Crash upon using TexGenAttrib with autoshader

[FenrirWolf]

Panda 1.6.2 from website, Windows 2003 (32), Python 2.5.2.

Use this code to test:

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from pandac.PandaModules import *
import direct.directbase.DirectStart

render.setShaderAuto()

smiley = loader.loadModel ('models/smiley.egg')
smiley.reparentTo (render)

tex = loader.loadTexture ('maps/envir-ground.jpg')
ts = TextureStage ('ts')

smiley.setTexture (ts, tex)
smiley.setTexGen(ts, TexGenAttrib.MWorldPosition)

run()
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The problem is that in ShaderGenerator::synthesize_shader, it enumerates all incoming texture coordinates to the shader. But it doesn't handle out-of-order texture stages with TexGenAttribs. It works fine if the first texture stage has a TexGen, but if it doesn't, there is a gap in the texcoord_vreg/texcoord_freg list, which causes a crash here:

for (int i=0; i<_num_textures; i++) {
    if (!tex_gen->has_stage(texture->get_on_stage(i))) {
      texcoord_vreg.push_back(alloc_vreg());
      texcoord_freg.push_back(alloc_freg());
      text << "\t in float4 vtx_texcoord" << i << " : " << texcoord_vreg[i] << ",\n"; // <-- Oops, crashes because second stage has TexGen, first does not, so #2 referenced in a singular-entry list.
      text << "\t out float4 l_texcoord" << i << " : " << texcoord_freg[i] << ",\n";
    }
  }

Original forum topic: http://www.panda3d.org/phpbb2/viewtopic.php?t=7021