clouds: Added edge density

src/rendering/clouds/clo_definition.c

@@ -87,6 +87,8 @@ void cloudsLayerValidateDefinition(CloudsLayerDefinition* definition)
             curveQuickAddPoint(definition->_coverage_by_altitude, 1.0, 0.0);
             noiseAddLevelsSimple(definition->_shape_noise, 7, 1.0, 0.0, 1.0, 0.5);
             noiseSetFunctionParams(definition->_shape_noise, NOISE_FUNCTION_SIMPLEX, 0.4, 0.0);
+            noiseAddLevelsSimple(definition->_edge_noise, 2, 1.0, -0.5, 0.5, 0.5);
+            noiseSetFunctionParams(definition->_edge_noise, NOISE_FUNCTION_SIMPLEX, 0.8, 0.0);
             break;
         case CLOUDS_TYPE_STRATOCUMULUS:
             curveQuickAddPoint(definition->_coverage_by_altitude, 0.0, 0.0);
@@ -95,7 +97,7 @@ void cloudsLayerValidateDefinition(CloudsLayerDefinition* definition)
             curveQuickAddPoint(definition->_coverage_by_altitude, 1.0, 0.0);
             noiseAddLevelsSimple(definition->_shape_noise, 2, 1.0, 0.0, 1.0, 0.5);
             noiseSetFunctionParams(definition->_shape_noise, NOISE_FUNCTION_SIMPLEX, 0.3, 0.0);
-            noiseAddLevelsSimple(definition->_edge_noise, 8, 1.0, -0.5, 0.5, 0.5);
+            noiseAddLevelsSimple(definition->_edge_noise, 6, 1.0, -0.5, 0.5, 0.5);
             noiseSetFunctionParams(definition->_edge_noise, NOISE_FUNCTION_SIMPLEX, 0.5, 0.0);
             break;
         case CLOUDS_TYPE_STRATUS:
@@ -114,6 +116,7 @@ void cloudsLayerValidateDefinition(CloudsLayerDefinition* definition)
 
     noiseNormalizeAmplitude(definition->_coverage_noise, -1.0, 3.0, 0);
     noiseNormalizeAmplitude(definition->_shape_noise, -0.5, 0.5, 0);
+    noiseNormalizeAmplitude(definition->_edge_noise, -0.5, 0.5, 0);
 }
 
 CloudsLayerDefinition* cloudsLayerCreateDefinition()

src/rendering/clouds/clo_density.c

@@ -37,6 +37,24 @@ double cloudsGetLayerDensity(CloudsLayerDefinition* layer, Vector3 location, dou
     }
 }
 
+double cloudsGetEdgeDensity(CloudsLayerDefinition* layer, Vector3 location, double layer_density)
+{
+    if (layer_density == 0.0)
+    {
+        return 0.0;
+    }
+    else if (layer_density == 1.0)
+    {
+        return 1.0;
+    }
+    else
+    {
+        double density = noiseGet3DTotal(layer->_edge_noise, location.x / layer->edge_scaling, location.y / layer->edge_scaling, location.z / layer->edge_scaling);
+        density -= (0.5 - layer_density);
+        return (density <= 0.0) ? 0.0 : density;
+    }
+}
+
 static double _fakeGetDensity(Renderer* renderer, CloudsLayerDefinition* layer, Vector3 location)
 {
     UNUSED(layer);
@@ -46,9 +64,20 @@ static double _fakeGetDensity(Renderer* renderer, CloudsLayerDefinition* layer,
     return 0.0;
 }
 
+static double _fakeGetEdgeDensity(Renderer* renderer, CloudsLayerDefinition* layer, Vector3 location, double layer_density)
+{
+    UNUSED(layer);
+    UNUSED(renderer);
+    UNUSED(location);
+    UNUSED(layer_density);
+
+    return 0.0;
+}
+
 void cloudsBindFakeDensityToRenderer(CloudsRenderer* renderer)
 {
     renderer->getLayerDensity = _fakeGetDensity;
+    renderer->getEdgeDensity = _fakeGetEdgeDensity;
 }
 
 static double _realGetDensity(Renderer* renderer, CloudsLayerDefinition* layer, Vector3 location)
@@ -60,7 +89,15 @@ static double _realGetDensity(Renderer* renderer, CloudsLayerDefinition* layer,
     return cloudsGetLayerDensity(layer, location, coverage);
 }
 
+static double _realGetEdgeDensity(Renderer* renderer, CloudsLayerDefinition* layer, Vector3 location, double layer_density)
+{
+    UNUSED(renderer);
+
+    return cloudsGetEdgeDensity(layer, location, layer_density);
+}
+
 void cloudsBindRealDensityToRenderer(CloudsRenderer* renderer)
 {
     renderer->getLayerDensity = _realGetDensity;
+    renderer->getEdgeDensity = _realGetEdgeDensity;
 }

src/rendering/clouds/clo_density.h

@@ -13,7 +13,7 @@ extern "C"
 #endif
 
 /**
- * Get the local coverage of a cloud layer [0.0;1.0]
+ * Get the coverage of a cloud layer [0.0;1.0]
  *
  * 0.0 means no cloud is present.
  * 1.0 means full layer.
@@ -21,13 +21,18 @@ extern "C"
 double cloudsGetLayerCoverage(CloudsLayerDefinition* layer, Vector3 location);
 
 /**
- * Get the local density of a cloud layer at a given point [0.0;1.0].
+ * Get the global density of a cloud layer at a given point [0.0;1.0].
  *
  * 0.0 means no cloud is present.
  * 1.0 means full density (deep inside cloud).
  */
 double cloudsGetLayerDensity(CloudsLayerDefinition* layer, Vector3 location, double coverage);
 
+/**
+ * Get the local density of a cloud layer at a given point inside an edge [0.0;1.0].
+ */
+double cloudsGetEdgeDensity(CloudsLayerDefinition* layer, Vector3 location, double layer_density);
+
 /*
  * Bind fake density functions to a renderer.
  */

src/rendering/clouds/clo_rendering.c

@@ -125,7 +125,20 @@ static void _walkerMaterialCallback(CloudsWalker* walker)
 
     assert(data != NULL);
 
-    double density_integral = segment->length * (segment->start.global_density + segment->end.global_density) / 2.0;
+    double density_integral;
+    if (segment->subdivided)
+    {
+        density_integral = segment->length * (segment->start.local_density + segment->end.local_density) / 2.0;
+    }
+    else
+    {
+        if ((segment->start.global_density > 0.0 || segment->end.global_density > 0.0) && (segment->start.global_density < 1.0 || segment->end.global_density < 1.0))
+        {
+            cloudsWalkerOrderSubdivide(walker, renderer->render_quality + 3);
+            return;
+        }
+        density_integral = segment->length * (segment->start.global_density + segment->end.global_density) / 2.0;
+    }
 
     data->out_scattering += 0.5 * density_integral;
 

src/rendering/clouds/clo_walking.c

@@ -36,6 +36,7 @@ struct CloudsWalker
     double max_length;
     double step_size;
     int skip_void;
+    int local_density;
 
     int started;
     CloudWalkerStepInfo last_segment;
@@ -113,6 +114,7 @@ CloudsWalker* cloudsCreateWalker(Renderer* renderer, CloudsLayerDefinition* laye
     result->cursor = 0.0;
     result->step_size = 1.0;
     result->skip_void = 0;
+    result->local_density = -1;
 
     result->started = 0;
     result->subdivision_count = 0;
@@ -138,10 +140,15 @@ void cloudsWalkerSetStepSize(CloudsWalker* walker, double step)
     else
     {
         /* TODO Automatic settings (using rendering quality and cloud feature size) */
-        walker->step_size = 1.0;
+        walker->step_size = 5.0 / (double)walker->last_segment.renderer->render_quality;
     }
 }
 
+void cloudsWalkerToggleLocalDensity(CloudsWalker* walker, int enabled)
+{
+    walker->local_density = enabled;
+}
+
 void cloudsWalkerSetVoidSkipping(CloudsWalker* walker, int enabled)
 {
     walker->skip_void = enabled;
@@ -155,6 +162,15 @@ static void _getPoint(CloudsWalker* walker, double cursor, CloudWalkerPoint* out
     Renderer* renderer = walker->last_segment.renderer;
     CloudsLayerDefinition* layer = walker->last_segment.layer;
     out_point->global_density = renderer->clouds->getLayerDensity(renderer, layer, out_point->location);
+
+    if (walker->local_density > 0 || (walker->local_density < 0 && walker->subdivision_count > 0))
+    {
+        out_point->local_density = renderer->clouds->getEdgeDensity(renderer, layer, out_point->location, out_point->global_density);
+    }
+    else
+    {
+        out_point->local_density = 0.0;
+    }
 }
 
 static void _refineSegment(CloudsWalker* walker, double start_cursor, double start_density, double end_cursor, double end_density, double precision, CloudWalkerPoint* result)

src/rendering/clouds/clo_walking.h

@@ -18,6 +18,7 @@ typedef struct
     double distance_from_start;
     Vector3 location;
     double global_density;
+    double local_density;
 } CloudWalkerPoint;
 
 /**
@@ -86,6 +87,16 @@ void cloudsWalkerSetStepSize(CloudsWalker* walker, double step);
  */
 void cloudsWalkerSetVoidSkipping(CloudsWalker* walker, int enabled);
 
+/**
+ * Toggle the local density computing.
+ *
+ * When this option is set, the CloudWalkerStepInfo will contain information about local density.
+ * The automatic setting will set to 1 on subdivided steps, and 0 elsewhere.
+ * @param walker The walker to configure
+ * @param enabled 1 to enable local density, 0 to disable it, -1 for automatic setting.
+ */
+void cloudsWalkerToggleLocalDensity(CloudsWalker* walker, int enabled);
+
 /**
  * Perform a single step.
  *

src/rendering/clouds/public.h

@@ -61,6 +61,7 @@ typedef struct
 
 typedef Color (*FuncCloudsGetColor)(Renderer* renderer, Color base, Vector3 start, Vector3 end);
 typedef double (*FuncCloudsGetLayerDensity)(Renderer* renderer, CloudsLayerDefinition* layer, Vector3 location);
+typedef double (*FuncCloudsGetEdgeDensity)(Renderer* renderer, CloudsLayerDefinition* layer, Vector3 location, double layer_density);
 
 typedef struct
 {
@@ -69,6 +70,7 @@ typedef struct
     FuncCloudsGetColor getColor;
     FuncLightingAlterLight alterLight;
     FuncCloudsGetLayerDensity getLayerDensity;
+    FuncCloudsGetEdgeDensity getEdgeDensity;
 } CloudsRenderer;
 
 

src/testing/test_clouds.c

@@ -200,6 +200,15 @@ static double _getLayerDensitySinX(Renderer* renderer, CloudsLayerDefinition* la
     return (density > 0.0) ? density : 0.0;
 }
 
+static double _getEdgeDensitySquared(Renderer* renderer, CloudsLayerDefinition* layer, Vector3 location, double edge_density)
+{
+    UNUSED(renderer);
+    UNUSED(layer);
+    UNUSED(location);
+    return edge_density * edge_density;
+}
+
+
 START_TEST(test_clouds_walking)
 {
     /* Init */
@@ -414,7 +423,52 @@ START_TEST(test_clouds_walking)
 }
 END_TEST
 
+START_TEST(test_clouds_walking_local)
+{
+    /* Init */
+    CloudsLayerDefinition* layer;
+    layer = cloudsGetLayerType().callback_create();
+    layer->lower_altitude = -1.0;
+    layer->thickness = 2.0;
+    cloudsGetLayerType().callback_validate(layer);
+
+    Renderer* renderer;
+    renderer = rendererCreate();
+
+    renderer->render_quality = 8;
+    renderer->clouds->getLayerDensity = _getLayerDensitySinX;
+    renderer->clouds->getEdgeDensity = _getEdgeDensitySquared;
+
+    CloudsWalker* walker = cloudsCreateWalker(renderer, layer, v3(0.0, 0.0, 0.0), v3(1.0, 0.0, 0.0));
+    CloudWalkerStepInfo* segment;
+    int result;
+
+    /* Test that local density is off by default */
+    cloudsWalkerSetStepSize(walker, 0.3);
+    result = cloudsWalkerPerformStep(walker);
+    segment = cloudsWalkerGetLastSegment(walker);
+    ck_assert_int_eq(result, 1);
+    ck_assert_double_eq(segment->length, 0.3);
+    ck_assert_double_eq(segment->start.global_density, 0.0);
+    ck_assert_double_eq(segment->start.local_density, 0.0);
+    ck_assert_double_eq(segment->end.global_density, 0.951056516295);
+    ck_assert_double_eq(segment->end.local_density, 0.0);
+
+    /* Test it's automatically enabled on subdivision */
+    cloudsWalkerOrderSubdivide(walker, 2);
+    result = cloudsWalkerPerformStep(walker);
+    segment = cloudsWalkerGetLastSegment(walker);
+    ck_assert_int_eq(result, 1);
+    ck_assert_double_eq(segment->length, 0.15);
+    ck_assert_double_eq(segment->start.global_density, 0.0);
+    ck_assert_double_eq(segment->start.local_density, 0.0);
+    ck_assert_double_eq(segment->end.global_density, 0.809016994375);
+    ck_assert_double_eq(segment->end.local_density, 0.654508497187);
+}
+END_TEST
+
 TEST_CASE(clouds,
           test_clouds_density,
+          test_clouds_walking,
           test_clouds_walking_boundaries,
-          test_clouds_walking)
+          test_clouds_walking_local)