79 lines
2.0 KiB
Go
79 lines
2.0 KiB
Go
package doodads
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import (
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"git.kirsle.net/apps/doodle/level"
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"git.kirsle.net/apps/doodle/render"
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)
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// Actor is a reusable run-time drawing component used in Doodle. Actors are an
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// active instance of a Doodad which have a position, velocity, etc.
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type Actor interface {
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ID() string
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// Position and velocity, not saved to disk.
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Position() render.Point
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Velocity() render.Point
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Size() render.Rect
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Grounded() bool
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SetGrounded(bool)
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// Movement commands.
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MoveBy(render.Point) // Add {X,Y} to current Position.
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MoveTo(render.Point) // Set current Position to {X,Y}.
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// Implement the Draw function.
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Draw(render.Engine)
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}
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// GetBoundingRect computes the full pairs of points for the collision box
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// around a doodad actor.
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func GetBoundingRect(d Actor) render.Rect {
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var (
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P = d.Position()
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S = d.Size()
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)
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return render.Rect{
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X: P.X,
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Y: P.Y,
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W: S.W,
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H: S.H,
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}
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}
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// ScanBoundingBox scans all of the pixels in a bounding box on the grid and
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// returns if any of them intersect with level geometry.
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func (c *Collide) ScanBoundingBox(box render.Rect, grid *level.Chunker) bool {
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col := GetCollisionBox(box)
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c.ScanGridLine(col.Top[0], col.Top[1], grid, Top)
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c.ScanGridLine(col.Bottom[0], col.Bottom[1], grid, Bottom)
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c.ScanGridLine(col.Left[0], col.Left[1], grid, Left)
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c.ScanGridLine(col.Right[0], col.Right[1], grid, Right)
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return c.IsColliding()
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}
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// ScanGridLine scans all of the pixels between p1 and p2 on the grid and tests
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// for any pixels to be set, implying a collision between level geometry and the
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// bounding boxes of the doodad.
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func (c *Collide) ScanGridLine(p1, p2 render.Point, grid *level.Chunker, side Side) {
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for point := range render.IterLine2(p1, p2) {
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if _, err := grid.Get(point); err == nil {
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// A hit!
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switch side {
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case Top:
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c.Top = true
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c.TopPoint = point
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case Bottom:
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c.Bottom = true
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c.BottomPoint = point
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case Left:
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c.Left = true
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c.LeftPoint = point
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case Right:
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c.Right = true
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c.RightPoint = point
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}
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}
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}
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}
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