michael@0: 
michael@0: /*
michael@0:  * Copyright 2011 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: 
michael@0: #include "GrStencil.h"
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: // Stencil Rules for Merging user stencil space into clip
michael@0: 
michael@0: // We can't include the clip bit in the ref or mask values because the division
michael@0: // between user and clip bits in the stencil depends on the number of stencil
michael@0: // bits in the runtime. Comments below indicate what the code should do to
michael@0: // incorporate the clip bit into these settings.
michael@0: 
michael@0: ///////
michael@0: // Replace
michael@0: 
michael@0: // set the ref to be the clip bit, but mask it out for the test
michael@0: GR_STATIC_CONST_SAME_STENCIL(gUserToClipReplace,
michael@0:     kReplace_StencilOp,
michael@0:     kZero_StencilOp,
michael@0:     kLess_StencilFunc,
michael@0:     0xffff,           // unset clip bit
michael@0:     0x0000,           // set clip bit
michael@0:     0xffff);
michael@0: 
michael@0: GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipReplace,
michael@0:     kReplace_StencilOp,
michael@0:     kZero_StencilOp,
michael@0:     kEqual_StencilFunc,
michael@0:     0xffff,           // unset clip bit
michael@0:     0x0000,           // set clip bit
michael@0:     0xffff);
michael@0: 
michael@0: ///////
michael@0: // Intersect
michael@0: GR_STATIC_CONST_SAME_STENCIL(gUserToClipIsect,
michael@0:     kReplace_StencilOp,
michael@0:     kZero_StencilOp,
michael@0:     kLess_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0000,           // set clip bit
michael@0:     0xffff);
michael@0: 
michael@0: GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipIsect,
michael@0:     kReplace_StencilOp,
michael@0:     kZero_StencilOp,
michael@0:     kEqual_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0000,           // set clip bit
michael@0:     0xffff);
michael@0: 
michael@0: ///////
michael@0: // Difference
michael@0: GR_STATIC_CONST_SAME_STENCIL(gUserToClipDiff,
michael@0:     kReplace_StencilOp,
michael@0:     kZero_StencilOp,
michael@0:     kEqual_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0000,           // set clip bit
michael@0:     0xffff);
michael@0: 
michael@0: GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipDiff,
michael@0:     kReplace_StencilOp,
michael@0:     kZero_StencilOp,
michael@0:     kLess_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0000,           // set clip bit
michael@0:     0xffff);
michael@0: 
michael@0: ///////
michael@0: // Union
michael@0: 
michael@0: // first pass makes all the passing cases >= just clip bit set.
michael@0: GR_STATIC_CONST_SAME_STENCIL(gUserToClipUnionPass0,
michael@0:     kReplace_StencilOp,
michael@0:     kKeep_StencilOp,
michael@0:     kLEqual_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0001,           // set clip bit
michael@0:     0xffff);
michael@0: 
michael@0: // second pass allows anything greater than just clip bit set to pass
michael@0: GR_STATIC_CONST_SAME_STENCIL(gUserToClipUnionPass1,
michael@0:     kReplace_StencilOp,
michael@0:     kZero_StencilOp,
michael@0:     kLEqual_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0000,           // set clip bit
michael@0:     0xffff);
michael@0: 
michael@0: // first pass finds zeros in the user bits and if found sets
michael@0: // the clip bit to 1
michael@0: GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipUnionPass0,
michael@0:     kReplace_StencilOp,
michael@0:     kKeep_StencilOp,
michael@0:     kEqual_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0000,           // set clip bit
michael@0:     0x0000            // set clip bit
michael@0: );
michael@0: 
michael@0: // second pass zeros the user bits
michael@0: GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipUnionPass1,
michael@0:     kZero_StencilOp,
michael@0:     kZero_StencilOp,
michael@0:     kLess_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0000,
michael@0:     0xffff            // unset clip bit
michael@0: );
michael@0: 
michael@0: ///////
michael@0: // Xor
michael@0: GR_STATIC_CONST_SAME_STENCIL(gUserToClipXorPass0,
michael@0:     kInvert_StencilOp,
michael@0:     kKeep_StencilOp,
michael@0:     kEqual_StencilFunc,
michael@0:     0xffff,           // unset clip bit
michael@0:     0x0000,
michael@0:     0xffff);
michael@0: 
michael@0: GR_STATIC_CONST_SAME_STENCIL(gUserToClipXorPass1,
michael@0:     kReplace_StencilOp,
michael@0:     kZero_StencilOp,
michael@0:     kGreater_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0000,          // set clip bit
michael@0:     0xffff);
michael@0: 
michael@0: GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipXorPass0,
michael@0:     kInvert_StencilOp,
michael@0:     kKeep_StencilOp,
michael@0:     kEqual_StencilFunc,
michael@0:     0xffff,           // unset clip bit
michael@0:     0x0000,
michael@0:     0xffff);
michael@0: 
michael@0: GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipXorPass1,
michael@0:     kReplace_StencilOp,
michael@0:     kZero_StencilOp,
michael@0:     kLess_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0000,          // set clip bit
michael@0:     0xffff);
michael@0: 
michael@0: ///////
michael@0: // Reverse Diff
michael@0: GR_STATIC_CONST_SAME_STENCIL(gUserToClipRDiffPass0,
michael@0:     kInvert_StencilOp,
michael@0:     kZero_StencilOp,
michael@0:     kLess_StencilFunc,
michael@0:     0xffff,         // unset clip bit
michael@0:     0x0000,         // set clip bit
michael@0:     0xffff);
michael@0: 
michael@0: GR_STATIC_CONST_SAME_STENCIL(gUserToClipRDiffPass1,
michael@0:     kReplace_StencilOp,
michael@0:     kZero_StencilOp,
michael@0:     kEqual_StencilFunc,
michael@0:     0x0000,          // set clip bit
michael@0:     0x0000,          // set clip bit
michael@0:     0xffff);
michael@0: 
michael@0: // We are looking for stencil values that are all zero. The first pass sets the
michael@0: // clip bit if the stencil is all zeros. The second pass clears the user bits.
michael@0: GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipRDiffPass0,
michael@0:     kInvert_StencilOp,
michael@0:     kZero_StencilOp,
michael@0:     kEqual_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0000,
michael@0:     0x0000           // set clip bit
michael@0: );
michael@0: 
michael@0: GR_STATIC_CONST_SAME_STENCIL(gInvUserToClipRDiffPass1,
michael@0:     kZero_StencilOp,
michael@0:     kZero_StencilOp,
michael@0:     kAlways_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0000,
michael@0:     0xffff           // unset clip bit
michael@0: );
michael@0: 
michael@0: ///////
michael@0: // Direct to Stencil
michael@0: 
michael@0: // We can render a clip element directly without first writing to the client
michael@0: // portion of the clip when the fill is not inverse and the set operation will
michael@0: // only modify the in/out status of samples covered by the clip element.
michael@0: 
michael@0: // this one only works if used right after stencil clip was cleared.
michael@0: // Our clip mask creation code doesn't allow midstream replace ops.
michael@0: GR_STATIC_CONST_SAME_STENCIL(gReplaceClip,
michael@0:     kReplace_StencilOp,
michael@0:     kReplace_StencilOp,
michael@0:     kAlways_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0000,           // set clip bit
michael@0:     0x0000            // set clipBit
michael@0: );
michael@0: 
michael@0: GR_STATIC_CONST_SAME_STENCIL(gUnionClip,
michael@0:     kReplace_StencilOp,
michael@0:     kReplace_StencilOp,
michael@0:     kAlways_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0000,           // set clip bit
michael@0:     0x0000            // set clip bit
michael@0: );
michael@0: 
michael@0: GR_STATIC_CONST_SAME_STENCIL(gXorClip,
michael@0:     kInvert_StencilOp,
michael@0:     kInvert_StencilOp,
michael@0:     kAlways_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0000,
michael@0:     0x0000            // set clip bit
michael@0: );
michael@0: 
michael@0: GR_STATIC_CONST_SAME_STENCIL(gDiffClip,
michael@0:     kZero_StencilOp,
michael@0:     kZero_StencilOp,
michael@0:     kAlways_StencilFunc,
michael@0:     0xffff,
michael@0:     0x0000,
michael@0:     0x0000            // set clip bit
michael@0: );
michael@0: 
michael@0: bool GrStencilSettings::GetClipPasses(
michael@0:                             SkRegion::Op op,
michael@0:                             bool canBeDirect,
michael@0:                             unsigned int stencilClipMask,
michael@0:                             bool invertedFill,
michael@0:                             int* numPasses,
michael@0:                             GrStencilSettings settings[kMaxStencilClipPasses]) {
michael@0:     if (canBeDirect && !invertedFill) {
michael@0:         *numPasses = 0;
michael@0:         switch (op) {
michael@0:             case SkRegion::kReplace_Op:
michael@0:                 *numPasses = 1;
michael@0:                 settings[0] = gReplaceClip;
michael@0:                 break;
michael@0:             case SkRegion::kUnion_Op:
michael@0:                 *numPasses = 1;
michael@0:                 settings[0] = gUnionClip;
michael@0:                 break;
michael@0:             case SkRegion::kXOR_Op:
michael@0:                 *numPasses = 1;
michael@0:                 settings[0] = gXorClip;
michael@0:                 break;
michael@0:             case SkRegion::kDifference_Op:
michael@0:                 *numPasses = 1;
michael@0:                 settings[0] = gDiffClip;
michael@0:                 break;
michael@0:             default: // suppress warning
michael@0:                 break;
michael@0:         }
michael@0:         if (1 == *numPasses) {
michael@0:             settings[0].fFuncRefs[kFront_Face]   |= stencilClipMask;
michael@0:             settings[0].fWriteMasks[kFront_Face] |= stencilClipMask;
michael@0:             settings[0].fFuncRefs[kBack_Face] =
michael@0:                 settings[0].fFuncRefs[kFront_Face];
michael@0:             settings[0].fWriteMasks[kBack_Face] =
michael@0:                 settings[0].fWriteMasks[kFront_Face];
michael@0:             return true;
michael@0:         }
michael@0:     }
michael@0:     switch (op) {
michael@0:         // if we make the path renderer go to stencil we always give it a
michael@0:         // non-inverted fill and we use the stencil rules on the client->clipbit
michael@0:         // pass to select either the zeros or nonzeros.
michael@0:         case SkRegion::kReplace_Op:
michael@0:             *numPasses= 1;
michael@0:             settings[0] = invertedFill ? gInvUserToClipReplace :
michael@0:                                          gUserToClipReplace;
michael@0:             settings[0].fFuncMasks[kFront_Face] &= ~stencilClipMask;
michael@0:             settings[0].fFuncRefs[kFront_Face] |= stencilClipMask;
michael@0:             settings[0].fFuncMasks[kBack_Face] =
michael@0:                 settings[0].fFuncMasks[kFront_Face];
michael@0:             settings[0].fFuncRefs[kBack_Face] =
michael@0:                 settings[0].fFuncRefs[kFront_Face];
michael@0:             break;
michael@0:         case SkRegion::kIntersect_Op:
michael@0:             *numPasses = 1;
michael@0:             settings[0] = invertedFill ? gInvUserToClipIsect : gUserToClipIsect;
michael@0:             settings[0].fFuncRefs[kFront_Face] = stencilClipMask;
michael@0:             settings[0].fFuncRefs[kBack_Face] =
michael@0:                 settings[0].fFuncRefs[kFront_Face];
michael@0:             break;
michael@0:         case SkRegion::kUnion_Op:
michael@0:             *numPasses = 2;
michael@0:             if (invertedFill) {
michael@0:                 settings[0] = gInvUserToClipUnionPass0;
michael@0:                 settings[0].fFuncMasks[kFront_Face] &= ~stencilClipMask;
michael@0:                 settings[0].fFuncMasks[kBack_Face] =
michael@0:                     settings[0].fFuncMasks[kFront_Face];
michael@0:                 settings[0].fFuncRefs[kFront_Face] |= stencilClipMask;
michael@0:                 settings[0].fFuncRefs[kBack_Face] =
michael@0:                     settings[0].fFuncRefs[kFront_Face];
michael@0:                 settings[0].fWriteMasks[kFront_Face] |= stencilClipMask;
michael@0:                 settings[0].fWriteMasks[kBack_Face] =
michael@0:                     settings[0].fWriteMasks[kFront_Face];
michael@0: 
michael@0:                 settings[1] = gInvUserToClipUnionPass1;
michael@0:                 settings[1].fWriteMasks[kFront_Face] &= ~stencilClipMask;
michael@0:                 settings[1].fWriteMasks[kBack_Face] &=
michael@0:                     settings[1].fWriteMasks[kFront_Face];
michael@0: 
michael@0:             } else {
michael@0:                 settings[0] = gUserToClipUnionPass0;
michael@0:                 settings[0].fFuncMasks[kFront_Face] &= ~stencilClipMask;
michael@0:                 settings[0].fFuncRefs[kFront_Face] |= stencilClipMask;
michael@0:                 settings[0].fFuncMasks[kBack_Face] =
michael@0:                     settings[0].fFuncMasks[kFront_Face];
michael@0:                 settings[0].fFuncRefs[kBack_Face] =
michael@0:                     settings[0].fFuncRefs[kFront_Face];
michael@0: 
michael@0:                 settings[1] = gUserToClipUnionPass1;
michael@0:                 settings[1].fFuncRefs[kFront_Face] |= stencilClipMask;
michael@0:                 settings[1].fFuncRefs[kBack_Face] =
michael@0:                     settings[1].fFuncRefs[kFront_Face];
michael@0:             }
michael@0:             break;
michael@0:         case SkRegion::kXOR_Op:
michael@0:             *numPasses = 2;
michael@0:             if (invertedFill) {
michael@0:                 settings[0] = gInvUserToClipXorPass0;
michael@0:                 settings[0].fFuncMasks[kFront_Face] &= ~stencilClipMask;
michael@0:                 settings[0].fFuncMasks[kBack_Face] =
michael@0:                     settings[0].fFuncMasks[kFront_Face];
michael@0: 
michael@0:                 settings[1] = gInvUserToClipXorPass1;
michael@0:                 settings[1].fFuncRefs[kFront_Face] |= stencilClipMask;
michael@0:                 settings[1].fFuncRefs[kBack_Face] =
michael@0:                     settings[1].fFuncRefs[kFront_Face];
michael@0:             } else {
michael@0:                 settings[0] = gUserToClipXorPass0;
michael@0:                 settings[0].fFuncMasks[kFront_Face] &= ~stencilClipMask;
michael@0:                 settings[0].fFuncMasks[kBack_Face] =
michael@0:                     settings[0].fFuncMasks[kFront_Face];
michael@0: 
michael@0:                 settings[1] = gUserToClipXorPass1;
michael@0:                 settings[1].fFuncRefs[kFront_Face] |= stencilClipMask;
michael@0:                 settings[1].fFuncRefs[kBack_Face] =
michael@0:                     settings[1].fFuncRefs[kFront_Face];
michael@0:             }
michael@0:             break;
michael@0:         case SkRegion::kDifference_Op:
michael@0:             *numPasses = 1;
michael@0:             settings[0] = invertedFill ? gInvUserToClipDiff : gUserToClipDiff;
michael@0:             settings[0].fFuncRefs[kFront_Face] |= stencilClipMask;
michael@0:             settings[0].fFuncRefs[kBack_Face] =
michael@0:                 settings[0].fFuncRefs[kFront_Face];
michael@0:             break;
michael@0:         case SkRegion::kReverseDifference_Op:
michael@0:             if (invertedFill) {
michael@0:                 *numPasses = 2;
michael@0:                 settings[0] = gInvUserToClipRDiffPass0;
michael@0:                 settings[0].fWriteMasks[kFront_Face] |= stencilClipMask;
michael@0:                 settings[0].fWriteMasks[kBack_Face] =
michael@0:                     settings[0].fWriteMasks[kFront_Face];
michael@0:                 settings[1] = gInvUserToClipRDiffPass1;
michael@0:                 settings[1].fWriteMasks[kFront_Face] &= ~stencilClipMask;
michael@0:                 settings[1].fWriteMasks[kBack_Face] =
michael@0:                     settings[1].fWriteMasks[kFront_Face];
michael@0:             } else {
michael@0:                 *numPasses = 2;
michael@0:                 settings[0] = gUserToClipRDiffPass0;
michael@0:                 settings[0].fFuncMasks[kFront_Face] &= ~stencilClipMask;
michael@0:                 settings[0].fFuncMasks[kBack_Face] =
michael@0:                     settings[0].fFuncMasks[kFront_Face];
michael@0:                 settings[0].fFuncRefs[kFront_Face] |= stencilClipMask;
michael@0:                 settings[0].fFuncRefs[kBack_Face] =
michael@0:                     settings[0].fFuncRefs[kFront_Face];
michael@0: 
michael@0:                 settings[1] = gUserToClipRDiffPass1;
michael@0:                 settings[1].fFuncMasks[kFront_Face] |= stencilClipMask;
michael@0:                 settings[1].fFuncRefs[kFront_Face] |= stencilClipMask;
michael@0:                 settings[1].fFuncMasks[kBack_Face] =
michael@0:                     settings[1].fFuncMasks[kFront_Face];
michael@0:                 settings[1].fFuncRefs[kBack_Face] =
michael@0:                     settings[1].fFuncRefs[kFront_Face];
michael@0:             }
michael@0:             break;
michael@0:         default:
michael@0:             GrCrash("Unknown set op");
michael@0:     }
michael@0:     return false;
michael@0: }