Replace GetRayCollisionGround with GetCollisionQuad

examples/models/models_mesh_picking.c

@@ -42,6 +42,12 @@ int main(void)
     Vector3 towerPos = { 0.0f, 0.0f, 0.0f };                    // Set model position
     BoundingBox towerBBox = GetMeshBoundingBox(tower.meshes[0]);   // Get mesh bounding box
 
+    // Ground quad
+    Vector3 g0 = (Vector3){ -50.0f, 0.0f, -50.0f };
+    Vector3 g1 = (Vector3){ -50.0f, 0.0f,  50.0f };
+    Vector3 g2 = (Vector3){  50.0f, 0.0f,  50.0f };
+    Vector3 g3 = (Vector3){  50.0f, 0.0f, -50.0f };
+
     // Test triangle
     Vector3 ta = (Vector3){ -25.0f, 0.5f, 0.0f };
     Vector3 tb = (Vector3){ -4.0f, 2.5f, 1.0f };
@@ -75,14 +81,15 @@ int main(void)
         ray = GetMouseRay(GetMousePosition(), camera);
 
         // Check ray collision against ground plane
-        /*RayCollision groundHitInfo = GetCollisionRayQuad(ray, 0.0f);
+        RayCollision groundHitInfo = GetRayCollisionQuad(ray, g0, g1, g2, g3);
+        DrawPoint3D(g0, RED);
 
         if ((groundHitInfo.hit) && (groundHitInfo.distance < nearestHit.distance))
         {
             nearestHit = groundHitInfo;
             cursorColor = GREEN;
             hitObjectName = "Ground";
-        }*/
+        }
 
         // Check ray collision against test triangle
         RayCollision triHitInfo = GetRayCollisionTriangle(ray, ta, tb, tc);

src/models.c

@@ -3019,11 +3019,12 @@ RayCollision GetRayCollisionBox(Ray ray, BoundingBox box)
     RayCollision result = { 0 };
 
     // Note: If ray.position is inside the box, the distance is negative (as if the ray was reversed)
-    // Reversing ray.direction before will give use the correct result.
+    // Reversing ray.direction will give use the correct result.
     bool insideBox = 
         ray.position.x > box.min.x && ray.position.x < box.max.x &&
         ray.position.y > box.min.y && ray.position.y < box.max.y &&
         ray.position.z > box.min.z && ray.position.z < box.max.z;
+
     if (insideBox) {
         ray.direction = Vector3Negate(ray.direction);
     }
@@ -3140,6 +3141,7 @@ RayCollision GetRayCollisionModel(Ray ray, Model model)
 }
 
 // Get collision info between ray and triangle
+// NOTE: The points are expected to be in counter-clockwise winding
 // NOTE: Based on https://en.wikipedia.org/wiki/M%C3%B6ller%E2%80%93Trumbore_intersection_algorithm
 RayCollision GetRayCollisionTriangle(Ray ray, Vector3 p1, Vector3 p2, Vector3 p3)
 {
@@ -3197,26 +3199,14 @@ RayCollision GetRayCollisionTriangle(Ray ray, Vector3 p1, Vector3 p2, Vector3 p3
     return result;
 }
 
-// Get collision info between ray and ground plane (Y-normal plane)
+// Get collision info between ray and quad
-RayCollision GetRayCollisionGround(Ray ray, float groundHeight)
+// NOTE: The points are expected to be in counter-clockwise winding
-{
+RayCollision GetRayCollisionQuad(Ray ray, Vector3 p1, Vector3 p2, Vector3 p3, Vector3 p4) {
-    #define EPSILON 0.000001        // A small number
-
     RayCollision result = { 0 };
 
-    if (fabsf(ray.direction.y) > EPSILON)
+    result = GetRayCollisionTriangle(ray, p1, p2, p4);
-    {
-        float distance = (ray.position.y - groundHeight)/-ray.direction.y;
 
-        if (distance >= 0.0)
+    if (!result.hit) result = GetRayCollisionTriangle(ray, p2, p3, p4);
-        {
-            result.hit = true;
-            result.distance = distance;
-            result.normal = (Vector3){ 0.0, 1.0, 0.0 };
-            result.point = Vector3Add(ray.position, Vector3Scale(ray.direction, distance));
-            result.point.y = groundHeight;
-        }
-    }
 
     return result;
 }