Add support for clipstack to Gr. GrClip is now a list of rects and paths with set operations to combine them. The stencil buffer is used to perform the set operations to put the clip into the stencil buffer. Building Gr's clip from Skia's clipStack is currently disabled due to the fact that Skia's clipStack is relative to the root layer not the current layer. This will be fixed in a subsequent CL.
git-svn-id: http://skia.googlecode.com/svn/trunk@878 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/src/GrStencil.cpp b/gpu/src/GrStencil.cpp
new file mode 100644
index 0000000..9d68c65
--- /dev/null
+++ b/gpu/src/GrStencil.cpp
@@ -0,0 +1,398 @@
+/*
+ Copyright 2011 Google Inc.
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+ */
+
+#include "GrStencil.h"
+
+const GrStencilSettings GrStencilSettings::gDisabled = {};
+GR_STATIC_ASSERT(0 == kKeep_StencilOp);
+GR_STATIC_ASSERT(0 == kAlways_StencilFunc);
+
+////////////////////////////////////////////////////////////////////////////////
+// Stencil Rules for Merging user stencil space into clip
+
+// We can't include the clip bit in the ref or mask values because the division
+// between user and clip bits in the stencil depends on the number of stencil
+// bits in the runtime. Comments below indicate what the code should do to
+// incorporate the clip bit into these settings.
+
+///////
+// Replace
+
+// set the ref to be the clip bit, but mask it out for the test
+static const GrStencilSettings gUserToClipReplace = {
+ kReplace_StencilOp, kReplace_StencilOp,
+ kZero_StencilOp, kZero_StencilOp,
+ kLess_StencilFunc, kLess_StencilFunc,
+ 0xffffffff, 0xffffffff, // unset clip bit
+ 0x0, 0x0, // set clip bit
+ 0xffffffff, 0xffffffff
+};
+static const GrStencilSettings gInvUserToClipReplace = {
+ kReplace_StencilOp, kReplace_StencilOp,
+ kZero_StencilOp, kZero_StencilOp,
+ kEqual_StencilFunc, kEqual_StencilFunc,
+ 0xffffffff, 0xffffffff, // unset clip bit
+ 0x0, 0x0, // set clip bit
+ 0xffffffff, 0xffffffff
+};
+
+///////
+// Intersect
+static const GrStencilSettings gUserToClipIsect = {
+ kReplace_StencilOp, kReplace_StencilOp,
+ kZero_StencilOp, kZero_StencilOp,
+ kLess_StencilFunc, kLess_StencilFunc,
+ 0xffffffff, 0xffffffff,
+ 0x0, 0x0, // set clip bit
+ 0xffffffff, 0xffffffff
+};
+static const GrStencilSettings gInvUserToClipIsect = {
+ kReplace_StencilOp, kReplace_StencilOp,
+ kZero_StencilOp, kZero_StencilOp,
+ kEqual_StencilFunc, kEqual_StencilFunc,
+ 0xffffffff, 0xffffffff,
+ 0x0, 0x0, // set clip bit
+ 0xffffffff, 0xffffffff
+};
+
+///////
+// Difference
+static const GrStencilSettings gUserToClipDiff = {
+ kReplace_StencilOp, kReplace_StencilOp,
+ kZero_StencilOp, kZero_StencilOp,
+ kEqual_StencilFunc, kEqual_StencilFunc,
+ 0xffffffff, 0xffffffff,
+ 0x0, 0x0, // set clip bit
+ 0xffffffff, 0xffffffff
+};
+static const GrStencilSettings gInvUserToClipDiff = {
+ kReplace_StencilOp, kReplace_StencilOp,
+ kZero_StencilOp, kZero_StencilOp,
+ kLess_StencilFunc, kLess_StencilFunc,
+ 0xffffffff, 0xffffffff,
+ 0x0, 0x0, // set clip bit
+ 0xffffffff, 0xffffffff
+};
+
+///////
+// Union
+
+// first pass makes all the passing cases >= just clip bit set.
+static const GrStencilSettings gUserToClipUnionPass0 = {
+ kReplace_StencilOp, kReplace_StencilOp,
+ kKeep_StencilOp, kKeep_StencilOp,
+ kLEqual_StencilFunc, kLEqual_StencilFunc,
+ 0xffffffff, 0xffffffff, // unset clip bit
+ 0x00000001, 0x00000001, // set clip bit
+ 0xffffffff, 0xffffffff
+};
+
+// second pass allows anything greater than just clip bit set to pass
+static const GrStencilSettings gUserToClipUnionPass1 = {
+ kReplace_StencilOp, kReplace_StencilOp,
+ kZero_StencilOp, kZero_StencilOp,
+ kLEqual_StencilFunc, kLEqual_StencilFunc,
+ 0xffffffff, 0xffffffff,
+ 0x00000000, 0x00000000, // set clip bit
+ 0xffffffff, 0xffffffff
+};
+
+// for inverse first pass finds non-zerp user with clip bit set
+// and converts it to just clip bit set
+static const GrStencilSettings gInvUserToClipUnionPass0 = {
+ kReplace_StencilOp, kReplace_StencilOp,
+ kKeep_StencilOp, kKeep_StencilOp,
+ kLess_StencilFunc, kLess_StencilFunc,
+ 0xffffffff, 0xffffffff,
+ 0x00000000, 0x00000000, // set clip bit
+ 0xffffffff, 0xffffffff
+};
+
+// second pass lets anything through with a nonzero user portion
+// and writes a ref value with just the clip bit set to it.
+static const GrStencilSettings gInvUserToClipUnionPass1 = {
+ kReplace_StencilOp, kReplace_StencilOp,
+ kZero_StencilOp, kZero_StencilOp,
+ kLess_StencilFunc, kLess_StencilFunc,
+ 0xffffffff, 0xffffffff, // unset clip bit
+ 0x00000000, 0x00000000, // set clip bit
+ 0xffffffff, 0xffffffff
+};
+
+///////
+// Xor
+static const GrStencilSettings gUserToClipXorPass0 = {
+ kInvert_StencilOp, kInvert_StencilOp,
+ kKeep_StencilOp, kKeep_StencilOp,
+ kEqual_StencilFunc, kEqual_StencilFunc,
+ 0xffffffff, 0xffffffff, // unset clip bit
+ 0x00000000, 0x00000000,
+ 0xffffffff, 0xffffffff
+};
+
+static const GrStencilSettings gUserToClipXorPass1 = {
+ kReplace_StencilOp, kReplace_StencilOp,
+ kZero_StencilOp, kZero_StencilOp,
+ kGreater_StencilFunc, kGreater_StencilFunc,
+ 0xffffffff, 0xffffffff,
+ 0x00000000, 0x00000000, // set clip bit
+ 0xffffffff, 0xffffffff
+};
+
+static const GrStencilSettings gInvUserToClipXorPass0 = {
+ kInvert_StencilOp, kInvert_StencilOp,
+ kKeep_StencilOp, kKeep_StencilOp,
+ kEqual_StencilFunc, kEqual_StencilFunc,
+ 0xffffffff, 0xffffffff, // unset clip bit
+ 0x00000000, 0x00000000,
+ 0xffffffff, 0xffffffff
+};
+
+static const GrStencilSettings gInvUserToClipXorPass1 = {
+ kReplace_StencilOp, kReplace_StencilOp,
+ kZero_StencilOp, kZero_StencilOp,
+ kLess_StencilFunc, kLess_StencilFunc,
+ 0xffffffff, 0xffffffff,
+ 0x00000000, 0x00000000, // set clip bit
+ 0xffffffff, 0xffffffff
+};
+
+///////
+// Reverse Diff
+static const GrStencilSettings gUserToClipRDiffPass0 = {
+ kInvert_StencilOp, kInvert_StencilOp,
+ kZero_StencilOp, kZero_StencilOp,
+ kLess_StencilFunc, kLess_StencilFunc,
+ 0xffffffff, 0xffffffff, // unset clip bit
+ 0x00000000, 0x00000000, // set clip bit
+ 0xffffffff, 0xffffffff
+};
+
+static const GrStencilSettings gUserToClipRDiffPass1 = {
+ kReplace_StencilOp, kReplace_StencilOp,
+ kZero_StencilOp, kZero_StencilOp,
+ kEqual_StencilFunc, kEqual_StencilFunc,
+ 0x00000000, 0x00000000, // set clip bit
+ 0x00000000, 0x00000000, // set clip bit
+ 0xffffffff, 0xffffffff
+};
+
+static const GrStencilSettings gInvUserToClipRDiff = {
+ kInvert_StencilOp, kInvert_StencilOp,
+ kZero_StencilOp, kZero_StencilOp,
+ kEqual_StencilFunc, kEqual_StencilFunc,
+ 0xffffffff, 0xffffffff,
+ 0x00000000, 0x00000000,
+ 0x00000000, 0x00000000 // set clip bit
+};
+///////
+// Direct to Stencil
+
+// We can render a clip element directly without first writing to the client
+// portion of the clip when the fill is not inverse and the set operation will
+// only modify the in/out status of samples covered by the clip element.
+
+// this one only works if used right after stencil clip was cleared.
+// Our GrClip doesn't allow midstream replace ops.
+static const GrStencilSettings gReplaceClip = {
+ kReplace_StencilOp, kReplace_StencilOp,
+ kReplace_StencilOp, kReplace_StencilOp,
+ kAlways_StencilFunc, kAlways_StencilFunc,
+ 0xffffffff, 0xffffffff,
+ 0x00000000, 0x00000000, // set clip bit
+ 0x00000000, 0x00000000 // set clipBit
+};
+
+static const GrStencilSettings gUnionClip = {
+ kReplace_StencilOp, kReplace_StencilOp,
+ kReplace_StencilOp, kReplace_StencilOp,
+ kAlways_StencilFunc, kAlways_StencilFunc,
+ 0xffffffff, 0xffffffff,
+ 0x00000000, 0x00000000, // set clip bit
+ 0x00000000, 0x00000000 // set clip bit
+};
+
+static const GrStencilSettings gXorClip = {
+ kInvert_StencilOp, kInvert_StencilOp,
+ kInvert_StencilOp, kInvert_StencilOp,
+ kAlways_StencilFunc, kAlways_StencilFunc,
+ 0xffffffff, 0xffffffff,
+ 0x00000000, 0x00000000,
+ 0x00000000, 0x00000000 // set clip bit
+};
+
+static const GrStencilSettings gDiffClip = {
+ kZero_StencilOp, kZero_StencilOp,
+ kZero_StencilOp, kZero_StencilOp,
+ kAlways_StencilFunc, kAlways_StencilFunc,
+ 0xffffffff, 0xffffffff,
+ 0x00000000, 0x00000000,
+ 0x00000000, 0x00000000 // set clip bit
+};
+
+static const GrPathFill gNonInvertedFills[] = {
+ kWinding_PathFill, // kWinding_PathFill
+ kEvenOdd_PathFill, // kEvenOdd_PathFill
+ kWinding_PathFill, // kInverseWinding_PathFill
+ kEvenOdd_PathFill, // kInverseEvenOdd_PathFill
+ kWinding_PathFill, // kHairLine_PathFill
+};
+
+static const bool gIsFillInverted[] = {
+ false, // kWinding_PathFill
+ false, // kEvenOdd_PathFill
+ true, // kInverseWinding_PathFill
+ true, // kInverseEvenOdd_PathFill
+ false, // kHairLine_PathFill
+};
+GR_STATIC_ASSERT(0 == kWinding_PathFill);
+GR_STATIC_ASSERT(1 == kEvenOdd_PathFill);
+GR_STATIC_ASSERT(2 == kInverseWinding_PathFill);
+GR_STATIC_ASSERT(3 == kInverseEvenOdd_PathFill);
+GR_STATIC_ASSERT(4 == kHairLine_PathFill);
+GR_STATIC_ASSERT(5 == kPathFillCount);
+
+bool GrStencilSettings::GetClipPasses(GrSetOp op,
+ bool canBeDirect,
+ unsigned int stencilClipMask,
+ GrPathFill* fill,
+ int* numPasses,
+ GrStencilSettings settings[kMaxStencilClipPasses]) {
+ if (canBeDirect) {
+ if (!gIsFillInverted[*fill]) {
+ *numPasses = 0;
+ switch (op) {
+ case kReplace_SetOp:
+ *numPasses = 1;
+ settings[0] = gReplaceClip;
+ break;
+ case kUnion_SetOp:
+ *numPasses = 1;
+ settings[0] = gUnionClip;
+ break;
+ case kXor_SetOp:
+ *numPasses = 1;
+ settings[0] = gXorClip;
+ break;
+ case kDifference_SetOp:
+ *numPasses = 1;
+ settings[0] = gDiffClip;
+ break;
+ default: // suppress warning
+ break;
+ }
+ if (1 == *numPasses) {
+ settings[0].fFrontFuncRef |= stencilClipMask;
+ settings[0].fFrontWriteMask |= stencilClipMask;
+ settings[0].fBackFuncRef = settings[0].fFrontFuncRef;
+ settings[0].fBackWriteMask = settings[0].fFrontWriteMask;
+ return true;
+ }
+ }
+ }
+ switch (op) {
+ case kReplace_SetOp:
+ *numPasses= 1;
+ settings[0] = gIsFillInverted[*fill] ? gInvUserToClipReplace : gUserToClipReplace;
+ settings[0].fFrontFuncMask &= ~stencilClipMask;
+ settings[0].fFrontFuncRef |= stencilClipMask;
+ settings[0].fBackFuncMask = settings[0].fFrontFuncMask;
+ settings[0].fBackFuncRef = settings[0].fFrontFuncRef;
+
+ case kIntersect_SetOp:
+ *numPasses = 1;
+ settings[0] = gIsFillInverted[*fill] ? gInvUserToClipIsect : gUserToClipIsect;
+ settings[0].fFrontFuncRef = stencilClipMask;
+ settings[0].fBackFuncRef = settings[0].fFrontFuncRef;
+ break;
+ case kUnion_SetOp:
+ *numPasses = 2;
+ if (gIsFillInverted[*fill]) {
+ settings[0] = gInvUserToClipUnionPass0;
+ settings[0].fFrontFuncRef |= stencilClipMask;
+ settings[0].fBackFuncRef = settings[0].fFrontFuncMask;
+
+ settings[1] = gInvUserToClipUnionPass1;
+ settings[1].fFrontFuncMask &= ~stencilClipMask;
+ settings[1].fFrontFuncRef |= stencilClipMask;
+ settings[1].fBackFuncMask = settings[1].fFrontFuncMask;
+ settings[1].fBackFuncRef = settings[1].fFrontFuncRef;
+
+ } else {
+ settings[0] = gUserToClipUnionPass0;
+ settings[0].fFrontFuncMask &= ~stencilClipMask;
+ settings[0].fFrontFuncRef |= stencilClipMask;
+ settings[0].fBackFuncMask = settings[0].fFrontFuncMask;
+ settings[0].fBackFuncRef = settings[0].fFrontFuncRef;
+
+ settings[1] = gUserToClipUnionPass1;
+ settings[1].fFrontFuncRef |= stencilClipMask;
+ settings[1].fBackFuncRef = settings[1].fFrontFuncRef;
+ }
+ break;
+ case kXor_SetOp:
+ *numPasses = 2;
+ if (gIsFillInverted[*fill]) {
+ settings[0] = gInvUserToClipXorPass0;
+ settings[0].fFrontFuncMask &= ~stencilClipMask;
+ settings[0].fBackFuncMask = settings[0].fFrontFuncMask;
+
+ settings[1] = gInvUserToClipXorPass1;
+ settings[1].fFrontFuncRef |= stencilClipMask;
+ settings[1].fBackFuncRef = settings[1].fFrontFuncRef;
+ } else {
+ settings[0] = gUserToClipXorPass0;
+ settings[0].fFrontFuncMask &= ~stencilClipMask;
+ settings[0].fBackFuncMask = settings[0].fFrontFuncMask;
+
+ settings[1] = gUserToClipXorPass1;
+ settings[1].fFrontFuncRef |= stencilClipMask;
+ settings[1].fBackFuncRef = settings[1].fFrontFuncRef;
+ }
+ break;
+ case kDifference_SetOp:
+ *numPasses = 1;
+ settings[0] = gIsFillInverted[*fill] ? gInvUserToClipDiff : gUserToClipDiff;
+ settings[0].fFrontFuncRef |= stencilClipMask;
+ settings[0].fBackFuncRef = settings[0].fFrontFuncRef;
+ break;
+ case kReverseDifference_SetOp:
+ if (gIsFillInverted[*fill]) {
+ *numPasses = 1;
+ settings[0] = gInvUserToClipRDiff;
+ settings[0].fFrontWriteMask |= stencilClipMask;
+ settings[0].fBackWriteMask = settings[0].fFrontWriteMask;
+ } else {
+ *numPasses = 2;
+ settings[0] = gUserToClipRDiffPass0;
+ settings[0].fFrontFuncMask &= ~stencilClipMask;
+ settings[0].fBackFuncMask = settings[0].fFrontFuncMask;
+ settings[0].fFrontFuncRef |= stencilClipMask;
+ settings[0].fBackFuncRef = settings[0].fFrontFuncRef;
+
+ settings[1] = gUserToClipRDiffPass1;
+ settings[1].fFrontFuncMask |= stencilClipMask;
+ settings[1].fFrontFuncRef |= stencilClipMask;
+ settings[1].fBackFuncMask = settings[1].fFrontFuncMask;
+ settings[1].fBackFuncRef = settings[1].fFrontFuncRef;
+ }
+ break;
+ default:
+ GrCrash("Unknown set op");
+ }
+ *fill = gNonInvertedFills[*fill];
+ return false;
+}
\ No newline at end of file