I want to export Points form Blender model

Pipeline
1

I make a geometry shader. The shader be able to vertices into grass. But when export a only point model, VertexPool is empty.


64af0977jw1e6qanjq755j20ma0hhaex.jpg690×541

2

YABEE works with polygons and ignores vertices, which not assigned to them. You can try to export vertices through *.x format and then convert it with x2egg.

3

This is my gress.x file:

xof 0303txt 0032

Frame Root {
  FrameTransformMatrix {
     1.000000, 0.000000, 0.000000, 0.000000,
     0.000000, 0.000000, 1.000000, 0.000000,
     0.000000, 1.000000,-0.000000, 0.000000,
     0.000000, 0.000000, 0.000000, 1.000000;;
  }
  Frame gress2 {
    FrameTransformMatrix {
      -1.000000,-0.000000, 0.000000, 0.000000,
       0.000000,-1.000000, 0.000000, 0.000000,
       0.000000, 0.000000, 1.000000, 0.000000,
       0.000000, 0.000000, 0.000000, 1.000000;;
    }
    Mesh { //Plane_003 Mesh
      0;
      0;
      MeshNormals { //Plane_003 Normals
        0;
        0;
      } //End of Plane_003 Normals
      MeshMaterialList { //Plane_003 Material List
        0;
        0;
      } //End of Plane_003 Material List
      MeshTextureCoords { //Plane_003 UV Coordinates
        0;
      } //End of Plane_003 UV Coordinates
    } //End of Plane_003 Mesh
  } //End of gress2
  Frame gress1 {
    FrameTransformMatrix {
       1.000000, 0.000000, 0.000000, 0.000000,
       0.000000, 1.000000, 0.000000, 0.000000,
       0.000000, 0.000000, 1.000000, 0.000000,
       0.000000, 0.000000, 0.000000, 1.000000;;
    }
    Mesh { //Plane_003 Mesh
      0;
      0;
      MeshNormals { //Plane_003 Normals
        0;
        0;
      } //End of Plane_003 Normals
      MeshMaterialList { //Plane_003 Material List
        0;
        0;
      } //End of Plane_003 Material List
      MeshTextureCoords { //Plane_003 UV Coordinates
        0;
      } //End of Plane_003 UV Coordinates
    } //End of Plane_003 Mesh
  } //End of gress1
} //End of Root Frame

“grass1” and “grass2” are still empty.

4

Hmm… seems that *.x also not support separate vertices. Another variant - *.obj -> obj2egg

5

Indeed there are many vertices in the gress.obj file, but when I use obj2egg, the gress.egg is:

<CoordinateSystem> { Z-Up }

<Comment> {
  "obj2egg gress.obj -o gress.egg"
}
<VertexPool> vpool {
}
<Group> root {
}

When I use:

...
...
g = loader.loadModel('bridge')
g.reparentTo(render)
gress = loader.loadModel('gress.obj')
gress.reparentTo(render)
gress.ls()
...
...
...
shader = Shader.load(Shader.SLGLSL, 'vshader.glsl', 'fshader.glsl', 'gshader.glsl')
gress.setShader(shader)
...
...

I got:

ModelRoot /home/liu/code/panda/tut/4/gress.obj
  PandaNode 
    GeomNode points (1 geoms)
:display:gsg:glgsg(error): at 3388 of panda/src/glstuff/glGraphicsStateGuardian_src.cxx : invalid operation
[VGL] NOTICE: Pixel format of 2D X server does not match pixel format of
[VGL]    Pbuffer.  Disabling PBO readback.
:display:gsg:glgsg(error): at 3388 of panda/src/glstuff/glGraphicsStateGuardian_src.cxx : invalid operation
:display:gsg:glgsg(error): at 3388 of panda/src/glstuff/glGraphicsStateGuardian_src.cxx : invalid operation
:display:gsg:glgsg(error): at 3388 of panda/src/glstuff/glGraphicsStateGuardian_src.cxx : invalid operation
...
...
6

Seems that obj2egg is varies according to the Panda version.
With the dev version I also get empty vertex pool, but with another (don’t remember exactly, possible 1.8.1) - I get vertex pool with vertices

7

Could you perhaps get around the problem by triangulating your set of vertices and deleting the resultant NodePath when you’re done?

8

It seems like you’ll need to do what Thaumaturge suggested. When I try to load a model with vertices but no faces, Panda3d seems to ignore them and not create any geom nodes to store their positions in. You’ll probably need to make them a part of an actual model to ensure panda3d doesn’t optimise them away.

9

I update model:

and geomerty shader:

//GLSL

//gshader

#version 150

in VertexData {
	vec2 texCoord;
	vec3 normal;
} VertexIn[3];

out VertexData {
	vec2 texCoord;
	vec3 normal;
} VertexOut;

void main() {

	vec4 p00 = gl_in[0].gl_Position;
	if(p00.z > 0 && p00.z < 200) {
		if(p00.x/p00.z>-1.3 && p00.x/p00.z<1.3) {
			for(int i = 0; i < gl_in.length(); i++) {
				p00 = gl_in[i].gl_Position;
	  
				gl_Position =  (vec4(-1.6,0,0.0,0.0) + p00);  
				VertexOut.texCoord = vec2(0.02,0.52);
				EmitVertex();  
			  
				gl_Position =  (vec4(1.6,0,0.0,0.0) + p00); 
				VertexOut.texCoord = vec2(0.48,0.52); 
				EmitVertex();  

				gl_Position =  (vec4(-1.6,3.5,0.0,0.0) + p00); 
				VertexOut.texCoord = vec2(0.02,0.98); 
				EmitVertex();  
				gl_Position =  (vec4(1.6,3.5,0.0,0.0) + p00); 
				VertexOut.texCoord = vec2(0.48,0.98); 
				EmitVertex();
				EndPrimitive(); 
			}  
		}
	}
}

// 草坪的纹理来自 xsinick+Tristan.

May be it better performance.

64af0977jw1e6s6v9ghyej20ma0hhaeq.jpg690×541