clean up default precision handling

R=joshualitt@google.com

Review URL: https://codereview.chromium.org/766753006

4 files changed, 9 insertions, 19 deletions

diff --git a/include/gpu/GrShaderVar.h b/include/gpu/GrShaderVar.h
index cbc074df7b..967ae82689 100644
--- a/include/gpu/GrShaderVar.h
+++ b/include/gpu/GrShaderVar.h
@@ -35,14 +35,13 @@ public:
     };
 
     enum Precision {
-        kLow_Precision,         // lowp
-        kMedium_Precision,      // mediump
-        kHigh_Precision,        // highp
-        kDefault_Precision,     // Default for the current context. We make
-                                // fragment shaders default to mediump on ES2
-                                // because highp support is not guaranteed (and
-                                // we haven't been motivated to test for it).
-                                // Otherwise, highp.
+        kLow_Precision,
+        kMedium_Precision,
+        kHigh_Precision,
+
+        // Default precision is medium. This is because on OpenGL ES 2 highp support is not
+        // guaranteed. On (non-ES) OpenGL the specifiers have no effect on precision.
+        kDefault_Precision = kMedium_Precision,
     };
 
     /**
diff --git a/src/gpu/gl/GrGLShaderVar.h b/src/gpu/gl/GrGLShaderVar.h
index c7514f55bc..7705c30db0 100644
--- a/src/gpu/gl/GrGLShaderVar.h
+++ b/src/gpu/gl/GrGLShaderVar.h
@@ -207,8 +207,6 @@ public:
                     return "mediump ";
                 case kHigh_Precision:
                     return "highp ";
-                case kDefault_Precision:
-                    return "";
                 default:
                     SkFAIL("Unexpected precision type.");
             }
diff --git a/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp b/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp
index 6aeba7a9ee..56bc496532 100644
--- a/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp
+++ b/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp
@@ -13,8 +13,6 @@
 #define GL_CALL(X) GR_GL_CALL(fProgramBuilder->gpu()->glInterface(), X)
 #define GL_CALL_RET(R, X) GR_GL_CALL_RET(fProgramBuilder->gpu()->glInterface(), R, X)
 
-// ES2 FS only guarantees mediump and lowp support
-static const GrGLShaderVar::Precision kDefaultFragmentPrecision = GrGLShaderVar::kMedium_Precision;
 const char* GrGLFragmentShaderBuilder::kDstCopyColorName = "_dstColor";
 static const char* declared_color_output_name() { return "fsColorOut"; }
 static const char* dual_source_output_name() { return "dualSourceOut"; }
@@ -33,8 +31,6 @@ static void append_default_precision_qualifier(GrGLShaderVar::Precision p,
             case GrGLShaderVar::kLow_Precision:
                 str->append("precision lowp float;\n");
                 break;
-            case GrGLShaderVar::kDefault_Precision:
-                SkFAIL("Default precision now allowed.");
             default:
                 SkFAIL("Unknown precision value.");
         }
@@ -310,7 +306,7 @@ bool GrGLFragmentShaderBuilder::compileAndAttachShaders(GrGLuint programId,
     GrGpuGL* gpu = fProgramBuilder->gpu();
     SkString fragShaderSrc(GrGetGLSLVersionDecl(gpu->ctxInfo()));
     fragShaderSrc.append(fExtensions);
-    append_default_precision_qualifier(kDefaultFragmentPrecision,
+    append_default_precision_qualifier(GrShaderVar::kDefault_Precision,
                                        gpu->glStandard(),
                                        &fragShaderSrc);
     fProgramBuilder->appendUniformDecls(GrGLProgramBuilder::kFragment_Visibility, &fragShaderSrc);
diff --git a/src/gpu/gl/builders/GrGLProgramBuilder.cpp b/src/gpu/gl/builders/GrGLProgramBuilder.cpp
index fb26867cf6..4d8011cd97 100644
--- a/src/gpu/gl/builders/GrGLProgramBuilder.cpp
+++ b/src/gpu/gl/builders/GrGLProgramBuilder.cpp
@@ -21,9 +21,6 @@
 #define GL_CALL(X) GR_GL_CALL(this->gpu()->glInterface(), X)
 #define GL_CALL_RET(R, X) GR_GL_CALL_RET(this->gpu()->glInterface(), R, X)
 
-// ES2 FS only guarantees mediump and lowp support
-static const GrGLShaderVar::Precision kDefaultFragmentPrecision = GrGLShaderVar::kMedium_Precision;
-
 //////////////////////////////////////////////////////////////////////////////
 
 const int GrGLProgramBuilder::kVarsPerBlock = 8;
@@ -175,7 +172,7 @@ GrGLProgramDataManager::UniformHandle GrGLProgramBuilder::addUniformArray(uint32
     // to use the default FS precision.
     if ((kVertex_Visibility | kFragment_Visibility) == visibility) {
         // the fragment and vertex precisions must match
-        uni.fVariable.setPrecision(kDefaultFragmentPrecision);
+        uni.fVariable.setPrecision(GrShaderVar::kDefault_Precision);
     }
 
     if (outName) {