commit 6ae6008259d9b6f7933d230627f0fcde2c949531
parent eae17b82d73b94f6d30f2f9b8467a471dc8ebd7b
Author: Nicolas Silva <nical@fastmail.com>
Date: Fri, 17 Oct 2025 08:18:24 +0000
Bug 1978773 - Move findGradientStopPair up so it can be used by more functions. r=lsalzman
Differential Revision: https://phabricator.services.mozilla.com/D268099
Diffstat:
1 file changed, 73 insertions(+), 73 deletions(-)
diff --git a/gfx/wr/swgl/src/swgl_ext.h b/gfx/wr/swgl/src/swgl_ext.h
@@ -1509,6 +1509,79 @@ static ALWAYS_INLINE WideRGBA8 dither(WideRGBA8 color, int32_t fragCoordX,
return color + ditherNoiseYIndexed[fragCoordX & 7];
}
+// Finds the gradient stop pair that affects the provided offset.
+//
+// The returned index corresponds to the gradient stop immediately before the
+// current offset (in increasing offset order), so the gradient stop pair
+// is defined by [index, index + 1].
+//
+// Output parameters:
+// - (out) prevOffset is set to the offset of the returned stop.
+// - (out) nextOffset is set to the offset of the following stop.
+// - (in/out) initialIndex is the index at which to start the search.
+// It is updated by this function.
+// - (in/out) initialOffset is the offset of the stop at initalOffset.
+// It is updated by this function.
+static int32_t findGradientStopPair(float offset, float* stops,
+ int32_t numStops, int32_t& initialIndex,
+ float& initialOffset, float& prevOffset,
+ float& nextOffset) {
+ int32_t index = initialIndex;
+
+ // Walk forward or backward depending on where the target offset is relative
+ // to the initial offset.
+ if (offset >= initialOffset) {
+ // Walk the gradient stops forward
+ float next = stops[initialIndex];
+ float prev = stops[max(initialIndex - 1, 0)];
+ while (index < numStops) {
+ if (next > offset) {
+ break;
+ }
+
+ index += 1;
+ prev = next;
+ next = stops[index];
+ }
+
+ // We wither:
+ // - Walked 1 stop past the one we are looking for, so we need to
+ // adjust the index by decrementing it.
+ // - Walked past the last stop so the index is out of bounds. We
+ // don't *have* to decrement it since we are going to clamp it
+ // at the end of the function but doing it does not break the
+ // logic either.
+ index -= 1;
+
+ prevOffset = prev;
+ nextOffset = next;
+ } else {
+ // Walk back.
+ float next = stops[initialIndex];
+ float prev = stops[min(initialIndex + 1, numStops - 1)];
+ while (index > 0) {
+ if (next < offset) {
+ break;
+ }
+
+ index -= 1;
+ prev = next;
+ next = stops[index];
+ }
+
+ // Since we are walking backwards, prev and next are swapped.
+ prevOffset = next;
+ nextOffset = prev;
+ }
+
+ index = clamp(index, 0, numStops - 2);
+
+ initialIndex = index;
+ initialOffset = prevOffset;
+
+ return index;
+}
+
// Samples an entire span of a linear gradient by crawling the gradient table
// and looking for consecutive stops that can be merged into a single larger
// gradient, then interpolating between those larger gradients within the span.
@@ -2023,79 +2096,6 @@ static bool commitRadialGradient(sampler2D sampler, int address, float size,
return true;
}
-// Finds the gradient stop pair that affects the provided offset.
-//
-// The returned index corresponds to the gradient stop immediately before the
-// current offset (in increasing offset order), so the gradient stop pair
-// is defined by [index, index + 1].
-//
-// Output parameters:
-// - (out) prevOffset is set to the offset of the returned stop.
-// - (out) nextOffset is set to the offset of the following stop.
-// - (in/out) initialIndex is the index at which to start the search.
-// It is updated by this function.
-// - (in/out) initialOffset is the offset of the stop at initalOffset.
-// It is updated by this function.
-static int32_t findGradientStopPair(float offset, float* stops,
- int32_t numStops, int32_t& initialIndex,
- float& initialOffset, float& prevOffset,
- float& nextOffset) {
- int32_t index = initialIndex;
-
- // Walk forward or backward depending on where the target offset is relative
- // to the initial offset.
- if (offset >= initialOffset) {
- // Walk the gradient stops forward
- float next = stops[initialIndex];
- float prev = stops[max(initialIndex - 1, 0)];
- while (index < numStops) {
- if (next > offset) {
- break;
- }
-
- index += 1;
- prev = next;
- next = stops[index];
- }
-
- // We wither:
- // - Walked 1 stop past the one we are looking for, so we need to
- // adjust the index by decrementing it.
- // - Walked past the last stop so the index is out of bounds. We
- // don't *have* to decrement it since we are going to clamp it
- // at the end of the function but doing it does not break the
- // logic either.
- index -= 1;
-
- prevOffset = prev;
- nextOffset = next;
- } else {
- // Walk back.
- float next = stops[initialIndex];
- float prev = stops[min(initialIndex + 1, numStops - 1)];
- while (index > 0) {
- if (next < offset) {
- break;
- }
-
- index -= 1;
- prev = next;
- next = stops[index];
- }
-
- // Since we are walking backwards, prev and next are swapped.
- prevOffset = next;
- nextOffset = prev;
- }
-
- index = clamp(index, 0, numStops - 2);
-
- initialIndex = index;
- initialOffset = prevOffset;
-
- return index;
-}
-
// Samples an entire span of a radial gradient.
template <bool BLEND, bool DITHER>
static bool commitRadialGradientFromStops(sampler2D sampler, int offsetsAddress,
