SkyDome.cpp

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/*
 * This source file is part of the osgOcean library
 *
 * Copyright (C) 2009 Kim Bale
 * Copyright (C) 2009 The University of Hull, UK
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free Software
 * Foundation; either version 3 of the License, or (at your option) any later
 * version.

 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
 * http://www.gnu.org/copyleft/lesser.txt.
 */

#include <uwsim/SkyDome.h>
#include <osgOcean/ShaderManager>

SkyDome::SkyDome(void)
{

}

SkyDome::SkyDome(const SkyDome& copy, const osg::CopyOp& copyop) :
    SphereSegment(copy, copyop)
{

}

SkyDome::SkyDome(float radius, unsigned int longSteps, unsigned int latSteps, osg::TextureCubeMap* cubemap)
{
  compute(radius, longSteps, latSteps, 90.f, 180.f, 0.f, 360.f);
  setupStateSet(cubemap);
}

SkyDome::~SkyDome(void)
{
}

void SkyDome::create(float radius, unsigned int latSteps, unsigned int longSteps, osg::TextureCubeMap* cubemap)
{
  compute(radius, longSteps, latSteps, 90.f, 180.f, 0.f, 360.f);
  setupStateSet(cubemap);
}

void SkyDome::setupStateSet(osg::TextureCubeMap* cubemap)
{
  osg::StateSet* ss = new osg::StateSet;

  ss->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
  ss->setTextureAttributeAndModes(0, cubemap, osg::StateAttribute::ON);
  ss->setAttributeAndModes(createShader().get(), osg::StateAttribute::ON);
  ss->addUniform(new osg::Uniform("uEnvironmentMap", 0));

  setStateSet(ss);
}

osg::ref_ptr<osg::Program> SkyDome::createShader(void)
{
  osg::ref_ptr < osg::Program > program = new osg::Program;

  // Do not use shaders if they were globally disabled.
  if (osgOcean::ShaderManager::instance().areShadersEnabled())
  {
    char vertexSource[] = "varying vec3 vTexCoord;\n"
        "\n"
        "void main(void)\n"
        "{\n"
        "    gl_Position = ftransform();\n"
        "    vTexCoord = gl_Vertex.xyz;\n"
        "}\n";

    char fragmentSource[] = "uniform samplerCube uEnvironmentMap;\n"
        "varying vec3 vTexCoord;\n"
        "\n"
        "void main(void)\n"
        "{\n"
        "   vec3 texcoord = vec3(vTexCoord.x, vTexCoord.y, -vTexCoord.z);\n"
        "   gl_FragData[0] = textureCube( uEnvironmentMap, texcoord.xzy );\n"
        "   gl_FragData[0].a = 0.0;\n"
        "   gl_FragData[1] = vec4(0.0);\n"
        "}\n";

    program->setName("sky_dome_shader");
    program->addShader(new osg::Shader(osg::Shader::VERTEX, vertexSource));
    program->addShader(new osg::Shader(osg::Shader::FRAGMENT, fragmentSource));
  }

  return program;
}