+#define LEFTUNLOCKSCROLL (RIGHTUNLOCKSCROLL-1)
 
 // Keep track of some pause menu data for visual goodness.
 extern struct challengesmenu_s {
@@ -1092,16 +1094,18 @@ extern struct challengesmenu_s {
 	tic_t ticker;		// How long the menu's been open for
 	INT16 offset;		// To make the icons move smoothly when we transition!
 
-	UINT8 fade;
 	UINT8 currentunlock;
 	tic_t unlockanim;
 
-	UINT8 row, col, hilix, hiliy;
+	SINT8 row, hilix, focusx;
+	UINT8 col, hiliy;
 
 	UINT8 *extradata;
 
 	boolean pending;
 	boolean requestnew;
+
+	UINT8 fade;
 } challengesmenu;
 
 menu_t *M_InterruptMenuWithChallenges(menu_t *desiredmenu);

src/k_menudraw.c

@@ -4611,9 +4611,13 @@ void M_DrawChallenges(void)
 
 	x -= 16;
 
+	x += challengesmenu.offset;
+
 	if (challengegridloops)
 	{
-		i = challengesmenu.col;
+		if (!challengesmenu.col && challengesmenu.hilix)
+			x -= gamedata->challengegridwidth*16;
+		i = challengesmenu.col + challengesmenu.focusx;
 		explodex = x - (i*16);
 
 		while (x < BASEVIDWIDTH-16)

src/k_menufunc.c

@@ -6929,6 +6929,12 @@ void M_Challenges(INT32 choice)
 
 			challengesmenu.col = challengesmenu.hilix = i/CHALLENGEGRIDHEIGHT;
 			challengesmenu.row = challengesmenu.hiliy = i%CHALLENGEGRIDHEIGHT;
+
+			challengesmenu.focusx = 0;
+			if (challengesmenu.currentunlock < MAXUNLOCKABLES
+				&& !unlockables[challengesmenu.currentunlock].majorunlock
+				&& M_RandomChance(FRACUNIT/2))
+					challengesmenu.focusx--;
 			break;
 		}
 	}
@@ -6939,6 +6945,8 @@ void M_Challenges(INT32 choice)
 void M_ChallengesTick(void)
 {
 	UINT8 i, newunlock = MAXUNLOCKABLES;
+	SINT8 work;
+	boolean fresh = (challengesmenu.currentunlock >= MAXUNLOCKABLES);
 
 	challengesmenu.ticker++;
 
@@ -6970,8 +6978,60 @@ void M_ChallengesTick(void)
 						continue;
 					}
 
+					work = (challengesmenu.col + challengesmenu.focusx);
+
 					challengesmenu.col = challengesmenu.hilix = i/CHALLENGEGRIDHEIGHT;
 					challengesmenu.row = challengesmenu.hiliy = i%CHALLENGEGRIDHEIGHT;
+
+					if (fresh)
+					{
+						challengesmenu.focusx = 0;
+						if (!unlockables[challengesmenu.currentunlock].majorunlock
+							&& M_RandomChance(FRACUNIT/2))
+								challengesmenu.focusx--;
+					}
+					else
+					{
+						work -= challengesmenu.col;
+						if (work <= -gamedata->challengegridwidth/2)
+							work += gamedata->challengegridwidth;
+						else if (work >= gamedata->challengegridwidth/2)
+							work -= gamedata->challengegridwidth;
+
+						if (work > 0)
+						{
+							if (work > LEFTUNLOCKSCROLL)
+							{
+								work -= LEFTUNLOCKSCROLL;
+								challengesmenu.focusx = LEFTUNLOCKSCROLL;
+							}
+							else
+							{
+								challengesmenu.focusx = work;
+								work = 0;
+							}
+						}
+						else if (work < 0)
+						{
+							if (work < -RIGHTUNLOCKSCROLL)
+							{
+								challengesmenu.focusx = -RIGHTUNLOCKSCROLL;
+								work += RIGHTUNLOCKSCROLL;
+							}
+							else
+							{
+								challengesmenu.focusx = work;
+								work = 0;
+							}
+						}
+						else
+						{
+							challengesmenu.focusx = 0;
+						}
+
+						challengesmenu.offset = -work*16;
+					}
+
 					break;
 				}
 			}
@@ -7046,6 +7106,8 @@ void M_ChallengesTick(void)
 	}
 	else if (challengesmenu.fade > 0)
 		challengesmenu.fade--;
+
+	challengesmenu.offset /= 2;
 }
 
 boolean M_ChallengesInputs(INT32 ch)
@@ -7087,6 +7149,12 @@ boolean M_ChallengesInputs(INT32 ch)
 
 				challengesmenu.col = challengesmenu.hilix = i/CHALLENGEGRIDHEIGHT;
 				challengesmenu.row = challengesmenu.hiliy = i%CHALLENGEGRIDHEIGHT;
+
+				challengesmenu.focusx = 0;
+				if (!unlockables[challengesmenu.currentunlock].majorunlock
+					&& M_RandomChance(FRACUNIT/2))
+						challengesmenu.focusx--;
+
 				break;
 			}
 
@@ -7165,6 +7233,8 @@ boolean M_ChallengesInputs(INT32 ch)
 				i = 2;
 				while (i > 0)
 				{
+					if (challengesmenu.focusx > -RIGHTUNLOCKSCROLL)
+						challengesmenu.focusx--;
 					if (challengesmenu.col < gamedata->challengegridwidth-1)
 					{
 						challengesmenu.col++;
@@ -7193,6 +7263,8 @@ boolean M_ChallengesInputs(INT32 ch)
 						& CHE_CONNECTEDLEFT) ? 2 : 1;
 				while (i > 0)
 				{
+					if (challengesmenu.focusx < LEFTUNLOCKSCROLL)
+						challengesmenu.focusx++;
 					if (challengesmenu.col > 0)
 					{
 						challengesmenu.col--;
@@ -7213,6 +7285,10 @@ boolean M_ChallengesInputs(INT32 ch)
 
 			challengesmenu.hilix = challengesmenu.col;
 			challengesmenu.hiliy = challengesmenu.row;
+
+			if (challengesmenu.currentunlock < MAXUNLOCKABLES
+				&& unlockables[challengesmenu.currentunlock].majorunlock)
+			{
 				if (challengesmenu.hiliy > 0 && (challengesmenu.extradata[i] & CHE_CONNECTEDUP))
 				{
 					challengesmenu.hiliy--;
@@ -7231,6 +7307,7 @@ boolean M_ChallengesInputs(INT32 ch)
 				}
 			}
 		}
+	}
 
 	return true;
 }