Separated different usage of transforming bounds

Signed-off-by: Tobias Frisch <tfrisch@uni-koblenz.de>

modules/scene/include/vkcv/scene/Bounds.hpp

@@ -32,6 +32,13 @@ namespace vkcv::scene {
          * box.
          */
 		Bounds();
+		
+		/**
+         * Constructor creating a zero volume axis aligned bounding
+         * box around a certain point.
+         * @param[in] point Center of the box as 3D vector
+         */
+		Bounds(const glm::vec3& point);
 
         /**
          * Constructor creating an axis aligned bounding box with given

modules/scene/include/vkcv/scene/Frustum.hpp

@@ -9,6 +9,16 @@ namespace vkcv::scene {
      * @addtogroup vkcv_scene
      * @{
      */
+	
+	/**
+     * Transform a given axis aligned bounding box into frustum coordinates
+     * using a given 4x4 transformation matrix to return a new axis aligned
+     * bounding box containing that transformed box.
+     * @param[in] transform Frustum defining 4x4 matrix
+     * @param[in] bounds Axis aligned bounding box
+     * @return Bounds containing box in frustum coordinates
+     */
+	Bounds transformBounds(const glm::mat4& transform, const Bounds& bounds);
 
     /**
      * Transform a given axis aligned bounding box into frustum coordinates
@@ -16,10 +26,10 @@ namespace vkcv::scene {
      * bounding box containing that transformed box.
      * @param[in] transform Frustum defining 4x4 matrix
      * @param[in] bounds Axis aligned bounding box
-     * @param[out] negative_w Flag if w-coordinate is negative (optional)
+     * @param[out] negative_w Flag if w-coordinate is negative
      * @return Bounds containing box in frustum coordinates
      */
-	Bounds transformBounds(const glm::mat4& transform, const Bounds& bounds, bool* negative_w = nullptr);
+	Bounds transformBounds(const glm::mat4& transform, const Bounds& bounds, bool& negative_w);
 
     /**
      * Check if an axis aligned bounding box is intersecting a given frustum

modules/scene/src/vkcv/scene/Bounds.cpp

@@ -7,6 +7,11 @@ namespace vkcv::scene {
 	m_min(glm::vec3(0)),
 	m_max(glm::vec3(0)) {}
 	
+	Bounds::Bounds(const glm::vec3 &point) :
+	m_min(point),
+	m_max(point)
+	{}
+	
 	Bounds::Bounds(const glm::vec3 &min, const glm::vec3 &max) :
 	m_min(min),
 	m_max(max)

modules/scene/src/vkcv/scene/Frustum.cpp

@@ -3,10 +3,9 @@
 
 namespace vkcv::scene {
 	
-	static glm::vec3 transformPoint(const glm::mat4& transform, const glm::vec3& point, bool* negative_w) {
+	static glm::vec3 transformPoint(const glm::mat4& transform, const glm::vec3& point, bool& negative_w) {
 		const glm::vec4 position = transform * glm::vec4(point, 1.0f);
 		
-		
 		/*
 		 * We divide by the absolute of the 4th coorditnate because
 		 * clipping is weird and points have to move to the other
@@ -16,39 +15,35 @@ namespace vkcv::scene {
 		 * to know if all corners are behind the camera. So these can
 		 * be culled as well
 		 */
-		if (negative_w) {
-			const float perspective = std::abs(position[3]);
-			
-			*negative_w &= (position[3] < 0.0f);
-			
-			return glm::vec3(
-					position[0] / perspective,
-					position[1] / perspective,
-					position[2] / perspective
-			);
-		} else {
-			return glm::vec3(
-					position[0],
-					position[1],
-					position[2]
-			);
-		}
+		const float perspective = std::abs(position[3]);
+		negative_w &= (position[3] < 0.0f);
+		return glm::vec3(
+				position[0] / perspective,
+				position[1] / perspective,
+				position[2] / perspective
+		);
 	}
 	
-	Bounds transformBounds(const glm::mat4& transform, const Bounds& bounds, bool* negative_w) {
+	Bounds transformBounds(const glm::mat4& transform, const Bounds& bounds) {
 		const auto corners = bounds.getCorners();
 		
-		if (negative_w) {
-			*negative_w = true;
+		Bounds result (glm::vec3(transform * glm::vec4(corners[0], 1.0f)));
+		
+		for (size_t j = 1; j < corners.size(); j++) {
+			result.extend(glm::vec3(transform * glm::vec4(corners[j], 1.0f)));
 		}
 		
-		auto projected = transformPoint(transform, corners[0], negative_w);
+		return result;
+	}
+	
+	Bounds transformBounds(const glm::mat4& transform, const Bounds& bounds, bool& negative_w) {
+		const auto corners = bounds.getCorners();
+		negative_w = true;
 		
-		Bounds result (projected, projected);
+		Bounds result (transformPoint(transform, corners[0], negative_w));
 		
 		for (size_t j = 1; j < corners.size(); j++) {
-			projected = transformPoint(transform, corners[j], negative_w);
-			result.extend(projected);
+			result.extend(transformPoint(transform, corners[j], negative_w));
 		}
 		
 		return result;
@@ -61,7 +56,7 @@ namespace vkcv::scene {
 		);
 		
 		bool negative_w;
-		auto box = transformBounds(transform, bounds, &negative_w);
+		auto box = transformBounds(transform, bounds, negative_w);
 		
 		if (negative_w) {
 			return false;