grab from latest android
git-svn-id: http://skia.googlecode.com/svn/trunk@27 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/effects/SkEmbossMask.cpp b/src/effects/SkEmbossMask.cpp
new file mode 100644
index 0000000..28e38a1
--- /dev/null
+++ b/src/effects/SkEmbossMask.cpp
@@ -0,0 +1,182 @@
+/* libs/graphics/effects/SkEmbossMask.cpp
+**
+** Copyright 2006, The Android Open Source Project
+**
+** 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 "SkEmbossMask.h"
+
+static inline int nonzero_to_one(int x)
+{
+#if 0
+ return x != 0;
+#else
+ return ((unsigned)(x | -x)) >> 31;
+#endif
+}
+
+static inline int neq_to_one(int x, int max)
+{
+#if 0
+ return x != max;
+#else
+ SkASSERT(x >= 0 && x <= max);
+ return ((unsigned)(x - max)) >> 31;
+#endif
+}
+
+static inline int neq_to_mask(int x, int max)
+{
+#if 0
+ return -(x != max);
+#else
+ SkASSERT(x >= 0 && x <= max);
+ return (x - max) >> 31;
+#endif
+}
+
+static inline unsigned div255(unsigned x)
+{
+ SkASSERT(x <= (255*255));
+ return x * ((1 << 24) / 255) >> 24;
+}
+
+#define kDelta 32 // small enough to show off angle differences
+
+#include "SkEmbossMask_Table.h"
+
+#if defined(SK_BUILD_FOR_WIN32) && defined(SK_DEBUG)
+
+#include <stdio.h>
+
+void SkEmbossMask_BuildTable()
+{
+ // build it 0..127 x 0..127, so we use 2^15 - 1 in the numerator for our "fixed" table
+
+ FILE* file = ::fopen("SkEmbossMask_Table.h", "w");
+ SkASSERT(file);
+ ::fprintf(file, "#include \"SkTypes.h\"\n\n");
+ ::fprintf(file, "static const U16 gInvSqrtTable[128 * 128] = {\n");
+ for (int dx = 0; dx <= 255/2; dx++)
+ {
+ for (int dy = 0; dy <= 255/2; dy++)
+ {
+ if ((dy & 15) == 0)
+ ::fprintf(file, "\t");
+
+ U16 value = SkToU16((1 << 15) / SkSqrt32(dx * dx + dy * dy + kDelta*kDelta/4));
+
+ ::fprintf(file, "0x%04X", value);
+ if (dx * 128 + dy < 128*128-1)
+ ::fprintf(file, ", ");
+ if ((dy & 15) == 15)
+ ::fprintf(file, "\n");
+ }
+ }
+ ::fprintf(file, "};\n#define kDeltaUsedToBuildTable\t%d\n", kDelta);
+ ::fclose(file);
+}
+
+#endif
+
+void SkEmbossMask::Emboss(SkMask* mask, const SkEmbossMaskFilter::Light& light)
+{
+ SkASSERT(kDelta == kDeltaUsedToBuildTable);
+
+ SkASSERT(mask->fFormat == SkMask::k3D_Format);
+
+ int specular = light.fSpecular;
+ int ambient = light.fAmbient;
+ SkFixed lx = SkScalarToFixed(light.fDirection[0]);
+ SkFixed ly = SkScalarToFixed(light.fDirection[1]);
+ SkFixed lz = SkScalarToFixed(light.fDirection[2]);
+ SkFixed lz_dot_nz = lz * kDelta;
+ int lz_dot8 = lz >> 8;
+
+ size_t planeSize = mask->computeImageSize();
+ uint8_t* alpha = mask->fImage;
+ uint8_t* multiply = (uint8_t*)alpha + planeSize;
+ uint8_t* additive = multiply + planeSize;
+
+ int rowBytes = mask->fRowBytes;
+ int maxy = mask->fBounds.height() - 1;
+ int maxx = mask->fBounds.width() - 1;
+
+ int prev_row = 0;
+ for (int y = 0; y <= maxy; y++)
+ {
+ int next_row = neq_to_mask(y, maxy) & rowBytes;
+
+ for (int x = 0; x <= maxx; x++)
+ {
+ if (alpha[x])
+ {
+ int nx = alpha[x + neq_to_one(x, maxx)] - alpha[x - nonzero_to_one(x)];
+ int ny = alpha[x + next_row] - alpha[x - prev_row];
+
+ SkFixed numer = lx * nx + ly * ny + lz_dot_nz;
+ int mul = ambient;
+ int add = 0;
+
+ if (numer > 0) // preflight when numer/denom will be <= 0
+ {
+#if 0
+ int denom = SkSqrt32(nx * nx + ny * ny + kDelta*kDelta);
+ SkFixed dot = numer / denom;
+ dot >>= 8; // now dot is 2^8 instead of 2^16
+#else
+ // can use full numer, but then we need to call SkFixedMul, since
+ // numer is 24 bits, and our table is 12 bits
+
+ // SkFixed dot = SkFixedMul(numer, gTable[]) >> 8
+ SkFixed dot = (unsigned)(numer >> 4) * gInvSqrtTable[(SkAbs32(nx) >> 1 << 7) | (SkAbs32(ny) >> 1)] >> 20;
+#endif
+ mul = SkFastMin32(mul + dot, 255);
+
+ // now for the reflection
+
+ // R = 2 (Light * Normal) Normal - Light
+ // hilite = R * Eye(0, 0, 1)
+
+ int hilite = (2 * dot - lz_dot8) * lz_dot8 >> 8;
+ if (hilite > 0)
+ {
+ // pin hilite to 255, since our fast math is also a little sloppy
+ hilite = SkClampMax(hilite, 255);
+
+ // specular is 4.4
+ // would really like to compute the fractional part of this
+ // and then possibly cache a 256 table for a given specular
+ // value in the light, and just pass that in to this function.
+ add = hilite;
+ for (int i = specular >> 4; i > 0; --i)
+ add = div255(add * hilite);
+ }
+ }
+ multiply[x] = SkToU8(mul);
+ additive[x] = SkToU8(add);
+
+ // multiply[x] = 0xFF;
+ // additive[x] = 0;
+ // ((uint8_t*)alpha)[x] = alpha[x] * multiply[x] >> 8;
+ }
+ }
+ alpha += rowBytes;
+ multiply += rowBytes;
+ additive += rowBytes;
+ prev_row = rowBytes;
+ }
+}
+
+