c++ array init help

esrrms · 05-16-2005, 01:30 PM

Could someone tell me why this throws an error? I thought you could initialize an array like this.

light.hh

Code:

#ifndef _LIGHT_HH
#define _LIGHT_HH

#include <GL/gl.h>

class light
{
public:
  light(GLenum);

private:
  GLenum m_lightNum;
  GLfloat m_ambient[4];
  GLfloat m_diffuse[4];
  GLfloat m_specular[4];
  GLfloat m_position[4];
  GLfloat m_spotDirection[3];
  GLfloat m_spotExponent;
  GLfloat m_spotCutOff;
  GLfloat m_constantAttenuation;
  GLfloat m_linearAttenuation;
  GLfloat m_quadraticAttenuation;
};

#endif // _LIGHT_HH

light.cc

Code:

#include "light.hh"

light::light(GLenum p_lightNum)
  : m_lightNum(p_lightNum)
    , m_ambient(0.0, 0.0, 0.0, 1.0) // <----- this throws the error.
{
}

jtshaw · 05-16-2005, 01:40 PM

try

Code:

m_ambient = {0.0, 0.0, 0.0, 1.0};

esrrms · 05-16-2005, 01:43 PM

nope, that throws an error too.

jtshaw · 05-16-2005, 01:56 PM

Oh.. right... I'm an idiot... only works if you do init like that on declaration.

Works:

Code:

char array[4] = {'a', 'b', 'c', 'd'};

Doesn't work:

Code:

char array[4];
array = {'a','b','c','d');

deiussum · 05-16-2005, 02:27 PM

You've got a couple of options:

Code:

light::light(GLenum p_lightNum)
  : m_lightNum(p_lightNum)
{
    m_ambient[0] = 0.0;
    m_ambient[1] = 0.0;
    m_ambient[2] = 0.0;
    m_ambient[3] = 1.0;
}

Or:

Code:

light::light(GLenum p_lightNum)
  : m_lightNum(p_lightNum)
{
    GLfloat temp[] = {0.0, 0.0, 0.0, 1.0};
    
    // Could do the following with something like memcpy too
    for (int c=0;c<4;c++) m_ambient[c] = temp[c];
}

esrrms · 05-16-2005, 07:06 PM

thanks guys, appreciate it.