simplify/unify xferproc api

src/core/SkXfermodeU64.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkHalf.h"
 #include "SkPM4fPriv.h"
 #include "SkUtils.h"
 #include "SkXfermode.h"
 
 static void sk_memset64(uint64_t dst[], uint64_t value, int count) {
     for (int i = 0; i < count; ++i) {
         dst[i] = value;
     }
 }
 
-struct U64ProcPair {
-    SkXfermode::U64Proc1 fP1;
-    SkXfermode::U64ProcN fPN;
-};
-
 enum DstType {
     kU16_Dst,
     kF16_Dst,
 };
 
 static Sk4f lerp_by_coverage(const Sk4f& src, const Sk4f& dst, uint8_t srcCoverage) {
     return dst + (src - dst) * Sk4f(srcCoverage * (1/255.0f));
 }
 
 template <DstType D> Sk4f unit_to_bias(const Sk4f& x4) {
@@ skipping 31 matching lines @@
     if (SkPM4f::R == 0) {
         return x;   // we're already RGBA
     } else {
         // we're BGRA, so swap R and B
         return SkNx_shuffle<2, 1, 0, 3>(x);
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
-template <DstType D> void xfer_u64_1(const SkXfermode::U64State& state, uint64_t dst[],
-                                     const SkPM4f& src, int count, const SkAlpha aa[]) {
-    SkXfermodeProc4f proc = state.fXfer->getProc4f();
+template <DstType D> void xfer_u64_1(const SkXfermode* xfer, uint64_t dst[],
+                                     const SkPM4f* src, int count, const SkAlpha aa[]) {
+    SkXfermodeProc4f proc = xfer->getProc4f();
     SkPM4f d;
     if (aa) {
         for (int i = 0; i < count; ++i) {
             Sk4f d4 = bias_to_unit<D>(load_from_dst<D>(dst[i]));
             d4.store(d.fVec);
-            Sk4f r4 = unit_to_bias<D>(Sk4f::Load(proc(src, d).fVec));
+            Sk4f r4 = unit_to_bias<D>(Sk4f::Load(proc(*src, d).fVec));
             dst[i] = store_to_dst<D>(lerp_by_coverage(r4, d4, aa[i]));
         }
     } else {
         for (int i = 0; i < count; ++i) {
             bias_to_unit<D>(load_from_dst<D>(dst[i])).store(d.fVec);
-            Sk4f r4 = unit_to_bias<D>(Sk4f::Load(proc(src, d).fVec));
+            Sk4f r4 = unit_to_bias<D>(Sk4f::Load(proc(*src, d).fVec));
             dst[i] = store_to_dst<D>(r4);
         }
     }
 }
 
-template <DstType D> void xfer_u64_n(const SkXfermode::U64State& state, uint64_t dst[],
+template <DstType D> void xfer_u64_n(const SkXfermode* xfer, uint64_t dst[],
                                      const SkPM4f src[], int count, const SkAlpha aa[]) {
-    SkXfermodeProc4f proc = state.fXfer->getProc4f();
+    SkXfermodeProc4f proc = xfer->getProc4f();
     SkPM4f d;
     if (aa) {
         for (int i = 0; i < count; ++i) {
             Sk4f d4 = bias_to_unit<D>(load_from_dst<D>(dst[i]));
             d4.store(d.fVec);
             Sk4f r4 = unit_to_bias<D>(Sk4f::Load(proc(src[i], d).fVec));
             dst[i] = store_to_dst<D>(lerp_by_coverage(r4, d4, aa[i]));
         }
     } else {
         for (int i = 0; i < count; ++i) {
             bias_to_unit<D>(load_from_dst<D>(dst[i])).store(d.fVec);
             Sk4f r4 = unit_to_bias<D>(Sk4f::Load(proc(src[i], d).fVec));
             dst[i] = store_to_dst<D>(r4);
         }
     }
 }
 
-const U64ProcPair gU64Procs_General[] = {
-    { xfer_u64_1<kU16_Dst>, xfer_u64_n<kU16_Dst> },   // U16     alpha
-    { xfer_u64_1<kU16_Dst>, xfer_u64_n<kU16_Dst> },   // U16     opaque
-    { xfer_u64_1<kF16_Dst>, xfer_u64_n<kF16_Dst> },   // F16     alpha
-    { xfer_u64_1<kF16_Dst>, xfer_u64_n<kF16_Dst> },   // F16     opaque
+const SkXfermode::D64Proc gProcs_General[] = {
+    xfer_u64_n<kU16_Dst>,   xfer_u64_n<kU16_Dst>,
+    xfer_u64_1<kU16_Dst>,   xfer_u64_1<kU16_Dst>,
+    xfer_u64_n<kF16_Dst>,   xfer_u64_n<kF16_Dst>,
+    xfer_u64_1<kF16_Dst>,   xfer_u64_1<kF16_Dst>,
 };
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
-template <DstType D> void src_1(const SkXfermode::U64State& state, uint64_t dst[],
-                                const SkPM4f& src, int count, const SkAlpha aa[]) {
-    const Sk4f s4 = pm_to_rgba_order(unit_to_bias<D>(Sk4f::Load(src.fVec)));
+template <DstType D> void clear(const SkXfermode*, uint64_t dst[],
+                                const SkPM4f*, int count, const SkAlpha aa[]) {
+    if (aa) {
+        for (int i = 0; i < count; ++i) {
+            if (aa[i]) {
+                const Sk4f d4 = load_from_dst<D>(dst[i]);
+                dst[i] = store_to_dst<D>(d4 * Sk4f((255 - aa[i]) * 1.0f/255));
+            }
+        }
+    } else {
+        sk_memset64(dst, 0, count);
+    }
+}
+
+const SkXfermode::D64Proc gProcs_Clear[] = {
+    clear<kU16_Dst>,    clear<kU16_Dst>,
+    clear<kU16_Dst>,    clear<kU16_Dst>,
+    clear<kF16_Dst>,    clear<kF16_Dst>,
+    clear<kF16_Dst>,    clear<kF16_Dst>,
+};
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+template <DstType D> void src_1(const SkXfermode*, uint64_t dst[],
+                                const SkPM4f* src, int count, const SkAlpha aa[]) {
+    const Sk4f s4 = pm_to_rgba_order(unit_to_bias<D>(Sk4f::Load(src->fVec)));
     if (aa) {
         for (int i = 0; i < count; ++i) {
             const Sk4f d4 = load_from_dst<D>(dst[i]);
             dst[i] = store_to_dst<D>(lerp_by_coverage(s4, d4, aa[i]));
         }
     } else {
         sk_memset64(dst, store_to_dst<D>(s4), count);
     }
 }
 
-template <DstType D> void src_n(const SkXfermode::U64State& state, uint64_t dst[],
+template <DstType D> void src_n(const SkXfermode*, uint64_t dst[],
                                 const SkPM4f src[], int count, const SkAlpha aa[]) {
     if (aa) {
         for (int i = 0; i < count; ++i) {
             const Sk4f s4 = pm_to_rgba_order(unit_to_bias<D>(Sk4f::Load(src[i].fVec)));
             const Sk4f d4 = load_from_dst<D>(dst[i]);
             dst[i] = store_to_dst<D>(lerp_by_coverage(s4, d4, aa[i]));
         }
     } else {
         for (int i = 0; i < count; ++i) {
             const Sk4f s4 = pm_to_rgba_order(unit_to_bias<D>(Sk4f::Load(src[i].fVec)));
             dst[i] = store_to_dst<D>(s4);
         }
     }
 }
 
-const U64ProcPair gU64Procs_Src[] = {
-    { src_1<kU16_Dst>, src_n<kU16_Dst>  },   // U16     alpha
-    { src_1<kU16_Dst>, src_n<kU16_Dst>  },   // U16     opaque
-    { src_1<kF16_Dst>, src_n<kF16_Dst>  },   // F16     alpha
-    { src_1<kF16_Dst>, src_n<kF16_Dst>  },   // F16     opaque
+const SkXfermode::D64Proc gProcs_Src[] = {
+    src_n<kU16_Dst>,    src_n<kU16_Dst>,
+    src_1<kU16_Dst>,    src_1<kU16_Dst>,
+    src_n<kF16_Dst>,    src_n<kF16_Dst>,
+    src_1<kF16_Dst>,    src_1<kF16_Dst>,
 };
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
-template <DstType D> void srcover_1(const SkXfermode::U64State& state, uint64_t dst[],
-                                    const SkPM4f& src, int count, const SkAlpha aa[]) {
-    const Sk4f s4 = pm_to_rgba_order(Sk4f::Load(src.fVec));
+static void dst(const SkXfermode*, uint64_t*, const SkPM4f*, int count, const SkAlpha[]) {}
+
+const SkXfermode::D64Proc gProcs_Dst[] = {
+    dst, dst, dst, dst, dst, dst, dst, dst,
+};
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+template <DstType D> void srcover_1(const SkXfermode*, uint64_t dst[],
+                                    const SkPM4f* src, int count, const SkAlpha aa[]) {
+    const Sk4f s4 = pm_to_rgba_order(Sk4f::Load(src->fVec));
     const Sk4f dst_scale = Sk4f(1 - get_alpha(s4));
     const Sk4f s4bias = unit_to_bias<D>(s4);
     for (int i = 0; i < count; ++i) {
         const Sk4f d4bias = load_from_dst<D>(dst[i]);
         const Sk4f r4bias = s4bias + d4bias * dst_scale;
         if (aa) {
             dst[i] = store_to_dst<D>(lerp_by_coverage(r4bias, d4bias, aa[i]));
         } else {
             dst[i] = store_to_dst<D>(r4bias);
         }
     }
 }
 
-template <DstType D> void srcover_n(const SkXfermode::U64State& state, uint64_t dst[],
+template <DstType D> void srcover_n(const SkXfermode*, uint64_t dst[],
                                     const SkPM4f src[], int count, const SkAlpha aa[]) {
     for (int i = 0; i < count; ++i) {
         const Sk4f s4 = pm_to_rgba_order(Sk4f::Load(src[i].fVec));
         const Sk4f dst_scale = Sk4f(1 - get_alpha(s4));
         const Sk4f s4bias = unit_to_bias<D>(s4);
         const Sk4f d4bias = load_from_dst<D>(dst[i]);
         const Sk4f r4bias = s4bias + d4bias * dst_scale;
         if (aa) {
             dst[i] = store_to_dst<D>(lerp_by_coverage(r4bias, d4bias, aa[i]));
         } else {
             dst[i] = store_to_dst<D>(r4bias);
         }
     }
 }
 
-const U64ProcPair gU64Procs_SrcOver[] = {
-    { srcover_1<kU16_Dst>,  srcover_n<kU16_Dst> },   // U16     alpha
-    { src_1<kU16_Dst>,      src_n<kU16_Dst>     },   // U16     opaque
-    { srcover_1<kF16_Dst>,  srcover_n<kF16_Dst> },   // F16     alpha
-    { src_1<kF16_Dst>,      src_n<kF16_Dst>     },   // F16     opaque
+const SkXfermode::D64Proc gProcs_SrcOver[] = {
+    srcover_n<kU16_Dst>,    src_n<kU16_Dst>,
+    srcover_1<kU16_Dst>,    src_1<kU16_Dst>,
+    srcover_n<kF16_Dst>,    src_n<kF16_Dst>,
+    srcover_1<kF16_Dst>,    src_1<kF16_Dst>,
 };
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
-static U64ProcPair find_procs(SkXfermode::Mode mode, uint32_t flags) {
-    SkASSERT(0 == (flags & ~3));
-    flags &= 3;
+static SkXfermode::D64Proc find_proc(SkXfermode::Mode mode, uint32_t flags) {
+    SkASSERT(0 == (flags & ~7));
+    flags &= 7;
 
     switch (mode) {
-        case SkXfermode::kSrc_Mode:     return gU64Procs_Src[flags];
-        case SkXfermode::kSrcOver_Mode: return gU64Procs_SrcOver[flags];
+        case SkXfermode::kClear_Mode:   return gProcs_Clear[flags];
+        case SkXfermode::kSrc_Mode:     return gProcs_Src[flags];
+        case SkXfermode::kDst_Mode:     return gProcs_Dst[flags];
+        case SkXfermode::kSrcOver_Mode: return gProcs_SrcOver[flags];
         default:
             break;
     }
-    return gU64Procs_General[flags];
+    return gProcs_General[flags];
 }
 
-SkXfermode::U64Proc1 SkXfermode::GetU64Proc1(Mode mode, uint32_t flags) {
-    return find_procs(mode, flags).fP1;
+SkXfermode::D64Proc SkXfermode::onGetD64Proc(uint32_t flags) const {
+    SkASSERT(0 == (flags & ~7));
+    flags &= 7;
+    
+    Mode mode;
+    return this->asMode(&mode) ? find_proc(mode, flags) : gProcs_General[flags];
 }
 
-SkXfermode::U64ProcN SkXfermode::GetU64ProcN(Mode mode, uint32_t flags) {
-    return find_procs(mode, flags).fPN;
+SkXfermode::D64Proc SkXfermode::GetD64Proc(SkXfermode* xfer, uint32_t flags) {
+    return xfer ? xfer->onGetD64Proc(flags) : find_proc(SkXfermode::kSrcOver_Mode, flags);
 }
+