commit d318489a15662e7c06af57d5e1f17e095b0564bd
author Mike Klein <mtklein@google.com> Wed Jul 22 17:39:20 2020 -0500
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Thu Jul 23 00:55:42 2020 +0000
tree 0d9da17ea04a8db1f7a24d6fe18b0698e8eff820
parent 4739b1d353d28af6797f5c7b53ce3bdeaf9c11a7

use new cubic code for old cubics

Change-Id: Id1926ce12106644a90ce15c9b537d6a4d4f2419a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/305384
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>

src/shaders/SkImageShader.cpp

diff --git a/src/shaders/SkImageShader.cpp b/src/shaders/SkImageShader.cpp
index 7b449fd..30fe2ef 100755
--- a/src/shaders/SkImageShader.cpp
+++ b/src/shaders/SkImageShader.cpp
@@ -58,7 +58,6 @@
     , fFilterEnum(filtering)
     , fClampAsIfUnpremul(clampAsIfUnpremul)
     , fFilterOptions({})    // ignored
-    , fCubic({})            // ignored
 {
     SkASSERT(filtering != kUseFilterOptions);
 }
@@ -74,7 +73,6 @@
     , fFilterEnum(FilterEnum::kUseFilterOptions)
     , fClampAsIfUnpremul(false)
     , fFilterOptions(options)
-    , fCubic({})    // ignored
 {}
 
 SkImageShader::SkImageShader(sk_sp<SkImage> img,
@@ -1024,40 +1022,24 @@
             skvm::F32 wx[4],
                       wy[4];
 
-            if (fFilterEnum == kUseCubicResampler) {
-                SkM44 weights = CubicResamplerMatrix(fCubic.B, fCubic.C);
+            SkM44 weights = CubicResamplerMatrix(fCubic.B, fCubic.C);
 
-                auto dot = [](const skvm::F32 a[], const skvm::F32 b[]) {
-                    return a[0]*b[0] + a[1]*b[1] + a[2]*b[2] + a[3]*b[3];
-                };
-                const skvm::F32 tmpx[] =  { p->splat(1.0f), fx, fx*fx, fx*fx*fx };
-                const skvm::F32 tmpy[] =  { p->splat(1.0f), fy, fy*fy, fy*fy*fy };
+            auto dot = [](const skvm::F32 a[], const skvm::F32 b[]) {
+                return a[0]*b[0] + a[1]*b[1] + a[2]*b[2] + a[3]*b[3];
+            };
+            const skvm::F32 tmpx[] =  { p->splat(1.0f), fx, fx*fx, fx*fx*fx };
+            const skvm::F32 tmpy[] =  { p->splat(1.0f), fy, fy*fy, fy*fy*fy };
 
-                for (int row = 0; row < 4; ++row) {
-                    SkV4 r = weights.row(row);
-                    skvm::F32 ru[] = {
-                        p->uniformF(uniforms->pushF(r[0])),
-                        p->uniformF(uniforms->pushF(r[1])),
-                        p->uniformF(uniforms->pushF(r[2])),
-                        p->uniformF(uniforms->pushF(r[3])),
-                    };
-                    wx[row] = dot(ru, tmpx);
-                    wy[row] = dot(ru, tmpy);
-                }
-            } else {    // legacy hard-coded weights
-                auto near = [&](skvm::F32 t) {
-                    // 1/18 + 9/18t + 27/18t^2 - 21/18t^3 == t ( t ( -21/18t + 27/18) + 9/18) + 1/18
-                    return t * (t * (t * (-21/18.0f) + 27/18.0f) + 9/18.0f) + 1/18.0f;
+            for (int row = 0; row < 4; ++row) {
+                SkV4 r = weights.row(row);
+                skvm::F32 ru[] = {
+                    p->uniformF(uniforms->pushF(r[0])),
+                    p->uniformF(uniforms->pushF(r[1])),
+                    p->uniformF(uniforms->pushF(r[2])),
+                    p->uniformF(uniforms->pushF(r[3])),
                 };
-                auto far = [&](skvm::F32 t) {
-                    // 0/18 + 0/18*t - 6/18t^2 + 7/18t^3 == t^2 (7/18t - 6/18)
-                    return t * t * (t * (7/18.0f) - 6/18.0f);
-                };
-
-                wx[0] = far (1.0f - fx);  wy[0] = far (1.0f - fy);
-                wx[1] = near(1.0f - fx);  wy[1] = near(1.0f - fy);
-                wx[2] = near(       fx);  wy[2] = near(       fy);
-                wx[3] = far (       fx);  wy[3] = far (       fy);
+                wx[row] = dot(ru, tmpx);
+                wy[row] = dot(ru, tmpy);
             }
 
             skvm::Color c;