Models don't render properly

OpenGL Development
#1

Hey Guys,
I wrote an OBJ Loader for my Engine but my Models look very weird.I export the models with the following options but they look not the same like in Blender :confused:

Export Settings:

https://www2.pic-upload.de/thumb/32943671/34930cd3a6f067d62369ad0df4a77c46.png

Engine Look:

https://www2.pic-upload.de/thumb/32943653/3ef610991747b04e37a911378615cadd.png

OBJ Loader Code:


public class OBJLoader {

	public static RawModel loadObjModel(String fileName, ModelLoader loader) {
		FileReader fr = null;
		try {
			fr = new FileReader(new File("maps/testMap/" + fileName + ".obj"));
		} catch (FileNotFoundException e) {
			System.out.println("Couldn't load file!");
			e.printStackTrace();
		}
		BufferedReader reader = new BufferedReader(fr);
		String line;
		List<Vector3f> vertices = new ArrayList<Vector3f>();
		List<Vector2f> textures = new ArrayList<Vector2f>();
		List<Vector3f> normals = new ArrayList<Vector3f>();
		List<Integer> indices = new ArrayList<Integer>();
		float[] verticesArray = null;
		float[] normalsArray = null;
		float[] textureArray = null;
		int[] indicesArray = null;
		try {

			while (true) {
				line = reader.readLine();
				String[] currentLine = line.split(" ");
				if (line.startsWith("v ")) {
					Vector3f vertex = new Vector3f(Float.parseFloat(currentLine[1]), Float.parseFloat(currentLine[2]), Float.parseFloat(currentLine[3]));
					vertices.add(vertex);
				} else if (line.startsWith("vt ")) {
					Vector2f texture = new Vector2f(Float.parseFloat(currentLine[1]), Float.parseFloat(currentLine[2]));
					textures.add(texture);
				} else if (line.startsWith("vn ")) {
					Vector3f normal = new Vector3f(Float.parseFloat(currentLine[1]), Float.parseFloat(currentLine[2]), Float.parseFloat(currentLine[3]));
					normals.add(normal);
				} else if (line.startsWith("f ")) {
					textureArray = new float[vertices.size() * 2];
					normalsArray = new float[vertices.size() * 3];
					break;
				}
			}

			while (line != null) {
				if (!line.startsWith("f ")) {
					line = reader.readLine();
					continue;
				}
				String[] currentLine = line.split(" ");
				String[] vertex1 = currentLine[1].split("/");
				String[] vertex2 = currentLine[2].split("/");
				String[] vertex3 = currentLine[3].split("/");

				processVertex(vertex1, indices, textures, normals, textureArray, normalsArray);
				processVertex(vertex2, indices, textures, normals, textureArray, normalsArray);
				processVertex(vertex3, indices, textures, normals, textureArray, normalsArray);
				line = reader.readLine();
			}
			reader.close();

		} catch (Exception e) {
			e.printStackTrace();
		}

		verticesArray = new float[vertices.size() * 3];
		indicesArray = new int[indices.size()];

		int vertexPointer = 0;
		for (Vector3f vertex : vertices) {
			verticesArray[vertexPointer++] = vertex.x;
			verticesArray[vertexPointer++] = vertex.y;
			verticesArray[vertexPointer++] = vertex.z;
		}

		for (int i = 0; i < indices.size(); i++) {
			indicesArray[i] = indices.get(i);
		}
		return loader.loadToVAO(verticesArray, textureArray, indicesArray);

	}

	private static void processVertex(String[] vertexData, List<Integer> indices, List<Vector2f> textures, List<Vector3f> normals, float[] textureArray, float[] normalsArray) {
		int currentVertexPointer = Integer.parseInt(vertexData[0]) - 1;
		indices.add(currentVertexPointer);
		Vector2f currentTex = textures.get(Integer.parseInt(vertexData[1]) - 1);
		textureArray[currentVertexPointer * 2] = currentTex.x;
		textureArray[currentVertexPointer * 2 + 1] = 1 - currentTex.y;
		Vector3f currentNorm = normals.get(Integer.parseInt(vertexData[2]) - 1);
		normalsArray[currentVertexPointer * 3] = currentNorm.x;
		normalsArray[currentVertexPointer * 3 + 1] = currentNorm.y;
		normalsArray[currentVertexPointer * 3 + 2] = currentNorm.z;
	}

}
#2

It looks like it’s just a texture coordinate issue…

#3

Yeah I thought about that too but what could be wrong ? :confused:

#4

You are not taking into account that the same vertex position (the ‘v’ lines) can be shared by multiple faces (the ‘f’ lines) when at the same time the texture coordinates are not being shared.
This becomes apparent in the first line of the ‘processVertex’ method:
[icode]int currentVertexPointer = Integer.parseInt(vertexData[0]) - 1;[/icode]
which you use to index into the textureArray. This leads to the same element inside the textureArray being overwritten multiple times. So you try to index into the textureArray by the vertex position index. You cannot do this.

#5

So what could I do do solve this Problem, because I use this Code from ThinMatrix Tutorials and for him the Loader works.Or is there an option in Blender for this ?

#6

Am I to take you seriously here? You copied someone’s code. Then you asked why it is not working. Then you were given the reason why, and now you want to know how to fix it?
Where in this chain of whys and hows is there any work done by you?
So, either:

  • copy someone else’s code that actually works
  • understand the Wavefront OBJ format and write a small custom loader
#7

Ah sorry I fixed the Problem :slight_smile: The solution was that I apply Edge Split in Blender and now everything works fine and yes this is only temporary, I rewrite the OBJ Loader and yes I understand the Wavefront OBJ Format very well :slight_smile: