doodle/pkg/uix/actor_collision.go

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package uix
import (
"errors"
"sync"
"time"
"git.kirsle.net/go/render"
"git.kirsle.net/apps/doodle/pkg/balance"
"git.kirsle.net/apps/doodle/pkg/collision"
"git.kirsle.net/apps/doodle/pkg/doodads"
"git.kirsle.net/apps/doodle/pkg/log"
"git.kirsle.net/apps/doodle/pkg/scripting"
"github.com/robertkrimen/otto"
)
// loopActorCollision is the Loop function that checks if pairs of
// actors are colliding with each other, and handles their scripting
// responses to such collisions.
func (w *Canvas) loopActorCollision() error {
if w.scripting == nil {
return errors.New("Canvas.loopActorCollision: scripting engine not attached to Canvas")
}
var (
// Current time of this tick so we can advance animations.
now = time.Now()
// As we iterate over all actors below to process their movement, track
// their bounding rectangles so we can later see if any pair of actors
// intersect each other. Also, in case of actor scripts protesting a
// collision later, store each actor's original position before the move.
boxes = make([]render.Rect, len(w.actors))
originalPositions = map[string]render.Point{}
)
// Loop over all the actors in parallel, processing their movement and
// checking collision data against the level geometry.
var wg sync.WaitGroup
for i, a := range w.actors {
wg.Add(1)
go func(i int, a *Actor) {
defer wg.Done()
originalPositions[a.ID()] = a.Position()
// Advance any animations for this actor.
if a.activeAnimation != nil && a.activeAnimation.nextFrameAt.Before(now) {
if done := a.TickAnimation(a.activeAnimation); done {
// Animation has finished, run the callback script.
if a.animationCallback.IsFunction() {
a.animationCallback.Call(otto.NullValue())
}
// Clean up the animation state.
a.StopAnimation()
}
}
// Get the actor's velocity to see if it's moving this tick.
v := a.Velocity()
if a.hasGravity {
v.Y += int32(balance.Gravity)
}
// If not moving, grab the bounding box right now.
if v == render.Origin {
boxes[i] = doodads.GetBoundingRect(a)
return
}
// Create a delta point from their current location to where they
// want to move to this tick.
delta := a.Position()
delta.Add(v)
// Check collision with level geometry.
info, ok := collision.CollidesWithGrid(a, w.chunks, delta)
if ok {
// Collision happened with world.
if w.OnLevelCollision != nil {
w.OnLevelCollision(a, info)
}
}
delta = info.MoveTo // Move us back where the collision check put us
// Move the actor's World Position to the new location.
a.MoveTo(delta)
// Keep the actor from leaving the world borders of bounded maps.
w.loopContainActorsInsideLevel(a)
// Store this actor's bounding box after they've moved.
boxes[i] = doodads.GetBoundingRect(a)
}(i, a)
wg.Wait()
}
var collidingActors = map[string]string{}
for tuple := range collision.BetweenBoxes(boxes) {
a, b := w.actors[tuple.A], w.actors[tuple.B]
collidingActors[a.ID()] = b.ID()
Improve Collision Detection: More Active w/ Actors * Improve the collision detection algorithm so that Actor OnCollide scripts get called more often WHILE an actor is moving, to prevent a fast-moving actor from zipping right through the "solid" hitbox and not giving the subject actor time to protest the movement. * It's implemented by adding a `Settled` boolean to the OnCollide event object. When the game is testing out movement, Settled=false to give the actor a chance to say "I'm solid!" and have the moving party be stopped early. * After all this is done, for any pair of actors still with overlapping hitboxes, OnCollide is called one last time with Settled=true. This is when the actor should run its actions (like publishing messages to other actors, changing state as in a trapdoor, etc.) * The new collision detection algorithm works as follows: * Stage 1 is the same as before, all mobile actors are moved and tested against level geometry. They record their Original and New position during this phase. * Stage 2 is where we re-run that movement but ping actors being intersected each step of the way. We trace the steps between Original and New position, test OnCollide handler, and if it returns false we move the mobile actor to the Last Good Position along the trace. * Stage 3 we run the final OnCollide(Settled=true) to let actors run actions they wanted to for their collide handler, WITHOUT spamming those actions during Stage 2. * This should now allow for tweaking of gravity speed and player speed without breaking all actor collision checking.
2019-07-17 04:07:38 +00:00
// Call the OnCollide handler for A informing them of B's intersection.
if w.scripting != nil {
Improve Collision Detection: More Active w/ Actors * Improve the collision detection algorithm so that Actor OnCollide scripts get called more often WHILE an actor is moving, to prevent a fast-moving actor from zipping right through the "solid" hitbox and not giving the subject actor time to protest the movement. * It's implemented by adding a `Settled` boolean to the OnCollide event object. When the game is testing out movement, Settled=false to give the actor a chance to say "I'm solid!" and have the moving party be stopped early. * After all this is done, for any pair of actors still with overlapping hitboxes, OnCollide is called one last time with Settled=true. This is when the actor should run its actions (like publishing messages to other actors, changing state as in a trapdoor, etc.) * The new collision detection algorithm works as follows: * Stage 1 is the same as before, all mobile actors are moved and tested against level geometry. They record their Original and New position during this phase. * Stage 2 is where we re-run that movement but ping actors being intersected each step of the way. We trace the steps between Original and New position, test OnCollide handler, and if it returns false we move the mobile actor to the Last Good Position along the trace. * Stage 3 we run the final OnCollide(Settled=true) to let actors run actions they wanted to for their collide handler, WITHOUT spamming those actions during Stage 2. * This should now allow for tweaking of gravity speed and player speed without breaking all actor collision checking.
2019-07-17 04:07:38 +00:00
var (
rect = doodads.GetBoundingRect(b)
lastGoodBox = boxes[tuple.B] // worst case scenario we get blocked right away
)
// Firstly we want to make sure B isn't able to clip through A's
// solid hitbox if A protests the movement. Trace a vector from
// B's original position to their current one and ping A's
// OnCollide handler for each step, with Settled=false. A should
// only return false if it protests the movement, but not trigger
// any actions (such as emit messages to linked doodads) until
// Settled=true.
if origPoint, ok := originalPositions[b.ID()]; ok {
// Trace a vector back from the actor's current position
// to where they originated from. If A protests B's position at
// ANY time, we mark didProtest=true and continue backscanning
// B's movement. The next time A does NOT protest, that is to be
// B's new position.
var firstPoint = true
for point := range render.IterLine(
origPoint,
b.Position(),
) {
test := render.Rect{
X: point.X,
Y: point.Y,
W: rect.W,
H: rect.H,
}
if info, err := collision.CompareBoxes(boxes[tuple.A], test); err == nil {
// B is overlapping A's box, call its OnCollide handler
// with Settled=false and see if it protests the overlap.
err := w.scripting.To(a.ID()).Events.RunCollide(&CollideEvent{
Actor: b,
Overlap: info.Overlap,
InHitbox: info.Overlap.Intersects(a.Hitbox()),
Settled: false,
})
// Did A protest?
if err == scripting.ErrReturnFalse {
break
} else {
lastGoodBox = test
}
}
Improve Collision Detection: More Active w/ Actors * Improve the collision detection algorithm so that Actor OnCollide scripts get called more often WHILE an actor is moving, to prevent a fast-moving actor from zipping right through the "solid" hitbox and not giving the subject actor time to protest the movement. * It's implemented by adding a `Settled` boolean to the OnCollide event object. When the game is testing out movement, Settled=false to give the actor a chance to say "I'm solid!" and have the moving party be stopped early. * After all this is done, for any pair of actors still with overlapping hitboxes, OnCollide is called one last time with Settled=true. This is when the actor should run its actions (like publishing messages to other actors, changing state as in a trapdoor, etc.) * The new collision detection algorithm works as follows: * Stage 1 is the same as before, all mobile actors are moved and tested against level geometry. They record their Original and New position during this phase. * Stage 2 is where we re-run that movement but ping actors being intersected each step of the way. We trace the steps between Original and New position, test OnCollide handler, and if it returns false we move the mobile actor to the Last Good Position along the trace. * Stage 3 we run the final OnCollide(Settled=true) to let actors run actions they wanted to for their collide handler, WITHOUT spamming those actions during Stage 2. * This should now allow for tweaking of gravity speed and player speed without breaking all actor collision checking.
2019-07-17 04:07:38 +00:00
firstPoint = false
}
// Were we stopped before we even began?
if firstPoint {
// TODO: undo the effect of gravity this tick. Use case:
// the player lands on top of a solid door, and their
// movement is blocked the first step by the door. Originally
// he'd continue falling, so I had to move him up to stop it,
// turns out moving up by the -gravity is exactly the distance
// to go. Don't know why.
b.MoveBy(render.NewPoint(0, int32(-balance.Gravity)))
} else {
Improve Collision Detection: More Active w/ Actors * Improve the collision detection algorithm so that Actor OnCollide scripts get called more often WHILE an actor is moving, to prevent a fast-moving actor from zipping right through the "solid" hitbox and not giving the subject actor time to protest the movement. * It's implemented by adding a `Settled` boolean to the OnCollide event object. When the game is testing out movement, Settled=false to give the actor a chance to say "I'm solid!" and have the moving party be stopped early. * After all this is done, for any pair of actors still with overlapping hitboxes, OnCollide is called one last time with Settled=true. This is when the actor should run its actions (like publishing messages to other actors, changing state as in a trapdoor, etc.) * The new collision detection algorithm works as follows: * Stage 1 is the same as before, all mobile actors are moved and tested against level geometry. They record their Original and New position during this phase. * Stage 2 is where we re-run that movement but ping actors being intersected each step of the way. We trace the steps between Original and New position, test OnCollide handler, and if it returns false we move the mobile actor to the Last Good Position along the trace. * Stage 3 we run the final OnCollide(Settled=true) to let actors run actions they wanted to for their collide handler, WITHOUT spamming those actions during Stage 2. * This should now allow for tweaking of gravity speed and player speed without breaking all actor collision checking.
2019-07-17 04:07:38 +00:00
b.MoveTo(lastGoodBox.Point())
}
} else {
log.Error(
"ERROR: Actors %s and %s overlap and the script returned false,"+
"but I didn't store %s original position earlier??",
a.Doodad.Title, b.Doodad.Title, b.Doodad.Title,
)
}
// Movement has been settled. Check if B's point is still invading
// A's box and call its OnCollide handler one last time in
// Settled=true mode so it can run its actions.
if info, err := collision.CompareBoxes(boxes[tuple.A], lastGoodBox); err == nil {
if err := w.scripting.To(a.ID()).Events.RunCollide(&CollideEvent{
Actor: b,
Overlap: info.Overlap,
InHitbox: info.Overlap.Intersects(a.Hitbox()),
Settled: true,
}); err != nil && err != scripting.ErrReturnFalse {
log.Error(err.Error())
}
}
}
}
// Check for lacks of collisions since last frame.
for sourceID, targetID := range w.collidingActors {
if _, ok := collidingActors[sourceID]; !ok {
w.scripting.To(sourceID).Events.RunLeave(targetID)
}
}
// Store this frame's colliding actors for next frame.
w.collidingActors = collidingActors
return nil
}