tiny_bvh_minimal.cpp

// Minimal example for tiny_bvh.h

#define TINYBVH_IMPLEMENTATION
#include "tiny_bvh.h"
#ifdef _MSC_VER
#include "stdlib.h"		// for rand
#include "stdio.h"		// for printf
#else
#include <cstdlib>
#include <cstdio>
#endif

#define TRIANGLE_COUNT	8192

tinybvh::bvhvec4 triangles[TRIANGLE_COUNT * 3]; // must be 16 byte!

float uniform_rand() { return (float)rand() / (float)RAND_MAX; }

int main()
{
	// create a scene consisting of some random small triangles
	for (int i = 0; i < TRIANGLE_COUNT; i++)
	{
		// create a random triangle
		tinybvh::bvhvec4& v0 = triangles[i * 3 + 0];
		tinybvh::bvhvec4& v1 = triangles[i * 3 + 1];
		tinybvh::bvhvec4& v2 = triangles[i * 3 + 2];
		// triangle position, x/y/z = 0..1
		float x = uniform_rand();
		float y = uniform_rand();
		float z = uniform_rand();
		// set first vertex
		v0.x = x + 0.1f * uniform_rand();
		v0.y = y + 0.1f * uniform_rand();
		v0.z = z + 0.1f * uniform_rand();
		// set second vertex
		v1.x = x + 0.1f * uniform_rand();
		v1.y = y + 0.1f * uniform_rand();
		v1.z = z + 0.1f * uniform_rand();
		// set third vertex
		v2.x = x + 0.1f * uniform_rand();
		v2.y = y + 0.1f * uniform_rand();
		v2.z = z + 0.1f * uniform_rand();
	}

	tinybvh::bvhvec3 O( 0.5f, 0.5f, -1 );
	tinybvh::bvhvec3 D( 0.1f, 0, 2 );
	tinybvh::Ray ray( O, D );

	// build a BVH over the scene
	{
		tinybvh::BVH bvh;
		bvh.Build( triangles, TRIANGLE_COUNT );
		// bvh.Convert( tinybvh::BVH::WALD_32BYTE, tinybvh::BVH::VERBOSE );
		// bvh.Refit( tinybvh::BVH::VERBOSE );

		// from here: play with the BVH!
		int steps = bvh.Intersect( ray );
		printf( "std: nearest intersection: %f (found in %i traversal steps).\n", ray.hit.t, steps );
	}

#if defined(BVH_USEAVX)
	// same thing, using the AVX builder.
	{
		tinybvh::BVH bvh;
		bvh.BuildAVX( triangles, TRIANGLE_COUNT );

		int steps = bvh.Intersect( ray );
		printf( "avx: nearest intersection: %f (found in %i traversal steps).\n", ray.hit.t, steps );
	}
#endif

	// all done.
	return 0;
}