Collision layers and entity rendering offsets

physics/physics.jai

@@ -26,9 +26,29 @@ Trigger_Overlap :: struct {
 
 MAX_TRIGGER_OVERLAPS :: 16;
 
+Collision_Layers :: enum_flags {
+    NONE;
+
+    LAYER1;
+    LAYER2;
+    LAYER3;
+    LAYER4;
+    LAYER5;
+    LAYER6;
+    LAYER7;
+    LAYER8;
+    LAYER9;
+    LAYER10;
+
+    ALL :: .LAYER1 | LAYER2 | .LAYER3 | .LAYER4 | .LAYER5 | .LAYER6 | .LAYER7 | .LAYER8 | .LAYER9 | .LAYER10;
+}
+
 Collider :: struct {
     type : Collider_Type;
 
+    layer: Collision_Layers = .LAYER1;
+    collides_with_layers: Collision_Layers = .LAYER1;
+
     aabb: AABB;
     override_aabb: bool;
     union {
@@ -166,6 +186,10 @@ add_trigger_overlap_if_new :: (e: *Entity, other_e: *Entity) {
     e.collider.num_overlaps += 1;
 }
 
+can_collide :: (e: *Entity, other: *Entity) -> bool {
+    return xx (e.collider.collides_with_layers & other.collider.layer);
+}
+
 physics_step :: (scene: *Scene, timestep: float) {
     update_gravity(scene, timestep);
     update_positions(scene, timestep);
@@ -179,6 +203,7 @@ physics_step :: (scene: *Scene, timestep: float) {
             for other_e: scene.entities {
                 if e == other_e continue;
                 if other_e.collider.ignore continue;
+                if !can_collide(e, other_e) continue;
 
                 if other_e.flags & .COLLISION {
                     point := gjk(e.collider, other_e.collider);