Point in a Triangle

function IsPointOnSideOfLineAsPoint takes location loc, location locs, location loc1, location loc2 returns boolean
    local boolean check
    local real angle = AngleBetweenPoints(loc1, loc2)
    local real angle2 = AngleBetweenPoints(loc1, locs)
    local real angle3
    local real angle4 = AngleBetweenPoints(loc1, loc)
    local real angle5
    if angle2 < 0 then
        set angle2 = 360 + angle2
    endif
    if angle4 < 0 then
        set angle4= 360 + angle4
    endif
    set angle3 = angle2 - angle
    set angle5 = angle4 - angle
    if angle3 >= 0 and angle3 <= 180 then
        if angle5 >= 0 and angle5 <= 180 then
            set check = true
        else
            set check = false
        endif
    else
        if angle5 >= 0 and angle5 <= 180 then
            set check = false
        else
            set check = true
        endif
    endif
    return check
endfunction

function IsPointInTriangle takes location loc, location loc1, location loc2, location loc3 returns boolean
    local boolean check
    if IsPointOnSideOfLineAsPoint(loc, loc3, loc1, loc2) then
        if IsPointOnSideOfLineAsPoint(loc, loc1, loc2, loc3) then
            if IsPointOnSideOfLineAsPoint(loc, loc2, loc3, loc1) then
                set check = true
            else
                set check = false
            endif
        else
            set check = false
        endif
    else
        set check = false
    endif
    return check
endfunction

inline bool VertexInTriangle(vec3 vtxPoint,
                             vec3 vtx0,
                             vec3 vtx1,
                             vec3 vtx2)
{
    double dAngle;

    vec3 vec0 = Normalize( vtxPoint - vtx0 );
    vec3 vec1 = Normalize( vtxPoint - vtx1 );
    vec3 vec2 = Normalize( vtxPoint - vtx2 );

    dAngle =
        acos( DotProduct(vec0,vec1) ) + 
        acos( DotProduct(vec1,vec2) ) + 
        acos( DotProduct(vec2,vec0) ) ;


    if( fabs( dAngle - 2*pi ) < epsilon )
        return true;
else
return false;
}