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>
28 #include <osg/Program>
29 #include <osg/Uniform>
30 #include <osg/ref_ptr>
31 #include <osg/Texture2D>
32 #include <osg/NodeVisitor>
33 #include <osg/PositionAttitudeTransform>
34 #include <osg/Material>
35 #include <osgUtil/UpdateVisitor>
36 #include <osgDB/ReadFile>
37 #include <osgDB/FileUtils>
40 #include <simgear/compiler.h>
43 #include <simgear/math/sg_random.h>
44 #include <simgear/misc/sg_path.hxx>
45 #include <simgear/misc/PathOptions.hxx>
46 #include <simgear/scene/model/model.hxx>
47 #include <simgear/scene/util/StateAttributeFactory.hxx>
48 #include <simgear/scene/util/SGUpdateVisitor.hxx>
53 #include "cloudfield.hxx"
54 #include "newcloud.hxx"
55 #include "CloudShaderGeometry.hxx"
57 using namespace simgear;
60 typedef std::map<std::string, osg::ref_ptr<osg::StateSet> > StateSetMap;
62 static StateSetMap cloudTextureMap;
64 static char vertexShaderSource[] =
67 "varying float fogFactor;\n"
68 "varying float alphaBlend;\n"
69 "attribute float textureIndexX;\n"
70 "attribute float textureIndexY;\n"
71 "attribute float wScale;\n"
72 "attribute float hScale;\n"
73 "attribute float shade;\n"
76 " gl_TexCoord[0] = gl_MultiTexCoord0 + vec4(textureIndexX, textureIndexY, 0.0, 0.0);\n"
77 " vec4 ep = gl_ModelViewMatrixInverse * vec4(0.0,0.0,0.0,1.0);\n"
78 " vec4 l = gl_ModelViewMatrixInverse * vec4(0.0,0.0,1.0,1.0);\n"
79 " vec3 u = normalize(ep.xyz - l.xyz);\n"
80 // Find a rotation matrix that rotates 1,0,0 into u. u, r and w are
81 // the columns of that matrix.
82 " vec3 absu = abs(u);\n"
83 " vec3 r = normalize(vec3(-u.y, u.x, 0));\n"
84 " vec3 w = cross(u, r);\n"
85 // Do the matrix multiplication by [ u r w pos]. Assume no
86 // scaling in the homogeneous component of pos.
87 " gl_Position = vec4(0.0, 0.0, 0.0, 1.0);\n"
88 " gl_Position.xyz = gl_Vertex.x * u * wScale;\n"
89 " gl_Position.xyz += gl_Vertex.y * r * hScale;\n"
90 " gl_Position.xyz += gl_Vertex.z * w;\n"
91 " gl_Position.xyz += gl_Color.xyz;\n"
92 // Determine a lighting normal based on the sprites position from the
93 // center of the cloud.
94 " float n = dot(normalize(gl_LightSource[0].position.xyz), normalize(mat3x3(gl_ModelViewMatrix) * gl_Position.xyz));\n"
95 // Determine the position - used for fog and shading calculations
96 " vec3 ecPosition = vec3(gl_ModelViewMatrix * gl_Position);\n"
97 " float fogCoord = abs(ecPosition.z);\n"
98 // Final position of the sprite
99 " gl_Position = gl_ModelViewProjectionMatrix * gl_Position;\n"
100 // Limit the normal range from [0,1.0], and apply the shading (vertical factor)
101 " n = min(smoothstep(-0.5, 0.5, n), shade);\n"
102 // This lighting normal is then used to mix between almost pure ambient (0) and diffuse (1.0) light
103 " vec4 backlight = 0.8 * gl_LightSource[0].ambient + 0.2 * gl_LightSource[0].diffuse;\n"
104 " gl_FrontColor = mix(backlight, gl_LightSource[0].diffuse, n);\n"
105 " gl_FrontColor += gl_FrontLightModelProduct.sceneColor;\n"
106 " gl_FrontColor.a = smoothstep(10.0, 100.0, fogCoord);\n"
107 " gl_BackColor = gl_FrontColor;\n"
108 // Fog doesn't affect clouds as much as other objects.
109 " fogFactor = exp( -gl_Fog.density * fogCoord);\n"
110 " fogFactor = clamp(fogFactor, 0.0, 1.0);\n"
111 // As we get within 100m of the sprite, it is faded out
112 " alphaBlend = smoothstep(10.0, 100.0, fogCoord);\n"
115 static char fragmentShaderSource[] =
116 "uniform sampler2D baseTexture; \n"
117 "varying float fogFactor;\n"
118 "varying float alphaBlend;\n"
122 " vec4 base = texture2D( baseTexture, gl_TexCoord[0].st);\n"
123 " vec4 finalColor = base * gl_Color;\n"
124 // " finalColor.a = min(alphaBlend, finalColor.a);\n"
125 " gl_FragColor = mix(gl_Fog.color, finalColor, fogFactor );\n"
128 class SGCloudFogUpdateCallback : public osg::StateAttribute::Callback {
130 virtual void operator () (osg::StateAttribute* sa, osg::NodeVisitor* nv)
132 SGUpdateVisitor* updateVisitor = static_cast<SGUpdateVisitor*>(nv);
133 osg::Fog* fog = static_cast<osg::Fog*>(sa);
134 fog->setMode(osg::Fog::EXP);
135 fog->setColor(updateVisitor->getFogColor().osg());
136 fog->setDensity(updateVisitor->getFogExpDensity());
140 SGNewCloud::SGNewCloud(const SGPath &tex_path,
158 min_sprite_width(min_sprite_w),
159 max_sprite_width(max_sprite_w),
160 min_sprite_height(min_sprite_h),
161 max_sprite_height(max_sprite_h),
164 num_textures_x(nt_x),
165 num_textures_y(nt_y),
168 // Create a new StateSet for the texture, if required.
169 StateSetMap::iterator iter = cloudTextureMap.find(texture);
171 if (iter == cloudTextureMap.end()) {
172 stateSet = new osg::StateSet;
174 osg::ref_ptr<osgDB::ReaderWriter::Options> options = makeOptionsFromPath(tex_path);
176 osg::Texture2D *tex = new osg::Texture2D;
177 tex->setWrap( osg::Texture2D::WRAP_S, osg::Texture2D::CLAMP );
178 tex->setWrap( osg::Texture2D::WRAP_T, osg::Texture2D::CLAMP );
179 tex->setImage(osgDB::readImageFile(texture, options.get()));
181 StateAttributeFactory* attribFactory = StateAttributeFactory::instance();
183 stateSet->setMode(GL_LIGHTING, osg::StateAttribute::ON);
184 stateSet->setMode(GL_CULL_FACE, osg::StateAttribute::OFF);
187 osg::Fog* fog = new osg::Fog;
188 fog->setUpdateCallback(new SGCloudFogUpdateCallback);
189 stateSet->setAttributeAndModes(fog);
190 stateSet->setDataVariance(osg::Object::DYNAMIC);
192 stateSet->setAttributeAndModes(attribFactory->getSmoothShadeModel());
193 stateSet->setAttributeAndModes(attribFactory->getStandardBlendFunc());
195 stateSet->setTextureAttributeAndModes(0, tex, osg::StateAttribute::ON );
196 stateSet->setRenderBinDetails(osg::StateSet::TRANSPARENT_BIN, "DepthSortedBin");
198 static ref_ptr<AlphaFunc> alphaFunc;
199 static ref_ptr<Program> program;
200 static ref_ptr<Uniform> baseTextureSampler;
201 static ref_ptr<Material> material;
203 // Generate the shader etc, if we don't already have one.
204 if (!program.valid()) {
205 alphaFunc = new AlphaFunc;
206 alphaFunc->setFunction(AlphaFunc::GREATER,0.002f);
207 program = new Program;
208 baseTextureSampler = new osg::Uniform("baseTexture", 0);
209 Shader* vertex_shader = new Shader(Shader::VERTEX, vertexShaderSource);
210 program->addShader(vertex_shader);
211 program->addBindAttribLocation("textureIndexX", CloudShaderGeometry::TEXTURE_INDEX_X);
212 program->addBindAttribLocation("textureIndexY", CloudShaderGeometry::TEXTURE_INDEX_Y);
213 program->addBindAttribLocation("wScale", CloudShaderGeometry::WIDTH);
214 program->addBindAttribLocation("hScale", CloudShaderGeometry::HEIGHT);
215 program->addBindAttribLocation("shade", CloudShaderGeometry::SHADE);
217 Shader* fragment_shader = new Shader(Shader::FRAGMENT, fragmentShaderSource);
218 program->addShader(fragment_shader);
219 material = new Material;
220 // DonĀ“t track vertex color
221 material->setColorMode(Material::OFF);
223 // We don't actually use the material information either - see shader.
224 material->setAmbient(Material::FRONT_AND_BACK,
225 Vec4(0.5f, 0.5f, 0.5f, 1.0f));
226 material->setDiffuse(Material::FRONT_AND_BACK,
227 Vec4(0.5f, 0.5f, 0.5f, 1.0f));
230 stateSet->setAttributeAndModes(alphaFunc.get());
231 stateSet->setAttribute(program.get());
232 stateSet->addUniform(baseTextureSampler.get());
233 stateSet->setMode(GL_VERTEX_PROGRAM_TWO_SIDE, StateAttribute::ON);
234 stateSet->setAttribute(material.get());
236 // Add the newly created texture to the map for use later.
237 cloudTextureMap.insert(StateSetMap::value_type(texture, stateSet));
239 stateSet = iter->second.get();
243 SGNewCloud::~SGNewCloud() {
246 osg::Geometry* createOrthQuad(float w, float h, int varieties_x, int varieties_y)
248 // Create front and back polygons so we don't need to screw around
249 // with two-sided lighting in the shader.
250 osg::Vec3Array& v = *(new osg::Vec3Array(4));
251 osg::Vec3Array& n = *(new osg::Vec3Array(4));
252 osg::Vec2Array& t = *(new osg::Vec2Array(4));
256 v[0].set(0.0f, -cw, 0.0f);
257 v[1].set(0.0f, cw, 0.0f);
258 v[2].set(0.0f, cw, h);
259 v[3].set(0.0f, -cw, h);
261 // The texture coordinate range is not the
262 // entire coordinate space - as the texture
263 // has a number of different clouds on it.
264 float tx = 1.0f/varieties_x;
265 float ty = 1.0f/varieties_y;
267 t[0].set(0.0f, 0.0f);
272 // The normal isn't actually use in lighting.
273 n[0].set(1.0f, -1.0f, -1.0f);
274 n[1].set(1.0f, 1.0f, -1.0f);
275 n[2].set(1.0f, 1.0f, 1.0f);
276 n[3].set(1.0f, -1.0f, 1.0f);
278 osg::Geometry *geom = new osg::Geometry;
280 geom->setVertexArray(&v);
281 geom->setTexCoordArray(0, &t);
282 geom->setNormalArray(&n);
283 geom->setNormalBinding(Geometry::BIND_PER_VERTEX);
284 // No color for now; that's used to pass the position.
285 geom->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::QUADS,0,4));
290 // return a random number between -n/2 and n/2, tending to 0
291 static float Rnd(float n) {
292 return n * (-0.5f + (sg_random() + sg_random()) / 2.0f);
295 osg::ref_ptr<LOD> SGNewCloud::genCloud() {
296 LOD* result = new LOD;
297 Geode* geode = new Geode;
298 CloudShaderGeometry* sg = new CloudShaderGeometry(num_textures_x, num_textures_y);
300 Geometry* quad = createOrthQuad(min_sprite_width, min_sprite_height, num_textures_x, num_textures_y);
302 // Determine how big this specific cloud instance is.
303 float width = min_width + sg_random() * (max_width - min_width);
304 float height = min_height + sg_random() * (max_height - min_height);
306 // Determine the cull distance. This is used to remove sprites that are too close together.
307 // The value is squared as we use vector calculations.
308 float cull_distance_squared = min_sprite_height * min_sprite_height * 0.1f;
310 for (int i = 0; i < num_sprites; i++)
312 // Determine the position of the sprite.
313 SGVec3f *pos = new SGVec3f(Rnd(width),
317 // Determine the height and width as scaling factors on the minimum size (used to create the quad)
318 float sprite_width = 1.0f + sg_random() * (max_sprite_width - min_sprite_width) / min_sprite_width;
319 float sprite_height = 1.0f + sg_random() * (max_sprite_height - min_sprite_height) / min_sprite_height;
321 // The shade varies from bottom_shade to 1.0 non-linearly
323 if (pos->z() > 0.0f) {
326 shade = ((2 * pos->z() + height) / height) * (1 - bottom_shade) + bottom_shade;
329 // Determine the sprite texture indexes;
330 int index_x = (int) floor(sg_random() * num_textures_x);
331 if (index_x == num_textures_x) { index_x--; }
333 int index_y = (int) floor(sg_random() * num_textures_y);
334 if (index_y == num_textures_y) { index_y--; }
336 sg->addSprite(*pos, index_x, index_y, sprite_width, sprite_height, shade, cull_distance_squared);
339 sg->setGeometry(quad);
340 geode->addDrawable(sg);
341 geode->setName("3D cloud");
342 geode->setStateSet(stateSet.get());
343 result->addChild(geode, 0, 20000);