FGFS-4.1/simgear
3
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix degenerate random building placement case which resulted in buildings

Browse Source 
being placed outside of the triangle bounds.
This commit is contained in:
Stuart Buchanan
2012-07-13 20:00:06 +01:00
parent ddfdbd75b8
commit 8ed0fec364
1 changed files with 11 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
simgear/scene/tgdb/obj.cxx
View File

@@ -553,12 +553,12 @@ struct SGTileGeometryBin {
float b = mt_rand(&seed) * stepv1;
// Place an object each unit of area
while ( num > 1.0 ) {
while (num > 1.0) {
// Set the next location to place a building
a += stepv0;
if ( a + b > 1.0f ) {
if ((a + b) > 1.0f) {
// Reached the end of the scan-line on v0. Reset and increment
// scan-line on v1
a = mt_rand(&seed) * stepv0;
@@ -567,8 +567,15 @@ struct SGTileGeometryBin {
if (b > 1.0f) {
// In a degenerate case of a single point, we might be outside the
// scanline.
b = mt_rand(&seed) * stepv1;
// scanline. Note that we need to still ensure that a+b < 1.
b = mt_rand(&seed) * stepv1 * (1.0f - a);
}
if ((a + b) > 1.0f ) {
// Truly degenerate case - simply choose a random point guaranteed
// to fulfil the constraing of a+b < 1.
a = mt_rand(&seed);
b = mt_rand(&seed) * (1.0f - a);
}
SGVec3f randomPoint = vorigin + a*v0 + b*v1;