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POC++ Initializing a Static Stack
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copied!<p>I have some questions about initializing a static collection. Here is an example I coded that seems to work:</p> <pre><code>#include <stack> #include <iostream> using namespace std; class A { private: static stack<int> numbers; static stack<int> initializeNumbers(); public: A(); }; A::A() { cout << numbers.top() << endl; } stack<int> A::initializeNumbers() { stack<int> numbers; numbers.push(42); return numbers; } stack<int> A::numbers = initializeNumbers(); int main() { A a; } </code></pre> <p>Now, is this the best way to do what I'm trying to accomplish? For some reason, when I try this exact same scheme in my real code, calling <em>top()</em> prints gibberish. Could there be any reason for this?</p> <p>If my example is fine, perhaps I will resort to posting my real code.</p> <hr> <p>Here is the real code:</p> <p><em>Light.h</em></p> <pre><code>#ifndef LIGHT_H_ #define LIGHT_H_ #include <stack> #include "Vector4.h" class Light { private: static stack<GLenum> availableLights; static stack<GLenum> initializeAvailableLights(); public: GLenum lightID; Vector4 ambient, diffuse, specular, position, spotDirection; GLfloat constantAttenuation, linearAttenuation, quadraticAttenuation, spotExponent, spotCutoff; Light( const Vector4& ambient = Vector4(0.0, 0.0, 0.0, 1.0), const Vector4& diffuse = Vector4(1.0, 1.0, 1.0, 1.0), const Vector4& specular = Vector4(1.0, 1.0, 1.0, 1.0), const Vector4& position = Vector4(0.0, 0.0, 1.0, 0.0), const Vector4& spotDirection = Vector4(0.0, 0.0, -1.0, 0.0), GLfloat constantAttenuation = 1.0, GLfloat linearAttenuation = 0.0, GLfloat quadraticAttenuation = 0.0, GLfloat spotExponent = 0.0, GLfloat spotCutoff = 180.0); ~Light(); }; #endif /*LIGHT_H_*/ </code></pre> <p><em>Light.cpp</em></p> <pre><code>#include <stdexcept> // runtime_error #include <iostream> using namespace std; #include "Light.h" Light::Light( const Vector4& ambient, const Vector4& diffuse, const Vector4& specular, const Vector4& position, const Vector4& spotDirection, GLfloat constantAttenuation, GLfloat linearAttenuation, GLfloat quadraticAttenuation, GLfloat spotExponent, GLfloat spotCutoff) : ambient(ambient), diffuse(diffuse), specular(specular), position(position), spotDirection(spotDirection), constantAttenuation(constantAttenuation), linearAttenuation(linearAttenuation), quadraticAttenuation(quadraticAttenuation), spotExponent(spotExponent), spotCutoff(spotCutoff) { // This prints gibberish. cout << availableLights.size() << endl; // The error is indeed thrown. if(availableLights.empty()) throw runtime_error("The are no more available light identifiers."); else { lightID = availableLights.top(); availableLights.pop(); } } Light::~Light() { availableLights.push(this -> lightID); } stack<GLenum> Light::initializeAvailableLights() { stack<GLenum> availableLights; availableLights.push(GL_LIGHT7); availableLights.push(GL_LIGHT6); availableLights.push(GL_LIGHT5); availableLights.push(GL_LIGHT4); availableLights.push(GL_LIGHT3); availableLights.push(GL_LIGHT2); availableLights.push(GL_LIGHT1); availableLights.push(GL_LIGHT0); return availableLights; } stack<GLenum> Light::availableLights = initializeAvailableLights(); </code></pre> <hr> <p>And since I can't get the code with the stack to work, I've opted for this at the moment:</p> <p><em>Light.h</em></p> <pre><code>#ifndef LIGHT_H_ #define LIGHT_H_ #include <stack> #include "Vector4.h" class Light { private: static const unsigned int LIGHTS = 9; static bool availableLights[]; static GLenum lights[]; static GLenum getAvailableLight(); public: GLenum lightID; Vector4 ambient, diffuse, specular, position, spotDirection; GLfloat constantAttenuation, linearAttenuation, quadraticAttenuation, spotExponent, spotCutoff; Light( const Vector4& ambient = Vector4(0.0, 0.0, 0.0, 1.0), const Vector4& diffuse = Vector4(1.0, 1.0, 1.0, 1.0), const Vector4& specular = Vector4(1.0, 1.0, 1.0, 1.0), const Vector4& position = Vector4(0.0, 0.0, 1.0, 0.0), const Vector4& spotDirection = Vector4(0.0, 0.0, -1.0, 0.0), GLfloat constantAttenuation = 1.0, GLfloat linearAttenuation = 0.0, GLfloat quadraticAttenuation = 0.0, GLfloat spotExponent = 0.0, GLfloat spotCutoff = 180.0); ~Light(); }; #endif /*LIGHT_H_*/ </code></pre> <p><em>Light.cpp</em></p> <pre><code>#include <stdexcept> // runtime_error #include "Light.h" Light::Light( const Vector4& ambient, const Vector4& diffuse, const Vector4& specular, const Vector4& position, const Vector4& spotDirection, GLfloat constantAttenuation, GLfloat linearAttenuation, GLfloat quadraticAttenuation, GLfloat spotExponent, GLfloat spotCutoff) : ambient(ambient), diffuse(diffuse), specular(specular), position(position), spotDirection(spotDirection), constantAttenuation(constantAttenuation), linearAttenuation(linearAttenuation), quadraticAttenuation(quadraticAttenuation), spotExponent(spotExponent), spotCutoff(spotCutoff) { lightID = getAvailableLight(); } Light::~Light() { for(unsigned int i = 0; i < LIGHTS; i++) if(lights[i] == lightID) availableLights[i] = true; } bool Light::availableLights[] = {true, true, true, true, true, true, true, true}; GLenum Light::lights[] = {GL_LIGHT0, GL_LIGHT1, GL_LIGHT2, GL_LIGHT3, GL_LIGHT4, GL_LIGHT5, GL_LIGHT6, GL_LIGHT7}; GLenum Light::getAvailableLight() { for(unsigned int i = 0; i < LIGHTS; i++) if(availableLights[i]) { availableLights[i] = false; return lights[i]; } throw runtime_error("The are no more available light identifiers."); } </code></pre> <hr> <p>Can anyone spot an error in the code with the stack, or perhaps improve upon my hastily coded workaround?</p>

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