This repository has been archived on 2022-05-21. You can view files and clone it, but cannot push or open issues or pull requests.
LEFTONE/util/coly2d/hittest.c

172 lines
4.4 KiB
C
Raw Normal View History

#include "./hittest.h"
#include <assert.h>
#include <stdbool.h>
#include "util/math/algorithm.h"
#include "util/math/vector.h"
bool coly2d_hittest_point_and_rect(
const vec2_t* pos1, const vec2_t* pos2, const vec2_t* size2) {
assert(vec2_valid(pos1));
assert(vec2_valid(pos2));
assert(vec2_valid(size2));
vec2_t rpos;
vec2_sub(&rpos, pos2, pos1);
return
MATH_ABS(rpos.x) < size2->x &&
MATH_ABS(rpos.y) < size2->y;
}
bool coly2d_hittest_point_and_triangle(
const vec2_t* pos1,
const vec2_t* pos2_a,
const vec2_t* pos2_b,
const vec2_t* pos2_c) {
assert(vec2_valid(pos1));
assert(vec2_valid(pos2_a));
assert(vec2_valid(pos2_b));
assert(vec2_valid(pos2_c));
vec2_t v1, v2;
vec2_sub(&v1, pos1, pos2_a);
vec2_sub(&v2, pos2_b, pos2_a);
float a = vec2_cross(&v1, &v2);
vec2_sub(&v1, pos1, pos2_b);
vec2_sub(&v2, pos2_c, pos2_b);
if (a * vec2_cross(&v1, &v2) <= 0) return false;
vec2_sub(&v1, pos1, pos2_c);
vec2_sub(&v2, pos2_a, pos2_c);
return a*vec2_cross(&v1, &v2) > 0;
}
bool coly2d_hittest_lineseg_and_lineseg(
const vec2_t* pos1_st,
const vec2_t* pos1_ed,
const vec2_t* pos2_st,
const vec2_t* pos2_ed) {
assert(vec2_valid(pos1_st));
assert(vec2_valid(pos1_ed));
assert(vec2_valid(pos2_st));
assert(vec2_valid(pos2_ed));
vec2_t x;
vec2_sub(&x, pos1_ed, pos1_st);
vec2_t a;
vec2_sub(&a, pos2_st, pos1_st);
vec2_t b;
vec2_sub(&b, pos2_ed, pos1_st);
vec2_t y;
vec2_sub(&y, pos2_ed, pos2_st);
vec2_t c;
vec2_sub(&c, pos1_st, pos2_st);
vec2_t d;
vec2_sub(&d, pos1_ed, pos2_st);
return
vec2_cross(&x, &a) * vec2_cross(&x, &b) < 0 &&
vec2_cross(&y, &c) * vec2_cross(&y, &d) < 0;
}
bool coly2d_hittest_lineseg_and_rect(
const vec2_t* pos1_st,
const vec2_t* pos1_ed,
const vec2_t* pos2,
const vec2_t* size2) {
assert(vec2_valid(pos1_st));
assert(vec2_valid(pos1_ed));
assert(vec2_valid(pos2));
assert(vec2_valid(size2));
if (coly2d_hittest_point_and_rect(pos1_st, pos2, size2) ||
coly2d_hittest_point_and_rect(pos1_ed, pos2, size2)) {
return true;
}
const float left = pos2->x - size2->x;
const float right = pos2->x + size2->x;
const float top = pos2->y + size2->y;
const float bottom = pos2->y - size2->y;
const vec2_t v1 = vec2(left, top);
const vec2_t v2 = vec2(left, bottom);
const vec2_t v3 = vec2(right, bottom);
const vec2_t v4 = vec2(right, top);
return
coly2d_hittest_lineseg_and_lineseg(pos1_st, pos1_ed, &v1, &v2) ||
coly2d_hittest_lineseg_and_lineseg(pos1_st, pos1_ed, &v2, &v3) ||
coly2d_hittest_lineseg_and_lineseg(pos1_st, pos1_ed, &v3, &v4) ||
coly2d_hittest_lineseg_and_lineseg(pos1_st, pos1_ed, &v4, &v1);
}
bool coly2d_hittest_lineseg_and_ellipse(
const vec2_t* pos1_st,
const vec2_t* pos1_ed,
const vec2_t* pos2,
const vec2_t* size2) {
assert(vec2_valid(pos1_st));
assert(vec2_valid(pos1_ed));
assert(vec2_valid(pos2));
assert(vec2_valid(size2));
vec2_t p2 = *pos2;
p2.x /= size2->x;
p2.y /= size2->y;
vec2_t p1st = *pos1_st;
p1st.x /= size2->x;
p1st.y /= size2->y;
vec2_t c1;
vec2_sub(&c1, &p2, &p1st);
if (vec2_pow_length(&c1) < 1) return true;
vec2_t p1ed = *pos1_ed;
p1ed.x /= size2->x;
p1ed.y /= size2->y;
vec2_t c2;
vec2_sub(&c2, &p2, &p1ed);
if (vec2_pow_length(&c2) < 1) return true;
vec2_t ed;
vec2_sub(&ed, &p1ed, &p1st);
const float cross = vec2_cross(&ed, &c1);
if (MATH_ABS(cross) >= vec2_length(&ed)) return false;
vec2_t st;
vec2_sub(&st, &p1st, &p1ed);
return vec2_dot(&c1, &ed)*vec2_dot(&c2, &st) >= 0;
}
bool coly2d_hittest_lineseg_and_triangle(
const vec2_t* pos1_st,
const vec2_t* pos1_ed,
const vec2_t* pos2_a,
const vec2_t* pos2_b,
const vec2_t* pos2_c) {
assert(vec2_valid(pos1_st));
assert(vec2_valid(pos1_ed));
assert(vec2_valid(pos2_a));
assert(vec2_valid(pos2_b));
assert(vec2_valid(pos2_c));
/* TODO(catfoot): Tomas Moller's algorithm may make this function faster. */
if (coly2d_hittest_lineseg_and_lineseg(pos1_st, pos1_ed, pos2_a, pos2_b) ||
coly2d_hittest_lineseg_and_lineseg(pos1_st, pos1_ed, pos2_b, pos2_c) ||
coly2d_hittest_lineseg_and_lineseg(pos1_st, pos1_ed, pos2_c, pos2_a)) {
return true;
}
return
coly2d_hittest_point_and_triangle(pos1_st, pos2_a, pos2_b, pos2_c) ||
coly2d_hittest_point_and_triangle(pos1_ed, pos2_a, pos2_b, pos2_c);
}