Start on raytracing

src/physics/collision_scene.c

@@ -80,4 +80,24 @@ int collisionSceneIsTouchingPortal(struct Vector3* contactPoint) {
 
 int collisionSceneIsPortalOpen() {
     return gCollisionScene.portalTransforms[0] != NULL && gCollisionScene.portalTransforms[1] != NULL;
+}
+
+#define NO_RAY_HIT_DISTANCE 1000000000000.0f
+
+int collisionSceneRayTrace(struct CollisionScene* scene, struct Vector3* at, struct Vector3* dir, int passThroughPortals, struct RayTraceHit* hit) {
+    hit->distance = NO_RAY_HIT_DISTANCE;
+    
+    for (int i = 0; i < scene->quadCount; ++i) {
+        struct RayTraceHit hitTest;
+
+        if (rayTraceQuad(at, dir, scene->quads[i].collider->data, &hitTest) && hitTest.distance < hit->distance) {
+
+            hit->at = hitTest.at;
+            hit->normal = hitTest.normal;
+            hit->distance = hitTest.distance;
+            hit->object = &scene->quads[i];
+        }
+    }
+
+    return hit->distance != NO_RAY_HIT_DISTANCE;
 }

src/physics/collision_scene.h

@@ -2,6 +2,7 @@
 #define __COLLISION_SCENE_H__
 
 #include "collision_object.h"
+#include "ray_tracing.h"
 
 #define PORTAL_THICKNESS        0.11f
 #define PORTAL_X_RADIUS         0.5f
@@ -24,4 +25,6 @@ int collisionSceneIsPortalOpen();
 
 void collisionObjectQueryScene(struct CollisionObject* object, struct CollisionScene* scene, void* data, ManifoldCallback callback);
 
+int collisionSceneRayTrace(struct CollisionScene* scene, struct Vector3* at, struct Vector3* dir, int passThroughPortals, struct RayTraceHit* hit);
+
 #endif

src/physics/ray_tracing.c

@@ -0,0 +1,24 @@
+#include "ray_tracing.h"
+
+#include "math/mathf.h"
+
+#define NEAR_DOT_ZERO       0.00001f
+
+int rayTraceQuad(struct Vector3* from, struct Vector3* dir, struct CollisionQuad* quad, struct RayTraceHit* contact) {
+    float normalDot = vector3Dot(dir, &quad->plane.normal);
+
+    if (fabsf(normalDot) < NEAR_DOT_ZERO) {
+        return 0;
+    }
+
+    contact->distance = -(vector3Dot(from, &quad->plane.normal) + quad->plane.d) / normalDot;
+    vector3AddScaled(from, dir, contact->distance, &contact->at);
+
+    if (collisionQuadDetermineEdges(&contact->at, quad)) {
+        return 0;
+    }
+
+    contact->normal = quad->plane.normal;
+
+    return 1;
+}

src/physics/ray_tracing.h

@@ -0,0 +1,16 @@
+#ifndef __RAY_TRACING_H__
+#define __RAY_TRACING_H__
+
+#include "collision_quad.h"
+#include "collision_object.h"
+
+struct RayTraceHit {
+    struct Vector3 at;
+    struct Vector3 normal;
+    float distance;
+    struct CollisionObject* object;
+};
+
+int rayTraceQuad(struct Vector3* from, struct Vector3* dir, struct CollisionQuad* quad, struct RayTraceHit* contact);
+
+#endif