Enable sRGB on iOS, make sRGB decode support optional

src/gpu/gl/GrGLCaps.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "GrGLCaps.h"
 
@@ skipping 33 matching lines @@
     fBaseInstanceSupport = false;
     fIsCoreProfile = false;
     fBindFragDataLocationSupport = false;
     fRectangleTextureSupport = false;
     fTextureSwizzleSupport = false;
     fRGBA8888PixelsOpsAreSlow = false;
     fPartialFBOReadIsSlow = false;
     fMipMapLevelAndLodControlSupport = false;
     fRGBAToBGRAReadbackConversionsAreSlow = false;
     fDoManualMipmapping = false;
+    fSRGBDecodeDisableSupport = false;
 
     fBlitFramebufferFlags = kNoSupport_BlitFramebufferFlag;
 
     fShaderCaps.reset(new GrShaderCaps(contextOptions));
 
     this->init(contextOptions, ctxInfo, glInterface);
 }
 
 void GrGLCaps::init(const GrContextOptions& contextOptions,
                     const GrGLContextInfo& ctxInfo,
@@ skipping 536 matching lines @@
     // glGenerateMipmap. Our implementation requires mip-level sampling control. Additionally,
     // it can be much slower (especially on mobile GPUs), so we opt-in only when necessary:
     if (fMipMapLevelAndLodControlSupport &&
         (contextOptions.fDoManualMipmapping ||
          (kIntel_GrGLVendor == ctxInfo.vendor()) ||
          (kNVIDIA_GrGLDriver == ctxInfo.driver() && isMAC) ||
          (kATI_GrGLVendor == ctxInfo.vendor()))) {
         fDoManualMipmapping = true;
     }
 
+    fSRGBDecodeDisableSupport = ctxInfo.hasExtension("GL_EXT_texture_sRGB_decode");
+
     // Requires fTextureRedSupport, fTextureSwizzleSupport, msaa support, ES compatibility have
     // already been detected.
-    this->initConfigTable(ctxInfo, gli, shaderCaps);
+    this->initConfigTable(contextOptions, ctxInfo, gli, shaderCaps);
 
     this->applyOptionsOverrides(contextOptions);
     shaderCaps->applyOptionsOverrides(contextOptions);
 }
 
 const char* get_glsl_version_decl_string(GrGLStandard standard, GrGLSLGeneration generation,
                                          bool isCoreProfile) {
     switch (generation) {
         case k110_GrGLSLGeneration:
             if (kGLES_GrGLStandard == standard) {
@@ skipping 759 matching lines @@
     if (memoryIsAlphaOnly && !surfaceIsAlphaOnly) {
         if (this->textureRedSupport()) {
             SkASSERT(GR_GL_RED == *externalFormat);
             *externalFormat = GR_GL_ALPHA;
         }
     }
 
     return true;
 }
 
-void GrGLCaps::initConfigTable(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli,
+void GrGLCaps::initConfigTable(const GrContextOptions& contextOptions,
+                               const GrGLContextInfo& ctxInfo, const GrGLInterface* gli,
                                GrShaderCaps* shaderCaps) {
     /*
         Comments on renderability of configs on various GL versions.
           OpenGL < 3.0:
             no built in support for render targets.
             GL_EXT_framebuffer_object adds possible support for any sized format with base internal
               format RGB, RGBA and NV float formats we don't use.
               This is the following:
                 R3_G3_B2, RGB4, RGB5, RGB8, RGB10, RGB12, RGB16, RGBA2, RGBA4, RGB5_A1, RGBA8
                 RGB10_A2, RGBA12,RGBA16
@@ skipping 165 matching lines @@
             if (ctxInfo.hasExtension("GL_ARB_framebuffer_sRGB") ||
                 ctxInfo.hasExtension("GL_EXT_framebuffer_sRGB")) {
                 fSRGBSupport = true;
             }
         }
         // All the above srgb extensions support toggling srgb writes
         if (fSRGBSupport) {
             fSRGBWriteControl = true;
         }
     } else {
-        // See https://bug.skia.org/4148 for PowerVR issue.
-        fSRGBSupport = kPowerVRRogue_GrGLRenderer != ctxInfo.renderer() &&
-            (ctxInfo.version() >= GR_GL_VER(3,0) || ctxInfo.hasExtension("GL_EXT_sRGB"));
+        fSRGBSupport = ctxInfo.version() >= GR_GL_VER(3,0) || ctxInfo.hasExtension("GL_EXT_sRGB");
+#if defined(SK_CPU_X86)
+        if (kPowerVRRogue_GrGLRenderer == ctxInfo.renderer()) {
+            // NexusPlayer has strange bugs with sRGB (skbug.com/4148). This is a targeted fix to
+            // blacklist that device (and any others that might be sharing the same driver).
+            fSRGBSupport = false;
+        }
+#endif
         // ES through 3.1 requires EXT_srgb_write_control to support toggling
         // sRGB writing for destinations.
         // See https://bug.skia.org/5329 for Adreno4xx issue.
         fSRGBWriteControl = kAdreno4xx_GrGLRenderer != ctxInfo.renderer() &&
             ctxInfo.hasExtension("GL_EXT_sRGB_write_control");
     }
-    if (!ctxInfo.hasExtension("GL_EXT_texture_sRGB_decode")) {
-        // To support "legacy" L32 mode, we require the ability to turn off sRGB decode:
+    if (contextOptions.fRequireDecodeDisableForSRGB && !fSRGBDecodeDisableSupport) {
+        // To support "legacy" L32 mode, we require the ability to turn off sRGB decode. Clients
+        // can opt-out of that requirement, if they intend to always do linear blending.
         fSRGBSupport = false;
     }
+
+    // This is very conservative, if we're on a platform where N32 is BGRA, and using ES, disable
+    // all sRGB support. Too much code relies on creating surfaces with N32 + sRGB colorspace,
+    // and sBGRA is basically impossible to support on any version of ES (with our current code).
+    // In particular, ES2 doesn't support sBGRA at all, and even in ES3, there is no valid pair
+    // of formats that can be used for TexImage calls to upload BGRA data to sRGBA (which is what
+    // we *have* to use as the internal format, because sBGRA doesn't exist). This primarily
+    // affects Windows.
+    if (kSkia8888_GrPixelConfig == kBGRA_8888_GrPixelConfig && kGLES_GrGLStandard == standard) {
+        fSRGBSupport = false;
+    }
+
     fConfigTable[kSRGBA_8888_GrPixelConfig].fFormats.fBaseInternalFormat = GR_GL_SRGB_ALPHA;
     fConfigTable[kSRGBA_8888_GrPixelConfig].fFormats.fSizedInternalFormat = GR_GL_SRGB8_ALPHA8;
     // GL does not do srgb<->rgb conversions when transferring between cpu and gpu. Thus, the
     // external format is GL_RGBA. See below for note about ES2.0 and glTex[Sub]Image.
     fConfigTable[kSRGBA_8888_GrPixelConfig].fFormats.fExternalFormat[kOther_ExternalFormatUsage] =
         GR_GL_RGBA;
     fConfigTable[kSRGBA_8888_GrPixelConfig].fFormats.fExternalType = GR_GL_UNSIGNED_BYTE;
     fConfigTable[kSRGBA_8888_GrPixelConfig].fFormatType = kNormalizedFixedPoint_FormatType;
     if (fSRGBSupport) {
         fConfigTable[kSRGBA_8888_GrPixelConfig].fFlags = ConfigInfo::kTextureable_Flag |
@@ skipping 474 matching lines @@
 void GrGLCaps::onApplyOptionsOverrides(const GrContextOptions& options) {
     if (options.fEnableInstancedRendering) {
         fInstancedSupport = gr_instanced::GLInstancedRendering::CheckSupport(*this);
 #ifndef SK_BUILD_FOR_MAC
         // OS X doesn't seem to write correctly to floating point textures when using
         // glDraw*Indirect, regardless of the underlying GPU.
         fAvoidInstancedDrawsToFPTargets = true;
 #endif
     }
 }