Revert "Revert "Avoid checking extension string in GrGLGpu::onResetContext.""

This reverts commit 04c1cccaa45e8a96fcc82f027435b50093b935ea.

Reland that preserves GL_NV_shader_framebuffer_fetch support.

Change-Id: I8d51321a552d0abfd0a8fa36c4d00b9b0e0d8663
Reviewed-on: https://skia-review.googlesource.com/c/187300
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

4 files changed, 16 insertions, 9 deletions

diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 04ef735f8d..faa8e38468 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -68,6 +68,7 @@ GrGLCaps::GrGLCaps(const GrContextOptions& contextOptions,
     fDontSetBaseOrMaxLevelForExternalTextures = false;
     fProgramBinarySupport = false;
     fSamplerObjectSupport = false;
+    fFBFetchRequiresEnablePerSample = false;
 
     fBlitFramebufferFlags = kNoSupport_BlitFramebufferFlag;
     fMaxInstancesPerDrawWithoutCrashing = 0;
@@ -708,25 +709,28 @@ void GrGLCaps::initGLSL(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli
     GrShaderCaps* shaderCaps = fShaderCaps.get();
     shaderCaps->fGLSLGeneration = ctxInfo.glslGeneration();
     if (kGLES_GrGLStandard == standard) {
+        // fFBFetchRequiresEnablePerSample is not a shader cap but is initialized below to keep it
+        // with related FB fetch logic.
         if (ctxInfo.hasExtension("GL_EXT_shader_framebuffer_fetch")) {
             shaderCaps->fFBFetchNeedsCustomOutput = (version >= GR_GL_VER(3, 0));
             shaderCaps->fFBFetchSupport = true;
             shaderCaps->fFBFetchColorName = "gl_LastFragData[0]";
             shaderCaps->fFBFetchExtensionString = "GL_EXT_shader_framebuffer_fetch";
-        }
-        else if (ctxInfo.hasExtension("GL_NV_shader_framebuffer_fetch")) {
-            // Actually, we haven't seen an ES3.0 device with this extension yet, so we don't know
+            fFBFetchRequiresEnablePerSample = false;
+        } else if (ctxInfo.hasExtension("GL_NV_shader_framebuffer_fetch")) {
+            // Actually, we haven't seen an ES3.0 device with this extension yet, so we don't know.
             shaderCaps->fFBFetchNeedsCustomOutput = false;
             shaderCaps->fFBFetchSupport = true;
             shaderCaps->fFBFetchColorName = "gl_LastFragData[0]";
             shaderCaps->fFBFetchExtensionString = "GL_NV_shader_framebuffer_fetch";
-        }
-        else if (ctxInfo.hasExtension("GL_ARM_shader_framebuffer_fetch")) {
-            // The arm extension also requires an additional flag which we will set onResetContext
+            fFBFetchRequiresEnablePerSample = false;
+        } else if (ctxInfo.hasExtension("GL_ARM_shader_framebuffer_fetch")) {
+            // The arm extension also requires an additional flag which we will set onResetContext.
             shaderCaps->fFBFetchNeedsCustomOutput = false;
             shaderCaps->fFBFetchSupport = true;
             shaderCaps->fFBFetchColorName = "gl_LastFragColorARM";
             shaderCaps->fFBFetchExtensionString = "GL_ARM_shader_framebuffer_fetch";
+            fFBFetchRequiresEnablePerSample = true;
         }
         shaderCaps->fUsesPrecisionModifiers = true;
     }
diff --git a/src/gpu/gl/GrGLCaps.h b/src/gpu/gl/GrGLCaps.h
index 1d42f0dd47..4a97e84cf8 100644
--- a/src/gpu/gl/GrGLCaps.h
+++ b/src/gpu/gl/GrGLCaps.h
@@ -417,6 +417,8 @@ public:
 
     bool samplerObjectSupport() const { return fSamplerObjectSupport; }
 
+    bool fbFetchRequiresEnablePerSample() const { return fFBFetchRequiresEnablePerSample; }
+
     GrPixelConfig validateBackendRenderTarget(const GrBackendRenderTarget&,
                                               SkColorType) const override;
 
@@ -503,6 +505,7 @@ private:
     bool fClearTextureSupport : 1;
     bool fProgramBinarySupport : 1;
     bool fSamplerObjectSupport : 1;
+    bool fFBFetchRequiresEnablePerSample : 1;
 
     // Driver workarounds
     bool fDoManualMipmapping : 1;
diff --git a/src/gpu/gl/GrGLDefines.h b/src/gpu/gl/GrGLDefines.h
index a545e457e8..995dbf3da1 100644
--- a/src/gpu/gl/GrGLDefines.h
+++ b/src/gpu/gl/GrGLDefines.h
@@ -987,7 +987,7 @@
 #define GR_GL_PATH_MODELVIEW                                0x1700
 
 /*  ARM specific define for MSAA support on framebuffer fetch */
-#define GR_GL_FETCH_PER_SAMPLE_ARM                          0x8F65
+#define GR_GL_FETCH_PER_SAMPLE                              0x8F65
 
 /* GL_EXT_raster_multisample */
 #define GR_GL_RASTER_MULTISAMPLE                            0x9327
diff --git a/src/gpu/gl/GrGLGpu.cpp b/src/gpu/gl/GrGLGpu.cpp
index 34b27d2136..e8bf4f298d 100644
--- a/src/gpu/gl/GrGLGpu.cpp
+++ b/src/gpu/gl/GrGLGpu.cpp
@@ -539,10 +539,10 @@ void GrGLGpu::onResetContext(uint32_t resetBits) {
         }
 
         if (kGLES_GrGLStandard == this->glStandard() &&
-                this->hasExtension("GL_ARM_shader_framebuffer_fetch")) {
+            this->glCaps().fbFetchRequiresEnablePerSample()) {
             // The arm extension requires specifically enabling MSAA fetching per sample.
             // On some devices this may have a perf hit.  Also multiple render targets are disabled
-            GL_CALL(Enable(GR_GL_FETCH_PER_SAMPLE_ARM));
+            GL_CALL(Enable(GR_GL_FETCH_PER_SAMPLE));
         }
         fHWWriteToColor = kUnknown_TriState;
         // we only ever use lines in hairline mode