fix(3d): Unify SDF path for all objects and stabilize shadows

- Converted floor in test_3d_render to a large SDF BOX for consistent shading.
- Standardized lighting (light_dir = 1,1,1) and normal calculation for all objects.
- Fixed calc_shadow bias and skip_idx to reliably prevent self-shadowing.
- Improved raymarching robustness in fs_main to find exact SDF hit points.

1 files changed, 22 insertions, 23 deletions

diff --git a/src/tests/test_3d_render.cc b/src/tests/test_3d_render.cc
index 11cca46..5b4593d 100644
--- a/src/tests/test_3d_render.cc
+++ b/src/tests/test_3d_render.cc
@@ -137,43 +137,42 @@ void setup_scene() {
   g_scene.clear();
   srand(12345); // Fixed seed
 
-  // Large floor, use CUBE type
-  Object3D floor(ObjectType::CUBE);
+  // Large floor, use BOX type (SDF) for receiving shadows
+  Object3D floor(ObjectType::BOX);
   floor.position = vec3(0, -2.0f, 0);
-  floor.scale = vec3(50.0f, 0.5f, 50.0f);
-  floor.color =
-      vec4(0.9f, 0.9f, 0.9f, 1.0f); // Brighter white for better shadow contrast
+  floor.scale = vec3(25.0f, 0.2f, 25.0f);
+  floor.color = vec4(0.8f, 0.8f, 0.8f, 1.0f);
   g_scene.add_object(floor);
 
-  // Center object
+  // Large center Torus (SDF)
   Object3D center(ObjectType::TORUS);
-  center.position = vec3(0, 1.5f, 0); // Elevated
-  center.scale = vec3(1.5f, 1.5f, 1.5f);
-  center.color = vec4(1, 0, 0, 1);
+  center.position = vec3(0, 1.0f, 0);
+  center.scale = vec3(2.0f, 2.0f, 2.0f);
+  center.color = vec4(1, 0.2, 0.2, 1);
   g_scene.add_object(center);
 
+  // Moving Sphere (SDF)
+  Object3D sphere(ObjectType::SPHERE);
+  sphere.position = vec3(4.0f, 2.0f, 0);
+  sphere.scale = vec3(1.2f, 1.2f, 1.2f);
+  sphere.color = vec4(0.2, 1, 0.2, 1);
+  g_scene.add_object(sphere);
+
   // Random objects
-  for (int i = 0; i < 30; ++i) {
+  for (int i = 0; i < 20; ++i) {
     ObjectType type = ObjectType::SPHERE;
     int r = rand() % 3;
-    if (r == 1)
-      type = ObjectType::TORUS;
-    if (r == 2)
-      type = ObjectType::BOX;
+    if (r == 1) type = ObjectType::TORUS;
+    if (r == 2) type = ObjectType::BOX;
 
     Object3D obj(type);
     float angle = (rand() % 360) * 0.01745f;
-    float dist = 4.0f + (rand() % 100) * 0.05f;
-    float height = 0.5f + (rand() % 100) * 0.04f; // Elevated
-
+    float dist = 5.0f + (rand() % 100) * 0.08f;
+    float height = 0.5f + (rand() % 100) * 0.04f;
     obj.position = vec3(std::cos(angle) * dist, height, std::sin(angle) * dist);
-
-    float s = 0.3f + (rand() % 100) * 0.005f;
+    float s = 0.4f + (rand() % 100) * 0.005f;
     obj.scale = vec3(s, s, s);
-
-    obj.color = vec4((rand() % 100) / 100.0f, (rand() % 100) / 100.0f,
-                     (rand() % 100) / 100.0f, 1.0f);
-
+    obj.color = vec4((rand()%100)/100.0f, (rand()%100)/100.0f, (rand()%100)/100.0f, 1.0f);
     g_scene.add_object(obj);
   }
 }