Move the GrGLGpu config stencil format index into ConfigTable

GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1526253007

Review URL: https://codereview.chromium.org/1526253007

2 files changed, 24 insertions, 28 deletions

diff --git a/src/gpu/gl/GrGLGpu.cpp b/src/gpu/gl/GrGLGpu.cpp
index 7be4d32b88..42c92687f7 100644
--- a/src/gpu/gl/GrGLGpu.cpp
+++ b/src/gpu/gl/GrGLGpu.cpp
@@ -160,14 +160,6 @@ bool GrGLGpu::BlendCoeffReferencesConstant(GrBlendCoeff coeff) {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-// Used in the map of pixel configs to stencil format indices. This value is used to
-// indicate that a stencil format has not yet been set for the given config.
-static const int kUnknownStencilIndex = -1;
-// This value is used as the stencil index when no stencil configs are supported with the
-// given pixel config.
-static const int kUnsupportedStencilIndex = -2;
-
-///////////////////////////////////////////////////////////////////////////////
 
 GrGpu* GrGLGpu::Create(GrBackendContext backendContext, const GrContextOptions& options,
                        GrContext* context) {
@@ -222,9 +214,6 @@ GrGLGpu::GrGLGpu(GrGLContext* ctx, GrContext* context)
 
     SkASSERT(this->glCaps().maxVertexAttributes() >= GrGeometryProcessor::kMaxVertexAttribs);
 
-    for (int i = 0; i < kGrPixelConfigCnt; ++i) {
-        fPixelConfigToStencilIndex[i] = kUnknownStencilIndex;
-    }
     fHWProgramID = 0;
     fTempSrcFBOID = 0;
     fTempDstFBOID = 0;
@@ -1279,9 +1268,9 @@ void inline get_stencil_rb_sizes(const GrGLInterface* gl,
 
 int GrGLGpu::getCompatibleStencilIndex(GrPixelConfig config) {
     static const int kSize = 16;
-    if (kUnknownStencilIndex == fPixelConfigToStencilIndex[config]) {
+    if (ConfigEntry::kUnknown_StencilIndex == fConfigTable[config].fStencilFormatIndex) {
         // Default to unsupported
-        fPixelConfigToStencilIndex[config] = kUnsupportedStencilIndex;
+        fConfigTable[config].fStencilFormatIndex = ConfigEntry::kUnsupported_StencilFormatIndex;
         // Create color texture
         GrGLuint colorID = 0;
         GL_CALL(GenTextures(1, &colorID));
@@ -1307,8 +1296,7 @@ int GrGLGpu::getCompatibleStencilIndex(GrPixelConfig config) {
         if (!this->configToGLFormats(config, useSizedFormat, &internalFormat,
                                      &externalFormat, &externalType)) {
             GL_CALL(DeleteTextures(1, &colorID));
-            fPixelConfigToStencilIndex[config] = kUnsupportedStencilIndex;
-            return kUnsupportedStencilIndex;
+            return ConfigEntry::kUnsupported_StencilFormatIndex;
         }
 
         CLEAR_ERROR_BEFORE_ALLOC(this->glInterface());
@@ -1322,8 +1310,7 @@ int GrGLGpu::getCompatibleStencilIndex(GrPixelConfig config) {
                                                       NULL));
         if (GR_GL_NO_ERROR != GR_GL_GET_ERROR(this->glInterface())) {
             GL_CALL(DeleteTextures(1, &colorID));
-            fPixelConfigToStencilIndex[config] = kUnsupportedStencilIndex;
-            return kUnsupportedStencilIndex;
+            return ConfigEntry::kUnsupported_StencilFormatIndex;
         }
 
         // unbind the texture from the texture unit before binding it to the frame buffer
@@ -1380,7 +1367,7 @@ int GrGLGpu::getCompatibleStencilIndex(GrPixelConfig config) {
                                                         GR_GL_RENDERBUFFER, 0));
                     }
                 } else {
-                    fPixelConfigToStencilIndex[config] = i;
+                    fConfigTable[config].fStencilFormatIndex = i;
                     break;
                 }
             }
@@ -1391,8 +1378,8 @@ int GrGLGpu::getCompatibleStencilIndex(GrPixelConfig config) {
         GL_CALL(BindFramebuffer(GR_GL_FRAMEBUFFER, 0));
         GL_CALL(DeleteFramebuffers(1, &fb));
     }
-    SkASSERT(kUnknownStencilIndex != fPixelConfigToStencilIndex[config]);
-    return fPixelConfigToStencilIndex[config];
+    SkASSERT(ConfigEntry::kUnknown_StencilIndex != fConfigTable[config].fStencilFormatIndex);
+    return fConfigTable[config].fStencilFormatIndex;
 }
 
 GrStencilAttachment* GrGLGpu::createStencilAttachmentForRenderTarget(const GrRenderTarget* rt,
@@ -1408,7 +1395,7 @@ GrStencilAttachment* GrGLGpu::createStencilAttachmentForRenderTarget(const GrRen
     GrGLStencilAttachment::IDDesc sbDesc;
 
     int sIdx = this->getCompatibleStencilIndex(rt->config());
-    if (sIdx == kUnsupportedStencilIndex) {
+    if (sIdx < 0) {
         return nullptr;
     }
 
diff --git a/src/gpu/gl/GrGLGpu.h b/src/gpu/gl/GrGLGpu.h
index 409aae8f43..4f3b37ee9d 100644
--- a/src/gpu/gl/GrGLGpu.h
+++ b/src/gpu/gl/GrGLGpu.h
@@ -153,7 +153,7 @@ private:
     GrRenderTarget* onWrapBackendRenderTarget(const GrBackendRenderTargetDesc&,
                                               GrWrapOwnership) override;
     // Given a GrPixelConfig return the index into the stencil format array on GrGLCaps to a
-    // compatible stencil format.
+    // compatible stencil format, or negative if there is no compatible stencil format.
     int getCompatibleStencilIndex(GrPixelConfig config);
 
     void onClear(GrRenderTarget*, const SkIRect& rect, GrColor color) override;
@@ -541,18 +541,27 @@ private:
 
     struct ConfigEntry {
         // Default constructor inits to known bad GL enum values.
-        ConfigEntry() { memset(this, 0xAB, sizeof(ConfigEntry)); }
+        ConfigEntry() {
+            memset(this, 0xAB, sizeof(ConfigEntry));
+            fStencilFormatIndex = kUnknown_StencilIndex;
+        }
         GrGLenum fBaseInternalFormat;
         GrGLenum fSizedInternalFormat;
         GrGLenum fExternalFormat;
         GrGLenum fExternalType;
-    };
 
-    ConfigEntry fConfigTable[kLast_GrPixelConfig + 1];
+        // Index into GrGLCaps's list of stencil formats. Support is determined experimentally and
+        // lazily.
+        int      fStencilFormatIndex;
+        enum {
+            // This indicates that a stencil format has not yet been determined for the config.
+            kUnknown_StencilIndex = -1,
+            // This indicates that there is no supported stencil format for the config.
+            kUnsupported_StencilFormatIndex = -2
+        };
+    };
 
-    // Mapping of pixel configs to known supported stencil formats to be used
-    // when adding a stencil buffer to a framebuffer.
-    int fPixelConfigToStencilIndex[kGrPixelConfigCnt];
+    ConfigEntry fConfigTable[kGrPixelConfigCnt];
 
     typedef GrGpu INHERITED;
     friend class GrGLPathRendering; // For accessing setTextureUnit.