jumper, finish blend modes

I've decided to ignore our existing CPU implementations and start from
scratch, mostly referencing the GL ES 3.2 spec and w3 spec.

This implementation ought to look a lot like the reference
implementation I've written in gm/hsl.cpp, with the addition of
handling alpha: unpremul, blend, re-premul with a simple SrcOver alpha.

Change-Id: I38cf6be2dc66a6f46d7b18b91847f6933d2fab62
Reviewed-on: https://skia-review.googlesource.com/15316
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/core/SkModeColorFilter.cpp b/src/core/SkModeColorFilter.cpp
index a5ec5e08ac..33d7977592 100644
--- a/src/core/SkModeColorFilter.cpp
+++ b/src/core/SkModeColorFilter.cpp
@@ -98,10 +98,10 @@ bool SkModeColorFilter::onAppendStages(SkRasterPipeline* p,
     p->append(SkRasterPipeline::move_src_dst);
     p->append(SkRasterPipeline::constant_color, color);
     auto mode = (SkBlendMode)fMode;
-    if (!SkBlendMode_AppendStages(mode, p)) {
-        return false;
+    SkBlendMode_AppendStages(mode, p);
+    if (SkBlendMode_CanOverflow(mode)) {
+        p->append(SkRasterPipeline::clamp_a);
     }
-    if (SkBlendMode_CanOverflow(mode)) { p->append(SkRasterPipeline::clamp_a); }
     return true;
 }