fling
diff --git a/res/raw/rollo.c b/res/raw/rollo.c
index 7648270..bae390f 100644
--- a/res/raw/rollo.c
+++ b/res/raw/rollo.c
@@ -5,13 +5,6 @@
#define PI 3.14159f
-// Allocations ======
-#define ALLOC_PARAMS 0
-#define ALLOC_STATE 1
-#define ALLOC_SCRATCH 2
-#define ALLOC_ICON_IDS 3
-#define ALLOC_LABEL_IDS 4
-
// Variables from java ======
// Parameters ======
@@ -23,11 +16,13 @@
// State ======
#define STATE_ICON_COUNT 0
#define STATE_SCROLL_X 1
+#define STATE_FLING_TIME 2
+#define STATE_FLING_VELOCITY_X 3
+#define STATE_ADJUSTED_DECELERATION 4
+#define STATE_CURRENT_SCROLL_X 5 /* with fling offset applied */
// Scratch variables ======
-#define SCRATCH_FADE 0
-#define SCRATCH_ZOOM 1
-#define SCRATCH_ROT 2
+#define SCRATCH_ADJUSTED_DECELERATION 0
// Drawing constants, should be parameters ======
#define SCREEN_WIDTH 480
@@ -49,19 +44,31 @@
#define COLUMN_GUTTER_PX 5
#define LABEL_WIDTH_PX 105
+
int
count_pages(int iconCount)
{
int iconsPerPage = COLUMNS_PER_PAGE * ROWS_PER_PAGE;
int pages = iconCount / iconsPerPage;
if (pages*iconsPerPage != iconCount) {
- iconCount++;
+ pages++;
}
- return iconCount;
+ return pages;
+}
+
+int current_page(float scrollXPx)
+{
+ return -scrollXPx / SCREEN_WIDTH;
+}
+
+float
+modf(float x, float y)
+{
+ return x-(y*floorf(x/y));
}
int
-main(void* con, int ft, int launchID)
+main(int launchID)
{
// Clear to transparent
pfClearColor(0.0f, 0.0f, 0.0f, 0.0f);
@@ -91,25 +98,104 @@
float labelTextureWidth = loadI32(ALLOC_PARAMS, PARAM_BUBBLE_BITMAP_WIDTH) * densityScale;
float labelTextureHeight = loadI32(ALLOC_PARAMS, PARAM_BUBBLE_BITMAP_HEIGHT) * densityScale;
- float pageLeft = -1;
- int icon = 0;
+ float scrollXPx = loadI32(ALLOC_STATE, STATE_SCROLL_X);
+ float maxScrollX = -(pageCount-1) * SCREEN_WIDTH;
+ int done = 0;
+
+ // 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);
+ 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
+ // page. Otherwise, we'll adjust the deceleration so it just makes it to the
+ // page boundary.
+ if (flingVelocityPxMs > 0) {
+ deceleration = -1000;
+ } else {
+ 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));
+
+ if (endPos > 0) {
+ endPos = 0;
+ }
+ if (endPos < maxScrollX) {
+ endPos = maxScrollX;
+ }
+ float screenWidthFloat = SCREEN_WIDTH;
+ float scrollOnPage = modf(endPos, screenWidthFloat);
+ }
+
+ // adjust the deceleration so we always hit a page boundary
+
+ int flingTime = loadI32(ALLOC_STATE, STATE_FLING_TIME);
+ int now = uptimeMillis();
+ 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 (scrollXPx > 0) {
+ scrollXPx = 0;
+ }
+ if (scrollXPx < maxScrollX) {
+ scrollXPx = maxScrollX;
+ }
+
+ storeI32(ALLOC_STATE, STATE_CURRENT_SCROLL_X, scrollXPx);
+ if (done) {
+ storeI32(ALLOC_STATE, STATE_SCROLL_X, scrollXPx);
+ storeI32(ALLOC_STATE, STATE_FLING_VELOCITY_X, 0);
+ storeF(ALLOC_STATE, STATE_ADJUSTED_DECELERATION, 0);
+ }
+
+ // don't draw everything, just the page before and after what we're viewing.
+ int currentPage = current_page(scrollXPx);
+ float screenWidth = SCREEN_WIDTH * densityScale;
+
+ float pageLeft = -1 + ((currentPage-1)*screenWidth);
+ int iconsPerPage = COLUMNS_PER_PAGE * ROWS_PER_PAGE;
+ int icon = (currentPage-1) * iconsPerPage;
+ if (icon < 0) {
+ icon = 0;
+ }
int page;
-
- int scrollXPx = loadI32(ALLOC_STATE, STATE_SCROLL_X);
- debugI32("scrollXPx", scrollXPx);
+ int lastIcon = icon + (iconsPerPage*3);
+ if (lastIcon >= iconCount) {
+ lastIcon = iconCount-1;
+ }
pageLeft += scrollXPx * densityScale;
-
- for (page=0; page<pageCount; page++) {
+ for (page=currentPage-1; page<pageCount && page<=(currentPage+1); page++) {
// Bug makes 1.0f alpha fail.
color(1.0f, 1.0f, 1.0f, 0.99f);
float cellTop = pagePaddingTop;
int row;
- for (row=0; row<ROWS_PER_PAGE && icon<iconCount; row++) {
+ for (row=0; row<ROWS_PER_PAGE && icon<=lastIcon; row++) {
float s = pageLeft; // distance along the linear strip of icons in normalized coords
s += pagePaddingLeft;
int col;
- for (col=0; col<COLUMNS_PER_PAGE && icon<iconCount; col++) {
+ for (col=0; col<COLUMNS_PER_PAGE && icon<=lastIcon; col++) {
// icon
float iconLeft = s + ((cellWidth-iconWidth)/2.0f);
float iconRight = iconLeft + iconWidth;
@@ -141,7 +227,6 @@
pageLeft += 2.0f;
}
- return 1;
+ return !done;
}
-