3 // Written by Harald JOHNSEN, started April 2005.
5 // Copyright (C) 2005 Harald JOHNSEN - hjohnsen@evc.net
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
24 # include <simgear_config.h>
27 #include <osg/AlphaFunc>
29 #include <osg/Program>
30 #include <osg/Uniform>
31 #include <osg/ref_ptr>
32 #include <osg/Texture2D>
33 #include <osg/NodeVisitor>
34 #include <osg/PositionAttitudeTransform>
35 #include <osg/Material>
36 #include <osgUtil/UpdateVisitor>
37 #include <osgDB/ReadFile>
38 #include <osgDB/FileUtils>
41 #include <simgear/compiler.h>
44 #include <simgear/math/sg_random.h>
45 #include <simgear/misc/sg_path.hxx>
46 #include <simgear/misc/PathOptions.hxx>
47 #include <simgear/scene/model/model.hxx>
48 #include <simgear/scene/util/StateAttributeFactory.hxx>
49 #include <simgear/scene/util/SGUpdateVisitor.hxx>
52 #include <osg/BlendFunc>
54 #include <osg/ShadeModel>
56 #include "cloudfield.hxx"
57 #include "newcloud.hxx"
58 #include "CloudShaderGeometry.hxx"
60 using namespace simgear;
63 typedef std::map<std::string, osg::ref_ptr<osg::StateSet> > StateSetMap;
65 StateSetMap cloudTextureMap;
66 double SGNewCloud::sprite_density = 1.0;
68 static char vertexShaderSource[] =
71 "varying float fogFactor;\n"
72 "attribute vec3 usrAttr1;\n"
73 "attribute vec3 usrAttr2;\n"
74 "float textureIndexX = usrAttr1.r;\n"
75 "float textureIndexY = usrAttr1.g;\n"
76 "float wScale = usrAttr1.b;\n"
77 "float hScale = usrAttr2.r;\n"
78 "float shade = usrAttr2.g;\n"
79 "float cloud_height = usrAttr2.b;\n"
82 " gl_TexCoord[0] = gl_MultiTexCoord0 + vec4(textureIndexX, textureIndexY, 0.0, 0.0);\n"
83 " vec4 ep = gl_ModelViewMatrixInverse * vec4(0.0,0.0,0.0,1.0);\n"
84 " vec4 l = gl_ModelViewMatrixInverse * vec4(0.0,0.0,1.0,1.0);\n"
85 " vec3 u = normalize(ep.xyz - l.xyz);\n"
86 // Find a rotation matrix that rotates 1,0,0 into u. u, r and w are
87 // the columns of that matrix.
88 " vec3 absu = abs(u);\n"
89 " vec3 r = normalize(vec3(-u.y, u.x, 0));\n"
90 " vec3 w = cross(u, r);\n"
91 // Do the matrix multiplication by [ u r w pos]. Assume no
92 // scaling in the homogeneous component of pos.
93 " gl_Position = vec4(0.0, 0.0, 0.0, 1.0);\n"
94 " gl_Position.xyz = gl_Vertex.x * u * wScale;\n"
95 " gl_Position.xyz += gl_Vertex.y * r * hScale;\n"
96 " gl_Position.xyz += gl_Vertex.z * w;\n"
97 " gl_Position.xyz += gl_Color.xyz;\n"
98 // Determine a lighting normal based on the vertex position from the
99 // center of the cloud, so that sprite on the opposite side of the cloud to the sun are darker.
100 " float n = dot(normalize(gl_LightSource[0].position.xyz), normalize(mat3x3(gl_ModelViewMatrix) * gl_Position.xyz));\n"
101 // Determine the position - used for fog and shading calculations
102 " vec3 ecPosition = vec3(gl_ModelViewMatrix * gl_Position);\n"
103 " float fogCoord = abs(ecPosition.z);\n"
104 " float fract = smoothstep(0.0, cloud_height, gl_Position.z + cloud_height);\n"
105 // Final position of the sprite
106 " gl_Position = gl_ModelViewProjectionMatrix * gl_Position;\n"
107 // Limit the normal range from [0,1.0], and apply the shading (vertical factor)
108 " n = min(smoothstep(-0.5, 0.5, n), shade * (1.0 - fract) + fract);\n"
109 // This lighting normal is then used to mix between almost pure ambient (0) and diffuse (1.0) light
110 " vec4 backlight = 0.9 * gl_LightSource[0].ambient + 0.1 * gl_LightSource[0].diffuse;\n"
111 " gl_FrontColor = mix(backlight, gl_LightSource[0].diffuse, n);\n"
112 " gl_FrontColor += gl_FrontLightModelProduct.sceneColor;\n"
113 // As we get within 100m of the sprite, it is faded out. Equally at large distances it also fades out.
114 " gl_FrontColor.a = min(smoothstep(10.0, 100.0, fogCoord), 1 - smoothstep(15000.0, 20000.0, fogCoord));\n"
115 " gl_BackColor = gl_FrontColor;\n"
116 // Fog doesn't affect clouds as much as other objects.
117 " fogFactor = exp( -gl_Fog.density * fogCoord * 0.5);\n"
118 " fogFactor = clamp(fogFactor, 0.0, 1.0);\n"
121 static char fragmentShaderSource[] =
122 "uniform sampler2D baseTexture; \n"
123 "varying float fogFactor;\n"
127 " vec4 base = texture2D( baseTexture, gl_TexCoord[0].st);\n"
128 " vec4 finalColor = base * gl_Color;\n"
129 " gl_FragColor.rgb = mix(gl_Fog.color.rgb, finalColor.rgb, fogFactor );\n"
130 " gl_FragColor.a = finalColor.a;\n"
133 SGNewCloud::SGNewCloud(string type,
134 const SGPath &tex_path,
152 min_sprite_width(min_sprite_w),
153 max_sprite_width(max_sprite_w),
154 min_sprite_height(min_sprite_h),
155 max_sprite_height(max_sprite_h),
158 num_textures_x(nt_x),
159 num_textures_y(nt_y),
163 // Create a new StateSet for the texture, if required.
164 StateSetMap::iterator iter = SGCloudField::cloudTextureMap.find(texture);
166 if (iter == SGCloudField::cloudTextureMap.end()) {
167 stateSet = new osg::StateSet;
169 osg::ref_ptr<osgDB::ReaderWriter::Options> options = makeOptionsFromPath(tex_path);
171 osg::Texture2D *tex = new osg::Texture2D;
172 tex->setWrap( osg::Texture2D::WRAP_S, osg::Texture2D::CLAMP );
173 tex->setWrap( osg::Texture2D::WRAP_T, osg::Texture2D::CLAMP );
174 tex->setImage(osgDB::readImageFile(texture, options.get()));
176 StateAttributeFactory* attribFactory = StateAttributeFactory::instance();
178 stateSet->setMode(GL_LIGHTING, osg::StateAttribute::ON);
179 stateSet->setMode(GL_CULL_FACE, osg::StateAttribute::OFF);
182 stateSet->setAttributeAndModes(attribFactory->getSmoothShadeModel());
183 stateSet->setAttributeAndModes(attribFactory->getStandardBlendFunc());
185 stateSet->setTextureAttributeAndModes(0, tex, osg::StateAttribute::ON );
186 stateSet->setRenderBinDetails(osg::StateSet::TRANSPARENT_BIN, "DepthSortedBin");
187 // Turn off z buffer writes. Standard hack for
188 // semi-transparent geometry to avoid sorting / flickering
190 stateSet->setAttributeAndModes(attribFactory->getDepthWritesDisabled());
191 static ref_ptr<AlphaFunc> alphaFunc;
192 static ref_ptr<Program> program;
193 static ref_ptr<Uniform> baseTextureSampler;
194 static ref_ptr<Material> material;
196 // Generate the shader etc, if we don't already have one.
197 if (!program.valid()) {
198 alphaFunc = new AlphaFunc;
199 alphaFunc->setFunction(AlphaFunc::GREATER,0.05f);
200 program = new Program;
201 baseTextureSampler = new osg::Uniform("baseTexture", 0);
202 Shader* vertex_shader = new Shader(Shader::VERTEX, vertexShaderSource);
203 program->addShader(vertex_shader);
204 program->addBindAttribLocation("usrAttr1", CloudShaderGeometry::USR_ATTR_1);
205 program->addBindAttribLocation("usrAttr2", CloudShaderGeometry::USR_ATTR_2);
206 Shader* fragment_shader = new Shader(Shader::FRAGMENT, fragmentShaderSource);
207 program->addShader(fragment_shader);
208 material = new Material;
209 // DonĀ“t track vertex color
210 material->setColorMode(Material::OFF);
212 // We don't actually use the material information either - see shader.
213 material->setAmbient(Material::FRONT_AND_BACK,
214 Vec4(0.5f, 0.5f, 0.5f, 1.0f));
215 material->setDiffuse(Material::FRONT_AND_BACK,
216 Vec4(0.5f, 0.5f, 0.5f, 1.0f));
219 stateSet->setAttributeAndModes(alphaFunc.get());
220 stateSet->setAttribute(program.get());
221 stateSet->addUniform(baseTextureSampler.get());
222 stateSet->setMode(GL_VERTEX_PROGRAM_TWO_SIDE, StateAttribute::ON);
223 stateSet->setAttribute(material.get());
225 // Add the newly created texture to the map for use later.
226 SGCloudField::cloudTextureMap.insert(StateSetMap::value_type(texture, stateSet));
228 stateSet = iter->second.get();
231 quad = createOrthQuad(min_sprite_width, min_sprite_height, num_textures_x, num_textures_y);
234 SGNewCloud::~SGNewCloud() {
237 osg::Geometry* SGNewCloud::createOrthQuad(float w, float h, int varieties_x, int varieties_y)
239 // Create front and back polygons so we don't need to screw around
240 // with two-sided lighting in the shader.
241 osg::Vec3Array& v = *(new osg::Vec3Array(4));
242 osg::Vec3Array& n = *(new osg::Vec3Array(4));
243 osg::Vec2Array& t = *(new osg::Vec2Array(4));
247 v[0].set(0.0f, -cw, 0.0f);
248 v[1].set(0.0f, cw, 0.0f);
249 v[2].set(0.0f, cw, h);
250 v[3].set(0.0f, -cw, h);
252 // The texture coordinate range is not the
253 // entire coordinate space - as the texture
254 // has a number of different clouds on it.
255 float tx = 1.0f/varieties_x;
256 float ty = 1.0f/varieties_y;
258 t[0].set(0.0f, 0.0f);
263 // The normal isn't actually use in lighting.
264 n[0].set(1.0f, -1.0f, -1.0f);
265 n[1].set(1.0f, 1.0f, -1.0f);
266 n[2].set(1.0f, 1.0f, 1.0f);
267 n[3].set(1.0f, -1.0f, 1.0f);
269 osg::Geometry *geom = new osg::Geometry;
271 geom->setVertexArray(&v);
272 geom->setTexCoordArray(0, &t);
273 geom->setNormalArray(&n);
274 geom->setNormalBinding(Geometry::BIND_PER_VERTEX);
275 // No color for now; that's used to pass the position.
276 geom->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::QUADS,0,4));
282 // return a random number between -n/2 and n/2, tending to 0
283 static float Rnd(float n) {
284 return n * (-0.5f + (sg_random() + sg_random()) / 2.0f);
288 osg::ref_ptr<Geode> SGNewCloud::genCloud() {
290 osg::ref_ptr<osg::Geode> geode = new Geode;
292 CloudShaderGeometry* sg = new CloudShaderGeometry(num_textures_x, num_textures_y, max_width, max_height);
294 // Determine how big this specific cloud instance is. Note that we subtract
295 // the sprite size because the width/height is used to define the limits of
296 // the center of the sprites, not their edges.
297 float width = min_width + sg_random() * (max_width - min_width) - min_sprite_width;
298 float height = min_height + sg_random() * (max_height - min_height) - min_sprite_height;
300 // Determine the cull distance. This is used to remove sprites that are too close together.
301 // The value is squared as we use vector calculations.
302 float cull_distance_squared = min_sprite_height * min_sprite_height * 0.1f;
304 // The number of sprites we actually used is a function of the (user-controlled) density
305 int n_sprites = num_sprites * sprite_density;
307 for (int i = 0; i < n_sprites; i++)
309 // Determine the position of the sprite. Rather than being completely random,
310 // we place them on the surface of a distorted sphere. However, we place
311 // the first and second sprites on the top and bottom, and the third in the
312 // center of the sphere (and at maximum size) to ensure good coverage and
313 // reduce the chance of there being "holes" in our cloud.
329 double theta = sg_random() * SGD_2PI;
330 double elev = sg_random() * SGD_PI;
331 x = width * cos(theta) * 0.5f * sin(elev);
332 y = width * sin(theta) * 0.5f * sin(elev);
333 z = height * cos(elev) * 0.5f;
336 SGVec3f *pos = new SGVec3f(x, y, z);
338 // Determine the height and width as scaling factors on the minimum size (used to create the quad)
339 float sprite_width = 1.0f + sg_random() * (max_sprite_width - min_sprite_width) / min_sprite_width;
340 float sprite_height = 1.0f + sg_random() * (max_sprite_height - min_sprite_height) / min_sprite_height;
343 // The center sprite is always maximum size to fill up any holes.
344 sprite_width = 1.0f + (max_sprite_width - min_sprite_width) / min_sprite_width;
345 sprite_height = 1.0f + (max_sprite_height - min_sprite_height) / min_sprite_height;
348 // Determine the sprite texture indexes;
349 int index_x = (int) floor(sg_random() * num_textures_x);
350 if (index_x == num_textures_x) { index_x--; }
352 int index_y = (int) floor(sg_random() * num_textures_y);
353 if (index_y == num_textures_y) { index_y--; }
361 cull_distance_squared,
365 sg->setGeometry(quad);
366 geode->addDrawable(sg);
367 geode->setName("3D cloud");
368 geode->setStateSet(stateSet.get());