CUDA: Add more math functions (#4793)

Author: oitel

source/MRCuda/MRCudaFloat.cuh

@@ -54,6 +54,11 @@ __device__ inline float lengthSq( const float2& a )
     return a.x * a.x + a.y * a.y;
 }
 
+__device__ inline float length( const float2& a )
+{
+    return sqrt( a.x * a.x + a.y * a.y );
+}
+
 __device__ inline float dot( const float2& a, const float2& b )
 {
     return a.x * b.x + a.y * b.y;

source/MRCuda/MRCudaMath.cuh

@@ -31,6 +31,11 @@ struct Box3
     float3 min;
     float3 max;
 
+    __device__ bool valid() const
+    {
+        return min.x <= max.x && min.y <= max.y && min.z <= max.z;
+    }
+
     __device__ float3 getBoxClosestPointTo( const float3& pt ) const
     {
         return { clamp( pt.x, min.x, max.x ), clamp( pt.y, min.y, max.y ), clamp( pt.z, min.z, max.z ) };
@@ -46,6 +51,18 @@ struct Box3
         if ( pt.z > max.z ) max.z = pt.z;
     }
 
+    __device__ Box3 intersection( const Box3& b ) const
+    {
+        Box3 res;
+        res.min.x = fmax( min.x, b.min.x );
+        res.min.y = fmax( min.y, b.min.y );
+        res.min.z = fmax( min.z, b.min.z );
+        res.max.x = fmin( max.x, b.max.x );
+        res.max.y = fmin( max.y, b.max.y );
+        res.max.z = fmin( max.z, b.max.z );
+        return res;
+    }
+
     __device__ float3 operator[]( const int i ) const
     {
         assert( i == 0 || i == 1 );