.obj-Loader-输出不完全正确 [英] .obj-Loader - output not quite right

问题描述

我正在研究一个小型3D引擎，以学习更多OpenGL.我正在使用Scala和lwjgl来完成任务.

加载手工制作"(所有顶点，纹理坐标和索引-手动指定的数组)模型的工作原理很吸引人，因此我想继续加载.obj文件.事实证明，那不是那么容易，或者，好吧，我在某种程度上误解了某些东西.

让我们看看我的解析方法:

private def parseObj(path: String): Model =
{
    val objSource: List[String] = Source.fromFile(path).getLines.toList

    val positions: List[Vector4] = objSource.filter(_.startsWith("v ")).map(_.split(" ")).map(v => new Vector4(v(1).toFloat,v(2).toFloat,v(3).toFloat, 1.0f))
    //  val normals: List[Vector4] = objSource.filter(_.startsWith("vn ")).map(_.split(" ")).map(v => new Vector4(v(1)toFloat,v(2).toFloat, v(3).toFloat, 0.0f))
    val textureCoordinates: List[Vector2] = objSource.filter(_.startsWith("vt ")).map(_.split(" ")).map(v => new Vector2(v(1).toDouble.toFloat,v(2).toDouble.toFloat))
    val faces: List[(Int, Int, Int)] = objSource.filter(_.startsWith("f ")).map(_.split(" ")).flatten.filterNot(_ == "f").map(_.split("/")).map(a => ((a(0).toInt, a(1).toInt, a(2).toInt)))

    val indices: List[Int] = faces.map(f => f._1-1) // Wrong?

    /*
    println(positions.map{p => s"v ${p.x} ${p.y} ${p.z}"}.mkString("\n"))
    println(textureCoordinates.map {t => s"vt ${t.x} ${t.y}"}.mkString("\n"))

    println(indices)
    */
    //println(faces.length)

    val vertices: List[Vertex] =  for(face <- faces) yield(new Vertex(positions(face._1-1), textureCoordinates(face._2-1)))
    println(vertices.mkString("\n"))

    new Model(vertices.toArray, indices.toArray)
}

现在，我在做什么? .obj文件如下所示:

v 0.000000 -1.000000 0.000000
v 0.723607 -0.447220 0.525725
v -0.276388 -0.447220 0.850649
v -0.894426 -0.447216 0.000000
v -0.276388 -0.447220 -0.850649
v 0.723607 -0.447220 -0.525725
v 0.276388 0.447220 0.850649
v -0.723607 0.447220 0.525725
v -0.723607 0.447220 -0.525725
v 0.276388 0.447220 -0.850649
v 0.894426 0.447216 0.000000
v 0.000000 1.000000 0.000000
v -0.162456 -0.850654 0.499995
v 0.425323 -0.850654 0.309011
v 0.262869 -0.525738 0.809012
v 0.850648 -0.525736 0.000000
v 0.425323 -0.850654 -0.309011
v -0.525730 -0.850652 0.000000
v -0.688189 -0.525736 0.499997
v -0.162456 -0.850654 -0.499995
v -0.688189 -0.525736 -0.499997
v 0.262869 -0.525738 -0.809012
v 0.951058 0.000000 0.309013
v 0.951058 0.000000 -0.309013
v 0.000000 0.000000 1.000000
v 0.587786 0.000000 0.809017
v -0.951058 0.000000 0.309013
v -0.587786 0.000000 0.809017
v -0.587786 0.000000 -0.809017
v -0.951058 0.000000 -0.309013
v 0.587786 0.000000 -0.809017
v 0.000000 0.000000 -1.000000
v 0.688189 0.525736 0.499997
v -0.262869 0.525738 0.809012
v -0.850648 0.525736 0.000000
v -0.262869 0.525738 -0.809012
v 0.688189 0.525736 -0.499997
v 0.162456 0.850654 0.499995
v 0.525730 0.850652 0.000000
v -0.425323 0.850654 0.309011
v -0.425323 0.850654 -0.309011
v 0.162456 0.850654 -0.499995
vt 0.534208 0.190162
vt 0.439232 0.259166
vt 0.570486 0.301814
vt 0.995860 0.190574
vt 0.999792 0.292763
vt 0.903537 0.265179
vt 0.651606 0.190162
vt 0.570486 0.078511
vt 0.439232 0.121159
vt 0.903535 0.129002
vt 0.092743 0.471488
vt 0.212444 0.449586
vt 0.158053 0.569043
vt 0.737562 0.458199
vt 0.632422 0.499661
vt 0.728679 0.579260
vt 0.408849 0.471488
vt 0.316315 0.457312
vt 0.342992 0.573818
vt 0.632005 0.463365
vt 0.528550 0.449586
vt 0.605329 0.564268
vt 0.999792 0.072423
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vt 0.847656 0.509327
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vt 0.793444 0.309553
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vt 0.343838 0.078511
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vt 0.793441 0.077875
vt 0.688301 0.119336
vt 0.747790 0.000208
vt 0.307560 0.190162
vt 0.226439 0.301814
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vt 0.343838 0.301814
vt 0.251881 0.380116
vt 0.095186 0.259166
vt 0.131462 0.370818
vt 0.028577 0.307559
vt 0.000208 0.190162
vt 0.737565 0.689877
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vt 0.103663 0.688500
vt 0.223364 0.666598
vt 0.201217 0.757552
vt 0.880811 0.006181
vt 0.632005 0.680774
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vt 0.289222 0.564268
vt 0.315898 0.680774
vt 0.943912 0.452748
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vt 0.632423 0.635839
vt 0.000208 0.457312
vt 0.315898 0.463365
vt 0.475509 0.009506
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vt 0.344255 0.190162
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vn -0.268000 -0.943500 0.194700
vn -0.268000 -0.943500 -0.194700
vn 0.102400 -0.943500 -0.315100
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vn -0.889700 -0.330400 0.315100
vn -0.574600 -0.330400 -0.748800
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vn 0.802600 -0.125600 0.583100
vn -0.306600 -0.125600 0.943500
vn -0.992100 -0.125600 0.000000
vn -0.306600 -0.125600 -0.943500
vn 0.802600 -0.125600 -0.583100
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vn -0.471300 0.661700 0.583100
vn -0.700200 0.661700 -0.268000
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vn 0.724000 0.661700 -0.194700
vn 0.268000 0.943500 -0.194700
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vn -0.102400 0.943500 -0.315100
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vn -0.102400 0.943500 0.315100
vn -0.187600 0.794700 0.577300
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vn -0.024700 0.330400 -0.943500
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vn -0.534600 0.330400 -0.777900
vn -0.905000 0.330400 -0.268000
vn -0.982200 0.187600 0.000000
vn -0.905000 0.330400 0.268000
vn -0.534600 0.330400 0.777900
vn -0.303500 0.187600 0.934200
vn -0.024700 0.330400 0.943500
vn 0.574600 0.330400 0.748800
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vn 0.889700 0.330400 0.315100
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vn 0.303500 -0.187600 -0.934200
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vn -0.802600 0.125600 -0.583100
vn -0.794700 -0.187600 -0.577300
vn -0.889700 -0.330400 -0.315100
vn -0.802600 0.125600 0.583100
vn -0.794700 -0.187600 0.577300
vn -0.574600 -0.330400 0.748800
vn 0.306600 0.125600 0.943500
vn 0.303500 -0.187600 0.934200
vn 0.534600 -0.330400 0.777900
vn 0.992100 0.125600 0.000000
vn 0.982200 -0.187600 0.000000
vn 0.905000 -0.330400 -0.268000
vn 0.471300 -0.661700 -0.583100
vn 0.187600 -0.794700 -0.577300
vn -0.038500 -0.661700 -0.748800
vn -0.408900 -0.661700 -0.628400
vn -0.491100 -0.794700 -0.356800
vn -0.724000 -0.661700 -0.194700
vn -0.724000 -0.661700 0.194700
vn -0.491100 -0.794700 0.356800
vn -0.408900 -0.661700 0.628400
vn 0.700200 -0.661700 -0.268000
vn 0.607100 -0.794700 0.000000
vn 0.331300 -0.943500 0.000000
vn -0.038500 -0.661700 0.748800
vn 0.187600 -0.794700 0.577300
vn 0.471300 -0.661700 0.583100
usemtl Material.001
s off
f 1/1/1 14/2/1 13/3/1
f 2/4/2 14/5/2 16/6/2
f 1/1/3 13/3/3 18/7/3
f 1/1/4 18/7/4 20/8/4
f 1/1/5 20/8/5 17/9/5
f 2/4/6 16/6/6 23/10/6
f 3/11/7 15/12/7 25/13/7
f 4/14/8 19/15/8 27/16/8
f 5/17/9 21/18/9 29/19/9
f 6/20/10 22/21/10 31/22/10
f 2/4/11 23/10/11 26/23/11
f 3/11/12 25/13/12 28/24/12
f 4/14/13 27/16/13 30/25/13
f 5/17/14 29/19/14 32/26/14
f 6/27/15 31/28/15 24/29/15
f 7/30/16 33/31/16 38/32/16
f 8/33/17 34/34/17 40/35/17
f 9/36/18 35/37/18 41/38/18
f 10/39/19 36/40/19 42/41/19
f 11/42/20 37/43/20 39/44/20
f 39/45/21 42/46/21 12/47/21
f 39/45/22 37/48/22 42/46/22
f 37/48/23 10/49/23 42/46/23
f 42/46/24 41/50/24 12/47/24
f 42/46/25 36/51/25 41/50/25
f 36/51/26 9/52/26 41/50/26
f 41/50/27 40/35/27 12/47/27
f 41/50/28 35/53/28 40/35/28
f 35/37/29 8/54/29 40/55/29
f 40/35/30 38/32/30 12/47/30
f 40/35/31 34/34/31 38/32/31
f 34/56/32 7/57/32 38/58/32
f 38/32/33 39/45/33 12/47/33
f 38/32/34 33/31/34 39/45/34
f 33/59/35 11/42/35 39/44/35
f 24/29/36 37/43/36 11/42/36
f 24/29/37 31/28/37 37/43/37
f 31/22/38 10/39/38 37/60/38
f 32/26/39 36/40/39 10/39/39
f 32/26/40 29/19/40 36/40/40
f 29/19/41 9/61/41 36/40/41
f 30/25/42 35/37/42 9/36/42
f 30/25/43 27/16/43 35/37/43
f 27/16/44 8/54/44 35/37/44
f 28/24/45 34/56/45 8/62/45
f 28/24/46 25/13/46 34/56/46
f 25/13/47 7/57/47 34/56/47
f 26/63/48 33/64/48 7/57/48
f 26/23/49 23/10/49 33/59/49
f 23/10/50 11/42/50 33/59/50
f 31/22/51 32/26/51 10/39/51
f 31/22/52 22/21/52 32/26/52
f 22/21/53 5/17/53 32/26/53
f 29/65/54 30/25/54 9/36/54
f 29/65/55 21/66/55 30/25/55
f 21/66/56 4/14/56 30/25/56
f 27/16/57 28/67/57 8/54/57
f 27/16/58 19/15/58 28/67/58
f 19/68/59 3/11/59 28/24/59
f 25/13/60 26/63/60 7/57/60
f 25/13/61 15/12/61 26/63/61
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f 18/75/72 19/15/72 4/14/72
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f 13/80/78 15/12/78 3/11/78
f 13/3/79 14/2/79 15/81/79
f 14/2/80 2/82/80 15/81/80
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v 0.894426 0.447216 0.000000
v 0.000000 1.000000 0.000000
v -0.162456 -0.850654 0.499995
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v 0.262869 -0.525738 0.809012
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v -0.850648 0.525736 0.000000
v -0.262869 0.525738 -0.809012
v 0.688189 0.525736 -0.499997
v 0.162456 0.850654 0.499995
v 0.525730 0.850652 0.000000
v -0.425323 0.850654 0.309011
v -0.425323 0.850654 -0.309011
v 0.162456 0.850654 -0.499995
vt 0.534208 0.190162
vt 0.439232 0.259166
vt 0.570486 0.301814
vt 0.995860 0.190574
vt 0.999792 0.292763
vt 0.903537 0.265179
vt 0.651606 0.190162
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vn 0.303500 -0.187600 0.934200
vn 0.534600 -0.330400 0.777900
vn 0.992100 0.125600 0.000000
vn 0.982200 -0.187600 0.000000
vn 0.905000 -0.330400 -0.268000
vn 0.471300 -0.661700 -0.583100
vn 0.187600 -0.794700 -0.577300
vn -0.038500 -0.661700 -0.748800
vn -0.408900 -0.661700 -0.628400
vn -0.491100 -0.794700 -0.356800
vn -0.724000 -0.661700 -0.194700
vn -0.724000 -0.661700 0.194700
vn -0.491100 -0.794700 0.356800
vn -0.408900 -0.661700 0.628400
vn 0.700200 -0.661700 -0.268000
vn 0.607100 -0.794700 0.000000
vn 0.331300 -0.943500 0.000000
vn -0.038500 -0.661700 0.748800
vn 0.187600 -0.794700 0.577300
vn 0.471300 -0.661700 0.583100
usemtl Material.001
s off
f 1/1/1 14/2/1 13/3/1
f 2/4/2 14/5/2 16/6/2
f 1/1/3 13/3/3 18/7/3
f 1/1/4 18/7/4 20/8/4
f 1/1/5 20/8/5 17/9/5
f 2/4/6 16/6/6 23/10/6
f 3/11/7 15/12/7 25/13/7
f 4/14/8 19/15/8 27/16/8
f 5/17/9 21/18/9 29/19/9
f 6/20/10 22/21/10 31/22/10
f 2/4/11 23/10/11 26/23/11
f 3/11/12 25/13/12 28/24/12
f 4/14/13 27/16/13 30/25/13
f 5/17/14 29/19/14 32/26/14
f 6/27/15 31/28/15 24/29/15
f 7/30/16 33/31/16 38/32/16
f 8/33/17 34/34/17 40/35/17
f 9/36/18 35/37/18 41/38/18
f 10/39/19 36/40/19 42/41/19
f 11/42/20 37/43/20 39/44/20
f 39/45/21 42/46/21 12/47/21
f 39/45/22 37/48/22 42/46/22
f 37/48/23 10/49/23 42/46/23
f 42/46/24 41/50/24 12/47/24
f 42/46/25 36/51/25 41/50/25
f 36/51/26 9/52/26 41/50/26
f 41/50/27 40/35/27 12/47/27
f 41/50/28 35/53/28 40/35/28
f 35/37/29 8/54/29 40/55/29
f 40/35/30 38/32/30 12/47/30
f 40/35/31 34/34/31 38/32/31
f 34/56/32 7/57/32 38/58/32
f 38/32/33 39/45/33 12/47/33
f 38/32/34 33/31/34 39/45/34
f 33/59/35 11/42/35 39/44/35
f 24/29/36 37/43/36 11/42/36
f 24/29/37 31/28/37 37/43/37
f 31/22/38 10/39/38 37/60/38
f 32/26/39 36/40/39 10/39/39
f 32/26/40 29/19/40 36/40/40
f 29/19/41 9/61/41 36/40/41
f 30/25/42 35/37/42 9/36/42
f 30/25/43 27/16/43 35/37/43
f 27/16/44 8/54/44 35/37/44
f 28/24/45 34/56/45 8/62/45
f 28/24/46 25/13/46 34/56/46
f 25/13/47 7/57/47 34/56/47
f 26/63/48 33/64/48 7/57/48
f 26/23/49 23/10/49 33/59/49
f 23/10/50 11/42/50 33/59/50
f 31/22/51 32/26/51 10/39/51
f 31/22/52 22/21/52 32/26/52
f 22/21/53 5/17/53 32/26/53
f 29/65/54 30/25/54 9/36/54
f 29/65/55 21/66/55 30/25/55
f 21/66/56 4/14/56 30/25/56
f 27/16/57 28/67/57 8/54/57
f 27/16/58 19/15/58 28/67/58
f 19/68/59 3/11/59 28/24/59
f 25/13/60 26/63/60 7/57/60
f 25/13/61 15/12/61 26/63/61
f 15/12/62 2/69/62 26/63/62
f 23/10/63 24/29/63 11/42/63
f 23/10/64 16/6/64 24/29/64
f 16/6/65 6/27/65 24/29/65
f 17/9/66 22/70/66 6/71/66
f 17/9/67 20/8/67 22/70/67
f 20/72/68 5/17/68 22/21/68
f 20/8/69 21/73/69 5/74/69
f 20/8/70 18/7/70 21/73/70
f 18/75/71 4/14/71 21/66/71
f 18/75/72 19/15/72 4/14/72
f 18/7/73 13/3/73 19/76/73
f 13/3/74 3/77/74 19/76/74
f 16/6/75 17/78/75 6/27/75
f 16/79/76 14/2/76 17/9/76
f 14/2/77 1/1/77 17/9/77
f 13/80/78 15/12/78 3/11/78
f 13/3/79 14/2/79 15/81/79
f 14/2/80 2/82/80 15/81/80

每行以 v 开头的行定义了顶点在3D空间中的位置. 因此，我将阅读所有这些内容并创建新的Vector4以获得均质坐标.

我暂时忽略 vn ，这些将是常态.

对于 vt -指定纹理坐标-与位置相同.

现在， f 位于非常有趣的行之前.这些是面，三角形定义为(顶点/纹理坐标/法线)的三倍.每一个都定义了哪个位置索引和纹理坐标映射在一起.

因此，例如在f 1/1/1 14/2/1 13/3/1 1/1/1中，意味着position(1)具有纹理坐标(1)(而第一个三元组中的最后一个将代表法线(1)中的法线)

14/2/1意味着position(14)和texturecoordinates(2)映射在一起.

整条线将连接这3个顶点，就像(1,14,13)会建立一个三角形.

直到这里我都正确理解了吗?

val faces: List[(Int, Int, Int)] = objSource.filter(_.startsWith("f ")).map(_.split(" ")).flatten.filterNot(_ == "f").map(_.split("/")).map(a => ((a(0).toInt, a(1).toInt, a(2).toInt)))

请给我这些三元组的清单.然后为每个条目创建一个顶点:

val vertices: List[Vertex] = for(face <- faces) yield(new Vertex(positions(face._1-1), textureCoordinates(face._2-1)))

顶点的定义如下:

case class Vertex(position: Vector4,/* normal: Vector4,*/ textureCoordinates: Vector2)

我需要在每个面上都做"-1"，以避免偏离一和IndexOutOfBoundsExceptions，因为List的索引以0开头，而索引以1开头.

最后是索引:在OpenGL中，您可以使用ELEMENT_ARRAY_BUFFER指定要连接的顶点并保存(可能很多)数据.

正如我前面说的，每个面f 1/1/1 14/2/1 13/3/1都是像这样v1/t1/n1 v2/t2/n2 v3/t3/n3(对于每一行)构建的，所以我只需要提取v1,v2,v3并将其打包到一个长列表中，然后由OpenGL完成其余工作. /p> 然后

v1/v2/v3/v4/v5/v6/.../vn将成为我的索引

直到这里我是对还是错?

最后但并非最不重要的一点是，我将创建一个新模型:

class Model(vertices: Array[Vertex], indices: Array[Int]/*, textures: Array[Texture]*/)
{
  // Create VAO, VBO and a buffer for the indices
  val vao: Int = glGenVertexArrays
  val vbo: Int = glGenBuffers
  val ibo: Int = glGenBuffers

  setup

  private def setup(): Unit =
  {
    val interleavedBuffer: FloatBuffer = prepareVertexBuffer(vertices)
    val indicesBuffer: IntBuffer = prepareIntBuffer(indices)

    // One VAO to bind them all!
    glBindVertexArray(vao)
      glBindBuffer(GL_ARRAY_BUFFER, vbo)
      glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo)

      // Fill buffers with data
      glBufferData(GL_ARRAY_BUFFER, interleavedBuffer, GL_STATIC_DRAW)
      glBufferData(GL_ELEMENT_ARRAY_BUFFER, indicesBuffer, GL_STATIC_DRAW)

      // Set vertex attribute pointers
      glVertexAttribPointer(0, 4, GL_FLOAT, false, 4*6, 0) // 0 = Position = Vector4(x,y,z,w)
      glVertexAttribPointer(1, 2, GL_FLOAT, false, 4*6, 4*4) // 1 = Texture Coordinates = Vector2(x,y) -> 2 (coordinates) * 4 (byte-size of float) => stride = 4 (position) + 2 (texture coordinates) = 6 * 4 (byte-size of float); offset = 4 (position) * 4 (byte-size of float)

      glBindBuffer(GL_ARRAY_BUFFER, 0)
    glBindVertexArray(0)
  }

  private def prepareIntBuffer(data: Array[Int]): IntBuffer =
  {
    val buffer: IntBuffer = BufferUtils.createIntBuffer(data.length)
    buffer.put(data)
    buffer.flip // Make the buffer readable

    buffer
  }

  private def prepareVertexBuffer(vertices: Array[Vertex]): FloatBuffer =
  {
    val positions: Array[Float] = vertices.map(v => v.position).map(_.toArray).flatten
    val textureCoordinates: Array[Float] = vertices.map(v => v.textureCoordinates).map(_.toArray).flatten

    // TODO remove hardcoded sizes for grouping
    val zipped: Array[Float] = (positions.grouped(4) zip textureCoordinates.grouped(2)).toArray.flatMap {case (x,y) => x ++ y}

    val buffer: FloatBuffer = BufferUtils.createFloatBuffer(zipped.size)
    buffer.put(zipped)
    buffer.flip

    buffer
  }

问题是，输出看起来像这样:

实际上它应该是Blender的Ico-Sphere. 因此，我的实现或对.obj-file-format的理解确实有些偏离.

我认为它与索引有关，但不知道.我进行了很多调试，手动将不同的列表与实际的.obj文件进行比较，但无济于事.一切看起来都还不错，所以我认为这确实是我的理解.

编辑:我不确定我误会了什么，但我没有直面创建顶点列表(我自己的课程)，给模型所有的位置，纹理坐标和贴图，网格外观看起来是正确的(除了错误的纹理化处理).

那我做了什么:

class Model(positions: Array[Vector3], texcoords: Array[Vector2], indices: Array[Int])




private def prepareVertexBuffer(positions: Array[Vector3], texcoords: Array[Vector2]): FloatBuffer =
  {
    val pos: Array[Float] = positions.map(_.toArray).flatten
    val textureCoordinates: Array[Float] = texcoords.map(_.toArray).flatten

    // TODO remove hardcoded sizes for grouping
    val zipped: Array[Float] = (pos.grouped(3) zip textureCoordinates.grouped(2)).toArray.flatMap {case (x,y) => x ++ y}

    println(zipped.toList.grouped(5).mkString("\n"))

    val buffer: FloatBuffer = BufferUtils.createFloatBuffer(zipped.size)
    buffer.put(zipped)
    buffer.flip

    buffer
  }

(注意:我现在也已切换回Vector3而不是Vector4.以为它可能有问题)

val indices: List[Int] = faces.map(f => f._1-1) // Wrong?
new Model(vertices.toArray, indices.toArray)

其余相同.所以我想我的纹理问题是由此产生的.

现在我只有42个顶点，而不是240个(来自面孔)，所以我失去了很多组合.

当前结果:

修改

问题归结为.obj和opengl之间的差异. OpenGL只能使用一个索引缓冲区，而在.obj中，每个属性都有一个.

所以我需要以适当的方式手动合并它们.我已经找到了用于C ++的函数，尽管我对C ++相当了解，但是我不确定为什么它在Scala上无法正常工作.

我只是找不到任何重复...

解决方案

您正在做的是v1-t1 v2-t2, v3-t3等.如果您查看原始的.obj文件，可能就没有发生任何事情.可能是v1-t1, v2-t1, v3-t1.谁知道.因此，您需要做的是找到与顶点匹配的texcoord.这将使您接近所需的位置，但是却不尽然，因为在.OBJ文件中，1个顶点可以具有多个texcoords，而现在您还不能处理.我在这里回答了类似的问题:

OpenGL-使用glDrawElements错误地映射了纹理

(请注意，您不必摆脱索引缓冲区，但是更容易)

I'm working on a small 3D engine to learn more of OpenGL. I'm using Scala and lwjgl for the task.

Loading "hand-made" (all vertices, texture coordinates and indices - arrays specified by hand) models works like a charm, so I wanted to move on to loading .obj files. Turns out, it's not that easy, or, well, I'm somehow misunderstanding something.

Let's look into my parsing-method:

private def parseObj(path: String): Model =
{
    val objSource: List[String] = Source.fromFile(path).getLines.toList

    val positions: List[Vector4] = objSource.filter(_.startsWith("v ")).map(_.split(" ")).map(v => new Vector4(v(1).toFloat,v(2).toFloat,v(3).toFloat, 1.0f))
    //  val normals: List[Vector4] = objSource.filter(_.startsWith("vn ")).map(_.split(" ")).map(v => new Vector4(v(1)toFloat,v(2).toFloat, v(3).toFloat, 0.0f))
    val textureCoordinates: List[Vector2] = objSource.filter(_.startsWith("vt ")).map(_.split(" ")).map(v => new Vector2(v(1).toDouble.toFloat,v(2).toDouble.toFloat))
    val faces: List[(Int, Int, Int)] = objSource.filter(_.startsWith("f ")).map(_.split(" ")).flatten.filterNot(_ == "f").map(_.split("/")).map(a => ((a(0).toInt, a(1).toInt, a(2).toInt)))

    val indices: List[Int] = faces.map(f => f._1-1) // Wrong?

    /*
    println(positions.map{p => s"v ${p.x} ${p.y} ${p.z}"}.mkString("\n"))
    println(textureCoordinates.map {t => s"vt ${t.x} ${t.y}"}.mkString("\n"))

    println(indices)
    */
    //println(faces.length)

    val vertices: List[Vertex] =  for(face <- faces) yield(new Vertex(positions(face._1-1), textureCoordinates(face._2-1)))
    println(vertices.mkString("\n"))

    new Model(vertices.toArray, indices.toArray)
}

Now, what am I doing? An .obj-file looks like this:

v 0.000000 -1.000000 0.000000
v 0.723607 -0.447220 0.525725
v -0.276388 -0.447220 0.850649
v -0.894426 -0.447216 0.000000
v -0.276388 -0.447220 -0.850649
v 0.723607 -0.447220 -0.525725
v 0.276388 0.447220 0.850649
v -0.723607 0.447220 0.525725
v -0.723607 0.447220 -0.525725
v 0.276388 0.447220 -0.850649
v 0.894426 0.447216 0.000000
v 0.000000 1.000000 0.000000
v -0.162456 -0.850654 0.499995
v 0.425323 -0.850654 0.309011
v 0.262869 -0.525738 0.809012
v 0.850648 -0.525736 0.000000
v 0.425323 -0.850654 -0.309011
v -0.525730 -0.850652 0.000000
v -0.688189 -0.525736 0.499997
v -0.162456 -0.850654 -0.499995
v -0.688189 -0.525736 -0.499997
v 0.262869 -0.525738 -0.809012
v 0.951058 0.000000 0.309013
v 0.951058 0.000000 -0.309013
v 0.000000 0.000000 1.000000
v 0.587786 0.000000 0.809017
v -0.951058 0.000000 0.309013
v -0.587786 0.000000 0.809017
v -0.587786 0.000000 -0.809017
v -0.951058 0.000000 -0.309013
v 0.587786 0.000000 -0.809017
v 0.000000 0.000000 -1.000000
v 0.688189 0.525736 0.499997
v -0.262869 0.525738 0.809012
v -0.850648 0.525736 0.000000
v -0.262869 0.525738 -0.809012
v 0.688189 0.525736 -0.499997
v 0.162456 0.850654 0.499995
v 0.525730 0.850652 0.000000
v -0.425323 0.850654 0.309011
v -0.425323 0.850654 -0.309011
v 0.162456 0.850654 -0.499995
vt 0.534208 0.190162
vt 0.439232 0.259166
vt 0.570486 0.301814
vt 0.995860 0.190574
vt 0.999792 0.292763
vt 0.903537 0.265179
vt 0.651606 0.190162
vt 0.570486 0.078511
vt 0.439232 0.121159
vt 0.903535 0.129002
vt 0.092743 0.471488
vt 0.212444 0.449586
vt 0.158053 0.569043
vt 0.737562 0.458199
vt 0.632422 0.499661
vt 0.728679 0.579260
vt 0.408849 0.471488
vt 0.316315 0.457312
vt 0.342992 0.573818
vt 0.632005 0.463365
vt 0.528550 0.449586
vt 0.605329 0.564268
vt 0.999792 0.072423
vt 0.026885 0.573818
vt 0.847656 0.509327
vt 0.474160 0.569043
vt 0.793444 0.309553
vt 0.688302 0.255514
vt 0.784558 0.198935
vt 0.251881 0.000208
vt 0.343838 0.078511
vt 0.226439 0.078511
vt 0.028577 0.072765
vt 0.131462 0.009506
vt 0.095186 0.121159
vt 0.939981 0.570899
vt 0.847658 0.645504
vt 0.943912 0.673088
vt 0.539471 0.666598
vt 0.419770 0.688500
vt 0.517323 0.757552
vt 0.793441 0.077875
vt 0.688301 0.119336
vt 0.747790 0.000208
vt 0.307560 0.190162
vt 0.226439 0.301814
vt 0.190162 0.190162
vt 0.343838 0.301814
vt 0.251881 0.380116
vt 0.095186 0.259166
vt 0.131462 0.370818
vt 0.028577 0.307559
vt 0.000208 0.190162
vt 0.737565 0.689877
vt 0.824936 0.743021
vt 0.103663 0.688500
vt 0.223364 0.666598
vt 0.201217 0.757552
vt 0.880811 0.006181
vt 0.632005 0.680774
vt 0.316315 0.674721
vt 0.000208 0.674721
vt 0.289222 0.564268
vt 0.315898 0.680774
vt 0.943912 0.452748
vt 0.824932 0.386505
vt 0.632423 0.635839
vt 0.000208 0.457312
vt 0.315898 0.463365
vt 0.475509 0.009506
vt 0.372624 0.072765
vt 0.430997 0.380533
vt 0.687884 0.078511
vt 0.595927 0.000208
vt 0.691911 0.380533
vt 0.687884 0.301814
vt 0.595927 0.380116
vt 0.880815 0.362696
vt 0.344255 0.190162
vt 0.114890 0.380533
vt 0.475509 0.370818
vt 0.372624 0.307559
vn 0.102400 -0.943500 0.315100
vn 0.700200 -0.661700 0.268000
vn -0.268000 -0.943500 0.194700
vn -0.268000 -0.943500 -0.194700
vn 0.102400 -0.943500 -0.315100
vn 0.905000 -0.330400 0.268000
vn 0.024700 -0.330400 0.943500
vn -0.889700 -0.330400 0.315100
vn -0.574600 -0.330400 -0.748800
vn 0.534600 -0.330400 -0.777900
vn 0.802600 -0.125600 0.583100
vn -0.306600 -0.125600 0.943500
vn -0.992100 -0.125600 0.000000
vn -0.306600 -0.125600 -0.943500
vn 0.802600 -0.125600 -0.583100
vn 0.408900 0.661700 0.628400
vn -0.471300 0.661700 0.583100
vn -0.700200 0.661700 -0.268000
vn 0.038500 0.661700 -0.748800
vn 0.724000 0.661700 -0.194700
vn 0.268000 0.943500 -0.194700
vn 0.491100 0.794700 -0.356800
vn 0.408900 0.661700 -0.628400
vn -0.102400 0.943500 -0.315100
vn -0.187600 0.794700 -0.577300
vn -0.471300 0.661700 -0.583100
vn -0.331300 0.943500 0.000000
vn -0.607100 0.794700 0.000000
vn -0.700200 0.661700 0.268000
vn -0.102400 0.943500 0.315100
vn -0.187600 0.794700 0.577300
vn 0.038500 0.661700 0.748800
vn 0.268000 0.943500 0.194700
vn 0.491100 0.794700 0.356800
vn 0.724000 0.661700 0.194700
vn 0.889700 0.330400 -0.315100
vn 0.794700 0.187600 -0.577300
vn 0.574600 0.330400 -0.748800
vn -0.024700 0.330400 -0.943500
vn -0.303500 0.187600 -0.934200
vn -0.534600 0.330400 -0.777900
vn -0.905000 0.330400 -0.268000
vn -0.982200 0.187600 0.000000
vn -0.905000 0.330400 0.268000
vn -0.534600 0.330400 0.777900
vn -0.303500 0.187600 0.934200
vn -0.024700 0.330400 0.943500
vn 0.574600 0.330400 0.748800
vn 0.794700 0.187600 0.577300
vn 0.889700 0.330400 0.315100
vn 0.306600 0.125600 -0.943500
vn 0.303500 -0.187600 -0.934200
vn 0.024700 -0.330400 -0.943500
vn -0.802600 0.125600 -0.583100
vn -0.794700 -0.187600 -0.577300
vn -0.889700 -0.330400 -0.315100
vn -0.802600 0.125600 0.583100
vn -0.794700 -0.187600 0.577300
vn -0.574600 -0.330400 0.748800
vn 0.306600 0.125600 0.943500
vn 0.303500 -0.187600 0.934200
vn 0.534600 -0.330400 0.777900
vn 0.992100 0.125600 0.000000
vn 0.982200 -0.187600 0.000000
vn 0.905000 -0.330400 -0.268000
vn 0.471300 -0.661700 -0.583100
vn 0.187600 -0.794700 -0.577300
vn -0.038500 -0.661700 -0.748800
vn -0.408900 -0.661700 -0.628400
vn -0.491100 -0.794700 -0.356800
vn -0.724000 -0.661700 -0.194700
vn -0.724000 -0.661700 0.194700
vn -0.491100 -0.794700 0.356800
vn -0.408900 -0.661700 0.628400
vn 0.700200 -0.661700 -0.268000
vn 0.607100 -0.794700 0.000000
vn 0.331300 -0.943500 0.000000
vn -0.038500 -0.661700 0.748800
vn 0.187600 -0.794700 0.577300
vn 0.471300 -0.661700 0.583100
usemtl Material.001
s off
f 1/1/1 14/2/1 13/3/1
f 2/4/2 14/5/2 16/6/2
f 1/1/3 13/3/3 18/7/3
f 1/1/4 18/7/4 20/8/4
f 1/1/5 20/8/5 17/9/5
f 2/4/6 16/6/6 23/10/6
f 3/11/7 15/12/7 25/13/7
f 4/14/8 19/15/8 27/16/8
f 5/17/9 21/18/9 29/19/9
f 6/20/10 22/21/10 31/22/10
f 2/4/11 23/10/11 26/23/11
f 3/11/12 25/13/12 28/24/12
f 4/14/13 27/16/13 30/25/13
f 5/17/14 29/19/14 32/26/14
f 6/27/15 31/28/15 24/29/15
f 7/30/16 33/31/16 38/32/16
f 8/33/17 34/34/17 40/35/17
f 9/36/18 35/37/18 41/38/18
f 10/39/19 36/40/19 42/41/19
f 11/42/20 37/43/20 39/44/20
f 39/45/21 42/46/21 12/47/21
f 39/45/22 37/48/22 42/46/22
f 37/48/23 10/49/23 42/46/23
f 42/46/24 41/50/24 12/47/24
f 42/46/25 36/51/25 41/50/25
f 36/51/26 9/52/26 41/50/26
f 41/50/27 40/35/27 12/47/27
f 41/50/28 35/53/28 40/35/28
f 35/37/29 8/54/29 40/55/29
f 40/35/30 38/32/30 12/47/30
f 40/35/31 34/34/31 38/32/31
f 34/56/32 7/57/32 38/58/32
f 38/32/33 39/45/33 12/47/33
f 38/32/34 33/31/34 39/45/34
f 33/59/35 11/42/35 39/44/35
f 24/29/36 37/43/36 11/42/36
f 24/29/37 31/28/37 37/43/37
f 31/22/38 10/39/38 37/60/38
f 32/26/39 36/40/39 10/39/39
f 32/26/40 29/19/40 36/40/40
f 29/19/41 9/61/41 36/40/41
f 30/25/42 35/37/42 9/36/42
f 30/25/43 27/16/43 35/37/43
f 27/16/44 8/54/44 35/37/44
f 28/24/45 34/56/45 8/62/45
f 28/24/46 25/13/46 34/56/46
f 25/13/47 7/57/47 34/56/47
f 26/63/48 33/64/48 7/57/48
f 26/23/49 23/10/49 33/59/49
f 23/10/50 11/42/50 33/59/50
f 31/22/51 32/26/51 10/39/51
f 31/22/52 22/21/52 32/26/52
f 22/21/53 5/17/53 32/26/53
f 29/65/54 30/25/54 9/36/54
f 29/65/55 21/66/55 30/25/55
f 21/66/56 4/14/56 30/25/56
f 27/16/57 28/67/57 8/54/57
f 27/16/58 19/15/58 28/67/58
f 19/68/59 3/11/59 28/24/59
f 25/13/60 26/63/60 7/57/60
f 25/13/61 15/12/61 26/63/61
f 15/12/62 2/69/62 26/63/62
f 23/10/63 24/29/63 11/42/63
f 23/10/64 16/6/64 24/29/64
f 16/6/65 6/27/65 24/29/65
f 17/9/66 22/70/66 6/71/66
f 17/9/67 20/8/67 22/70/67
f 20/72/68 5/17/68 22/21/68
f 20/8/69 21/73/69 5/74/69
f 20/8/70 18/7/70 21/73/70
f 18/75/71 4/14/71 21/66/71
f 18/75/72 19/15/72 4/14/72
f 18/7/73 13/3/73 19/76/73
f 13/3/74 3/77/74 19/76/74
f 16/6/75 17/78/75 6/27/75
f 16/79/76 14/2/76 17/9/76
f 14/2/77 1/1/77 17/9/77
f 13/80/78 15/12/78 3/11/78
f 13/3/79 14/2/79 15/81/79
f 14/2/80 2/82/80 15/81/80
v 0.000000 -1.000000 0.000000
v 0.723607 -0.447220 0.525725
v -0.276388 -0.447220 0.850649
v -0.894426 -0.447216 0.000000
v -0.276388 -0.447220 -0.850649
v 0.723607 -0.447220 -0.525725
v 0.276388 0.447220 0.850649
v -0.723607 0.447220 0.525725
v -0.723607 0.447220 -0.525725
v 0.276388 0.447220 -0.850649
v 0.894426 0.447216 0.000000
v 0.000000 1.000000 0.000000
v -0.162456 -0.850654 0.499995
v 0.425323 -0.850654 0.309011
v 0.262869 -0.525738 0.809012
v 0.850648 -0.525736 0.000000
v 0.425323 -0.850654 -0.309011
v -0.525730 -0.850652 0.000000
v -0.688189 -0.525736 0.499997
v -0.162456 -0.850654 -0.499995
v -0.688189 -0.525736 -0.499997
v 0.262869 -0.525738 -0.809012
v 0.951058 0.000000 0.309013
v 0.951058 0.000000 -0.309013
v 0.000000 0.000000 1.000000
v 0.587786 0.000000 0.809017
v -0.951058 0.000000 0.309013
v -0.587786 0.000000 0.809017
v -0.587786 0.000000 -0.809017
v -0.951058 0.000000 -0.309013
v 0.587786 0.000000 -0.809017
v 0.000000 0.000000 -1.000000
v 0.688189 0.525736 0.499997
v -0.262869 0.525738 0.809012
v -0.850648 0.525736 0.000000
v -0.262869 0.525738 -0.809012
v 0.688189 0.525736 -0.499997
v 0.162456 0.850654 0.499995
v 0.525730 0.850652 0.000000
v -0.425323 0.850654 0.309011
v -0.425323 0.850654 -0.309011
v 0.162456 0.850654 -0.499995
vt 0.534208 0.190162
vt 0.439232 0.259166
vt 0.570486 0.301814
vt 0.995860 0.190574
vt 0.999792 0.292763
vt 0.903537 0.265179
vt 0.651606 0.190162
vt 0.570486 0.078511
vt 0.439232 0.121159
vt 0.903535 0.129002
vt 0.092743 0.471488
vt 0.212444 0.449586
vt 0.158053 0.569043
vt 0.737562 0.458199
vt 0.632422 0.499661
vt 0.728679 0.579260
vt 0.408849 0.471488
vt 0.316315 0.457312
vt 0.342992 0.573818
vt 0.632005 0.463365
vt 0.528550 0.449586
vt 0.605329 0.564268
vt 0.999792 0.072423
vt 0.026885 0.573818
vt 0.847656 0.509327
vt 0.474160 0.569043
vt 0.793444 0.309553
vt 0.688302 0.255514
vt 0.784558 0.198935
vt 0.251881 0.000208
vt 0.343838 0.078511
vt 0.226439 0.078511
vt 0.028577 0.072765
vt 0.131462 0.009506
vt 0.095186 0.121159
vt 0.939981 0.570899
vt 0.847658 0.645504
vt 0.943912 0.673088
vt 0.539471 0.666598
vt 0.419770 0.688500
vt 0.517323 0.757552
vt 0.793441 0.077875
vt 0.688301 0.119336
vt 0.747790 0.000208
vt 0.307560 0.190162
vt 0.226439 0.301814
vt 0.190162 0.190162
vt 0.343838 0.301814
vt 0.251881 0.380116
vt 0.095186 0.259166
vt 0.131462 0.370818
vt 0.028577 0.307559
vt 0.000208 0.190162
vt 0.737565 0.689877
vt 0.824936 0.743021
vt 0.103663 0.688500
vt 0.223364 0.666598
vt 0.201217 0.757552
vt 0.880811 0.006181
vt 0.632005 0.680774
vt 0.316315 0.674721
vt 0.000208 0.674721
vt 0.289222 0.564268
vt 0.315898 0.680774
vt 0.943912 0.452748
vt 0.824932 0.386505
vt 0.632423 0.635839
vt 0.000208 0.457312
vt 0.315898 0.463365
vt 0.475509 0.009506
vt 0.372624 0.072765
vt 0.430997 0.380533
vt 0.687884 0.078511
vt 0.595927 0.000208
vt 0.691911 0.380533
vt 0.687884 0.301814
vt 0.595927 0.380116
vt 0.880815 0.362696
vt 0.344255 0.190162
vt 0.114890 0.380533
vt 0.475509 0.370818
vt 0.372624 0.307559
vn 0.102400 -0.943500 0.315100
vn 0.700200 -0.661700 0.268000
vn -0.268000 -0.943500 0.194700
vn -0.268000 -0.943500 -0.194700
vn 0.102400 -0.943500 -0.315100
vn 0.905000 -0.330400 0.268000
vn 0.024700 -0.330400 0.943500
vn -0.889700 -0.330400 0.315100
vn -0.574600 -0.330400 -0.748800
vn 0.534600 -0.330400 -0.777900
vn 0.802600 -0.125600 0.583100
vn -0.306600 -0.125600 0.943500
vn -0.992100 -0.125600 0.000000
vn -0.306600 -0.125600 -0.943500
vn 0.802600 -0.125600 -0.583100
vn 0.408900 0.661700 0.628400
vn -0.471300 0.661700 0.583100
vn -0.700200 0.661700 -0.268000
vn 0.038500 0.661700 -0.748800
vn 0.724000 0.661700 -0.194700
vn 0.268000 0.943500 -0.194700
vn 0.491100 0.794700 -0.356800
vn 0.408900 0.661700 -0.628400
vn -0.102400 0.943500 -0.315100
vn -0.187600 0.794700 -0.577300
vn -0.471300 0.661700 -0.583100
vn -0.331300 0.943500 0.000000
vn -0.607100 0.794700 0.000000
vn -0.700200 0.661700 0.268000
vn -0.102400 0.943500 0.315100
vn -0.187600 0.794700 0.577300
vn 0.038500 0.661700 0.748800
vn 0.268000 0.943500 0.194700
vn 0.491100 0.794700 0.356800
vn 0.724000 0.661700 0.194700
vn 0.889700 0.330400 -0.315100
vn 0.794700 0.187600 -0.577300
vn 0.574600 0.330400 -0.748800
vn -0.024700 0.330400 -0.943500
vn -0.303500 0.187600 -0.934200
vn -0.534600 0.330400 -0.777900
vn -0.905000 0.330400 -0.268000
vn -0.982200 0.187600 0.000000
vn -0.905000 0.330400 0.268000
vn -0.534600 0.330400 0.777900
vn -0.303500 0.187600 0.934200
vn -0.024700 0.330400 0.943500
vn 0.574600 0.330400 0.748800
vn 0.794700 0.187600 0.577300
vn 0.889700 0.330400 0.315100
vn 0.306600 0.125600 -0.943500
vn 0.303500 -0.187600 -0.934200
vn 0.024700 -0.330400 -0.943500
vn -0.802600 0.125600 -0.583100
vn -0.794700 -0.187600 -0.577300
vn -0.889700 -0.330400 -0.315100
vn -0.802600 0.125600 0.583100
vn -0.794700 -0.187600 0.577300
vn -0.574600 -0.330400 0.748800
vn 0.306600 0.125600 0.943500
vn 0.303500 -0.187600 0.934200
vn 0.534600 -0.330400 0.777900
vn 0.992100 0.125600 0.000000
vn 0.982200 -0.187600 0.000000
vn 0.905000 -0.330400 -0.268000
vn 0.471300 -0.661700 -0.583100
vn 0.187600 -0.794700 -0.577300
vn -0.038500 -0.661700 -0.748800
vn -0.408900 -0.661700 -0.628400
vn -0.491100 -0.794700 -0.356800
vn -0.724000 -0.661700 -0.194700
vn -0.724000 -0.661700 0.194700
vn -0.491100 -0.794700 0.356800
vn -0.408900 -0.661700 0.628400
vn 0.700200 -0.661700 -0.268000
vn 0.607100 -0.794700 0.000000
vn 0.331300 -0.943500 0.000000
vn -0.038500 -0.661700 0.748800
vn 0.187600 -0.794700 0.577300
vn 0.471300 -0.661700 0.583100
usemtl Material.001
s off
f 1/1/1 14/2/1 13/3/1
f 2/4/2 14/5/2 16/6/2
f 1/1/3 13/3/3 18/7/3
f 1/1/4 18/7/4 20/8/4
f 1/1/5 20/8/5 17/9/5
f 2/4/6 16/6/6 23/10/6
f 3/11/7 15/12/7 25/13/7
f 4/14/8 19/15/8 27/16/8
f 5/17/9 21/18/9 29/19/9
f 6/20/10 22/21/10 31/22/10
f 2/4/11 23/10/11 26/23/11
f 3/11/12 25/13/12 28/24/12
f 4/14/13 27/16/13 30/25/13
f 5/17/14 29/19/14 32/26/14
f 6/27/15 31/28/15 24/29/15
f 7/30/16 33/31/16 38/32/16
f 8/33/17 34/34/17 40/35/17
f 9/36/18 35/37/18 41/38/18
f 10/39/19 36/40/19 42/41/19
f 11/42/20 37/43/20 39/44/20
f 39/45/21 42/46/21 12/47/21
f 39/45/22 37/48/22 42/46/22
f 37/48/23 10/49/23 42/46/23
f 42/46/24 41/50/24 12/47/24
f 42/46/25 36/51/25 41/50/25
f 36/51/26 9/52/26 41/50/26
f 41/50/27 40/35/27 12/47/27
f 41/50/28 35/53/28 40/35/28
f 35/37/29 8/54/29 40/55/29
f 40/35/30 38/32/30 12/47/30
f 40/35/31 34/34/31 38/32/31
f 34/56/32 7/57/32 38/58/32
f 38/32/33 39/45/33 12/47/33
f 38/32/34 33/31/34 39/45/34
f 33/59/35 11/42/35 39/44/35
f 24/29/36 37/43/36 11/42/36
f 24/29/37 31/28/37 37/43/37
f 31/22/38 10/39/38 37/60/38
f 32/26/39 36/40/39 10/39/39
f 32/26/40 29/19/40 36/40/40
f 29/19/41 9/61/41 36/40/41
f 30/25/42 35/37/42 9/36/42
f 30/25/43 27/16/43 35/37/43
f 27/16/44 8/54/44 35/37/44
f 28/24/45 34/56/45 8/62/45
f 28/24/46 25/13/46 34/56/46
f 25/13/47 7/57/47 34/56/47
f 26/63/48 33/64/48 7/57/48
f 26/23/49 23/10/49 33/59/49
f 23/10/50 11/42/50 33/59/50
f 31/22/51 32/26/51 10/39/51
f 31/22/52 22/21/52 32/26/52
f 22/21/53 5/17/53 32/26/53
f 29/65/54 30/25/54 9/36/54
f 29/65/55 21/66/55 30/25/55
f 21/66/56 4/14/56 30/25/56
f 27/16/57 28/67/57 8/54/57
f 27/16/58 19/15/58 28/67/58
f 19/68/59 3/11/59 28/24/59
f 25/13/60 26/63/60 7/57/60
f 25/13/61 15/12/61 26/63/61
f 15/12/62 2/69/62 26/63/62
f 23/10/63 24/29/63 11/42/63
f 23/10/64 16/6/64 24/29/64
f 16/6/65 6/27/65 24/29/65
f 17/9/66 22/70/66 6/71/66
f 17/9/67 20/8/67 22/70/67
f 20/72/68 5/17/68 22/21/68
f 20/8/69 21/73/69 5/74/69
f 20/8/70 18/7/70 21/73/70
f 18/75/71 4/14/71 21/66/71
f 18/75/72 19/15/72 4/14/72
f 18/7/73 13/3/73 19/76/73
f 13/3/74 3/77/74 19/76/74
f 16/6/75 17/78/75 6/27/75
f 16/79/76 14/2/76 17/9/76
f 14/2/77 1/1/77 17/9/77
f 13/80/78 15/12/78 3/11/78
f 13/3/79 14/2/79 15/81/79
f 14/2/80 2/82/80 15/81/80

each line starting with v defines a vertex' position in 3D-space. So I'm reading all these in and create new Vector4 to get homogeneous coordinates.

I ignore vn for now, these would be the normals.

For vt - specifying texture coordinates - I do the same as for the positions.

Now f is prepending the really interesting lines. These are faces, triangles defined as triples of (vertexposition/texturecoordinates/normals). Each of these define which index of positions and texturecoordinates maps together.

So, for example in f 1/1/1 14/2/1 13/3/1 1/1/1 would mean that positions(1) has the texture coordinates(1) (and the last 1 in the first triple would stand for the normal in normals(1))

14/2/1 would mean that positions(14) and texturecoordinates(2) map together.

The whole line would connect these 3 vertices, like (1,14,13) would build up a triangle.

Am I understanding this correctly until here?

val faces: List[(Int, Int, Int)] = objSource.filter(_.startsWith("f ")).map(_.split(" ")).flatten.filterNot(_ == "f").map(_.split("/")).map(a => ((a(0).toInt, a(1).toInt, a(2).toInt)))

Would give me a List of these triples. For each of the entries I would then create a Vertex:

val vertices: List[Vertex] = for(face <- faces) yield(new Vertex(positions(face._1-1), textureCoordinates(face._2-1)))

Vertex is defined like so:

case class Vertex(position: Vector4,/* normal: Vector4,*/ textureCoordinates: Vector2)

I need to do "-1" on each face to avoid off-by-one and IndexOutOfBoundsExceptions, as the index of a List starts with 0 while the indices are starting with 1.

The last thing are the indices: In OpenGL you may use an ELEMENT_ARRAY_BUFFER to specify which vertices are connected and to save (possibly a lot) of data.

As I said earlier, each face f 1/1/1 14/2/1 13/3/1 is built up like this v1/t1/n1 v2/t2/n2 v3/t3/n3 (for each line) so I only need to extract v1,v2,v3, pack it into one long List and let OpenGL do the rest.

v1/v2/v3/v4/v5/v6/.../vn would then be my indices

Am I right or is something wrong until here?

Last but not least I would create a new model:

class Model(vertices: Array[Vertex], indices: Array[Int]/*, textures: Array[Texture]*/)
{
  // Create VAO, VBO and a buffer for the indices
  val vao: Int = glGenVertexArrays
  val vbo: Int = glGenBuffers
  val ibo: Int = glGenBuffers

  setup

  private def setup(): Unit =
  {
    val interleavedBuffer: FloatBuffer = prepareVertexBuffer(vertices)
    val indicesBuffer: IntBuffer = prepareIntBuffer(indices)

    // One VAO to bind them all!
    glBindVertexArray(vao)
      glBindBuffer(GL_ARRAY_BUFFER, vbo)
      glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo)

      // Fill buffers with data
      glBufferData(GL_ARRAY_BUFFER, interleavedBuffer, GL_STATIC_DRAW)
      glBufferData(GL_ELEMENT_ARRAY_BUFFER, indicesBuffer, GL_STATIC_DRAW)

      // Set vertex attribute pointers
      glVertexAttribPointer(0, 4, GL_FLOAT, false, 4*6, 0) // 0 = Position = Vector4(x,y,z,w)
      glVertexAttribPointer(1, 2, GL_FLOAT, false, 4*6, 4*4) // 1 = Texture Coordinates = Vector2(x,y) -> 2 (coordinates) * 4 (byte-size of float) => stride = 4 (position) + 2 (texture coordinates) = 6 * 4 (byte-size of float); offset = 4 (position) * 4 (byte-size of float)

      glBindBuffer(GL_ARRAY_BUFFER, 0)
    glBindVertexArray(0)
  }

  private def prepareIntBuffer(data: Array[Int]): IntBuffer =
  {
    val buffer: IntBuffer = BufferUtils.createIntBuffer(data.length)
    buffer.put(data)
    buffer.flip // Make the buffer readable

    buffer
  }

  private def prepareVertexBuffer(vertices: Array[Vertex]): FloatBuffer =
  {
    val positions: Array[Float] = vertices.map(v => v.position).map(_.toArray).flatten
    val textureCoordinates: Array[Float] = vertices.map(v => v.textureCoordinates).map(_.toArray).flatten

    // TODO remove hardcoded sizes for grouping
    val zipped: Array[Float] = (positions.grouped(4) zip textureCoordinates.grouped(2)).toArray.flatMap {case (x,y) => x ++ y}

    val buffer: FloatBuffer = BufferUtils.createFloatBuffer(zipped.size)
    buffer.put(zipped)
    buffer.flip

    buffer
  }

The problem is, the output looks like this:

While actually it should be an Ico-Sphere from Blender. So, something is really off with my implementation or understanding of the .obj-file-format.

I assume it has to do with the indices, but no idea. I've debugged a lot, manually compared the different Lists with the actual .obj-file but to no avail. Everything looks okay, so I assume it's really my understanding.

edit: I'm not yet sure what exactly I am misunderstanding but, instead of going through the faces to create a List of Vertices (my own class) I gave the model all the positions and texture coordinates and voilà, the meshes appearance looks right (apart from wrong texturing).

So what I did:

class Model(positions: Array[Vector3], texcoords: Array[Vector2], indices: Array[Int])




private def prepareVertexBuffer(positions: Array[Vector3], texcoords: Array[Vector2]): FloatBuffer =
  {
    val pos: Array[Float] = positions.map(_.toArray).flatten
    val textureCoordinates: Array[Float] = texcoords.map(_.toArray).flatten

    // TODO remove hardcoded sizes for grouping
    val zipped: Array[Float] = (pos.grouped(3) zip textureCoordinates.grouped(2)).toArray.flatMap {case (x,y) => x ++ y}

    println(zipped.toList.grouped(5).mkString("\n"))

    val buffer: FloatBuffer = BufferUtils.createFloatBuffer(zipped.size)
    buffer.put(zipped)
    buffer.flip

    buffer
  }

(Note: I've also switched back to Vector3 instead of Vector4 for now. Thought there might be a problem with it)

val indices: List[Int] = faces.map(f => f._1-1) // Wrong?
new Model(vertices.toArray, indices.toArray)

The rest is the same. So I guess my texturing problem results from this.

I now have only 42 vertices instead of 240 (coming from the faces), so I lose a lot of combinations.

The current result:

edit

The problem boils down to the difference between .obj and opengl. OpenGL may only use one index-buffer while in .obj there is one for each attribute.

So I need to manually merge these in an appropriate way. I've found C++ functions for that and although I know C++ quite a bit, I'm not sure why it's not working on my end with Scala.

I simply do not find any duplicates...

解决方案

What you're doing is v1-t1 v2-t2, v3-t3 etc. If you look at your original .obj file, thats probably not whats happening. It could be v1-t1, v2-t1, v3-t1. Who knows. So what you need to do is find the texcoord matching to the vertex. This will get you close to what you want, but not quite there, because in .OBJ files 1 vertex can have multiple texcoords, and right now you can't handle that yet. I have answered a similar question here:

OpenGL - texture are mapped incorrectly using glDrawElements

(Note that you don't HAVE to get rid of the index buffer, but its easier)

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