c++ with openGl can't render - c++

Question

I try to make the code cleaner by extracting the whole main Proramm in some classes. So I have a vertex buffer, index buffer and a shader class. Only the array buffer is in the main and it worked.
Now I created a layout class and a vertex array class to put different layouts in the vertex array and the renderfunction in my main stopped to work.
Here is my code:
vertexBuffer.cpp
#include "../headerData/VertexBuffer.h"
VertexBuffer::VertexBuffer(const void* data, unsigned int size) {
glGenBuffers(1, &bufferId);
glBindBuffer(GL_ARRAY_BUFFER, bufferId);
glBufferData(GL_ARRAY_BUFFER, size, data, GL_STATIC_DRAW);
}
VertexBuffer::~VertexBuffer() {
glDeleteBuffers(1, &bufferId);
}
void VertexBuffer::bind() const {
glBindBuffer(GL_ARRAY_BUFFER, bufferId);
}
void VertexBuffer::unbind() const {
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
vertex Index cpp:
#include "../headerData/IndexBuffer.h"
IndexBuffer::IndexBuffer(const void* data, unsigned int count) {
glGenBuffers(1, &bufferId);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, bufferId);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, count, data, GL_STATIC_DRAW);
}
IndexBuffer::~IndexBuffer() {
glDeleteBuffers(1, &bufferId);
}
void IndexBuffer::bind() const {
glBindBuffer(GL_ARRAY_BUFFER, bufferId);
}
void IndexBuffer::unbind() const {
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
VertexLayout.h
#pragma once
#include <vector>
//Stubides Layout da vieles vorgegeben wird
struct ElementLayout {
unsigned int size; //anzahl an koordinaten die zählen
unsigned int stride; //Die größe der
};
class VertexLayout {
private:
std::vector<ElementLayout> elements;
public:
VertexLayout();
~VertexLayout();
void layoutPush(unsigned int size);
std::vector<ElementLayout> getElements() const;
};
vertexLayout.cpp:
#include"../headerData/VertexLayout.h"
VertexLayout::VertexLayout() {}
VertexLayout::~VertexLayout() {}
void VertexLayout::layoutPush(unsigned int size)
{
elements.push_back({ size, size * sizeof(float) });
}
std::vector<ElementLayout> VertexLayout::getElements() const {
return elements;
}
VertexArray.cpp
#include "../headerData/VertexArray.h"
#include <iostream>
VertexArray::VertexArray() {
glGenVertexArrays(1, &vertexArrayID);
}
VertexArray::~VertexArray() {
glDeleteVertexArrays(1, &vertexArrayID);
}
void VertexArray::bind() const {
glBindVertexArray(vertexArrayID);
}
void VertexArray::unbind() const {
glBindVertexArray(0);
}
//Vom Buffer soll auch das zugehörige Layout übergeben werden
void VertexArray::addBuffer(VertexBuffer& vb, VertexLayout& layout) {
bind();
vb.bind();
std::vector<ElementLayout> element = layout.getElements();
unsigned int offset = 0;
for (int i = 0; i < element.size(); i++) {
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, element[i].size, GL_FLOAT, GL_FALSE, element[i].stride, (void*)0);
offset += element[i].size * sizeof(float);
std::cout << GL_NO_ERROR;
}
std::cout << glGetError();
}
main.cpp:
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include "headerData/VertexBuffer.h"
#include "headerData/IndexBuffer.h"
#include "headerData/Shader.h"
#include "headerData/VertexLayout.h"
#include "headerData/VertexArray.h"
void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow* window)
{
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
glfwSetWindowShouldClose(window, true);
}
int main()
{
// glfw: initialize and configure
// ------------------------------
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
#ifdef __APPLE__
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif
// glfw window creation
// --------------------
GLFWwindow* window = glfwCreateWindow(800, 800, "LearnOpenGL", NULL, NULL);
if (window == NULL)
{
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
// glad: load all OpenGL function pointers
// ---------------------------------------
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
std::cout << "Failed to initialize GLAD" << std::endl;
return -1;
}
Shader shader;
shader.bind();
// set up vertex data (and buffer(s)) and configure vertex attributes
// ------------------------------------------------------------------
float vertices[] = {
0.5f, 0.5f, 0.0f, // top right
0.5f, -0.5f, 0.0f, // bottom right
-0.5f, -0.5f, 0.0f, // bottom left
-0.5f, 0.5f, 0.0f, // top left
-1.0f, -1.0f, 0.0f //zum Testen
//dreieck
};
unsigned int indices[] = { // note that we start from 0!
0, 1, 3, // first triangle
1, 2, 3 // second triangle
};
float vertices2[] = {
-1.0f, -1.0f, 0.0f,
1.0f, -1.0f, 0.0f,
0.0f, 0.0f, 0.0f
};
unsigned int test;
glGenVertexArrays(1, &test);
// bind the Vertex Array Object first, then bind and set vertex buffer(s), and then configure vertex attributes(s).
glBindVertexArray(test);
//glBindBuffer(GL_ARRAY_BUFFER, VBO);
//glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
VertexBuffer vb(vertices, 5 * 3 * sizeof(float));
IndexBuffer ib(indices, 6 * sizeof(unsigned int));
VertexLayout layout;
layout.layoutPush(3);
VertexArray va;
//va.addBuffer(vb, layout);
//va.addBuffer(vb, layout); when this is uncomment the render function doesn't work
//Parameter
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)(0));
//glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(0);
//glEnableVertexAttribArray(1);
// uncomment this call to draw in wireframe polygons.
//glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
// render loop
// -----------
while (!glfwWindowShouldClose(window))
{
// input
// -----
processInput(window);
// render
// ------
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
shader.bind();
//glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_INT, (void*)(sizeof(unsigned int) * 3));
//glDrawArrays(GL_TRIANGLES, 0, 3);
//glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_INT, (void*)(sizeof(unsigned int) * 3));
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
// glBindVertexArray(0); // no need to unbind it every time
// glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
// -------------------------------------------------------------------------------
glfwSwapBuffers(window);
glfwPollEvents();
}
// optional: de-allocate all resources once they've outlived their purpose:
// ------------------------------------------------------------------------
glDeleteVertexArrays(1, &test);
// glfw: terminate, clearing all previously allocated GLFW resources.
// ------------------------------------------------------------------
glfwTerminate();
return 0;
}
With glGetError() I get the number 1281 =>invalid value but where.

Answer 1

The index buffer (ELEMENT_ARRAY_BUFFER) binding is stored within the Vertex Array Object. When glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, bufferId) is called a reference to the element buffer object is stored in the currently bound Vertex Array Object. Therefore the VAO must be bound before the element buffer with glBindVertexArray(vertexArrayID):
VertexArray va;
va.bind();
IndexBuffer ib(indices, 6 * sizeof(unsigned int));