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shape.cpp
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shape.cpp
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#include "shape.hpp"
#include "debug.hpp"
#include "pupumath.hpp"
#include "ray.hpp"
#include "ValueBlock.hpp"
#include <vector>
using namespace pupumath;
class Sphere : public Shape {
public:
bool intersect(Ray& ray, bool is_originator, bool inside_originator) const
{
float a = dot(ray.direction, ray.direction);
float b = 2 * dot(ray.origin, ray.direction);
float c = dot(ray.origin, ray.origin) - 1.0;
float d = b * b - 4 * a * c;
if (d < 0) {
return false;
}
// float t1 = (-b - sqrtf(d)) / (2.0 * a);
// float t2 = (-b + sqrtf(d)) / (2.0 * a);
float t1 = (b + sqrtf(d)) / (-2.0 * a);
float t2 = (b - sqrtf(d)) / (-2.0 * a);
float t;
if (is_originator) {
t = inside_originator ? t2 : t1;
}
else {
t = (t1 < 0.0f) ? t2 : t1;
}
// float t = t1;
// if (t > ray.tmax) return false;
// if (t < 0.0f) t = t2;
if (t < 0.0f) return false;
if (t > ray.tmax) return false;
ray.tmax = t;
ray.position = ray.origin + ray.direction * t;
ray.normal = normalize(ray.position);
return true;
}
};
class ScaledSphere : public Shape {
public:
ScaledSphere(float r) : radius(r) {}
float radius;
bool intersect(Ray& ray, bool is_originator, bool inside_originator) const
{
float a = dot(ray.direction, ray.direction);
float b = 2 * dot(ray.origin, ray.direction);
float c = dot(ray.origin, ray.origin) - radius * radius;
float d = b * b - 4 * a * c;
if (d < 0) {
return false;
}
// float t1 = (-b - sqrtf(d)) / (2.0 * a);
// float t2 = (-b + sqrtf(d)) / (2.0 * a);
float t1 = (b + sqrtf(d)) / (-2.0 * a);
float t2 = (b - sqrtf(d)) / (-2.0 * a);
float t;
if (is_originator) {
t = inside_originator ? t2 : t1;
}
else {
t = (t1 < 0.0f) ? t2 : t1;
}
// float t = t1;
// if (t > ray.tmax) return false;
// if (t < 0.0f) t = t2;
if (t < 0.0f) return false;
if (t > ray.tmax) return false;
ray.tmax = t;
ray.position = ray.origin + ray.direction * t;
ray.normal = normalize(ray.position);
return true;
}
};
class Plane : public Shape {
public:
bool intersect(Ray& ray, bool is_originator, bool inside_originator) const
{
if (ray.direction.y == 0) return false;
if (is_originator) {
if (inside_originator && ray.direction.y < 0) return false;
if (!inside_originator && ray.direction.y > 0) return false;
}
float t = -ray.origin.y / ray.direction.y;
if (t < 0.0f) return false;
if (t > ray.tmax) return false;
ray.tmax = t;
ray.position = ray.origin + ray.direction * t;
ray.normal = vec3(0, 1, 0);
return true;
}
};
class QuadMesh : public Shape {
public:
QuadMesh(std::vector<vec3> v, std::vector<int> f) : vertdata(v), facedata(f)
{
}
std::vector<vec3> vertdata;
std::vector<int> facedata;
bool intersect(Ray& ray, bool is_originator, bool inside_originator) const
{
// An Efficient Ray-Quadrilateral Intersection Test
// Area Lagae, Philip Dutré
float tmax = ray.tmax;
bool hit = false;
vec3 n;
for (size_t i = 0; i < facedata.size() / 4; ++i) {
vec3 v0 = vertdata[facedata[i * 4 + 0]];
vec3 v1 = vertdata[facedata[i * 4 + 1]];
vec3 v2 = vertdata[facedata[i * 4 + 2]];
vec3 v3 = vertdata[facedata[i * 4 + 3]];
// Reject rays using the barycentric coordinates of
// the intersection point with respect to T.
vec3 e01 = v1 - v0;
vec3 e03 = v3 - v0;
vec3 p = cross(ray.direction, e03);
float det = dot(e01, p);
if (fabs(det) == 0) continue;
vec3 T = ray.origin - v0;
float a = dot(T, p) / det;
if (a < 0 || a > 1) continue;
vec3 q = cross(T, e01);
float b = dot(ray.direction, q) / det;
if (b < 0 || b > 1) continue;
// Reject rays using the barycentric coordinates of
// the intersection point with respect to T'.
if ((a + b) > 1) {
vec3 e23 = v3 - v2;
vec3 e21 = v1 - v2;
vec3 p = cross(ray.direction, e21);
float det = dot(e23, p);
if (fabs(det) == 0) continue;
vec3 T = ray.origin - v2;
float a = dot(T, p) / det;
if (a < 0 || a > 1) continue;
vec3 q = cross(T, e23);
float b = dot(ray.direction, q) / det;
if (b < 0 || b > 1) continue;
}
// Compute the ray parameter of the intersection point.
float t = dot(e03, q) / det;
if (t < 0.0f) continue;
if (t > tmax) continue;
n = cross(e01, e03);
if (is_originator) {
bool inbound = (dot(ray.direction, n) < 0);
if (inside_originator && inbound) continue;
if (!inside_originator && !inbound) continue;
}
tmax = t;
hit = true;
}
if (!hit) return false;
ray.tmax = tmax;
ray.position = ray.origin + ray.direction * tmax;
ray.normal = normalize(n);
return true;
}
};
std::shared_ptr<Shape> build_shape(const ValueBlock& block)
{
auto type = block.get<std::string>("type");
if (type == "sphere") {
return std::make_shared<Sphere>();
}
else if (type == "plane") {
return std::make_shared<Plane>();
}
else if (type == "quadmesh") {
return std::make_shared<QuadMesh>(block.get<std::vector<vec3>>("vertices"),
block.get<std::vector<int>>("faces"));
}
else {
throw std::runtime_error("unknown shape");
}
}