94 lines
2.4 KiB
Go
94 lines
2.4 KiB
Go
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package trace
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import (
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"github.com/df-mc/dragonfly/server/block/cube"
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"github.com/df-mc/dragonfly/server/block/model"
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"github.com/df-mc/dragonfly/server/world"
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"github.com/go-gl/mathgl/mgl64"
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"math"
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)
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// BlockResult is the result of a ray trace collision with a block's model.
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type BlockResult struct {
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bb cube.BBox
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pos mgl64.Vec3
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face cube.Face
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blockPos cube.Pos
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}
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// BBox returns the BBox that was collided within the block's model.
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func (r BlockResult) BBox() cube.BBox {
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return r.bb
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}
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// Position ...
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func (r BlockResult) Position() mgl64.Vec3 {
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return r.pos
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}
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// Face returns the hit block face.
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func (r BlockResult) Face() cube.Face {
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return r.face
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}
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// BlockPosition returns the block that was collided with.
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func (r BlockResult) BlockPosition() cube.Pos {
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return r.blockPos
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}
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// BlockIntercept performs a ray trace and calculates the point on the block model's edge nearest to the start position
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// that the ray collided with.
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// BlockIntercept returns a BlockResult with the block collided with and with the colliding vector closest to the start position,
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// if no colliding point was found, a zero BlockResult is returned and ok is false.
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func BlockIntercept(pos cube.Pos, src world.BlockSource, b world.Block, start, end mgl64.Vec3) (result BlockResult, ok bool) {
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bbs := b.Model().BBox(pos, src)
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if len(bbs) == 0 {
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return
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}
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var (
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hit Result
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dist = math.MaxFloat64
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)
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for _, bb := range bbs {
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next, ok := BBoxIntercept(bb.Translate(pos.Vec3()), start, end)
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if !ok {
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continue
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}
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nextDist := next.Position().Sub(start).LenSqr()
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if nextDist < dist {
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hit = next
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dist = nextDist
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}
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}
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if hit == nil {
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return result, false
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}
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return BlockResult{bb: hit.BBox(), pos: hit.Position(), face: hit.Face(), blockPos: pos}, true
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}
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// BlockIntersects checks if the line segment from start to end intersects the block model of b at pos. Unlike
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// BlockIntercept, it only reports whether an intersection exists and does not calculate the closest hit position, face,
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// or bounding box.
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func BlockIntersects(pos cube.Pos, src world.BlockSource, b world.Block, start, end mgl64.Vec3) bool {
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m := b.Model()
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switch m.(type) {
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case model.Empty:
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return false
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case model.Solid:
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return BBoxIntersects(cube.Box(0, 0, 0, 1, 1, 1).Translate(pos.Vec3()), start, end)
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}
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for _, bb := range m.BBox(pos, src) {
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if BBoxIntersects(bb.Translate(pos.Vec3()), start, end) {
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return true
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}
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}
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return false
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}
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