Texture mapping issue following Cherno's OpenGL Tutorial series

OpenGL
1

I’ve been trying to map a texture using vertices,vertex buffers,shaders and such.
I’m following Cherno’s OpenGL tutorial series and I followed it step by step the video is linked here: https://youtu.be/W3gAzLwfIP0
In the video his texture mapped properly but mine isn’t.

I’m using OpenGL,GLFW and GLEW libraries.

Here is the code in my main application cpp file

#include "glew.h"
#include "glfw3.h"
#include "Renderer.h"
#include "VertexBuffer.h"
#include "IndexBuffer.h"
#include "VertexArray.h"
#include "VertexBufferLayout.h"
#include "Texture.h"
#include "Shader.h"
#include <iostream>
#include <fstream>
#include <string>
#include<sstream>





int main(void)
{
    GLFWwindow* window;

    /* Initialize the library */
    if (!glfwInit())
        return -1;
    glewExperimental = GL_TRUE;

    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR,3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE,GLFW_OPENGL_CORE_PROFILE);

    /* Create a windowed mode window and its OpenGL context */
    window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
    if (!window)
    {
        glfwTerminate();
        return -1;
    }

    /* Make the window's context current */
    glfwMakeContextCurrent(window);
    glfwSwapInterval(1);

    glewInit();
    float positions[] = {
        -0.5f, -0.5f, 0.0f, 0.0f,
         0.5f, -0.5f, 1.0f, 0.0f,
         0.5f, 0.5f, 1.0f, 1.0f, 
        -0.5f, 0.5f, 0.0f, -1.0f };
    unsigned int indices[] = { 0,1,2,2,3,0};
   
    GLCall(glEnable(GL_BLEND));
    GLCall(glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA));
   
    unsigned int vao;
    GLCall(glGenVertexArrays(1, &vao));
    GLCall(glBindVertexArray(vao));

    VertexArray va;
    VertexBuffer vb(positions, 4 * 4 * sizeof(float));
    VertexBufferLayout layout;
    layout.Push<float>(2);   
    layout.Push<float>(2);
    va.AddBuffer(vb,layout);

  

    GLCall(glEnableVertexAttribArray(0));
    GLCall(glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 2, 0));

    IndexBuffer ib(indices, 6);
    

    Shader shader("C:/Users/Michael/source/repos/OGL  Test/OGL  Test/Basic.Shader");
    shader.Bind();
    shader.SetUniform4f("u_Color", 0.2f, 0.3f, 0.8f, 1.0f);
  
    Texture texture("resources/textures/hoofcoverart.png");
     texture.Bind();
     shader.SetUniform1i("u_Texture", 0);
    va.Unbind();
    vb.Unbind();
    ib.Unbind();
    shader.Unbind();
    /*std::cout << "Vertex" << std::endl;
    std::cout << source.VertexSource << std::endl;
    std::cout << "Fragment" << std::endl;
    std::cout << source.FragmentSource << std::endl;
*/
    Renderer renderer;
    float r = 0.0f;
    float increment = 0.05f;
    std::cout << glGetString(GL_VERSION);

    /* Loop until the user closes the window */
    while (!glfwWindowShouldClose(window))
    {
        /* Render here */
        renderer.Clear();

        shader.Bind();
        shader.SetUniform4f("u_Color", r, 0.3f, 0.8f, 1.0f);
        
   
        va.Bind();
        ib.Bind();
        renderer.Draw(va, ib, shader);

       //GLCall(glDrawElements(GL_TRIANGLES, 6,GL_UNSIGNED_INT,nullptr));
      
        if (r > 1.0f)
        {
            increment = -0.05f;
        }
        else if (r < 0.0f)
        {
            increment = 0.05f;
        }

        r += increment;

        /* Swap front and back buffers */
        glfwSwapBuffers(window);

        /* Poll for and process events */
        glfwPollEvents();


    }

   

    glfwTerminate();
    return 0;
}

VertexBuffer Code

#include "VertexBuffer.h"
#include "Renderer.h"
VertexBuffer::VertexBuffer(const void* data, unsigned int size)
{
    GLCall(glGenBuffers(1, &m_RendererID));
    GLCall(glBindBuffer(GL_ARRAY_BUFFER, m_RendererID));
    GLCall(glBufferData(GL_ARRAY_BUFFER, size, data, GL_STATIC_DRAW));

}
VertexBuffer::~VertexBuffer()
{
    GLCall(glDeleteBuffers(1, &m_RendererID));
}

void VertexBuffer::Bind() const
{
    GLCall(glBindBuffer(GL_ARRAY_BUFFER, m_RendererID));

}

void VertexBuffer::Unbind() const
{
    GLCall(glBindBuffer(GL_ARRAY_BUFFER, 0));

}

VertexArray Code

#include "VertexArray.h"
#include "VertexBufferLayout.h"
#include "Renderer.h"


VertexArray::VertexArray()
{
	GLCall(glGenVertexArrays(1, &m_RendererID));

}

VertexArray::~VertexArray()
{

	GLCall(glDeleteVertexArrays(1, &m_RendererID));

}

void VertexArray::AddBuffer(const VertexBuffer& vb, const VertexBufferLayout& layout)
{
	Bind();
	vb.Bind();
	const auto& elements = layout.GetElements();
	unsigned int offset = 0;
	for (unsigned int i = 0; i < elements.size(); i++)
	{
		const auto& element = elements[i];
		GLCall(glEnableVertexAttribArray(i));
		GLCall(glVertexAttribPointer(i, element.count, element.type, element.normalized, layout.GetStride(), (const void*)offset));
		offset += element.count * VertexBufferElement::GetSizeOfType(element.type);
	}

	
}

void VertexArray::Bind() const
{
	GLCall(glBindVertexArray(m_RendererID));
}

void VertexArray::Unbind() const
{
	GLCall(glBindVertexArray(0));
}

Texture code

#include "Texture.h"
#include "vendor/stb_image/stb_image.h"

Texture::Texture(const std::string& path) : m_FilePath(path), m_LocalBuffer(nullptr),m_Width(0),m_Height(0),m_BPP(0)
{
	stbi_set_flip_vertically_on_load(1);
	m_LocalBuffer = stbi_load(path.c_str(), &m_Width, &m_Height, &m_BPP, 4);

	GLCall(glGenTextures(1,&m_RendererID));
	GLCall(glBindTexture(GL_TEXTURE_2D,m_RendererID));

	GLCall(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
	GLCall(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
	GLCall(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE));
	GLCall(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE));

	GLCall(glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, m_Width, m_Height, 0, GL_RGBA, GL_UNSIGNED_BYTE, m_LocalBuffer));
	GLCall(glBindTexture(GL_TEXTURE_2D,0));

	if (m_LocalBuffer)
	{
		stbi_image_free(m_LocalBuffer);
	}
}

Texture::~Texture()
{
	GLCall(glDeleteTextures(1, &m_RendererID));
}

void Texture::Bind(unsigned int slot) const
{
	GLCall(glActiveTexture(GL_TEXTURE0 + slot));
	GLCall(glBindTexture(GL_TEXTURE_2D, m_RendererID));

}

void Texture::Unbind()
{
	GLCall(glBindTexture(GL_TEXTURE_2D, 0));
}

Shader Code

#include "Shader.h"
#include <iostream>
#include <fstream>
#include <string>
#include<sstream>
#include "Renderer.h"

Shader::Shader(const std::string& filepath) : m_FilePath(filepath), m_RendererID(0)
{
    ShaderProgramSource source = ParseShader(filepath);
    m_RendererID = CreateShader(source.VertexSource, source.FragmentSource);

}

Shader::~Shader()
{
    GLCall(glDeleteProgram(m_RendererID));
}

void Shader::Bind() const
{
    GLCall(glUseProgram(m_RendererID));
}

void Shader::Unbind() const
{
    GLCall(glUseProgram(0));
}

void Shader::SetUniform1i(const std::string& name, int value)
{
    GLCall(glUniform1i(GetUniformLocation(name), value));

}

void Shader::SetUniform4f(const std::string& name, float v0, float v1, float v2, float v3)
{
    GLCall(glUniform4f(GetUniformLocation(name), v0, v1, v2, v3));
}



ShaderProgramSource Shader::ParseShader(const std::string& filepath)
{
    std::ifstream stream(filepath);

    enum class ShaderType
    {
        NONE = -1,
        VERTEX = 0,
        FRAGMENT = 1
    };

    std::string line;
    std::stringstream ss[2];
    ShaderType type = ShaderType::NONE;

    while (getline(stream, line))
    {
        if (line.find("#shader") != std::string::npos)
        {
            if (line.find("vertex") != std::string::npos)
            {
                type = ShaderType::VERTEX;
            }
            else if (line.find("fragment") != std::string::npos)
            {
                type = ShaderType::FRAGMENT;
            }
        }
        else
        {
            ss[(int)type] << line << "\n";
        }
    }

    return { ss[0].str(), ss[1].str() };

}

 unsigned int Shader::CreateShader(const std::string& vertexShader, const std::string& fragmentShader)
{
    unsigned int program = glCreateProgram();
    unsigned int vs = CompileShader(GL_VERTEX_SHADER, vertexShader);
    unsigned int fs = CompileShader(GL_FRAGMENT_SHADER, fragmentShader);

    glAttachShader(program, vs);
    glAttachShader(program, fs);
    glLinkProgram(program);
    glValidateProgram(program);

    glDeleteShader(vs);
    glDeleteShader(fs);

    return program;



}
 unsigned int Shader::CompileShader(unsigned int type, const std::string& source)
{
    unsigned int id = glCreateShader(type);
    const char* src = source.c_str();
    glShaderSource(id, 1, &src, nullptr);
    glCompileShader(id);

    int result;
    glGetShaderiv(id, GL_COMPILE_STATUS, &result);

    if (result == GL_FALSE)
    {
        int length;
        glGetShaderiv(id, GL_INFO_LOG_LENGTH, &length);
        char* message = (char*)_malloca(length * sizeof(char));
        glGetShaderInfoLog(id, length, &length, message);
        std::cout << "Failed to compile " << (type == GL_VERTEX_SHADER ? "vertex" : "fragment") << std::endl;
        std::cout << message << std::endl;
    }

    return id;
}

 int Shader::GetUniformLocation(const std::string& name)
{
    if (m_UniformLocationCache.find(name) != m_UniformLocationCache.end())
        return m_UniformLocationCache[name];

    GLCall( int location = glGetUniformLocation(m_RendererID, name.c_str()));
    if (location == -1)
    {
        std::cout << "Warning: Uniform " << name << " doesn't exist!" << std::endl;
    }
   
    m_UniformLocationCache[name] = location;
  
    return location;
}

IndexBuffer Code

#include "IndexBuffer.h"
#include "Renderer.h"
IndexBuffer::IndexBuffer(const unsigned int* data, unsigned int count)
    : m_Count(count)
{
    GLCall(glGenBuffers(1, &m_RendererID));
    GLCall(glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_RendererID));
    GLCall(glBufferData(GL_ELEMENT_ARRAY_BUFFER, count * sizeof(unsigned int), data, GL_STATIC_DRAW));

}
IndexBuffer::~IndexBuffer()
{
    GLCall(glDeleteBuffers(1, &m_RendererID));
}

void IndexBuffer::Bind() const
{
    GLCall(glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_RendererID));

}

void IndexBuffer::Unbind() const
{
    GLCall(glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0));

}

Renderer Code

#include "Renderer.h"
#include <iostream>

void GLClearError()
{
    while (glGetError() != GL_NO_ERROR);
}

bool GLLogCall(const char* function, const char* file, int line)
{
    while (GLenum error = glGetError())
    {
        std::cout << "Open GL Error : " << error << " | " << function << " | " << file << std::endl;
        return false;
    }
    return true;
}
void Renderer::Clear()
{
    glClear(GL_COLOR_BUFFER_BIT);
}

void Renderer::Draw(const  VertexArray& va, const IndexBuffer& ib, const Shader& shader) const
{
    shader.Bind();    
    va.Bind();
    ib.Bind();
    GLCall(glDrawElements(GL_TRIANGLES, ib.GetCount(), GL_UNSIGNED_INT, nullptr));

}

Shader file code

#shader vertex
 #version 330 core  
   
 layout(location = 0) in vec4 position;  
layout(location = 1) in vec2 textureCoordinate;

out vec2 v_TextureCoordinate;

 void main()  
 {  
  gl_Position = position;   
  v_TextureCoordinate = textureCoordinate;
 } ;
#shader fragment
#version 330 core  
   
 layout(location = 0) out vec4 color;  
   
in vec2 v_TextureCoordinate;

uniform vec4 u_Color;
uniform sampler2D u_Texture;

 void main()  
 {  
	vec4 textureColor = texture(u_Texture, v_TextureCoordinate);
	color = textureColor;  
 };

The above code results in an image that is not mapped correctly. I tried changing the vertices order around and changing the mapping positions in the positions array but nothing showed the image correctly.
Original Image:
Original Image
Mapped Texture:
Texture mapping

Any idea on how to fix this? Let me know if you need any more information!

I tried changing the vertices order around and changing the mapping positions in the positions array but nothing showed the image correctly.

2

Cross-ref:

Copy/paste of the solution:

3

Yep that’s me and that fixed it! I was going to post my solution after my post got approved like right now lol. Thank you!

Also:

Another thing since I already enable the glVertexAttribArray and the pointer in the buffer during an AddBuffer() call I was suppose to remove it from the application file since it’s doing it twice and long behold I found that it gets the correct stride in that function anyway…

4

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