add some cubes and stuff

engine/iso.go

@@ -1,6 +1,7 @@
 package engine
 
 import (
+	"encoding/gob"
 	"image"
 	"strconv"
 
@@ -25,6 +26,12 @@ var (
 	} = &IsoVoxelSide{}
 )
 
+func init() {
+	gob.Register(&IsoVoxmap{})
+	gob.Register(&IsoVoxel{})
+	gob.Register(&IsoVoxelSide{})
+}
+
 // Point3 is a an element of int^3.
 type Point3 struct {
 	X, Y, Z int
@@ -152,7 +159,7 @@ type IsoVoxmap struct {
 	DrawOrderBias image.Point // so boxes overdraw correctly
 	OffsetBack    image.Point // offsets the image drawn for the back
 	OffsetFront   image.Point // offsets the image drawn for the front
-	Proj          image.Point // IsoProjection parameter
+	Projection    image.Point // IsoProjection parameter
 	Sheet         Sheet
 	VoxSize       Point3 // size of each voxel
 }
@@ -201,10 +208,11 @@ func (v *IsoVoxel) Scan() []interface{} {
 	return []interface{}{&v.back, &v.front}
 }
 
-// Transform returns the transform for drawing this voxel.
+// Transform returns a translation of pos.CMul(VoxSize) iso-projected
+// (the top-left of the back of the voxel).
 func (v *IsoVoxel) Transform() (opts ebiten.DrawImageOptions) {
 	p3 := v.pos.CMul(v.ivm.VoxSize)
-	p2 := p3.IsoProject(v.ivm.Proj)
+	p2 := p3.IsoProject(v.ivm.Projection)
 	opts.GeoM.Translate(cfloat(p2))
 	return opts
 }

main.go

@@ -119,9 +119,30 @@ func writeLevel1() {
 				},
 				Factor: 0.5,
 			},
+			&engine.IsoVoxmap{
+				ID:            "voxmap",
+				DrawOrderBias: image.Pt(1, -1), // draw left before right, bottom before top
+				OffsetBack:    image.Pt(-8, 0),
+				OffsetFront:   image.Pt(-8, 0),
+				Projection:    image.Pt(-2, 2), // each step in Z becomes -1/2 step in X plus 1/2 step in Y.
+				VoxSize:       engine.Pt3(16, 16, 16),
+				Sheet: engine.Sheet{
+					CellSize: image.Pt(24, 24),
+					Src:      engine.ImageRef{Path: "assets/box16.png"},
+				},
+				Map: map[engine.Point3]*engine.IsoVoxel{
+					engine.Pt3(0, 2, 0): {CellBack: 0, CellFront: 1},
+					engine.Pt3(1, 2, 0): {CellBack: 0, CellFront: 1},
+					engine.Pt3(2, 2, 0): {CellBack: 0, CellFront: 1},
+
+					engine.Pt3(5, 0, 0): {CellBack: 0, CellFront: 1},
+					engine.Pt3(5, 1, 0): {CellBack: 0, CellFront: 1},
+					engine.Pt3(5, 2, 0): {CellBack: 0, CellFront: 1},
+				},
+			},
 			&engine.Tilemap{
 				ID:     "terrain",
-				ZOrder: 2,
+				ZOrder: 8,
 				Map:    tiles,
 				Sheet: engine.Sheet{
 					AnimDefs: map[string]*engine.AnimDef{
@@ -203,7 +224,7 @@ func writeLevel1() {
 						CellSize: image.Pt(10, 16),
 						Src:      engine.ImageRef{Path: "assets/aw.png"},
 					},
-					ZOrder: 3,
+					ZOrder: 9,
 				},
 			},
 		},