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How to draw a beauty OBJ file.

Posted Wednesday, 16 March, 2011 - 16:26 by Toanso

Hi every one, i want to draw a obj file as shown blow, but i donot know how to make it looks beauty as the third picture shown.
could any one give me some hits. Thanks a lot.

Images
using Triangles mode draw result
using Line_strip mode draw result
how to reach such effect?

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the Fiddler's picture

Re: How to draw a beauty OBJ file.

Posted Wednesday, 16 March, 2011 - 21:50 by the Fiddler

This is much more complex than it looks.

GPU Gems 3 has an article on advanced skin rendering techniques [1], but unless you know how to use shaders it won't be of much help. I'd suggest focusing on that first (learn about diffuse & specular lighting, normal mapping, shadowing and then you can move to more advanced topics such as subsurface scattering and BRDFs).

[1] Chapter 14. Advanced Techniques for Realistic Real-Time Skin Rendering

Toanso's picture

Re: How to draw a beauty OBJ file.

Posted Thursday, 17 March, 2011 - 05:13 by Toanso

I just set light
but it does not work, just as shown in picture,
Below are my render code

Triangles[] contain the vertices' index which in triangle. and normal [] contain the vertices' normal, and texcoord [] contain the vertice's texcoord
What's wrong with me ,Thanks a lot.

      float[] mat_ambient = new float[4] { 0.0f, 0.0f, 0.0f, 0.0f };
    float[] mat_diffuse = new float[4] { 0.2f, 0.3f, 0.5f, 0.0f };
    float[] mat_specular = new float[4] { 1.0f, 0.89f, 0.55f, 0.0f };
    float shineness = 10.0f;
 
      OpenTK.Graphics.OpenGL.GL.Material(MaterialFace.Front, MaterialParameter.Ambient, mat_ambient);
        OpenTK.Graphics.OpenGL.GL.Material(MaterialFace.Front, MaterialParameter.Diffuse, mat_diffuse);
        OpenTK.Graphics.OpenGL.GL.Material(MaterialFace.Front, MaterialParameter.Specular, mat_specular);
        OpenTK.Graphics.OpenGL.GL.Material(MaterialFace.Front, MaterialParameter.Shininess, shineness);
 
        OpenTK.Graphics.OpenGL.GL.Enable(OpenTK.Graphics.OpenGL.EnableCap.Lighting);
 
        OpenTK.Graphics.OpenGL.GL.Color3(mat_diffuse[0], mat_diffuse[1], mat_diffuse[2]);
        GL.Begin(BeginMode.Triangles);
        for (int i = 0; i< Triangles.Length; i++)
        {
            int a = Triangles[i].Index0;
            int b = Triangles[i].Index1;
            int c = Triangles[i].Index2;
 
            GL.Normal3(Vertices[a].Normal.X, Vertices[a].Normal.Y, Vertices[a].Normal.Z);
            GL.TexCoord2(Vertices[a].TexCoord.X, Vertices[a].TexCoord.Y);
            GL.Vertex3(Vertices[a].Vertex.X, Vertices[a].Vertex.Y, Vertices[a].Vertex.Z);
 
            GL.Normal3(Vertices[b].Normal.X, Vertices[b].Normal.Y, Vertices[b].Normal.Z);
            GL.TexCoord2(Vertices[b].TexCoord.X, Vertices[b].TexCoord.Y);
            GL.Vertex3(Vertices[b].Vertex.X, Vertices[b].Vertex.Y, Vertices[b].Vertex.Z);
 
            GL.Normal3(Vertices[c].Normal.X, Vertices[c].Normal.Y, Vertices[c].Normal.Z);
            GL.TexCoord2(Vertices[c].TexCoord.X, Vertices[c].TexCoord.Y);
            GL.Vertex3(Vertices[c].Vertex.X, Vertices[c].Vertex.Y, Vertices[c].Vertex.Z);
 
        }
        GL.End();
        GL.Enable(EnableCap.Lighting);
tksuoran's picture

Re: How to draw a beauty OBJ file.

Posted Thursday, 17 March, 2011 - 11:46 by tksuoran

Check http://glprogramming.com/red/chapter05.html

You don't seem to be specifying your light, so I do not know if the defaults are good for your scene. I do not even remember if any lights are enabled by default, you can individually enable/disable GL_LIGHTi, like glEnable(GL_LIGHT0);

You should check that your normals have valid values, and that they are unit length. If they seem to be otherwise valid but not unit length, you can enable GL_NORMALIZE, or normalize them yourself while you load them.