Require sRGB write control for sRGB support. Add flag to GrPaint to suppress linear -> sRGB convers…

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 28 matching lines @@
     fES2CompatibilitySupport = false;
     fMultisampleDisableSupport = false;
     fDrawIndirectSupport = false;
     fMultiDrawIndirectSupport = false;
     fBaseInstanceSupport = false;
     fUseNonVBOVertexAndIndexDynamicData = false;
     fIsCoreProfile = false;
     fBindFragDataLocationSupport = false;
     fRectangleTextureSupport = false;
     fTextureSwizzleSupport = false;
-    fSRGBWriteControl = false;
     fRGBA8888PixelsOpsAreSlow = false;
     fPartialFBOReadIsSlow = false;
     fMipMapLevelAndLodControlSupport = false;
     fRGBAToBGRAReadbackConversionsAreSlow = false;
 
     fBlitFramebufferSupport = kNone_BlitFramebufferSupport;
 
     fShaderCaps.reset(new GrGLSLCaps(contextOptions));
 
     this->init(contextOptions, ctxInfo, glInterface);
@@ skipping 1013 matching lines @@
     r.appendf("GL_ARB_imaging support: %s\n", (fImagingSupport ? "YES": "NO"));
     r.appendf("Vertex array object support: %s\n", (fVertexArrayObjectSupport ? "YES": "NO"));
     r.appendf("Direct state access support: %s\n", (fDirectStateAccessSupport ? "YES": "NO"));
     r.appendf("Debug support: %s\n", (fDebugSupport ? "YES": "NO"));
     r.appendf("Multisample disable support: %s\n", (fMultisampleDisableSupport ? "YES" : "NO"));
     r.appendf("Draw indirect support: %s\n", (fDrawIndirectSupport ? "YES" : "NO"));
     r.appendf("Multi draw indirect support: %s\n", (fMultiDrawIndirectSupport ? "YES" : "NO"));
     r.appendf("Base instance support: %s\n", (fBaseInstanceSupport ? "YES" : "NO"));
     r.appendf("Use non-VBO for dynamic data: %s\n",
              (fUseNonVBOVertexAndIndexDynamicData ? "YES" : "NO"));
-    r.appendf("SRGB write contol: %s\n", (fSRGBWriteControl ? "YES" : "NO"));
     r.appendf("RGBA 8888 pixel ops are slow: %s\n", (fRGBA8888PixelsOpsAreSlow ? "YES" : "NO"));
     r.appendf("Partial FBO read is slow: %s\n", (fPartialFBOReadIsSlow ? "YES" : "NO"));
     r.appendf("Bind uniform location support: %s\n", (fBindUniformLocationSupport ? "YES" : "NO"));
     r.appendf("Rectangle texture support: %s\n", (fRectangleTextureSupport? "YES" : "NO"));
     r.appendf("Texture swizzle support: %s\n", (fTextureSwizzleSupport ? "YES" : "NO"));
     r.appendf("BGRA to RGBA readback conversions are slow: %s\n", 
               (fRGBAToBGRAReadbackConversionsAreSlow ? "YES" : "NO"));
 
     r.append("Configs\n-------\n");
     for (int i = 0; i < kGrPixelConfigCnt; ++i) {
@@ skipping 333 matching lines @@
                     ConfigInfo::kRenderableWithMSAA_Flag;
             }
         }
     }
     if (texStorageSupported) {
         fConfigTable[kBGRA_8888_GrPixelConfig].fFlags |= ConfigInfo::kCanUseTexStorage_Flag;
     }
     fConfigTable[kBGRA_8888_GrPixelConfig].fSwizzle = GrSwizzle::RGBA();
 
     // We only enable srgb support if both textures and FBOs support srgb,
-    // *and* we can disable sRGB decode-on-read, to support "legacy" mode.
+    // *and* we can disable sRGB decode-on-read, to support "legacy" mode,
+    // *and* we can disable sRGB encode-on-write.
     if (kGL_GrGLStandard == standard) {
         if (ctxInfo.version() >= GR_GL_VER(3,0)) {
             fSRGBSupport = true;
         } else if (ctxInfo.hasExtension("GL_EXT_texture_sRGB")) {
             if (ctxInfo.hasExtension("GL_ARB_framebuffer_sRGB") ||
                 ctxInfo.hasExtension("GL_EXT_framebuffer_sRGB")) {
                 fSRGBSupport = true;
             }
         }
         // All the above srgb extensions support toggling srgb writes
-        fSRGBWriteControl = fSRGBSupport;
     } 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"));
         // ES through 3.1 requires EXT_srgb_write_control to support toggling
         // sRGB writing for destinations.
-        fSRGBWriteControl = ctxInfo.hasExtension("GL_EXT_sRGB_write_control");
+        fSRGBSupport = fSRGBSupport && 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:
         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] =
@@ skipping 401 matching lines @@
         for (int j = 0; j < kExternalFormatUsageCnt; ++j) {
             SkASSERT(defaultEntry.fFormats.fExternalFormat[j] !=
                      fConfigTable[i].fFormats.fExternalFormat[j]);
         }
         SkASSERT(defaultEntry.fFormats.fExternalType != fConfigTable[i].fFormats.fExternalType);
     }
 #endif
 }
 
 void GrGLCaps::onApplyOptionsOverrides(const GrContextOptions& options) {}