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  1. bool Entity::collides(Entity other)
  2. {
  3. 	// GETTING ORIENTED BOUNDING BOXES:
  4. 	vector<Point> e1 = this->getOBB();
  5. 	vector<Point> e2 = other.getOBB();
  6.  
  7. 	// GETTING NUMBER OF FACES FOR EACH ENTITY:
  8. 	int e1_faces = e1.size();
  9. 	int e2_faces = e2.size();
  10.  
  11. 	// MINIMUM OVERLAP:
  12. 	float overlap1 = FLT_MAX;
  13. 	float overlap2 = FLT_MAX;
  14.  
  15. 	// FOR EACH FACE RELATIVE TO THIS ENTITY:
  16. 	for(int i = 0; i < e1_faces; i++)
  17. 	{
  18. 		// GET CURRENT FACE:
  19. 		Point face(e1[i].x - e1[(i + 1) % e1_faces].x, e1[i].y - e1[(i + 1) % e1_faces].y);
  20.  
  21. 		// GET CURRENT AXIS PERPENDICULAR TO THE CURRENT FACE:
  22. 		Point axis(-face.y, face.x);
  23.  
  24. 		// NORMALIZE THE AXIS:
  25. 		axis /= sqrt(axis.x * axis.x + axis.y * axis.y);
  26.  
  27. 		// GET MAXIMUM AND MINIMUM POSSIBLE VALUES OF A FLOAT:
  28. 		Point e1_overlap(FLT_MAX, -FLT_MAX);
  29. 		Point e2_overlap(FLT_MAX, -FLT_MAX);
  30.  
  31. 		// GET THE MAXIMUM AND MINIMUM VALUES OF THIS ENTITY RELATIVE TO THE AXIS:
  32. 		for(int j = 0; j < e1_faces; j++)
  33. 		{
  34. 			float e1_proj = ((axis.x * e1[j].x) + (axis.y * e1[j].y)) / ((axis.x * axis.x) + (axis.y * axis.y));
  35. 			e1_overlap.x = min(e1_proj, e1_overlap.x);
  36. 			e1_overlap.y = max(e1_proj, e1_overlap.y);
  37. 		}
  38.  
  39. 		// GET THE MAXIMUM AND MINIMUM VALUES OF THE OTHER ENTITY RELATIVE TO THE AXIS:
  40. 		for(int j = 0; j < e2_faces; j++)
  41. 		{
  42. 			float e2_proj = ((axis.x * e2[j].x) + (axis.y * e2[j].y)) / ((axis.x * axis.x) + (axis.y * axis.y));
  43. 			e2_overlap.x = min(e2_proj, e2_overlap.x);
  44. 			e2_overlap.y = max(e2_proj, e2_overlap.y);
  45. 		}
  46. 		if((e1_overlap.y - e1_overlap.x) < overlap1)
  47. 		{
  48. 			overlap1 = (e1_overlap.y - e1_overlap.x);
  49. 		}
  50. 		if((e2_overlap.y - e2_overlap.x) < overlap2)
  51. 		{
  52. 			overlap2 = (e2_overlap.y - e2_overlap.x);
  53. 		}
  54.  
  55. 		// EXIT IF THE PROJECTIONS DO NOT OVERLAP:
  56. 		if(!(e1_overlap.y >= e2_overlap.x && e1_overlap.x <= e2_overlap.y))
  57. 		{
  58. 			return false;
  59. 		}
  60. 	}
  61. 	// IF ON ALL AXIS AN OVERLAP OCCURS THEN THE ENTITIES ARE INTERSECTING:
  62. 	return true;
  63. }
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https://ideone.com/ef7A3
language:
C++ (gcc 8.3)
created:
12 years ago
visibility:
public

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