| #include "Benchmark.h" |
| #include "SkPMFloat.h" |
| |
| // Used to prevent the compiler from optimizing away the whole loop. |
| volatile uint32_t blackhole = 0; |
| |
| // Not a great random number generator, but it's very fast. |
| // The code we're measuring is quite fast, so low overhead is essential. |
| static uint32_t lcg_rand(uint32_t* seed) { |
| *seed *= 1664525; |
| *seed += 1013904223; |
| return *seed; |
| } |
| |
| struct PMFloatBench : public Benchmark { |
| explicit PMFloatBench(bool clamp) : fClamp(clamp) {} |
| |
| const char* onGetName() SK_OVERRIDE { return fClamp ? "SkPMFloat_clamp" : "SkPMFloat_get"; } |
| bool isSuitableFor(Backend backend) SK_OVERRIDE { return backend == kNonRendering_Backend; } |
| |
| void onDraw(const int loops, SkCanvas* canvas) SK_OVERRIDE { |
| // Unlike blackhole, junk can and probably will be a register. |
| uint32_t junk = 0; |
| uint32_t seed = 0; |
| for (int i = 0; i < loops; i++) { |
| #ifdef SK_DEBUG |
| // Our SkASSERTs will remind us that it's technically required that we premultiply. |
| SkPMColor c = SkPreMultiplyColor(lcg_rand(&seed)); |
| #else |
| // But it's a lot faster not to, and this code won't really mind the non-PM colors. |
| SkPMColor c = lcg_rand(&seed); |
| #endif |
| SkPMFloat pmf; |
| pmf.set(c); |
| SkPMColor back = fClamp ? pmf.clamped() : pmf.get(); |
| junk ^= back; |
| } |
| blackhole ^= junk; |
| } |
| |
| bool fClamp; |
| }; |
| DEF_BENCH(return new PMFloatBench( true);) |
| DEF_BENCH(return new PMFloatBench(false);) |