RaycastVolume.cpp

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#include <vlVolume/RaycastVolume.hpp>
#include <vlGraphics/GLSL.hpp>
#include <vlGraphics/Light.hpp>
#include <vlGraphics/Camera.hpp>

using namespace vl;

RaycastVolume::RaycastVolume()
{
  VL_DEBUG_SET_OBJECT_NAME()
  // box geometry
  mGeometry = new Geometry;

  // install vertex coords array
  mVertCoord = new ArrayFloat3;
  mVertCoord->resize( 8 );
  mGeometry->setVertexArray( mVertCoord.get() );

  // install texture coords array
  mTexCoord = new ArrayFloat3;
  mTexCoord->resize( 8 );
  mGeometry->setTexCoordArray( 0, mTexCoord.get() );

  // install index array
  ref<DrawElementsUInt> de = new DrawElementsUInt( PT_TRIANGLES );
  mGeometry->drawCalls().push_back( de.get() );
  unsigned int de_indices[] =
  {
    0,1,2, 0,2,3, 1,5,6, 1,6,2, 5,4,7, 5,7,6, 4,0,3, 4,3,7, 3,2,6, 3,6,7, 4,5,1, 4,1,0
  };
  de->indexBuffer()->resize( 6 * 6 );
  memcpy( de->indexBuffer()->ptr(), de_indices, sizeof( de_indices ) );

  // generate default texture coordinates
  fvec3 texc[] =
  {
    fvec3( 0,0,0 ), fvec3( 1,0,0 ), fvec3( 1,1,0 ), fvec3( 0,1,0 ),
    fvec3( 0,0,1 ), fvec3( 1,0,1 ), fvec3( 1,1,1 ), fvec3( 0,1,1 )
  };
  memcpy( mTexCoord->ptr(), texc, sizeof( texc ) );

  // default box dimensions and geometry
  setBox( AABB( vec3( 0,0,0 ), vec3( 1,1,1 ) ) );
}
//-----------------------------------------------------------------------------
void RaycastVolume::updateUniforms( vl::Actor*actor, vl::real, const vl::Camera* camera, vl::Renderable*, const vl::Shader* shader )
{
  const GLSLProgram* glsl = shader->getGLSLProgram();
  VL_CHECK( glsl );

  // used later
  fmat4 inv_mat;
  if (actor->transform())
    inv_mat = ( fmat4 )actor->transform()->worldMatrix().getInverse();

  if ( glsl->getUniformLocation( "lights[0].position" ) != -1 && glsl->getUniformLocation( "lights[0].enabled" ) != -1 )
  {
    // computes up to 4 light positions ( in object space ) and enables
    fvec4 light_position;

    int ilight = 0;
    for( ; ilight < 4 && ilight < (int)mLights.size(); ++ilight )
    {
      const vl::Light* light = mLights[ilight].get();
      VL_CHECK( light );
      actor->gocUniform( String::printf("lights[%d].enabled", ilight).toStdString().c_str() )->setUniformI( true );
      if ( light )
      {
        // light position following transform
        if ( light->boundTransform() )
          light_position = ( fmat4 )light->boundTransform()->worldMatrix() * light->position();
        // light position following camera
        else
          light_position = ( ( fmat4 )camera->modelingMatrix() * light->position() );

        // light position in object space
        if ( actor->transform() )
          light_position = inv_mat * light_position;

        actor->gocUniform( String::printf("lights[%d].position", ilight).toStdString().c_str() )->setUniform( light_position );
        actor->gocUniform( String::printf("lights[%d].diffuse", ilight).toStdString().c_str() )->setUniform( light->diffuse() );
        actor->gocUniform( String::printf("lights[%d].specular", ilight).toStdString().c_str() )->setUniform( light->specular() );
        actor->gocUniform( String::printf("lights[%d].ambient", ilight).toStdString().c_str() )->setUniform( light->ambient() );
      }
    }

    // Disable remaining lights
    for( ; ilight < 4; ++ilight ) {
      actor->gocUniform( String::printf("lights[%d].enabled", ilight).toStdString().c_str() )->setUniformI( false );
    }
  }

  if ( glsl->getUniformLocation( "eye_position" ) != -1 )
  {
    // pass the eye position in object space

    // eye postion
    fvec3 eye = ( fvec3 )camera->modelingMatrix().getT();
    // world to object space
    if ( actor->transform() )
      eye = inv_mat * eye;
    actor->gocUniform( "eye_position" )->setUniform( eye );
  }

  if ( glsl->getUniformLocation( "eye_look" ) != -1 )
  {
    // pass the eye look direction in object space

    // eye postion
    fvec3 look = -( fvec3 )camera->modelingMatrix().getZ();
    // world to object space
    if ( actor->transform() )
    {
      // look = inv_mat * look;
      look = ( fmat4 )actor->transform()->worldMatrix().getInverse().getTransposed() * look;
    }
    actor->gocUniform( "eye_look" )->setUniform( look );
  }

  // Normalized x/y/z offeset required to center on a texel
  const Texture* tex = shader->getTextureImageUnit( 0 )->texture();
  fvec3 centering = fvec3(
    0.5f / tex->width(),
    0.5f / tex->height(),
    0.5f / tex->depth()
  );
  actor->gocUniform( "texel_centering" )->setUniform( centering );

  // Compute gradient delta: 0.25 seems to produce better results than 0.5.
  actor->gocUniform( "gradient_delta" )->setUniform( fvec3( 0.25f / tex->width(), 0.25f / tex->height(), 0.25f / tex->depth() ) );
}
//-----------------------------------------------------------------------------
void RaycastVolume::bindActor( Actor* actor )
{
  actor->actorEventCallbacks()->erase( this );
  actor->actorEventCallbacks()->push_back( this );
  actor->setLod( 0, mGeometry.get() );
}
//-----------------------------------------------------------------------------
void RaycastVolume::onActorRenderStarted( Actor* actor, real clock, const Camera* camera, Renderable* rend, const Shader* shader, int pass )
{
  if ( pass>0 )
    return;

  // setup uniform variables

  if ( shader->getGLSLProgram() ) {
    updateUniforms( actor, clock, camera, rend, shader );
  }
}
//-----------------------------------------------------------------------------
void RaycastVolume::generateTextureCoordinates( const ivec3& img_size )
{
  if ( ! img_size.x() || ! img_size.y() || ! img_size.z() )
  {
    Log::error( "RaycastVolume::generateTextureCoordinates(): failed! The size passed does not represent a 3D image.\n" );
    return;
  }

  float dx = 0.5f / img_size.x();
  float dy = 0.5f / img_size.y();
  float dz = 0.5f / img_size.z();

  float x0 = 0.0f + dx;
  float x1 = 1.0f - dx;
  float y0 = 0.0f + dy;
  float y1 = 1.0f - dy;
  float z0 = 0.0f + dz;
  float z1 = 1.0f - dz;

  fvec3 texc[] =
  {
    fvec3( x0,y0,z1 ), fvec3( x1,y0,z1 ), fvec3( x1,y1,z1 ), fvec3( x0,y1,z1 ),
    fvec3( x0,y0,z0 ), fvec3( x1,y0,z0 ), fvec3( x1,y1,z0 ), fvec3( x0,y1,z0 ),
  };
  memcpy( mTexCoord->ptr(), texc, sizeof( texc ) );
}
//-----------------------------------------------------------------------------
void RaycastVolume::setBox( const AABB& box )
{
  mBox = box;
  // generate the box geometry
  float x0 = box.minCorner().x();
  float y0 = box.minCorner().y();
  float z0 = box.minCorner().z();
  float x1 = box.maxCorner().x();
  float y1 = box.maxCorner().y();
  float z1 = box.maxCorner().z();
  fvec3 box_verts[] =
  {
    fvec3( x0,y0,z1 ), fvec3( x1,y0,z1 ), fvec3( x1,y1,z1 ), fvec3( x0,y1,z1 ),
    fvec3( x0,y0,z0 ), fvec3( x1,y0,z0 ), fvec3( x1,y1,z0 ), fvec3( x0,y1,z0 ),
  };
  memcpy( mVertCoord->ptr(), box_verts, sizeof( box_verts ) );
  mGeometry->setBoundsDirty( true );
}
//-----------------------------------------------------------------------------