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Unified Diff: src/effects/gradients/SkSweepGradient.cpp

Issue 117053002: remove SK_SCALAR_IS_[FLOAT,FIXED] and assume floats (Closed) Base URL: https://skia.googlecode.com/svn/trunk
Patch Set: Created 7 years ago
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Index: src/effects/gradients/SkSweepGradient.cpp
diff --git a/src/effects/gradients/SkSweepGradient.cpp b/src/effects/gradients/SkSweepGradient.cpp
index c38205b844ab15eeda5a1a1a022672f404fbe6ea..d60d8b6050d8971e624f14f943660a6502403026 100644
--- a/src/effects/gradients/SkSweepGradient.cpp
+++ b/src/effects/gradients/SkSweepGradient.cpp
@@ -52,178 +52,7 @@ void SkSweepGradient::flatten(SkFlattenableWriteBuffer& buffer) const {
buffer.writePoint(fCenter);
}
-#ifndef SK_SCALAR_IS_FLOAT
-#ifdef COMPUTE_SWEEP_TABLE
-#define PI 3.14159265
-static bool gSweepTableReady;
-static uint8_t gSweepTable[65];
-
-/* Our table stores precomputed values for atan: [0...1] -> [0..PI/4]
- We scale the results to [0..32]
-*/
-static const uint8_t* build_sweep_table() {
- if (!gSweepTableReady) {
- const int N = 65;
- const double DENOM = N - 1;
-
- for (int i = 0; i < N; i++)
- {
- double arg = i / DENOM;
- double v = atan(arg);
- int iv = (int)round(v * DENOM * 2 / PI);
-// printf("[%d] atan(%g) = %g %d\n", i, arg, v, iv);
- printf("%d, ", iv);
- gSweepTable[i] = iv;
- }
- gSweepTableReady = true;
- }
- return gSweepTable;
-}
-#else
-static const uint8_t gSweepTable[] = {
- 0, 1, 1, 2, 3, 3, 4, 4, 5, 6, 6, 7, 8, 8, 9, 9,
- 10, 11, 11, 12, 12, 13, 13, 14, 15, 15, 16, 16, 17, 17, 18, 18,
- 19, 19, 20, 20, 21, 21, 22, 22, 23, 23, 24, 24, 25, 25, 25, 26,
- 26, 27, 27, 27, 28, 28, 29, 29, 29, 30, 30, 30, 31, 31, 31, 32,
- 32
-};
-static const uint8_t* build_sweep_table() { return gSweepTable; }
-#endif
-#endif
-
-// divide numer/denom, with a bias of 6bits. Assumes numer <= denom
-// and denom != 0. Since our table is 6bits big (+1), this is a nice fit.
-// Same as (but faster than) SkFixedDiv(numer, denom) >> 10
-
-//unsigned div_64(int numer, int denom);
-#ifndef SK_SCALAR_IS_FLOAT
-static unsigned div_64(int numer, int denom) {
- SkASSERT(numer <= denom);
- SkASSERT(numer > 0);
- SkASSERT(denom > 0);
-
- int nbits = SkCLZ(numer);
- int dbits = SkCLZ(denom);
- int bits = 6 - nbits + dbits;
- SkASSERT(bits <= 6);
-
- if (bits < 0) { // detect underflow
- return 0;
- }
-
- denom <<= dbits - 1;
- numer <<= nbits - 1;
-
- unsigned result = 0;
-
- // do the first one
- if ((numer -= denom) >= 0) {
- result = 1;
- } else {
- numer += denom;
- }
-
- // Now fall into our switch statement if there are more bits to compute
- if (bits > 0) {
- // make room for the rest of the answer bits
- result <<= bits;
- switch (bits) {
- case 6:
- if ((numer = (numer << 1) - denom) >= 0)
- result |= 32;
- else
- numer += denom;
- case 5:
- if ((numer = (numer << 1) - denom) >= 0)
- result |= 16;
- else
- numer += denom;
- case 4:
- if ((numer = (numer << 1) - denom) >= 0)
- result |= 8;
- else
- numer += denom;
- case 3:
- if ((numer = (numer << 1) - denom) >= 0)
- result |= 4;
- else
- numer += denom;
- case 2:
- if ((numer = (numer << 1) - denom) >= 0)
- result |= 2;
- else
- numer += denom;
- case 1:
- default: // not strictly need, but makes GCC make better ARM code
- if ((numer = (numer << 1) - denom) >= 0)
- result |= 1;
- else
- numer += denom;
- }
- }
- return result;
-}
-#endif
-
-// Given x,y in the first quadrant, return 0..63 for the angle [0..90]
-#ifndef SK_SCALAR_IS_FLOAT
-static unsigned atan_0_90(SkFixed y, SkFixed x) {
-#ifdef SK_DEBUG
- {
- static bool gOnce;
- if (!gOnce) {
- gOnce = true;
- SkASSERT(div_64(55, 55) == 64);
- SkASSERT(div_64(128, 256) == 32);
- SkASSERT(div_64(2326528, 4685824) == 31);
- SkASSERT(div_64(753664, 5210112) == 9);
- SkASSERT(div_64(229376, 4882432) == 3);
- SkASSERT(div_64(2, 64) == 2);
- SkASSERT(div_64(1, 64) == 1);
- // test that we handle underflow correctly
- SkASSERT(div_64(12345, 0x54321234) == 0);
- }
- }
-#endif
-
- SkASSERT(y > 0 && x > 0);
- const uint8_t* table = build_sweep_table();
-
- unsigned result;
- bool swap = (x < y);
- if (swap) {
- // first part of the atan(v) = PI/2 - atan(1/v) identity
- // since our div_64 and table want v <= 1, where v = y/x
- SkTSwap<SkFixed>(x, y);
- }
-
- result = div_64(y, x);
-
-#ifdef SK_DEBUG
- {
- unsigned result2 = SkDivBits(y, x, 6);
- SkASSERT(result2 == result ||
- (result == 1 && result2 == 0));
- }
-#endif
-
- SkASSERT(result < SK_ARRAY_COUNT(gSweepTable));
- result = table[result];
-
- if (swap) {
- // complete the atan(v) = PI/2 - atan(1/v) identity
- result = 64 - result;
- // pin to 63
- result -= result >> 6;
- }
-
- SkASSERT(result <= 63);
- return result;
-}
-#endif
-
// returns angle in a circle [0..2PI) -> [0..255]
-#ifdef SK_SCALAR_IS_FLOAT
static unsigned SkATan2_255(float y, float x) {
// static const float g255Over2PI = 255 / (2 * SK_ScalarPI);
static const float g255Over2PI = 40.584510488433314f;
@@ -239,62 +68,6 @@ static unsigned SkATan2_255(float y, float x) {
SkASSERT(ir >= 0 && ir <= 255);
return ir;
}
-#else
-static unsigned SkATan2_255(SkFixed y, SkFixed x) {
- if (x == 0) {
- if (y == 0) {
- return 0;
- }
- return y < 0 ? 192 : 64;
- }
- if (y == 0) {
- return x < 0 ? 128 : 0;
- }
-
- /* Find the right quadrant for x,y
- Since atan_0_90 only handles the first quadrant, we rotate x,y
- appropriately before calling it, and then add the right amount
- to account for the real quadrant.
- quadrant 0 : add 0 | x > 0 && y > 0
- quadrant 1 : add 64 (90 degrees) | x < 0 && y > 0
- quadrant 2 : add 128 (180 degrees) | x < 0 && y < 0
- quadrant 3 : add 192 (270 degrees) | x > 0 && y < 0
-
- map x<0 to (1 << 6)
- map y<0 to (3 << 6)
- add = map_x ^ map_y
- */
- int xsign = x >> 31;
- int ysign = y >> 31;
- int add = ((-xsign) ^ (ysign & 3)) << 6;
-
-#ifdef SK_DEBUG
- if (0 == add)
- SkASSERT(x > 0 && y > 0);
- else if (64 == add)
- SkASSERT(x < 0 && y > 0);
- else if (128 == add)
- SkASSERT(x < 0 && y < 0);
- else if (192 == add)
- SkASSERT(x > 0 && y < 0);
- else
- SkDEBUGFAIL("bad value for add");
-#endif
-
- /* This ^ trick makes x, y positive, and the swap<> handles quadrants
- where we need to rotate x,y by 90 or -90
- */
- x = (x ^ xsign) - xsign;
- y = (y ^ ysign) - ysign;
- if (add & 64) { // quads 1 or 3 need to swap x,y
- SkTSwap<SkFixed>(x, y);
- }
-
- unsigned result = add + atan_0_90(y, x);
- SkASSERT(result < 256);
- return result;
-}
-#endif
void SkSweepGradient::shadeSpan(int x, int y, SkPMColor* SK_RESTRICT dstC,
int count) {

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