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Manifold contact optimization

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This commit is contained in:
sergeypdev 2025-01-19 21:44:42 +04:00
parent 82470ca3c7
commit 0961b7551a
2 changed files with 82 additions and 18 deletions
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11
game/game.odin
View File

@ -495,12 +495,11 @@ draw :: proc() {
box1_mat := linalg.Matrix4f32(1)
box1_mat = linalg.matrix4_rotate(45 * math.RAD_PER_DEG, rl.Vector3{0, 1, 0}) * box1_mat
box2_mat := linalg.Matrix4f32(1)
box2_mat = linalg.matrix4_translate(rl.Vector3{0.5, 0.2, 0}) * box2_mat
// box2_mat = linalg.matrix4_rotate(45 * math.RAD_PER_DEG, rl.Vector3{0, 0, 1}) * box2_mat
box2_mat = linalg.matrix4_translate(rl.Vector3{0.0, 0.2, 0}) * box2_mat
box2_mat = linalg.matrix4_rotate(45 * math.RAD_PER_DEG, rl.Vector3{0, 0, 1}) * box2_mat
// box2_mat = linalg.matrix4_rotate(f32(rl.GetTime()), rl.Vector3{0, -1, 0}) * box2_mat
box2_mat = linalg.matrix4_translate(rl.Vector3{0.5, 0.5, 0}) * box2_mat
box2_mat = linalg.matrix4_rotate(f32(rl.GetTime()), rl.Vector3{0, 1, 0}) * box2_mat
box2_mat = linalg.matrix4_translate(rl.Vector3{0.0, 0, 0}) * box2_mat
box2_mat = linalg.matrix4_rotate(f32(rl.GetTime()) * 0.1, rl.Vector3{0, 1, 0}) * box2_mat
box1, box2 := collision.Box {
pos = 0,
@ -529,7 +528,7 @@ draw :: proc() {
// rlgl_transform_scope(auto_cast linalg.matrix4_from_quaternion(rot2))
// rl.DrawCubeWiresV(box2.pos, box2.rad * 2, rl.RED)
// }
for p in manifold.points {
for p in manifold.points[:manifold.points_len] {
rl.DrawSphereWires(p, 0.05, 8, 8, rl.BLUE)
}

87
game/physics/collision/convex.odin
View File

@ -40,8 +40,9 @@ box_to_convex :: proc(box: Box, allocator := context.allocator) -> (convex: Conv
}
Contact_Manifold :: struct {
points: []Vec3,
normal: Vec3,
points: [4]Vec3,
points_len: int,
}
convex_vs_convex_sat :: proc(a, b: Convex) -> (manifold: Contact_Manifold, collision: bool) {
@ -109,8 +110,7 @@ query_separation_face_directions :: proc(a, b: Convex) -> (result: Face_Query) {
return
}
find_support_point_from_slice :: proc(points: []Vec3, normal: Vec3) -> Vec3 {
p: Vec3
find_support_point_from_slice :: proc(points: []Vec3, normal: Vec3) -> (p: Vec3) {
max_proj := min(f32)
for vert in points {
proj := lg.dot(vert, normal)
@ -120,7 +120,7 @@ find_support_point_from_slice :: proc(points: []Vec3, normal: Vec3) -> Vec3 {
}
}
return p
return
}
find_support_point :: proc(
@ -145,6 +145,18 @@ find_support_point :: proc(
return
}
find_furthest_point_from_point :: proc(points: []Vec3, ref: Vec3) -> (p: Vec3) {
max_dist_sq := min(f32)
for v in points {
dist_sq := lg.length2(v - ref)
if dist_sq > max_dist_sq {
p = v
max_dist_sq = dist_sq
}
}
return
}
query_separation_edges :: proc(
a, b: Convex,
) -> (
@ -393,20 +405,20 @@ create_face_contact_manifold :: proc(
}
}
// Final clipping, remove verts above ref face
ref_face_vert := ref_convex.vertices[ref_convex.edges[ref_face.edge].origin].pos
ref_plane := plane_from_point_normal(ref_face_vert, ref_face.normal)
// Final clipping, remove verts above ref face and project those left onto the reference plane
{
src_polygon := clip_bufs[get_other_clip_buf(clip_buf_idx)]
clipped_polygon := clip_bufs[clip_buf_idx]
ref_face_vert := ref_convex.vertices[ref_convex.edges[ref_face.edge].origin].pos
ref_plane := plane_from_point_normal(ref_face_vert, ref_face.normal)
j := 0
for i in 0 ..< vert_count {
d := signed_distance_plane(src_polygon[i], ref_plane)
if d <= 0 {
clipped_polygon[j] = src_polygon[i]
clipped_polygon[j] = src_polygon[i] - d * ref_plane.normal
j += 1
}
}
@ -414,8 +426,61 @@ create_face_contact_manifold :: proc(
clip_buf_idx = get_other_clip_buf(clip_buf_idx)
}
// Resulting polygon before contact optimization
full_clipped_polygon := clip_bufs[get_other_clip_buf(clip_buf_idx)][:vert_count]
// Contact optimization
if len(full_clipped_polygon) > 4 {
start_dir := lg.cross(ref_plane.normal, ref_face_vert)
first_point := find_support_point_from_slice(full_clipped_polygon, start_dir)
second_point := find_furthest_point_from_point(full_clipped_polygon, first_point)
third_point: Vec3
{
max_area := min(f32)
for v in full_clipped_polygon {
area := 0.5 * lg.dot(ref_plane.normal, lg.cross(first_point - v, second_point - v))
if area > max_area {
max_area = area
third_point = v
}
}
}
existing_edges := [][2]Vec3 {
{first_point, second_point},
{second_point, third_point},
{third_point, first_point},
}
fourth_point: Vec3
{
// We're looking for max negative area actually
min_area := max(f32)
for v in full_clipped_polygon {
for edge in existing_edges {
area := 0.5 * lg.dot(ref_plane.normal, lg.cross(edge[0] - v, edge[1] - v))
if area < min_area {
min_area = area
fourth_point = v
}
}
}
}
manifold.points[0] = first_point
manifold.points[1] = second_point
manifold.points[2] = third_point
manifold.points[3] = fourth_point
manifold.points_len = 4
} else {
copy(manifold.points[:], full_clipped_polygon)
manifold.points_len = len(full_clipped_polygon)
assert(len(full_clipped_polygon) <= 4)
}
manifold.normal = ref_face.normal
manifold.points = clip_bufs[get_other_clip_buf(clip_buf_idx)][:vert_count]
return
}
@ -435,8 +500,8 @@ create_edge_contact_manifold :: proc(
_, ps := closest_point_between_segments(a1, a2, b1, b2)
manifold.points = make([]Vec3, 1, context.temp_allocator)
manifold.points[0] = (ps[0] + ps[1]) * 0.5
manifold.points_len = 1
return
}