A mistake in range determination.

[lidan233]

` ############algrithm##############
@ti.func
def determineRange(self, idx):
l_r_range = ti.cast(ti.Vector([0, self.primitive_count-1]), ti.i32)

    if idx != 0:
        self_code = self.morton_code_s[idx][0]
        l         = idx-1
        r         = idx+1
        l_code    = self.morton_code_s[l][0]
        r_code    = self.morton_code_s[r][0]

        if  (l_code == self_code ) & (r_code == self_code) :
            l_r_range[0] = idx

            while  idx < self.primitive_count-1:
                idx += 1
                
                if(idx >= self.primitive_count-1):
                    break

                if (self.morton_code_s[idx][0] != self.morton_code_s[idx+1][0]):
                    break
            l_r_range[1] = idx 
        else:
            L_delta   = UF.common_upper_bits(self_code, l_code)
            R_delta   = UF.common_upper_bits(self_code, r_code)

            d = -1
            if R_delta > L_delta:
                d = 1
            delta_min = min(L_delta, R_delta)
            l_max = 2
            delta = -1
            i_tmp = idx + d * l_max

            if ( (0 <= i_tmp) &(i_tmp < self.primitive_count)):
                delta = UF.common_upper_bits(self_code, self.morton_code_s[i_tmp][0])


            while delta > delta_min:
                l_max <<= 1
                i_tmp = idx + d * l_max
                delta = -1
                if ( (0 <= i_tmp) & (i_tmp < self.primitive_count)):
                    delta = UF.common_upper_bits(self_code, self.morton_code_s[i_tmp][0])

            l = 0
            t = l_max >> 1

            while(t > 0):
                i_tmp = idx + (l + t) * d
                delta = -1
                if ( (0 <= i_tmp) & (i_tmp < self.primitive_count)):
                    delta = UF.common_upper_bits(self_code, self.morton_code_s[i_tmp][0])
                if(delta > delta_min):
                    l += t
                t >>= 1

            l_r_range[0] = idx
            l_r_range[1] = idx + l * d
            if(d < 0):
                tmp          = l_r_range[0]
                l_r_range[0] = l_r_range[1]
                l_r_range[1] = tmp 

    return l_r_range`

In this code, I find delta may be equal to delta_min at the end of 'while delta > delta_min:'. Therefore, at last, l_r_range[1] = l_r_range[0]'. This is a mistake?

[lidan233]

In other words, I notice my morton code is not increase. So how to fixed it?

[lyd405121]

给个输入的数据，比如obj给我，我来调一下，主要我也在厂里打工，不会很及时回复，见谅

In other words, I notice my morton code is not increase. So how to fixed it?

[lyd405121]

In other words, I notice my morton code is not increase. So how to fixed it?

• Recently, I make a new repostory to do bvh things
• And about the morton code which not increasing, we can use an leaf collapse process to combine those primitive as a leaf node
• Here is a slide about all things bvh constructing process which is wirrten by him
• ploc-slides.pdf