Meshpathlines.h

#pragma once
// Std. Includes
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
#include <vector>
using namespace std;
// GL Includes
#include <glew.h> // Contains all the necessery OpenGL includes
#include <glm.hpp>
#include <gtc/matrix_transform.hpp>

#include "Shader.h"


struct VertexPathlines {
    // Position
    glm::vec3 Position;
    // Normal
    glm::vec2 TimeAndVelocity;
    // TexCoords
    glm::vec2 TexCoords;
    //Tangent
    glm::vec3 Tangents;
};

class MeshPathlines {
public:
    /*  Mesh Data  */
    vector<VertexPathlines> vertices;
    vector<GLuint> indices;
    vector<Texture> textures;

    /*  Functions  */
    // Constructor
    MeshPathlines(vector<VertexPathlines> vertices, vector<GLuint> indices, vector<Texture> textures)
    {
        this->vertices = vertices;
        this->indices = indices;
        this->textures = textures;

        // Now that we have all the required data, set the vertex buffers and its attribute pointers.
        this->setupMesh();
    }

    // Render the mesh
    void Draw(Shader shader)
    {
        //Draw Settings
        glEnable(GL_STENCIL_TEST);
        glStencilFunc(GL_EQUAL, 1, 1);
        glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
        glEnable(GL_PRIMITIVE_RESTART);
        glPrimitiveRestartIndex(std::numeric_limits<GLuint>::max());


        // Bind appropriate textures
        GLuint diffuseNr = 1;
        GLuint specularNr = 1;
        for (GLuint i = 0; i < this->textures.size(); i++)
        {
            glActiveTexture(GL_TEXTURE0 + i); // Active proper texture unit before binding
                                              // Retrieve texture number (the N in diffuse_textureN)
            stringstream ss;
            string number;
            string name = this->textures[i].type;
            if (name == "texture_diffuse")
                ss << diffuseNr++; // Transfer GLuint to stream
            else if (name == "texture_specular")
                ss << specularNr++; // Transfer GLuint to stream
            number = ss.str();
            // Now set the sampler to the correct texture unit
            glUniform1i(glGetUniformLocation(shader.Program, (name + number).c_str()), i);
            // And finally bind the texture
            glBindTexture(GL_TEXTURE_2D, this->textures[i].id);
        }

        // Also set each mesh's shininess property to a default value (if you want you could extend this to another mesh property and possibly change this value)
        glUniform1f(glGetUniformLocation(shader.Program, "material.shininess"), 16.0f);

        // Draw mesh
        glBindVertexArray(this->VAO);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, this->EBO);
        glDrawElements(GL_LINE_STRIP, this->indices.size() * sizeof(GLuint), GL_UNSIGNED_INT, nullptr);//draw
        //glDrawElements(GL_POINTS, this->indices.size() * sizeof(GLuint), GL_UNSIGNED_INT, nullptr);

//      glDrawElements(GL_TRIANGLES, this->indices.size(), GL_UNSIGNED_INT, 0);
        glBindVertexArray(0);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

        //reset settings
        glDisable(GL_PRIMITIVE_RESTART);
        glDisable(GL_STENCIL_TEST);


        // Always good practice to set everything back to defaults once configured.
        for (GLuint i = 0; i < this->textures.size(); i++)
        {
            glActiveTexture(GL_TEXTURE0 + i);
            glBindTexture(GL_TEXTURE_2D, 0);
        }
    }

private:
    /*  Render data  */
    GLuint VAO, VBO, EBO;

    /*  Functions    */
    // Initializes all the buffer objects/arrays
    void setupMesh()
    {
        // Create buffers/arrays
        glGenVertexArrays(1, &this->VAO);
        glGenBuffers(1, &this->VBO);
        glGenBuffers(1, &this->EBO);

        glBindVertexArray(this->VAO);
        // Load data into vertex buffers
        glBindBuffer(GL_ARRAY_BUFFER, this->VBO);
        // A great thing about structs is that their memory layout is sequential for all its items.
        // The effect is that we can simply pass a pointer to the struct and it translates perfectly to a glm::vec3/2 array which
        // again translates to 3/2 floats which translates to a byte array.
        glBufferData(GL_ARRAY_BUFFER, this->vertices.size() * sizeof(VertexPathlines), &this->vertices[0], GL_STATIC_DRAW);

        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, this->EBO);
        glBufferData(GL_ELEMENT_ARRAY_BUFFER, this->indices.size() * sizeof(GLuint), &this->indices[0], GL_STATIC_DRAW);

        // Set the vertex attribute pointers
        // Vertex Positions
        glEnableVertexAttribArray(0);
        glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(VertexPathlines), (GLvoid*)0);
        // Vertex Time and Velocity
        glEnableVertexAttribArray(1);
        glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(VertexPathlines), (GLvoid*)offsetof(VertexPathlines, TimeAndVelocity));
        // Vertex Texture Coords
        glEnableVertexAttribArray(2);
        glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(VertexPathlines), (GLvoid*)offsetof(VertexPathlines, TexCoords));
        //freshly introduced tangents
        glEnableVertexAttribArray(3);
        glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE, sizeof(VertexPathlines), (GLvoid*)offsetof(VertexPathlines, Tangents));

        glBindVertexArray(0);
    }
};