normalize worley noise values to (-1,1)

diff --git a/src/noise.cpp b/src/noise.cpp
index 4400a1a4988e0b57aee77e7d6b7ae73a522a4441..c86f833ac3c126c894a53eeb5ad6df6c9c835d02 100644 (file)
--- a/src/noise.cpp
+++ b/src/noise.cpp
@@ -119,7 +119,7 @@ WorleyNoise::WorleyNoise(unsigned int seed)
 float WorleyNoise::operator ()(const glm::vec3 &in) const {
        glm::vec3 center = floor(in);
 
-       float closest = 4.0f;
+       float closest = 1.0f;  // cannot be farther away than 1.0
 
        for (int z = -1; z <= 1; ++z) {
                for (int y = -1; y <= 1; ++y) {
@@ -141,7 +141,7 @@ float WorleyNoise::operator ()(const glm::vec3 &in) const {
                                        point.z += float(cube_rand % 200000) / 200000.0f;
 
                                        glm::vec3 diff(in - point);
-                                       float distance = dot(diff, diff);
+                                       float distance = sqrt(dot(diff, diff));
                                        if (distance < closest) {
                                                closest = distance;
                                        }
@@ -150,7 +150,9 @@ float WorleyNoise::operator ()(const glm::vec3 &in) const {
                }
        }
 
-       return closest;
+       // closest ranges (0, 1), so normalizing to (-1,1) is trivial
+       // though heavily biased towards lower numbers
+       return 2.0f * closest - 1.0f;
 }
 
 }