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simgear/simgear/scene/sky/newcloud.cxx
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// 3D cloud class
//
// Written by Harald JOHNSEN, started April 2005.
//
// Copyright (C) 2005 Harald JOHNSEN - hjohnsen@evc.net
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 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
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
//
#ifdef HAVE_CONFIG_H
# include <simgear_config.h>
#endif
#include <osg/AlphaFunc>
#include <osg/Depth>
#include <osg/Program>
#include <osg/Uniform>
#include <osg/ref_ptr>
#include <osg/Texture2D>
#include <osg/NodeVisitor>
#include <osg/PositionAttitudeTransform>
#include <osg/Material>
#include <osgUtil/UpdateVisitor>
#include <osgDB/ReadFile>
#include <osgDB/FileUtils>
#include <simgear/compiler.h>
#include <simgear/math/sg_random.h>
#include <simgear/misc/sg_path.hxx>
#include <simgear/misc/PathOptions.hxx>
#include <simgear/props/props.hxx>
#include <simgear/scene/model/model.hxx>
#include <simgear/scene/model/SGReaderWriterXMLOptions.hxx>
#include <simgear/scene/util/StateAttributeFactory.hxx>
#include <simgear/scene/util/SGUpdateVisitor.hxx>
#include <algorithm>
#include <osg/BlendFunc>
#include <osg/GLU>
#include <osg/ShadeModel>
#include "cloudfield.hxx"
#include "newcloud.hxx"
#include "CloudShaderGeometry.hxx"
using namespace simgear;
using namespace osg;
namespace
{
typedef std::map<std::string, osg::ref_ptr<Effect> > EffectMap;
EffectMap effectMap;
}
double SGNewCloud::sprite_density = 1.0;
SGNewCloud::SGNewCloud(const SGPath &texture_root, const SGPropertyNode *cld_def)
{
min_width = cld_def->getDoubleValue("min-cloud-width-m", 500.0);
max_width = cld_def->getDoubleValue("max-cloud-width-m", 1000.0);
min_height = cld_def->getDoubleValue("min-cloud-height-m", min_width);
max_height = cld_def->getDoubleValue("max-cloud-height-m", max_width);
min_sprite_width = cld_def->getDoubleValue("min-sprite-width-m", 200.0);
max_sprite_width = cld_def->getDoubleValue("max-sprite-width-m", min_sprite_width);
min_sprite_height = cld_def->getDoubleValue("min-sprite-height-m", min_sprite_width);
max_sprite_height = cld_def->getDoubleValue("max-sprite-height-m", max_sprite_width);
num_sprites = cld_def->getIntValue("num-sprites", 20);
num_textures_x = cld_def->getIntValue("num-textures-x", 4);
num_textures_y = cld_def->getIntValue("num-textures-y", 4);
bottom_shade = cld_def->getDoubleValue("bottom-shade", 1.0);
zscale = cld_def->getDoubleValue("z-scale", 1.0);
texture = cld_def->getStringValue("texture", "cl_cumulus.png");
// Create a new Effect for the texture, if required.
EffectMap::iterator iter = effectMap.find(texture);
if (iter == effectMap.end()) {
SGPropertyNode_ptr pcloudEffect = new SGPropertyNode;
makeChild(pcloudEffect, "inherits-from")->setValue("Effects/cloud");
setValue(makeChild(makeChild(makeChild(pcloudEffect, "parameters"),
"texture"),
"image"),
texture);
ref_ptr<osgDB::ReaderWriter::Options> options
= makeOptionsFromPath(texture_root);
ref_ptr<SGReaderWriterXMLOptions> sgOptions
= new SGReaderWriterXMLOptions(*options.get());
if ((effect = makeEffect(pcloudEffect, true, sgOptions.get())))
effectMap.insert(EffectMap::value_type(texture, effect));
} else {
effect = iter->second.get();
}
quad = createOrthQuad(min_sprite_width, min_sprite_height,
num_textures_x, num_textures_y);
}
SGNewCloud::~SGNewCloud() {
}
osg::Geometry* SGNewCloud::createOrthQuad(float w, float h, int varieties_x, int varieties_y)
{
// Create front and back polygons so we don't need to screw around
// with two-sided lighting in the shader.
osg::Vec3Array& v = *(new osg::Vec3Array(4));
osg::Vec3Array& n = *(new osg::Vec3Array(4));
osg::Vec2Array& t = *(new osg::Vec2Array(4));
float cw = w*0.5f;
v[0].set(0.0f, -cw, 0.0f);
v[1].set(0.0f, cw, 0.0f);
v[2].set(0.0f, cw, h);
v[3].set(0.0f, -cw, h);
// The texture coordinate range is not the
// entire coordinate space - as the texture
// has a number of different clouds on it.
float tx = 1.0f/varieties_x;
float ty = 1.0f/varieties_y;
t[0].set(0.0f, 0.0f);
t[1].set( tx, 0.0f);
t[2].set( tx, ty);
t[3].set(0.0f, ty);
// The normal isn't actually use in lighting.
n[0].set(1.0f, -1.0f, -1.0f);
n[1].set(1.0f, 1.0f, -1.0f);
n[2].set(1.0f, 1.0f, 1.0f);
n[3].set(1.0f, -1.0f, 1.0f);
osg::Geometry *geom = new osg::Geometry;
geom->setVertexArray(&v);
geom->setTexCoordArray(0, &t);
geom->setNormalArray(&n);
geom->setNormalBinding(Geometry::BIND_PER_VERTEX);
// No color for now; that's used to pass the position.
geom->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::QUADS,0,4));
return geom;
}
#if 0
// return a random number between -n/2 and n/2, tending to 0
static float Rnd(float n) {
return n * (-0.5f + (sg_random() + sg_random()) / 2.0f);
}
#endif
osg::ref_ptr<EffectGeode> SGNewCloud::genCloud() {
osg::ref_ptr<EffectGeode> geode = new EffectGeode;
CloudShaderGeometry* sg = new CloudShaderGeometry(num_textures_x, num_textures_y, max_width, max_height, zscale);
// Determine how big this specific cloud instance is. Note that we subtract
// the sprite size because the width/height is used to define the limits of
// the center of the sprites, not their edges.
float width = min_width + sg_random() * (max_width - min_width) - min_sprite_width;
float height = min_height + sg_random() * (max_height - min_height) - min_sprite_height;
// Determine the cull distance. This is used to remove sprites that are too close together.
// The value is squared as we use vector calculations.
float cull_distance_squared = min_sprite_height * min_sprite_height * 0.1f;
// The number of sprites we actually use is a function of the (user-controlled) density
int n_sprites = num_sprites * sprite_density * (0.5 + sg_random());
for (int i = 0; i < n_sprites; i++)
{
// Determine the position of the sprite. Rather than being completely random,
// we place them on the surface of a distorted sphere. However, we place
// the first sprite in the center of the sphere (and at maximum size) to
// ensure good coverage and reduce the chance of there being "holes" in our
float x, y, z;
if (i == 0) {
x = 0;
y = 0;
z = 0;
} else {
double theta = sg_random() * SGD_2PI;
double elev = sg_random() * SGD_PI;
x = width * cos(theta) * 0.5f * sin(elev);
y = width * sin(theta) * 0.5f * sin(elev);
z = height * cos(elev) * 0.5f;
}
// Determine the height and width as scaling factors on the minimum size (used to create the quad).
float sprite_width = 1.0f + sg_random() * (max_sprite_width - min_sprite_width) / min_sprite_width;
float sprite_height = 1.0f + sg_random() * (max_sprite_height - min_sprite_height) / min_sprite_height;
// Sprites are never taller than square.
if (sprite_height * min_sprite_height > sprite_width * min_sprite_width)
{
sprite_height = sprite_width * min_sprite_width / min_sprite_height;
}
if (i == 0) {
// The center sprite is always maximum size to fill up any holes.
sprite_width = 1.0f + (max_sprite_width - min_sprite_width) / min_sprite_width;
sprite_height = 1.0f + (max_sprite_height - min_sprite_height) / min_sprite_height;
}
// Determine the sprite texture indexes.
int index_x = (int) floor(sg_random() * num_textures_x);
if (index_x == num_textures_x) { index_x--; }
// The y index depends on the positing of the sprite within the cloud.
// This allows cloud designers to have particular sprites for the base
// and tops of the cloud.
int index_y = (int) floor((z / height + 0.5f) * num_textures_y);
if (index_y == num_textures_y) { index_y--; }
sg->addSprite(SGVec3f(x, y, z),
index_x,
index_y,
sprite_width,
sprite_height,
bottom_shade,
cull_distance_squared,
height * 0.5f);
}
sg->setGeometry(quad);
geode->addDrawable(sg);
geode->setName("3D cloud");
geode->setEffect(effect.get());
return geode;
}