How Can I Pass a Multi Argument Function with an Array? - C++

Question

I am trying to pass an array containing an X, Y, and Z coordinate (type float) to the function glTranslatef() however I can't figure out a way to accomplish this.

As an example of what I am trying to accomplish;

float xyz[3] = {3,2,1};
glTranslatef(xyz);

I get the following error whenever I try to attempt something like this

cannot convert ‘float*’ to ‘GLfloat {aka float}’ for argument ‘1’ to ‘void glTranslatef(GLfloat, GLfloat, GLfloat)’

I have tried searching all over google but I couldn't find what I was looking for.

So, you're looking for a C++ equivalent to Python's func(*args) syntax? — dan04
– dan04, Commented Feb 11, 2012 at 23:08
Do not use ALL UPPERCASE names, except for macros, where you should use them. — Cheers and hth. - Alf
– Cheers and hth. - Alf, Commented Feb 11, 2012 at 23:13
@ Alf P. Steinbach That's not my real code, it's just an example — daxvena
– daxvena, Commented Feb 11, 2012 at 23:25

Lightness Races in Orbit · Accepted Answer · 2012-02-11 23:10:27Z

5

glTranslatef takes three float arguments, not one array argument. That's the end of it.

float XYZ[3] = {3,2,1};
glTranslatef(XYZ[0], XYZ[1], XYZ[2]);

If you're really desperate you can unpack it with a macro:

#define UNPACK_TRI_ARRAY(ar) ar[0], ar[1], ar[2]

float XYZ[3] = {3,2,1};
glTranslatef(UNPACK_TRI_ARRAY(XYZ));

But once you get to that point, you have to ask yourself why.

answered Feb 11, 2012 at 23:10

Lightness Races in Orbit

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3 Comments

daxvena Over a year ago

Ok, I just remember in some point in time (I don't even remember what language I was using) being able to accomplish this without having to repetitively and separately define the location in the array.

datenwolf Over a year ago

@MarkData: Maybe you were thinking about glVertexfv, glNormalfv, etc. which indeed take a vector/array.

Lightness Races in Orbit Over a year ago

Indeed. Unfortunately there is no v variant for glTranslatef.

damson · Accepted Answer · 2012-02-11 23:10:57Z

2

Try like this:

glTranslatef(XYZ[0], XYZ[1], XYZ[2]);

http://www.opengl.org/sdk/docs/man/xhtml/glTranslate.xml

Prototype:

void glTranslatef(GLfloat   x,
                  GLfloat   y,
                  GLfloat   z);

answered Feb 11, 2012 at 23:10

damson

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Comments

Dmitriy Kachko · Accepted Answer · 2012-02-11 23:11:05Z

0

glTranslatef(XYZ[0], XYZ[1], XYZ[2]);

answered Feb 11, 2012 at 23:11

Dmitriy Kachko

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Comments

user1149224 · Accepted Answer · 2012-02-11 23:13:59Z

0

AFAIK, I'd just define an overload for the function taking a const float * and then pass array elements to the original three-arguments (X,Y,Z) function.

answered Feb 11, 2012 at 23:13

user1149224

1 Comment

Lightness Races in Orbit Over a year ago

Why not a const float (&)[3]?

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