// Computes and adds random surface points to the points list for tree
// coverage.
void addRandomTreePoints(float wood_coverage,
- float tree_density,
- float wood_size,
osg::Texture2D* object_mask,
float vegetation_density,
std::vector<SGVec3f>& points)
if (area <= SGLimitsf::min())
continue;
- if (object_mask != NULL) {
- // For partial units of area, use a zombie door method to
- // create the proper random chance of a point being created
- // for this triangle
- float unit = area + mt_rand(&seed)*wood_coverage;
-
- // Vegetation density is linear, while we're creating woodland
- // by area.
- int woodcount = (int) (vegetation_density *
- vegetation_density *
- unit / wood_coverage);
-
- for (int j = 0; j < woodcount; j++) {
- float a = mt_rand(&seed);
- float b = mt_rand(&seed);
+ // For partial units of area, use a zombie door method to
+ // create the proper random chance of a point being created
+ // for this triangle
+ float unit = area + mt_rand(&seed)*wood_coverage;
+
+ // Vegetation density is linear, while we're creating woodland
+ // by area.
+ int woodcount = (int) (vegetation_density *
+ vegetation_density *
+ unit / wood_coverage);
+
+ for (int j = 0; j < woodcount; j++) {
+ float a = mt_rand(&seed);
+ float b = mt_rand(&seed);
- if ( a + b > 1.0f ) {
- a = 1.0f - a;
- b = 1.0f - b;
- }
+ if ( a + b > 1.0f ) {
+ a = 1.0f - a;
+ b = 1.0f - b;
+ }
- float c = 1.0f - a - b;
+ float c = 1.0f - a - b;
- SGVec3f randomPoint = a*v0 + b*v1 + c*v2;
+ SGVec3f randomPoint = a*v0 + b*v1 + c*v2;
+
+ if (object_mask != NULL) {
SGVec2f texCoord = a*t0 + b*t1 + c*t2;
// Check this random point against the object mask
- // green channel.
+ // green (for trees) channel.
osg::Image* img = object_mask->getImage();
unsigned int x = (int) (img->s() * texCoord.x()) % img->s();
unsigned int y = (int) (img->t() * texCoord.y()) % img->t();
- if (mt_rand(&seed) < img->getColor(x, y).g()) {
+ if (mt_rand(&seed) < img->getColor(x, y).g()) {
+ // The red channel contains the rotation for this object
points.push_back(randomPoint);
}
- }
- } else {
- // For partial units of area, use a zombie door method to
- // create the proper random chance of a point being created
- // for this triangle
- float unit = area + mt_rand(&seed)*wood_coverage;
- int woodcount = (int) (unit / wood_coverage);
-
- if (wood_size < 1.0) {
- // A wood size of 0 is used for an even spread of woodland,
- // where each wood contains a single tree. In this case we
- // need to apply the vegetation_density to the wood count rather
- // than the tree density.
- woodcount = woodcount * vegetation_density;
- }
-
- for (int j = 0; j < woodcount; j++) {
-
- if (wood_size < area) {
- // We need to place a wood within the triangle and populate it
-
- // Determine the center of the wood
- float x = mt_rand(&seed);
- float y = mt_rand(&seed);
-
- // Determine the size of this wood in m^2, and the number
- // of trees in the wood
- float ws = wood_size + wood_size * (mt_rand(&seed) - 0.5f);
- unsigned total_trees = ws / tree_density;
-
- if (wood_size >= 1.0) {
- total_trees = total_trees * vegetation_density;
- }
-
- float wood_length = sqrt(ws);
-
- // From our wood size, work out the fraction on the two axis.
- // This will be used as a factor when placing trees in the wood.
- float x_tree_factor = wood_length / length(v1 -v0);
- float y_tree_factor = wood_length / length(v2 -v0);
-
- for (unsigned k = 0; k <= total_trees; k++) {
-
- float a = x + x_tree_factor * (mt_rand(&seed) - 0.5f);
- float b = y + y_tree_factor * (mt_rand(&seed) - 0.5f);
-
-
- // In some cases, the triangle side lengths are so small that the
- // tree_factors become so large as to make placing the tree within
- // the triangle almost impossible. In this case, we place them
- // randomly across the triangle.
- if (a < 0.0f || a > 1.0f) a = mt_rand(&seed);
- if (b < 0.0f || b > 1.0f) b = mt_rand(&seed);
-
- if ( a + b > 1.0f ) {
- a = 1.0f - a;
- b = 1.0f - b;
- }
-
- float c = 1.0f - a - b;
- SGVec3f randomPoint = a*v0 + b*v1 + c*v2;
- points.push_back(randomPoint);
- }
- } else {
- // This triangle is too small to contain a complete wood, so just
- // distribute trees across it.
- unsigned total_trees = area / tree_density;
-
- for (unsigned k = 0; k <= total_trees; k++) {
-
- float a = mt_rand(&seed);
- float b = mt_rand(&seed);
-
- if ( a + b > 1.0f ) {
- a = 1.0f - a;
- b = 1.0f - b;
- }
-
- float c = 1.0f - a - b;
-
- SGVec3f randomPoint = a*v0 + b*v1 + c*v2;
- SGVec2f texCoord = a*t0 + b*t1 + c*t2;
- points.push_back(randomPoint);
- }
- }
- }
+ } else {
+ points.push_back(randomPoint);
+ }
}
}
}
projects / simgear.git / commitdiff