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author | Alon Zakai <alonzakai@gmail.com> | 2013-04-10 15:53:50 -0700 |
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committer | Alon Zakai <alonzakai@gmail.com> | 2013-04-10 15:53:50 -0700 |
commit | f84537c333524d0841923eaec66604584bf77326 (patch) | |
tree | 6a43fab885a397a80de2cd8117b6ebafdb00cdf5 /tests/box2d/Benchmark.cpp | |
parent | a4a20535e79f10c553b685b188fcfd6af12fac07 (diff) |
more work towards box2d benchmark
Diffstat (limited to 'tests/box2d/Benchmark.cpp')
-rw-r--r-- | tests/box2d/Benchmark.cpp | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/tests/box2d/Benchmark.cpp b/tests/box2d/Benchmark.cpp new file mode 100644 index 00000000..914c13a0 --- /dev/null +++ b/tests/box2d/Benchmark.cpp @@ -0,0 +1,122 @@ + + +// +// Based on joelgwebber's Box2D benchmarks, +// https://github.com/joelgwebber/bench2d/blob/master/c/Bench2d.cpp +// + + +// Settings ===================== +// Turn this on to include the y-position of the top box in the output. +#define DEBUG 0 + +#define WARMUP 64 +#define FRAMES 256 + +typedef struct { + float mean; + float stddev; +} result_t; +// ============================== + + + +#include <cstdio> +#include <time.h> +#include <math.h> + +#include "Box2D/Box2D.h" +#include "Bench2d.h" + +using namespace std; + +const int e_count = 40; + +result_t measure(clock_t times[FRAMES]) { + float values[FRAMES]; + result_t r; + + float total = 0; + for (int i = 0; i < FRAMES; ++i) { + values[i] = (float)times[i] / CLOCKS_PER_SEC * 1000; + total += values[i]; + } + r.mean = total / FRAMES; + + float variance = 0; + for (int i = 0; i < FRAMES; ++i) { + float diff = values[i] - r.mean; + variance += diff * diff; + } + r.stddev = sqrt(variance / FRAMES); + + return r; +} + +result_t bench() { + // Define the gravity vector. + b2Vec2 gravity(0.0f, -10.0f); + + // Construct a world object, which will hold and simulate the rigid bodies. + b2World world(gravity); + world.SetAllowSleeping(false); + + { + b2BodyDef bd; + b2Body* ground = world.CreateBody(&bd); + + b2EdgeShape shape; + shape.Set(b2Vec2(-40.0f, 0.0f), b2Vec2(40.0f, 0.0f)); + ground->CreateFixture(&shape, 0.0f); + } + + b2Body* topBody; + + { + float32 a = 0.5f; + b2PolygonShape shape; + shape.SetAsBox(a, a); + + b2Vec2 x(-7.0f, 0.75f); + b2Vec2 y; + b2Vec2 deltaX(0.5625f, 1); + b2Vec2 deltaY(1.125f, 0.0f); + + for (int32 i = 0; i < e_count; ++i) { + y = x; + + for (int32 j = i; j < e_count; ++j) { + b2BodyDef bd; + bd.type = b2_dynamicBody; + bd.position = y; + b2Body* body = world.CreateBody(&bd); + body->CreateFixture(&shape, 5.0f); + + topBody = body; + + y += deltaY; + } + + x += deltaX; + } + } + + for (int32 i = 0; i < WARMUP; ++i) { + world.Step(1.0f/60.0f, 3, 3); + } + + clock_t times[FRAMES]; + for (int32 i = 0; i < FRAMES; ++i) { + clock_t start = clock(); + world.Step(1.0f/60.0f, 3, 3); + clock_t end = clock(); + times[i] = end - start; +#if DEBUG + printf("%f :: ", topBody->GetPosition().y); + printf("%f\n", (float32)(end - start) / CLOCKS_PER_SEC * 1000); +#endif + } + + return measure(times); +} + |