OpenGL shader not drawing anything - bad sprite class - c++

Question

I'm trying to encapsulate OpenGL rendering in a renderer class.
I'm pretty sure my window class works fine (I've checked for errors) but I think the error is in my sprite class but I have no idea what it is.
This is my sprite class:
sprite_renderer.hpp
#ifndef SPRITE_RENDERER_H
#define SPRITE_RENDERER_H
#include <GL/glew.h>
#include "shader.hpp"
class SpriteRenderer
{
public:
SpriteRenderer(Shader &shader);
~SpriteRenderer();
void DrawSprite();
private:
Shader shader;
GLuint quadVAO;
void initRenderData();
};
#endif
sprite_renderer.cpp
#include "sprite_renderer.hpp"
SpriteRenderer::SpriteRenderer(Shader &shader)
{
this->shader = shader;
this->initRenderData();
}
SpriteRenderer::~SpriteRenderer()
{
glDeleteVertexArrays(1, &this->quadVAO);
}
void SpriteRenderer::DrawSprite()
{
this->shader.Use();
glBindVertexArray(this->quadVAO);
glDrawArrays(GL_TRIANGLES, 0, 6);
glBindVertexArray(0);
}
void SpriteRenderer::initRenderData()
{
GLuint VBO;
GLfloat vertices[] = {
// Pos
0.0f, 1.0f,
1.0f, 0.0f,
0.0f, 0.0f,
0.0f, 1.0f,
1.0f, 1.0f,
1.0f, 0.0f,
};
glGenVertexArrays(1, &this->quadVAO);
glGenBuffers(1, &VBO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindVertexArray(this->quadVAO);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(GLfloat), (GLvoid*)0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
}
I'm using it like this in my main.cpp:
int main()
{
Window window = Window();
Shader shader = ResourceManager::LoadShader("./assets/shaders/sprite.vert", "./assets/shaders/sprite.frag", "sprite");
SpriteRenderer* renderer = new SpriteRenderer(shader);
while (window.IsOpen())
{
window.BeginDraw();
renderer->DrawSprite();
window.EndDraw();
}
glfwTerminate();
return 0;
}
Where window.BeginDraw() and window.EndDraw() are just:
void Window::BeginDraw()
{
glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
}
void Window::EndDraw()
{
glfwSwapBuffers(window);
glfwPollEvents();
}

Answer 1

Just to rule out the obvious, try sticking a print statement in the destructor of your Shader class. Judging by the design of your Shader class, you should find it extremely easy to end up calling glDeleteProgram prior to actually using the shader.
In general, if you have a wrapper around a GLSL shader or program, you probably want to delete the copy constructor and assignment operator (or implement a ref counting system).
\edit to delete the copy ctor & assignment operator....
Shader(const Shader&) = delete;
Shader& operator = (const Shader&) = delete;
You probably want to manage these shaders somewhere (possibly ref counted), and only store pointers to them within your SpriteRenderer.
I can't see any other problem with the code you've posted above, so the issue may be within your shader, or how you are passing any uniform variables you're using.