fling better
diff --git a/res/raw/rollo.c b/res/raw/rollo.c
index bae390f..9168411 100644
--- a/res/raw/rollo.c
+++ b/res/raw/rollo.c
@@ -20,6 +20,8 @@
#define STATE_FLING_VELOCITY_X 3
#define STATE_ADJUSTED_DECELERATION 4
#define STATE_CURRENT_SCROLL_X 5 /* with fling offset applied */
+#define STATE_FLING_DURATION 6
+#define STATE_FLING_END_POS 7
// Scratch variables ======
#define SCRATCH_ADJUSTED_DECELERATION 0
@@ -44,7 +46,6 @@
#define COLUMN_GUTTER_PX 5
#define LABEL_WIDTH_PX 105
-
int
count_pages(int iconCount)
{
@@ -102,12 +103,21 @@
float maxScrollX = -(pageCount-1) * SCREEN_WIDTH;
int done = 0;
+ // Clamp -- because java doesn't know how big the icons are
+ if (scrollXPx > 0) {
+ scrollXPx = 0;
+ }
+ if (scrollXPx < maxScrollX) {
+ scrollXPx = maxScrollX;
+ }
+
// If we've been given a velocity, start a fling
float flingVelocityPxMs = loadI32(ALLOC_STATE, STATE_FLING_VELOCITY_X);
if (flingVelocityPxMs != 0) {
// how many screens will this velocity do? TODO: use long
// G * ppi * friction // why G? // friction = 0.015
float deceleration = loadF(ALLOC_STATE, STATE_ADJUSTED_DECELERATION);
+ float flingDurationMs;
if (deceleration == 0) {
// On the first frame, calculate which animation we're going to do. If it's
// going to end up less than halfway into a page, we'll bounce back the previous
@@ -119,9 +129,10 @@
deceleration = 1000;
}
// v' = v + at --> t = -v / a
- // x' = x + vt + .5 a t^2 --> x' = x + (-v^2/a) + (v^2/2a)
- float endPos = scrollXPx + (-(flingVelocityPxMs*flingVelocityPxMs)/deceleration)
- + ((flingVelocityPxMs*flingVelocityPxMs)/(2.0f*deceleration));
+ // x' = x + vt + .5 a t^2
+ flingDurationMs = - flingVelocityPxMs / deceleration;
+ float endPos = scrollXPx + (flingVelocityPxMs*flingDurationMs)
+ + ((deceleration*flingDurationMs*flingDurationMs)/2);
if (endPos > 0) {
endPos = 0;
@@ -129,8 +140,41 @@
if (endPos < maxScrollX) {
endPos = maxScrollX;
}
- float screenWidthFloat = SCREEN_WIDTH;
- float scrollOnPage = modf(endPos, screenWidthFloat);
+ float scrollOnPage = modf(endPos, SCREEN_WIDTH);
+ int endPage = -endPos/SCREEN_WIDTH;
+ if (flingVelocityPxMs < 0) {
+ if (scrollOnPage < (SCREEN_WIDTH/2)) {
+ // adjust the deceleration so we align on the page boundary
+ // a = 2(x-x0-v0t)/t^2
+ endPos = -(endPage+1) * SCREEN_WIDTH;
+ debugI32("endPos case", 1);
+ } else {
+ // TODO: bounce
+ endPos = -(endPage+1) * SCREEN_WIDTH;
+ debugI32("endPos case", 2);
+ }
+ } else {
+ if (scrollOnPage >= (SCREEN_WIDTH/2)) {
+ // adjust the deceleration so we align on the page boundary
+ endPos = -endPage * SCREEN_WIDTH;
+ debugI32("endPos case", 3);
+ } else {
+ // TODO: bounce
+ endPos = -endPage * SCREEN_WIDTH;
+ debugI32("endPos case", 4);
+ }
+ }
+ // v = v0 + at --> (v - v0) / t
+ deceleration = 2*(endPos-scrollXPx-(flingVelocityPxMs*flingDurationMs))
+ / (flingDurationMs*flingDurationMs);
+ endPos = scrollXPx + (flingVelocityPxMs*flingDurationMs)
+ + ((deceleration*flingDurationMs*flingDurationMs)/2);
+
+ storeF(ALLOC_STATE, STATE_ADJUSTED_DECELERATION, deceleration);
+ storeF(ALLOC_STATE, STATE_FLING_DURATION, flingDurationMs);
+ storeF(ALLOC_STATE, STATE_FLING_END_POS, endPos);
+ } else {
+ flingDurationMs = loadF(ALLOC_STATE, STATE_FLING_DURATION);
}
// adjust the deceleration so we always hit a page boundary
@@ -140,21 +184,17 @@
float elapsedTime = (now - flingTime) / 1000.0f;
int animEndTime = -flingVelocityPxMs / deceleration;
- done = elapsedTime >= animEndTime;
- if (done) {
- // clamp the time to the end value
- elapsedTime = animEndTime;
- }
-
- float tension = 2.0f;
- float interp = elapsedTime * elapsedTime * ((tension + 1) * elapsedTime + tension) + 1.0f; // normalized 0..1
-
int flingOffsetPx = (flingVelocityPxMs * elapsedTime)
+ (deceleration * elapsedTime * elapsedTime / 2.0f);
scrollXPx += flingOffsetPx;
+ if (elapsedTime > flingDurationMs) {
+ scrollXPx = loadF(ALLOC_STATE, STATE_FLING_END_POS);
+ done = 1;
+ }
}
+ // Clamp
if (scrollXPx > 0) {
scrollXPx = 0;
}
@@ -185,7 +225,7 @@
lastIcon = iconCount-1;
}
pageLeft += scrollXPx * densityScale;
- for (page=currentPage-1; page<pageCount && page<=(currentPage+1); page++) {
+ while (icon <= lastIcon) {
// Bug makes 1.0f alpha fail.
color(1.0f, 1.0f, 1.0f, 0.99f);
diff --git a/src/com/android/launcher2/AllAppsView.java b/src/com/android/launcher2/AllAppsView.java
index 662a9dc..8c0b83d 100644
--- a/src/com/android/launcher2/AllAppsView.java
+++ b/src/com/android/launcher2/AllAppsView.java
@@ -214,6 +214,8 @@
@AllocationIndex(3) public int flingVelocityX;
@AllocationIndex(4) public int adjustedDeceleration;
@AllocationIndex(5) public int currentScrollX;
+ @AllocationIndex(6) public int flingDuration;
+ @AllocationIndex(7) public int flingEndPos;
}
public RolloRS() {