+++ /dev/null
-#include "geometry.hpp"
-
-#include <limits>
-#include <glm/gtx/matrix_cross_product.hpp>
-#include <glm/gtx/optimum_pow.hpp>
-#include <glm/gtx/transform.hpp>
-
-
-namespace blank {
-
-glm::mat3 find_rotation(const glm::vec3 &a, const glm::vec3 &b) noexcept {
- glm::vec3 v(cross(a, b));
- if (iszero(v)) {
- // a and b are parallel
- if (iszero(a - b)) {
- // a and b are identical
- return glm::mat3(1.0f);
- } else {
- // a and b are opposite
- // create arbitrary unit vector perpendicular to a and
- // rotate 180° around it
- glm::vec3 arb(a);
- if (std::abs(a.x - 1.0f) > std::numeric_limits<float>::epsilon()) {
- arb.x += 1.0f;
- } else {
- arb.y += 1.0f;
- }
- glm::vec3 axis(normalize(cross(a, arb)));
- return glm::mat3(glm::rotate(PI, axis));
- }
- }
- float mv = length_squared(v);
- float c = dot(a, b);
- float f = (1 - c) / mv;
- glm::mat3 vx(matrixCross3(v));
- return glm::mat3(1.0f) + vx + (pow2(vx) * f);
-}
-
-bool Intersection(
- const Ray &ray,
- const AABB &aabb,
- const glm::mat4 &M,
- float *dist,
- glm::vec3 *normal
-) noexcept {
- float t_min = 0.0f;
- float t_max = std::numeric_limits<float>::infinity();
- const glm::vec3 aabb_pos(M[3].x, M[3].y, M[3].z);
- const glm::vec3 delta = aabb_pos - ray.orig;
-
- glm::vec3 t1(t_min, t_min, t_min), t2(t_max, t_max, t_max);
-
- for (int i = 0; i < 3; ++i) {
- const glm::vec3 axis(M[i].x, M[i].y, M[i].z);
- const float e = glm::dot(axis, delta);
- const float f = glm::dot(axis, ray.dir);
-
- if (std::abs(f) > std::numeric_limits<float>::epsilon()) {
- t1[i] = (e + aabb.min[i]) / f;
- t2[i] = (e + aabb.max[i]) / f;
-
- t_min = std::max(t_min, std::min(t1[i], t2[i]));
- t_max = std::min(t_max, std::max(t1[i], t2[i]));
-
- if (t_max < t_min) {
- return false;
- }
- } else {
- if (aabb.min[i] - e > 0.0f || aabb.max[i] - e < 0.0f) {
- return false;
- }
- }
- }
-
- glm::vec3 min_all(min(t1, t2));
-
- if (dist) {
- *dist = t_min;
- }
- if (normal) {
- if (min_all.x > min_all.y) {
- if (min_all.x > min_all.z) {
- normal->x = t2.x < t1.x ? 1 : -1;
- } else {
- normal->z = t2.z < t1.z ? 1 : -1;
- }
- } else if (min_all.y > min_all.z) {
- normal->y = t2.y < t1.y ? 1 : -1;
- } else {
- normal->z = t2.z < t1.z ? 1 : -1;
- }
- }
- return true;
-}
-
-
-bool Intersection(
- const AABB &a_box,
- const glm::mat4 &a_m,
- const AABB &b_box,
- const glm::mat4 &b_m,
- float &depth,
- glm::vec3 &normal
-) noexcept {
- glm::vec3 a_corners[8] = {
- glm::vec3(a_m * glm::vec4(a_box.min.x, a_box.min.y, a_box.min.z, 1)),
- glm::vec3(a_m * glm::vec4(a_box.min.x, a_box.min.y, a_box.max.z, 1)),
- glm::vec3(a_m * glm::vec4(a_box.min.x, a_box.max.y, a_box.min.z, 1)),
- glm::vec3(a_m * glm::vec4(a_box.min.x, a_box.max.y, a_box.max.z, 1)),
- glm::vec3(a_m * glm::vec4(a_box.max.x, a_box.min.y, a_box.min.z, 1)),
- glm::vec3(a_m * glm::vec4(a_box.max.x, a_box.min.y, a_box.max.z, 1)),
- glm::vec3(a_m * glm::vec4(a_box.max.x, a_box.max.y, a_box.min.z, 1)),
- glm::vec3(a_m * glm::vec4(a_box.max.x, a_box.max.y, a_box.max.z, 1)),
- };
-
- glm::vec3 b_corners[8] = {
- glm::vec3(b_m * glm::vec4(b_box.min.x, b_box.min.y, b_box.min.z, 1)),
- glm::vec3(b_m * glm::vec4(b_box.min.x, b_box.min.y, b_box.max.z, 1)),
- glm::vec3(b_m * glm::vec4(b_box.min.x, b_box.max.y, b_box.min.z, 1)),
- glm::vec3(b_m * glm::vec4(b_box.min.x, b_box.max.y, b_box.max.z, 1)),
- glm::vec3(b_m * glm::vec4(b_box.max.x, b_box.min.y, b_box.min.z, 1)),
- glm::vec3(b_m * glm::vec4(b_box.max.x, b_box.min.y, b_box.max.z, 1)),
- glm::vec3(b_m * glm::vec4(b_box.max.x, b_box.max.y, b_box.min.z, 1)),
- glm::vec3(b_m * glm::vec4(b_box.max.x, b_box.max.y, b_box.max.z, 1)),
- };
-
- glm::vec3 axes[6] = {
- glm::vec3(a_m * glm::vec4(1, 0, 0, 0)),
- glm::vec3(a_m * glm::vec4(0, 1, 0, 0)),
- glm::vec3(a_m * glm::vec4(0, 0, 1, 0)),
- glm::vec3(b_m * glm::vec4(1, 0, 0, 0)),
- glm::vec3(b_m * glm::vec4(0, 1, 0, 0)),
- glm::vec3(b_m * glm::vec4(0, 0, 1, 0)),
- };
-
- depth = std::numeric_limits<float>::infinity();
- int min_axis = 0;
-
- int cur_axis = 0;
- for (const glm::vec3 &axis : axes) {
- float a_min = std::numeric_limits<float>::infinity();
- float a_max = -std::numeric_limits<float>::infinity();
- for (const glm::vec3 &corner : a_corners) {
- float val = glm::dot(corner, axis);
- a_min = std::min(a_min, val);
- a_max = std::max(a_max, val);
- }
-
- float b_min = std::numeric_limits<float>::infinity();
- float b_max = -std::numeric_limits<float>::infinity();
- for (const glm::vec3 &corner : b_corners) {
- float val = glm::dot(corner, axis);
- b_min = std::min(b_min, val);
- b_max = std::max(b_max, val);
- }
-
- if (a_max < b_min || b_max < a_min) return false;
-
- float overlap = std::min(a_max, b_max) - std::max(a_min, b_min);
- if (overlap < depth) {
- depth = overlap;
- min_axis = cur_axis;
- }
-
- ++cur_axis;
- }
-
- normal = axes[min_axis];
- return true;
-}
-
-
-bool CullTest(const AABB &box, const glm::mat4 &MVP) noexcept {
- // transform corners into clip space
- glm::vec4 corners[8] = {
- { box.min.x, box.min.y, box.min.z, 1.0f },
- { box.min.x, box.min.y, box.max.z, 1.0f },
- { box.min.x, box.max.y, box.min.z, 1.0f },
- { box.min.x, box.max.y, box.max.z, 1.0f },
- { box.max.x, box.min.y, box.min.z, 1.0f },
- { box.max.x, box.min.y, box.max.z, 1.0f },
- { box.max.x, box.max.y, box.min.z, 1.0f },
- { box.max.x, box.max.y, box.max.z, 1.0f },
- };
- for (glm::vec4 &corner : corners) {
- corner = MVP * corner;
- corner /= corner.w;
- }
-
- int hits[6] = { 0, 0, 0, 0, 0, 0 };
-
- // check how many corners lie outside
- for (const glm::vec4 &corner : corners) {
- if (corner.x > 1.0f) ++hits[0];
- if (corner.x < -1.0f) ++hits[1];
- if (corner.y > 1.0f) ++hits[2];
- if (corner.y < -1.0f) ++hits[3];
- if (corner.z > 1.0f) ++hits[4];
- if (corner.z < -1.0f) ++hits[5];
- }
-
- // if all corners are outside any given clip plane, the test is true
- for (int hit : hits) {
- if (hit == 8) return true;
- }
-
- // otherwise the box might still get culled completely, but can't say for sure ;)
- return false;
-}
-
-}
projects / blank.git / blobdiff