122 lines
2.7 KiB
Go
122 lines
2.7 KiB
Go
package engine
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import (
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"encoding/gob"
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"image"
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"github.com/hajimehoshi/ebiten/v2"
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)
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var (
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_ interface {
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Prepper
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Scanner
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} = &IsoVoxmap{}
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_ interface {
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Prepper
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Scanner
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Transformer
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} = &IsoVoxel{}
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_ Drawer = &IsoVoxelSide{}
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)
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func init() {
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gob.Register(&IsoVoxmap{})
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gob.Register(&IsoVoxel{})
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gob.Register(&IsoVoxelSide{})
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}
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// IsoVoxmap implements a voxel map, painted using flat images in 2D.
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type IsoVoxmap struct {
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ID
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Disabled
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Hidden
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Map map[Point3]*IsoVoxel
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DrawOrderBias image.Point // so boxes overdraw correctly
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DrawOffset image.Point
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Projection image.Point // IsoProjection parameter
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Sheet Sheet
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VoxSize Point3 // size of each voxel
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}
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// Prepare makes sure all voxels know about the map and where they are, for
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// drawing.
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func (m *IsoVoxmap) Prepare(*Game) error {
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// Ensure all child units know about wall, which houses common attributes
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for p, u := range m.Map {
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u.pos, u.ivm = p, m
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}
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return nil
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}
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// Scan returns the Sheet and all voxels in the map.
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func (m *IsoVoxmap) Scan() []interface{} {
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c := make([]interface{}, 1, len(m.Map)+1)
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c[0] = &m.Sheet
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for _, voxel := range m.Map {
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c = append(c, voxel)
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}
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return c
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}
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// IsoVoxel is a voxel in an IsoVoxmap.
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type IsoVoxel struct {
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CellBack int // cell to draw for back side
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CellFront int // cell to draw for front side
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back IsoVoxelSide
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front IsoVoxelSide
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ivm *IsoVoxmap
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pos Point3
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}
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// Prepare tells the front and back about the voxel.
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func (v *IsoVoxel) Prepare(*Game) error {
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v.back.vox = v
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v.front.vox = v
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v.front.front = true
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return nil
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}
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// Scan returns the back and front of the voxel.
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func (v *IsoVoxel) Scan() []interface{} {
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return []interface{}{&v.back, &v.front}
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}
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// Transform returns a translation of first by DrawOffset, then by
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// pos.CMul(VoxSize) iso-projected (the top-left of the back of the voxel).
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func (v *IsoVoxel) Transform() (opts ebiten.DrawImageOptions) {
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opts.GeoM.Translate(cfloat(v.ivm.DrawOffset))
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p3 := v.pos.CMul(v.ivm.VoxSize)
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p2 := p3.IsoProject(v.ivm.Projection)
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opts.GeoM.Translate(cfloat(p2))
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return opts
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}
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// IsoVoxelSide is a side of a voxel.
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type IsoVoxelSide struct {
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front bool
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vox *IsoVoxel
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}
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// Draw draws this side.
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func (v *IsoVoxelSide) Draw(screen *ebiten.Image, opts *ebiten.DrawImageOptions) {
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cell := v.vox.CellBack
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if v.front {
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cell = v.vox.CellFront
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}
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screen.DrawImage(v.vox.ivm.Sheet.SubImage(cell), opts)
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}
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// DrawOrder returns the Z of the nearest or farthest vertex of the voxel,
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// with a bias equal to the dot product of the bias vector with pos.XY().
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func (v *IsoVoxelSide) DrawOrder() (int, int) {
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z := v.vox.pos.Z * v.vox.ivm.VoxSize.Z
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if v.front {
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z += v.vox.ivm.VoxSize.Z - 1
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}
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bias := dot(v.vox.pos.XY(), v.vox.ivm.DrawOrderBias)
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return z, bias
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}
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