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Fix RNG so it is passed in from above rather than generating the same

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seed continuously.
This commit is contained in:
Stuart Buchanan 2012-12-05 22:10:45 +00:00
parent e9b499b82d
commit 66786651b0
2 changed files with 20 additions and 20 deletions
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36
simgear/scene/sky/newcloud.cxx
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@ -70,11 +70,11 @@ EffectMap effectMap;
float SGNewCloud::sprite_density = 1.0;
SGNewCloud::SGNewCloud(const SGPath &texture_root, const SGPropertyNode *cld_def)
SGNewCloud::SGNewCloud(const SGPath &texture_root, const SGPropertyNode *cld_def, mt* s)
{
// Set up a RNG that is repeatable within 10 minutes to ensure that clouds
// are synced up in multi-process deployments.
mt_init_time_10(&seed);
// Set up the RNG with the passed in seed. This allows us to make the RNG repeatable
// if required.
seed = s;
min_width = cld_def->getFloatValue("min-cloud-width-m", 500.0);
max_width = cld_def->getFloatValue("max-cloud-width-m", min_width*2);
@ -135,7 +135,7 @@ SGNewCloud::~SGNewCloud() {
#if 0
// return a random number between -n/2 and n/2, tending to 0
static float Rnd(float n) {
return n * (-0.5f + (mt_rand(&seed) + mt_rand(&seed)) / 2.0f);
return n * (-0.5f + (mt_rand(seed) + mt_rand(seed)) / 2.0f);
}
#endif
@ -146,17 +146,17 @@ osg::ref_ptr<EffectGeode> SGNewCloud::genCloud() {
// 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 + mt_rand(&seed) * (max_width - min_width) - min_sprite_width;
float height = min_height + mt_rand(&seed) * (max_height - min_height) - min_sprite_height;
float width = min_width + mt_rand(seed) * (max_width - min_width) - min_sprite_width;
float height = min_height + mt_rand(seed) * (max_height - min_height) - min_sprite_height;
if (width < 0.0) { width = 0.0; }
if (height < 0.0) { height = 0.0; }
// Determine appropriate shading factors
float top_factor = min_top_lighting_factor + mt_rand(&seed) * (max_top_lighting_factor - min_top_lighting_factor);
float middle_factor = min_middle_lighting_factor + mt_rand(&seed) * (max_middle_lighting_factor - min_middle_lighting_factor);
float bottom_factor = min_bottom_lighting_factor + mt_rand(&seed) * (max_bottom_lighting_factor - min_bottom_lighting_factor);
float shade_factor = min_shade_lighting_factor + mt_rand(&seed) * (max_shade_lighting_factor - min_shade_lighting_factor);
float top_factor = min_top_lighting_factor + mt_rand(seed) * (max_top_lighting_factor - min_top_lighting_factor);
float middle_factor = min_middle_lighting_factor + mt_rand(seed) * (max_middle_lighting_factor - min_middle_lighting_factor);
float bottom_factor = min_bottom_lighting_factor + mt_rand(seed) * (max_bottom_lighting_factor - min_bottom_lighting_factor);
float shade_factor = min_shade_lighting_factor + mt_rand(seed) * (max_shade_lighting_factor - min_shade_lighting_factor);
//printf("Cloud: %2f, %2f, %2f, %2f\n", top_factor, middle_factor, bottom_factor, shade_factor);
@ -176,7 +176,7 @@ osg::ref_ptr<EffectGeode> SGNewCloud::genCloud() {
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 * (0.5f + mt_rand(&seed));
int n_sprites = num_sprites * sprite_density * (0.5f + mt_rand(seed));
for (int i = 0; i < n_sprites; i++)
{
@ -194,16 +194,16 @@ osg::ref_ptr<EffectGeode> SGNewCloud::genCloud() {
y = 0;
z = height * 0.5;
} else {
float theta = mt_rand(&seed) * SGD_2PI;
float elev = mt_rand(&seed) * SGD_PI;
float theta = mt_rand(seed) * SGD_2PI;
float elev = mt_rand(seed) * SGD_PI;
x = width * cos(theta) * 0.5f * sin(elev);
y = width * sin(theta) * 0.5f * sin(elev);
z = height * cos(elev) * 0.5f + height * 0.5f;
}
// Determine the height and width
float sprite_width = min_sprite_width + mt_rand(&seed) * (max_sprite_width - min_sprite_width);
float sprite_height = min_sprite_height + mt_rand(&seed) * (max_sprite_height - min_sprite_height);
float sprite_width = min_sprite_width + mt_rand(seed) * (max_sprite_width - min_sprite_width);
float sprite_height = min_sprite_height + mt_rand(seed) * (max_sprite_height - min_sprite_height);
// Sprites are never taller than square.
if (sprite_height > sprite_width )
@ -226,10 +226,10 @@ osg::ref_ptr<EffectGeode> SGNewCloud::genCloud() {
}
// Determine the sprite texture indexes.
int index_x = (int) floor(mt_rand(&seed) * num_textures_x);
int index_x = (int) floor(mt_rand(seed) * num_textures_x);
if (index_x >= num_textures_x) { index_x = num_textures_x - 1; }
int index_y = (int) floor(mt_rand(&seed) * num_textures_y);
int index_y = (int) floor(mt_rand(seed) * num_textures_y);
if (height_map_texture) {
// The y index depends on the position of the sprite within the cloud.

4
simgear/scene/sky/newcloud.hxx
View File

@ -41,7 +41,7 @@ using std::vector;
class SGNewCloud {
public:
SGNewCloud(const SGPath &texture_root, const SGPropertyNode *cld_def);
SGNewCloud(const SGPath &texture_root, const SGPropertyNode *cld_def, mt* s);
~SGNewCloud();
@ -103,7 +103,7 @@ private:
static float sprite_density;
// RNG seed for this cloud
mt seed;
mt* seed;
osg::Geometry* createOrthQuad(float w, float h, int varieties_x, int varieties_y);
};