Fix --m-rand (#46)

* Validate m_rand is > 0

Resolves: #45

* Update CHANGELOG

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+### Fixed
+- Validate that the `--m-rand` / `random_sample_locations` parameter is > 0. [#45](https://github.com/EmbarkStudios/texture-synthesis/issues/45)
+
 ## [0.6.0]
 ### Added
 - Added support for the alpha channel during generation, which was previously ignored

lib/src/lib.rs

@@ -656,7 +656,7 @@ impl<'a> SessionBuilder<'a> {
                 min: 0.0,
                 max: 1.0,
                 value: self.params.cauchy_dispersion,
-                name: "cauchy_dispersion",
+                name: "cauchy-dispersion",
             }));
         }
 
@@ -665,7 +665,7 @@ impl<'a> SessionBuilder<'a> {
                 min: 0.0,
                 max: 1.0,
                 value: self.params.backtrack_percent,
-                name: "backtrack_percent",
+                name: "backtrack-percent",
             }));
         }
 
@@ -674,7 +674,7 @@ impl<'a> SessionBuilder<'a> {
                 min: 0.0,
                 max: 1.0,
                 value: self.params.guide_alpha,
-                name: "guide_alpha",
+                name: "guide-alpha",
             }));
         }
 
@@ -684,11 +684,20 @@ impl<'a> SessionBuilder<'a> {
                     min: 1.0,
                     max: 1024.0,
                     value: max_count as f32,
-                    name: "max_thread_count",
+                    name: "max-thread-count",
                 }));
             }
         }
 
+        if self.params.random_sample_locations == 0 {
+            return Err(Error::InvalidRange(errors::InvalidRange {
+                min: 1.0,
+                max: 1024.0,
+                value: self.params.random_sample_locations as f32,
+                name: "m-rand",
+            }));
+        }
+
         Ok(())
     }
 

lib/src/multires_stochastic_texture_synthesis.rs

@@ -521,7 +521,7 @@ impl Generator {
         k_neighs: &[SignedCoord2D],
         example_maps: &[ImageBuffer<'_>],
         valid_samples_mask: &[SamplingMethod],
-        m: u32,
+        m_rand: u32,
         m_seed: u64,
     ) -> &'a [CandidateStruct] {
         let mut candidate_count = 0;
@@ -589,7 +589,7 @@ impl Generator {
         let mut rng = Pcg32::seed_from_u64(m_seed);
 
         //random candidates
-        for _ in 0..m {
+        for _ in 0..m_rand {
             let rand_map = (rng.gen_range(0, example_maps.len())) as u32;
             let dims = example_maps[rand_map as usize].dimensions();
             let dims = Dims {