Why? Can't see the problem here! HELP! i'm going crazy! Lua to C++ :((

GregBUG · August 2012

I have this Lua CODE:

local oBoxA = {
        { x = cx + ((Ax1 - cx) * cosAngleA) - ((Ay1 - cy) * sinAngleA) - w, y = cy + ((Ay1 - cy) * cosAngleA) + ((Ax1 - cx) * sinAngleA) - h },
        { x = cx + ((Ax2 - cx) * cosAngleA) - ((Ay2 - cy) * sinAngleA) - w, y = cy + ((Ay2 - cy) * cosAngleA) + ((Ax2 - cx) * sinAngleA) - h },
        { x = cx + ((Ax3 - cx) * cosAngleA) - ((Ay3 - cy) * sinAngleA) - w, y = cy + ((Ay3 - cy) * cosAngleA) + ((Ax3 - cx) * sinAngleA) - h },
        { x = cx + ((Ax4 - cx) * cosAngleA) - ((Ay4 - cy) * sinAngleA) - w, y = cy + ((Ay4 - cy) * cosAngleA) + ((Ax4 - cx) * sinAngleA) - h },
    }

it simply calculate vertices of my Rotated Box by an angle and work fine...

with a Box 128x256 positioned at 100,100 Pixel and rotated by 1 degree

it return
x1 y1
38.243655533963, -29.097458992004

x2 y2
166.22416051398, -26.863550968032

x3 y3
161.75634446604, 229.097458992

x4 y4
33.775839486019, 226.86355096803,

now tha same code of my C++ plugin

is

     oBoxA[0].x = cx + ((Ax1 - cx) * cosAngleA) - ((Ay1 - cy) * sinAngleA) - w;   <---- RESULT IS NOT CORRECT
     oBoxA[0].y = cy + ((Ay1 - cy) * cosAngleA) + ((Ax1 - cx) * sinAngleA) - h;   <---- RESULT OK!
 
     oBoxA[1].x = cx + ((Ax2 - cx) * cosAngleA) - ((Ay2 - cy) * sinAngleA) - w;   <---- RESULT OK!
     oBoxA[1].y = cy + ((Ay2 - cy) * cosAngleA) + ((Ax2 - cx) * sinAngleA) - h;   <---- RESULT OK!
 
     oBoxA[2].x = cx + ((Ax3 - cx) * cosAngleA) - ((Ay3 - cy) * sinAngleA) - w;   <---- RESULT OK!
     oBoxA[2].y = cy + ((Ay3 - cy) * cosAngleA) + ((Ax3 - cx) * sinAngleA) - h;   <---- RESULT OK!
 
     oBoxA[3].x = cx + ((Ax4 - cx) * cosAngleA) - ((Ay4 - cy) * sinAngleA) - w;    <---- RESULT IS NOT CORRECT
     oBoxA[3].y = cy + ((Ay4 - cy) * cosAngleA) + ((Ax4 - cx) * sinAngleA) - h;   <---- RESULT OK!

but the result is:
x1, y1
>>>226.86355102359<<< -29.097458940199
x2, y2
166.22416040756 -26.863551023585
x3, y3
161.75634457433 229.0974589402
x4, y4
>>>226.86355102359<<< 226.86355102359

has you can see the x1 and x4 are not correct!

why? really i can't see the error... but the result are not the same...

i have double checked the code... vars have the same values...

cy, cx, w, h, ax1... etc have the same values... (both in lua and C++ code)

if C++ all vars declared as "double" (in lua internally numbers are double)

can you help me?

i'm going mad!

(

zvardin · August 2012

Just a random stab in the dark without seeing more, but is it possible the SIN and COS values are varying between the two versions? (maybe one is using radians and one is using degrees) or something is off there. The reason I'm guessing this is your incorrect values are the exact same #s in some of the other values.

talis · August 2012

From these code segment nothing can be said i guess. It seems perfectly fine:) There are no miswritten variable name etc.

It will be so much general but the problem seems:
Somehow Lua is overwriting the variable(maybe out of scope or redifined in other scope etc) but you are not passing the correct overwritten value to c++.
Are you sure that you are converting Lua objects to C++ values as soon as they are created?

Maybe print the values of variables (debug them) and check if they are the same in lua and c++?

MikeHart · August 2012

Maybe your code to output the values is wrong.

OZApps · August 2012

@Greg, actually @Mike might be right on this one, the output of x1 and x4 which are wrong are the same as y4, so your cout statements might have that error or you are overwriting the values of x1 and x4 with the value of y4.

GregBUG · August 2012

ok. I double checked my code... there was a passing var error from lua to c
damn!!!

I just could not see it ... I'm getting old ... yes ... yes ... yes ... 8-X

thanks at @all anyway!!!

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Why? Can't see the problem here! HELP! i'm going crazy! Lua to C++ :((

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