CXX: problems with getting TextureAttribs to work

C++ coding using Panda3D
1

Hi,

I’d like to create some texture quads on the fly from CXX. I’ve managed the dynamic creation of the quads so far, but I can’t get texturing to work. I just can’t seem to set up the RenderState properly.

Look at the code below (sorry for the lenght, but I wanted to paste the whole, working program)

#include "pandaFramework.h"
#include "pandaSystem.h"
#include "geomVertexFormat.h"
#include "geomVertexArrayFormat.h"
#include "geomVertexData.h"
#include "geomVertexWriter.h"
#include "geomTriangles.h"
#include "geom.h"
#include "geomNode.h"
#include "renderState.h"
#include "TextureAttrib.h"
#include "TextureStage.h"
#include "TexturePool.h"

PandaFramework framework;

int main(int argc, char *argv[]) {
  // init framework, open window
  framework.open_framework(argc, argv);   
  framework.set_window_title("My Panda3D Window");
  WindowFramework *window = framework.open_window();

  
  NodePath cam = window->get_camera_group(); //get the camera and store it
  //load the environment model
  NodePath environ = window->load_model(framework.get_models(),"models/environment.egg");
  environ.reparent_to(window->get_render());
  environ.set_scale(0.25,0.25,0.25);
  environ.set_pos(-8,42,0);

  //load an additional texure for the textured quad 
  Texture* tex = TexturePool::load_texture("maps/panda-model.jpg");

  // build the geometry
  const GeomVertexFormat* gf = GeomVertexFormat::get_v3t2();
  PT(GeomVertexData) vdata = new GeomVertexData("test", gf, GeomEnums::UsageHint::UH_static);
  GeomVertexWriter vwriter(vdata, "vertex");
  GeomVertexWriter twriter(vdata, "texture");

  vwriter.add_data3f(-1,0,-1);
  twriter.add_data2f(0,0);
  vwriter.add_data3f(0,0,-1);
  twriter.add_data2f(1,0);
  vwriter.add_data3f(0,0,0);
  twriter.add_data2f(1,1);
  vwriter.add_data3f(-1,0,0);
  twriter.add_data2f(0,1);

  PT(GeomTriangles) prim = new GeomTriangles(GeomEnums::UsageHint::UH_static);
  prim->add_vertices(0,1,2);
  prim->close_primitive();
  prim->add_vertices(0,2,3);
  prim->close_primitive();

  PT(Geom) geom = new Geom(vdata);
  geom->add_primitive(prim);

  // create the render state
  CPT(RenderState) state = RenderState::make(TextureAttrib::make(tex));
  PT(GeomNode) node = new GeomNode("gnode");
  node->add_geom(geom, state);

  window->get_render_2d().attach_new_node(node);

  window->setup_trackball();

  framework.main_loop();

  framework.close_framework();
  return (0);
}

This program works, but it renders the quad untextured (white).
I’m guessing that either 1) the setup of the renderstate is wrong:

  // create the render state
  CPT(RenderState) state = RenderState::make(TextureAttrib::make(tex));
  PT(GeomNode) node = new GeomNode("gnode");
  node->add_geom(geom, state);

or that 2) maybe I need to enable texturing for this node somehow?

And furthermore I’m a bit uneasy because the inline doc says that the call to

TextureAttrib::make(Texture)

is deprecated. But I’m completely lost with the new multi-texture-stage…

Any help is (as usual) appreciated.

Thanks in advance,

Erik

2

I think your problem is this line:

GeomVertexWriter twriter(vdata, "texture");

There is no column called “texture”, so this is creating a writer that does nothing. (I’m surprised it’s not printing any error messages when you try to use it; I should fix that.) The name for the texture coordinate column is “texcoord”.

As to the deprecated interface, the multitexture way to do the same thing would be:

CPT(TextureAttrib) txa = TextureAttrib::make();
txa = txa->add_on_stage(TextureStage::get_default(), tex);
CPT(RenderState) state = RenderState::make(txa);

But this is clumsy enough that I think the original, simpler TextureAttrib interface should be used instead. We decided not to deprecate it since single-texturing is so common and useful. I’ll remove the stale comments about deprecation.

David

3

David,

You’re the man! Switching from “texture” to “texcoord” solved the problem.
And btw, it actually did complain about the mis-spelled column name, but I didn’t notice because I had the output level for the gsg set to ‘spam’, so I receive a lot of spew each frame and just hadn’t noticed.

Anyway, it works now and I’m happy! :smiley:

Thanks,

Erik