diff --git a/src/gpu/effects/GrAtlasedShaderHelpers.h b/src/gpu/effects/GrAtlasedShaderHelpers.h
index caa81fb..a7d445a 100644
--- a/src/gpu/effects/GrAtlasedShaderHelpers.h
+++ b/src/gpu/effects/GrAtlasedShaderHelpers.h
@@ -20,19 +20,31 @@
                                      GrGLSLVarying *uv,
                                      GrGLSLVarying *texIdx,
                                      GrGLSLVarying *st) {
+    using Interpolation = GrGLSLVaryingHandler::Interpolation;
+
+    // This extracts the texture index and texel coordinates from the same variable
     // Packing structure: texel coordinates are multiplied by 2 (or shifted left 1)
     //                    texture index is stored as lower bits of both x and y
-    args.fVertBuilder->codeAppendf("float2 indexTexCoords = float2(%s.x, %s.y);",
-                                    inTexCoordsName, inTexCoordsName);
-    args.fVertBuilder->codeAppend("float2 unormTexCoords = floor(0.5*indexTexCoords);");
-    args.fVertBuilder->codeAppend("float2 diff = indexTexCoords - 2.0*unormTexCoords;");
-    args.fVertBuilder->codeAppend("float texIdx = 2.0*diff.x + diff.y;");
+    if (args.fShaderCaps->integerSupport()) {
+        args.fVertBuilder->codeAppendf("int2 signedCoords = int2(%s.x, %s.y);",
+                                       inTexCoordsName, inTexCoordsName);
+        args.fVertBuilder->codeAppend("int texIdx = 2*(signedCoords.x & 0x1) + (signedCoords.y & 0x1);");
+        args.fVertBuilder->codeAppend("float2 unormTexCoords = float2(signedCoords.x/2, signedCoords.y/2);");
+    } else {
+        args.fVertBuilder->codeAppendf("float2 indexTexCoords = float2(%s.x, %s.y);",
+                                       inTexCoordsName, inTexCoordsName);
+        args.fVertBuilder->codeAppend("float2 unormTexCoords = floor(0.5*indexTexCoords);");
+        args.fVertBuilder->codeAppend("float2 diff = indexTexCoords - 2.0*unormTexCoords;");
+        args.fVertBuilder->codeAppend("float texIdx = 2.0*diff.x + diff.y;");
+    }
 
     // Multiply by 1/atlasSize to get normalized texture coordinates
     args.fVaryingHandler->addVarying("TextureCoords", uv);
     args.fVertBuilder->codeAppendf("%s = unormTexCoords * %s;", uv->vsOut(), atlasSizeInvName);
 
-    args.fVaryingHandler->addVarying("TexIndex", texIdx);
+    args.fVaryingHandler->addVarying("TexIndex", texIdx, args.fShaderCaps->integerSupport()
+                                                                 ? Interpolation::kMustBeFlat
+                                                                 : Interpolation::kCanBeFlat);
     args.fVertBuilder->codeAppendf("%s = texIdx;", texIdx->vsOut());
 
     if (st) {
@@ -46,17 +58,15 @@
                                        const GrGLSLVarying &texIdx,
                                        const char* coordName,
                                        const char* colorName) {
-    // Conditionally load from the indexed texture sampler.
-    // We treat an interval of values around each int as corresponding to that int
-    // (basically round to int) to correct for floating point variation in the frag shader
-    for (int i = numTextureSamplers-1; i > 0; --i) {
-        args.fFragBuilder->codeAppendf("if (%s > %d - 0.5) { %s = ", texIdx.fsIn(), i, colorName);
+    // conditionally load from the indexed texture sampler
+    for (int i = 0; i < numTextureSamplers-1; ++i) {
+        args.fFragBuilder->codeAppendf("if (%s == %d) { %s = ", texIdx.fsIn(), i, colorName);
         args.fFragBuilder->appendTextureLookup(args.fTexSamplers[i], coordName,
                                                kFloat2_GrSLType);
         args.fFragBuilder->codeAppend("; } else ");
     }
     args.fFragBuilder->codeAppendf("{ %s = ", colorName);
-    args.fFragBuilder->appendTextureLookup(args.fTexSamplers[0], coordName,
+    args.fFragBuilder->appendTextureLookup(args.fTexSamplers[numTextureSamplers-1], coordName,
                                            kFloat2_GrSLType);
     args.fFragBuilder->codeAppend("; }");
 }
diff --git a/src/gpu/effects/GrBitmapTextGeoProc.cpp b/src/gpu/effects/GrBitmapTextGeoProc.cpp
index cd98f1d..370b0e5 100644
--- a/src/gpu/effects/GrBitmapTextGeoProc.cpp
+++ b/src/gpu/effects/GrBitmapTextGeoProc.cpp
@@ -40,7 +40,8 @@
                                                           &atlasSizeInvName);
 
         GrGLSLVarying uv(kFloat2_GrSLType);
-        GrGLSLVarying texIdx(kFloat_GrSLType);
+        GrSLType texIdxType = args.fShaderCaps->integerSupport() ? kInt_GrSLType : kFloat_GrSLType;
+        GrGLSLVarying texIdx(texIdxType);
         append_index_uv_varyings(args, btgp.inTextureCoords().name(), atlasSizeInvName, &uv,
                                  &texIdx, nullptr);
 
diff --git a/src/gpu/effects/GrDistanceFieldGeoProc.cpp b/src/gpu/effects/GrDistanceFieldGeoProc.cpp
index 314a984..b0ddd91 100644
--- a/src/gpu/effects/GrDistanceFieldGeoProc.cpp
+++ b/src/gpu/effects/GrDistanceFieldGeoProc.cpp
@@ -68,7 +68,8 @@
 
         // add varyings
         GrGLSLVarying uv(kFloat2_GrSLType);
-        GrGLSLVarying texIdx(kFloat_GrSLType);
+        GrSLType texIdxType = args.fShaderCaps->integerSupport() ? kInt_GrSLType : kFloat_GrSLType;
+        GrGLSLVarying texIdx(texIdxType);
         GrGLSLVarying st(kFloat2_GrSLType);
         append_index_uv_varyings(args, dfTexEffect.inTextureCoords().name(), atlasSizeInvName, &uv,
                                  &texIdx, &st);
@@ -229,7 +230,7 @@
     } else {
         fInPosition = {"inPosition", kFloat2_GrVertexAttribType, kFloat2_GrSLType};
     }
-    fInColor = {"inColor", kUByte4_norm_GrVertexAttribType, kHalf4_GrSLType};
+    fInColor = {"inColor", kUByte4_norm_GrVertexAttribType, kHalf4_GrSLType };
     fInTextureCoords = {"inTextureCoords", kUShort2_GrVertexAttribType,
                         caps.integerSupport() ? kUShort2_GrSLType : kFloat2_GrSLType};
     this->setVertexAttributes(&fInPosition, 3);
@@ -344,7 +345,8 @@
                                                           &atlasSizeInvName);
 
         GrGLSLVarying uv(kFloat2_GrSLType);
-        GrGLSLVarying texIdx(kFloat_GrSLType);
+        GrSLType texIdxType = args.fShaderCaps->integerSupport() ? kInt_GrSLType : kFloat_GrSLType;
+        GrGLSLVarying texIdx(texIdxType);
         GrGLSLVarying st(kFloat2_GrSLType);
         append_index_uv_varyings(args, dfPathEffect.inTextureCoords().name(), atlasSizeInvName, &uv,
                                  &texIdx, &st);
@@ -648,7 +650,8 @@
 
         // set up varyings
         GrGLSLVarying uv(kFloat2_GrSLType);
-        GrGLSLVarying texIdx(kFloat_GrSLType);
+        GrSLType texIdxType = args.fShaderCaps->integerSupport() ? kInt_GrSLType : kFloat_GrSLType;
+        GrGLSLVarying texIdx(texIdxType);
         GrGLSLVarying st(kFloat2_GrSLType);
         append_index_uv_varyings(args, dfTexEffect.inTextureCoords().name(), atlasSizeInvName, &uv,
                                  &texIdx, &st);