Implement support for KHR_blend_equation_advanced

src/gpu/GrDrawTargetCaps.h

 
 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef GrDrawTargetCaps_DEFINED
 #define GrDrawTargetCaps_DEFINED
 
@@ skipping 124 matching lines @@
 #else
     bool gpuTracingSupport() const { return fGpuTracingSupport; }
 #endif
     bool compressedTexSubImageSupport() const { return fCompressedTexSubImageSupport; }
     bool oversizedStencilSupport() const { return fOversizedStencilSupport; }
     bool textureBarrierSupport() const { return fTextureBarrierSupport; }
 
     bool useDrawInsteadOfClear() const { return fUseDrawInsteadOfClear; }
 
     /**
+     * Indicates the capabilities of the fixed function blend unit.
+     */
+    enum BlendEquationSupport {

[egdaniel, 2015/05/05 21:20:01]

Can BlendEquationSupport and related functions be moved into GL?

[Chris Dalton, 2015/05/06 16:06:27]

Not easily, most the places where we add support for advanced blend equations
are not in GL (getBlendInfo, GrBlendEquation, willNeedXferBarrier, xferBarrier,
GrXferBarrierType, willNeedDstCopy, getOptimizations, etc.)

Advanced blend equations are a hardware feature, all the OpenGL extension does
is give you access to our dedicated blend unit in the ROP. They will definitely
be available in any non-proprietary API that skia ends up on, so I actually
think Gr (not GL) feels like the right spot for it.

(I did put "AdvancedBlendEqnInteraction" in GrGLSLCaps because that part of the
extension felt like an API-specific idiosyncrasy)

[egdaniel, 2015/05/06 17:57:46]

sgtm

+        kBasic_BlendEquationSupport,             //<! Support to select the operator that
+                                                 //   combines src and dst terms.
+        kAdvanced_BlendEquationSupport,          //<! Additional fixed function support for specific
+                                                 //   SVG/PDF blend modes. Requires blend barriers.
+        kAdvancedCoherent_BlendEquationSupport,  //<! Advanced blend equation support that does not
+                                                 //   require blend barriers, and permits overlap.
+
+        kLast_BlendEquationSupport = kAdvancedCoherent_BlendEquationSupport
+    };
+
+    BlendEquationSupport blendEquationSupport() const { return fBlendEquationSupport; }
+
+    bool advancedBlendEquationSupport() const {
+        return kBasic_BlendEquationSupport != fBlendEquationSupport;
+    }
+
+    /**
      * Indicates whether GPU->CPU memory mapping for GPU resources such as vertex buffers and
      * textures allows partial mappings or full mappings.
      */
     enum MapFlags {
         kNone_MapFlags   = 0x0,       //<! Cannot map the resource.
 
         kCanMap_MapFlag  = 0x1,       //<! The resource can be mapped. Must be set for any of
                                       //   the other flags to have meaning.k
         kSubset_MapFlag  = 0x2,       //<! The resource can be partially mapped.
     };
@@ skipping 30 matching lines @@
     bool fStencilWrapOpsSupport         : 1;
     bool fDiscardRenderTargetSupport    : 1;
     bool fReuseScratchTextures          : 1;
     bool fGpuTracingSupport             : 1;
     bool fCompressedTexSubImageSupport  : 1;
     bool fOversizedStencilSupport       : 1;
     bool fTextureBarrierSupport         : 1;
     // Driver workaround
     bool fUseDrawInsteadOfClear         : 1;
 
+    BlendEquationSupport fBlendEquationSupport;
     uint32_t fMapBufferFlags;
 
     int fMaxRenderTargetSize;
     int fMaxTextureSize;
     int fMaxSampleCount;
 
     // The first entry for each config is without msaa and the second is with.
     bool fConfigRenderSupport[kGrPixelConfigCnt][2];
     bool fConfigTextureSupport[kGrPixelConfigCnt];
 
 private:
     typedef SkRefCnt INHERITED;
 };
 
 #endif