Use the new terrain walker for improved shadows

src/render/opengl/OpenGLRenderer.cpp

@@ -17,6 +17,8 @@ OpenGLRenderer::OpenGLRenderer(Scenery* scenery):
 {
     ready = false;
 
+    render_quality = 3;
+
     functions = new OpenGLFunctions();
     shared_state = new OpenGLSharedState();
 

src/render/preview/SceneryTopDownPreviewRenderer.cpp

@@ -12,6 +12,7 @@ SceneryTopDownPreviewRenderer::SceneryTopDownPreviewRenderer(Scenery* scenery):
     scenery(scenery)
 {
     clouds_enabled = true;
+    render_quality = 3;
 }
 
 void SceneryTopDownPreviewRenderer::bindEvent(BasePreview* preview)

src/render/software/SoftwareRenderer.cpp

@@ -134,16 +134,16 @@ void SoftwareRenderer::disableAtmosphere()
     light.color.g = 1.5;
     light.color.b = 1.5;
     light.direction.x = -1.0;
-    light.direction.y = -0.5;
+    light.direction.y = -0.3;
     light.direction.z = 1.0;
     light.direction = light.direction.normalize();
     light.altered = 1;
     light.reflection = 0.0;
     lights.push_back(light);
 
-    light.color.r = 0.4;
+    light.color.r = 0.2;
-    light.color.g = 0.4;
+    light.color.g = 0.2;
-    light.color.b = 0.42;
+    light.color.b = 0.21;
     light.direction.x = 1.0;
     light.direction.y = -0.5;
     light.direction.z = -1.0;

src/render/software/TerrainRayWalker.cpp

@@ -6,6 +6,7 @@
 #include "TexturesDefinition.h"
 #include "TerrainRenderer.h"
 #include "TexturesRenderer.h"
+#include "Matrix4.h"
 
 TerrainRayWalker::TerrainRayWalker(SoftwareRenderer* renderer):
     renderer(renderer)
@@ -23,33 +24,57 @@ void TerrainRayWalker::update()
     ymin = info.min_height - disp;
     ymax = info.max_height + disp;
 
-    ydispmin = -disp;
+    ydispmax = disp * (0.5 + (double)renderer->render_quality * 0.1);
-    ydispmax = disp;
+    ydispmin = -ydispmax;
 
-    minstep = 0.01 * terrain->scaling / (double)renderer->render_quality;
+    minstep = 1.0 * terrain->scaling / (double)(renderer->render_quality * renderer->render_quality);
-    maxstep = 1.0 * terrain->scaling;
+    maxstep = 10.0 * terrain->scaling / (double)renderer->render_quality;
 }
 
-bool TerrainRayWalker::startWalking(Vector3 start, const Vector3 &direction, double escaping_factor, double max_length, TerrainHitResult &result)
+static inline Vector3 _getShiftAxis(const Vector3 &direction)
+{
+    if (fabs(direction.y) > 0.99)
+    {
+        // When the ray is vertical, we choose an arbitrary shift axis
+        return VECTOR_NORTH;
+    }
+    else
+    {
+        return VECTOR_UP.crossProduct(direction);
+    }
+}
+
+bool TerrainRayWalker::startWalking(const Vector3 &start, Vector3 direction, double escape_angle, double max_length, TerrainHitResult &result)
 {
     TerrainRenderer* terrain_renderer = renderer->getTerrainRenderer();
     TexturesRenderer* textures_renderer = renderer->getTexturesRenderer();
     TerrainRenderer::TerrainResult terrain_result;
-    Vector3 end, displaced;
+    Vector3 cursor, displaced;
-    bool hit;
     double diff;
+    Matrix4 shift_matrix;
+    double shift_step = 0.0;
 
+    Vector3 previous_cursor = start;
+    bool hit = false;
     double step_length = minstep;
     double walked_length = 0.0;
 
+    result.escape_angle = 0.0;
+    if (escape_angle != 0.0)
+    {
+        // Prepare escape
+        shift_step = escape_angle / (double)(renderer->render_quality * renderer->render_quality);
+        shift_matrix = Matrix4::newRotateAxis(-shift_step, _getShiftAxis(direction));
+    }
+
     do
     {
         // Perform a step
-        end = start.add(direction.scale(step_length));
+        cursor = previous_cursor.add(direction.scale(step_length));
 
         // Get the terrain info at end (without textures displacement)
-        terrain_result = terrain_renderer->getResult(end.x, end.z, true, false);
+        terrain_result = terrain_renderer->getResult(cursor.x, cursor.z, true, false);
-        diff = end.y - terrain_result.location.y;
+        diff = cursor.y - terrain_result.location.y;
 
         // If we are very under the terrain, consider a hit
         if (diff < ydispmin)
@@ -61,33 +86,42 @@ bool TerrainRayWalker::startWalking(Vector3 start, const Vector3 &direction, dou
         else if (diff < ydispmax)
         {
             displaced = textures_renderer->displaceTerrain(terrain_result);
-            diff = end.y - displaced.y;
+            diff = cursor.y - displaced.y;
-            hit = (diff < 0.0);
+            hit = diff < 0.0;
         }
 
         if (hit)
         {
-            // Refine the hit with dichotomy at high quality
+            // TODO Refine the hit with dichotomy at high quality
             /*if (renderer->render_quality > 7)
             {
-                end = refineHit(start, end, step_length);
+                cursor = refineHit(previous_cursor, cursor, step_length);
             }*/
 
-            // Find an escape
+            // Shift ray to escape terrain
-            /*if (escaping_factor != 0.0)
+            if (escape_angle != 0.0)
             {
-                result.escape_length = findEscape(end, walked_length, escaping_factor, max_length);
+                result.escape_angle += shift_step;
-            }*/
+                if (result.escape_angle > escape_angle)
+                {
+                    // Too much shifted to escape, make it a hit
+                    result.escape_angle = 0.0;
+                    return true;
+                }
+                hit = false;
+                direction = shift_matrix.multPoint(direction);
+                previous_cursor = start.add(shift_matrix.multPoint(previous_cursor.sub(start)));
+            }
 
-            result.hit_location = end;
+            result.hit_location = cursor;
         }
         else
         {
             // Prepare next step
-            start = end;
+            previous_cursor = cursor;
             walked_length += step_length;
 
-            step_length = diff / (double)renderer->render_quality;
+            step_length = diff * 3.0 / (double)renderer->render_quality;
             if (step_length < minstep)
             {
                 step_length = minstep;
@@ -97,7 +131,7 @@ bool TerrainRayWalker::startWalking(Vector3 start, const Vector3 &direction, dou
                 step_length = maxstep;
             }
         }
-    } while (not hit and start.y < ymax and walked_length < max_length);
+    } while (not hit and cursor.y < ymax and walked_length < max_length);
 
-    return hit;
+    return hit or result.escape_angle > 0.0;
 }

src/render/software/TerrainRayWalker.h

@@ -20,7 +20,7 @@ class SOFTWARESHARED_EXPORT TerrainRayWalker
 public:
     typedef struct {
         Vector3 hit_location; // Location of the hit
-        double escape_length; // Length walked before terrain was escaped after hit (0.0 if no escape)
+        double escape_angle;  // Angle used to shift the ray to escape the terrain (0.0 if no escape was possible)
     } TerrainHitResult;
 
 public:
@@ -36,12 +36,12 @@ public:
      *
      * \param start Point of origin of the ray
      * \param direction Ray direction (normalized vector)
-     * \param escaping_factor Factor used to escape the terrain on hit (mainly for shadows computing)
+     * \param escape_angle Maximal angle allowed to escape the terrain on hit (mainly for shadows computing)
      * \param max_length Maximum length to walk before considering no hit
      * \param result Object to store the results info
      * \return true if there was a hit
      */
-    bool startWalking(Vector3 start, const Vector3 &direction, double escaping_factor, double max_length, TerrainHitResult &result);
+    bool startWalking(const Vector3 &start, Vector3 direction, double escape_angle, double max_length, TerrainHitResult &result);
 
 private:
     SoftwareRenderer* renderer;

src/render/software/TerrainRenderer.cpp

@@ -151,16 +151,16 @@ RayCastingResult TerrainRenderer::castRay(const Vector3 &start, const Vector3 &d
 bool TerrainRenderer::applyLightFilter(LightComponent &light, const Vector3 &at)
 {
     TerrainDefinition* definition = parent->getScenery()->getTerrain();
-    Vector3 inc_vector, direction_to_light, cursor;
+    TerrainRayWalker::TerrainHitResult walk_result;
-    double inc_value, inc_base, inc_factor, height, diff, light_factor, smoothing, length;
 
+    // If location is above terrain, don't bother
     if (at.y > definition->getHeightInfo().max_height)
     {
-        // Location is above terrain, don't bother
         return true;
     }
 
-    direction_to_light = light.direction.scale(-1.0);
+    // Handle sun below horizon
+    Vector3 direction_to_light = light.direction.scale(-1.0);
     if (direction_to_light.y < -0.05)
     {
         light.color = COLOR_BLACK;
@@ -173,60 +173,31 @@ bool TerrainRenderer::applyLightFilter(LightComponent &light, const Vector3 &at)
         light.color.b *= (0.05 + direction_to_light.y) / 0.05;
     }
 
-    cursor = at;
+    // Walk to find an intersection
-    inc_factor = (double)parent->render_quality;
+    double escape_angle = definition->shadow_smoothing;
-    inc_base = definition->height / definition->scaling;
+    if (walker->startWalking(at, direction_to_light, escape_angle, 100.0, walk_result))
-    inc_value = inc_base / inc_factor;
-    smoothing = definition->shadow_smoothing;
-
-    light_factor = 1.0;
-    length = 0.0;
-    diff = 0.0;
-    do
     {
-        inc_vector = direction_to_light.scale(inc_value);
+        if (walk_result.escape_angle == 0.0)
-        length += inc_vector.getNorm();
-        cursor = cursor.add(inc_vector);
-        height = parent->getTerrainRenderer()->getResult(cursor.x, cursor.z, 1, 1).location.y;
-        diff = cursor.y - height;
-        if (diff < 0.0)
-        {
-            if (length * smoothing > 0.000001)
-            {
-                light_factor += diff * inc_vector.getNorm() / (length * smoothing);
-            }
-            else
-            {
-                light_factor = 0.0;
-            }
-        }
-
-        if (diff < inc_base / inc_factor)
-        {
-            inc_value = inc_base / inc_factor;
-        }
-        else if (diff > inc_base)
-        {
-            inc_value = inc_base;
-        }
-        else
-        {
-            inc_value = diff;
-        }
-    }
-    while (light_factor > 0.0 && length < (10.0 * inc_factor) && cursor.y <= definition->_max_height);
-
-    if (light_factor <= 0.0)
         {
+            // Hit, with no escape, cancelling the light
             light.color = COLOR_BLACK;
             return false;
         }
         else
         {
+            // Hit, with an escape
+            double light_factor = 1.0 - (walk_result.escape_angle / escape_angle);
+
             light.color.r *= light_factor;
             light.color.g *= light_factor;
             light.color.b *= light_factor;
 
+            return true;
+        }
+    }
+    else
+    {
+        // No hit, leave light alone
         return true;
     }
 }