mdl3.py 文件源码

def SetFog(self,fog):
        projection = (fog.function >> 3) & 1

        if projection:
            if fog.z_far == fog.z_near or fog.z_end == fog.z_start:
                A = 0
                C = 0
            else:
                A = (fog.z_far - fog.z_near)/(fog.z_end - fog.z_start)
                C = (fog.z_start - fog.z_near)/(fog.z_end - fog.z_start)
            b_shift = 0
            b_magnitude = 0

        else:
            if fog.z_far == fog.z_near or fog.z_end == fog.z_start:
                A = 0
                B = 0.5
                C = 0
            else:
                A = fog.z_far*fog.z_near/((fog.z_far - fog.z_near)*(fog.z_end - fog.z_start))
                B = fog.z_far/(fog.z_far - fog.z_near)
                C = fog.z_start/(fog.z_end - fog.z_start)

            if B > 1:
                b_shift = 1 + int(ceil(log(B,2)))
            elif 0 < B < 0.5:
                b_shift = 0
            else:
                b_shift = 1

            A /= 2**b_shift
            b_magnitude = int(2*(B/2**b_shift)*8388638)


        a_mantissa,a_exponent = frexp(A)
        self.fog_param0[0:11] = int(abs(a_mantissa)*2**12) & 0x7FF
        self.fog_param0[11:19] = a_exponent + 126 if A != 0 else 0
        self.fog_param0[19] = a_mantissa < 0

        self.fog_param1[0:24] = b_magnitude
        self.fog_param2[0:5] = b_shift

        c_mantissa,c_exponent = frexp(C)
        self.fog_param3[0:11] = int(abs(c_mantissa)*2**12) & 0x7FF
        self.fog_param3[11:19] = c_exponent + 126 if C != 0 else 0
        self.fog_param3[19] = c_mantissa < 0
        self.fog_param3[20:21] = projection
        self.fog_param3[21:24] = fog.function

        self.fog_color[0:8] = fog.color.b
        self.fog_color[8:16] = fog.color.g
        self.fog_color[16:24] = fog.color.r