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multiple-cube collision demo

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This commit is contained in:
Zack Buhman 2026-03-14 13:41:51 -05:00
parent ce2260e078
commit 0044c3352f
2 changed files with 78 additions and 17 deletions
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12
include/collision.h
View File

@ -174,7 +174,7 @@ namespace collision {
return true;
}
static const float interval_epsilon = 0.02f;
static const float interval_epsilon = 0.01f;
static inline bool intersect_moving_sphere_aabb(Sphere const & sphere, XMVECTOR const & direction,
float t0, float t1, AABB const & aabb,
@ -197,4 +197,14 @@ namespace collision {
return intersect_moving_sphere_aabb(sphere, direction, mid, t1, aabb, t, point);
}
static inline AABB moving_sphere_aabb(Sphere const & sphere, XMVECTOR const & direction)
{
XMVECTOR min = sphere.center + XMVectorReplicate(-sphere.radius);
XMVECTOR max = sphere.center + XMVectorReplicate( sphere.radius);
min = XMVectorMin(min, min + direction);
max = XMVectorMax(max, max + direction);
return AABB(min, max);
}
}

83
src/collision_scene.cpp
View File

@ -265,6 +265,38 @@ namespace collision_scene {
glDrawElementsBaseVertex(GL_LINE_STRIP, 5, GL_UNSIGNED_SHORT, (void*)(cube_base_index), cube_base_vertex);
}
static const XMVECTOR cubes[] = {
XMVectorSet(1, 1, 0, 1),
XMVectorSet(-1, 1, 0, 1),
XMVectorSet(-2, 1, 0, 1),
XMVectorSet(-2, -2, 0, 1),
XMVectorSet(-2, -3, 0, 1),
};
static const int cubes_length = (sizeof (cubes)) / (sizeof (cubes[0]));
static XMVECTOR min_intersection_point;
static XMVECTOR min_intersection_position;
static float min_t;
static bool min_intersected;
void check_collision(collision::Sphere const & sphere, XMVECTOR const & direction,
XMVECTOR const & cube_center)
{
collision::AABB aabb = collision::cube_aabb(cube_center, 0.5);
float t;
XMVECTOR intersection_point;
bool intersected = collision::intersect_moving_sphere_aabb(sphere, direction,
0, 1, aabb,
t, intersection_point);
XMVECTOR intersection_position = sphere.center + direction * t;
if (intersected && t < min_t) {
min_t = t;
min_intersected = true;
min_intersection_point = intersection_point;
min_intersection_position = intersection_position;
}
}
void draw()
{
glUseProgram(program);
@ -288,11 +320,32 @@ namespace collision_scene {
glUniform1i(location.uniform.use_grid_transform, 0);
collision::Sphere sphere(point_position[0], 0.5);
XMVECTOR direction = point_position[1] - point_position[0];
collision::AABB sphere_aabb = collision::moving_sphere_aabb(sphere, direction);
XMVECTOR min_floor = XMVectorFloor(sphere_aabb.min);
XMVECTOR max_ceiling = XMVectorCeiling(sphere_aabb.max);
//////////////////////////////////////////////////////////////////////
// reset intersections
//////////////////////////////////////////////////////////////////////
min_t = FLT_MAX;
min_intersected = false;
glLineWidth(3.0f);
glUniform3f(location.uniform.base_color, 0.5, 1.0, 0.0);
XMVECTOR cube_center = XMVectorSet(1, 1, 0, 1);
draw_cube(transform, cube_center);
for (int i = 0; i < cubes_length; i++) {
XMVECTOR center = cubes[i];
XMVECTOR le = XMVectorLessOrEqual(min_floor, center);
XMVECTOR ge = XMVectorGreaterOrEqual(max_ceiling, center);
if (XMVectorGetX(le) == 0 || XMVectorGetY(le) == 0 || XMVectorGetZ(le) == 0 ||
XMVectorGetX(ge) == 0 || XMVectorGetY(ge) == 0 || XMVectorGetZ(ge) == 0) {
glUniform3f(location.uniform.base_color, 0.5, 1.0, 0.0);
} else {
check_collision(sphere, direction, center);
glUniform3f(location.uniform.base_color, 0.5, 0.5, 0.5);
}
draw_cube(transform, center);
}
glUniform3f(location.uniform.base_color, 0, 0.0, 1.0);
draw_sphere(transform, point_position[0], 0.5);
@ -300,23 +353,21 @@ namespace collision_scene {
draw_sphere(transform, point_position[1], point_radius);
draw_line(transform, point_position[0], point_position[1]);
collision::Sphere sphere(point_position[0], 0.5);
XMVECTOR direction = point_position[1] - point_position[0];
collision::AABB aabb = collision::cube_aabb(cube_center, 0.5);
float t;
XMVECTOR intersection_point;
bool intersected = collision::intersect_moving_sphere_aabb(sphere, direction,
0, 1, aabb,
t, intersection_point);
if (intersected){
if (min_intersected){
glUniform3f(location.uniform.base_color, 1.0, 0.5, 0.0);
XMVECTOR intersection_position = point_position[0] + direction * t;
draw_sphere(transform, intersection_position, 0.5);
draw_sphere(transform, min_intersection_position, 0.5);
glUniform3f(location.uniform.base_color, 1.0, 0.0, 0.0);
draw_sphere(transform, intersection_point, point_radius);
draw_sphere(transform, min_intersection_point, point_radius);
}
XMVECTOR pa = XMVectorSelect(sphere_aabb.min, sphere_aabb.max, g_XMSelect1000);
XMVECTOR pb = XMVectorSelect(sphere_aabb.min, sphere_aabb.max, g_XMSelect0101);
draw_line(transform, sphere_aabb.min, pa);
draw_line(transform, pa, sphere_aabb.max);
draw_line(transform, sphere_aabb.max, pb);
draw_line(transform, pb, sphere_aabb.min);
//sphere_aabb.max,
/*
// segments
glUniform3f(location.uniform.base_color, 0, 0.5, 1.0);