Two common functions written using DirectX

1: Find the line formed by the intersection of two planes: bool getintersectionline (d3dxplane & plane01, d3dxplane & plane02, crayline & line) {d3dxplanenormalize (& plane01, & plane01 ); crop (& plane02, & plane02); d3dxvector3 plane01normal =-d3dxvector3 (crop, crop, crop); d3dxvector3 plane02normal =-d3dxvector3 (crop, crop, crop); d3dxvector3 tempd; d3dxvec3cross (& tempd, & plane01normal, & plane02normal); If (d3dxvec3length (& tempd) <0.0001) return false; line. setdirection (tempd); float S1, S2, a, B; S1 = plane01.d; S2 = plane02.d; float n1n2dot = d3dxvec3dot (& plane01normal, & plane02normal ); float n1normsqr = d3dxvec3dot (& plane01normal, & plane01normal); float n2normsqr = d3dxvec3dot (& plane02normal, & plane02normal); A = (S2 * n1n2dot-s1 * n2normsqr) /(n1n2dot * n1n2dot-n1normsqr * n2normsqr); B = (S1 * n1n2dot-s2 * n2normsqr)/(n1n2dot * n1n2dot-n1normsqr * n2normsqr); line. setorigin (A * plane01normal + B * plane02normal); Return true;} 2: calculates the intersection of a straight line and a plane. bool tool: lineintersectplane (const crayline & line, const d3dxplane & plane, float & T, d3dxvector3 & intersection) {float S1 = d3dxvec3dot (& line. getdirection (), & d3dxvector3 (plane. a, plane. b, plane. c); float S2 = line. getorigin (). x * plane. A + line. getorigin (). y * plane. B + line. getorigin (). z * plane. c + plane. d; If (ABS (S1) <0.00001) {If (ABS (S2) <0.00001) {T = 0; return true ;}else {return false ;}} T =-S2; t = T/S1; intersection = line. getorigin () + T * line. getdirection (); Return true ;}