tiny_bvh_minimal.cpp - main - redgpu/tinybvh

tiny_bvh_minimal.cpp
61 строка2 KB
jbikker
Updated minimal example.
22 май 2025, 10:55
22 май 2025, 10:553f709bb
// Minimal example for TinyBVH.
// The code in main generates a collection of random triangles.
// All triangles are specified as 3 vertices; each vertex is a 'vec4'. 
// A Ray is constructed using an origin and direction.
// A BVH is instantiated and constructed using BVH::Build( .. ). 
// A ray is traced using BVH::Intersect( .. ).
// The intersection result is obtained from the ray.hit record.

#define TINYBVH_IMPLEMENTATION
#include "tiny_bvh.h"
#include <cstdlib>
#include <cstdio>

#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 );

	// 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 );

	// all done.
	return 0;
}