opengl- vertex normal not taken in account - c++

Question

I was just getting into diffuse lighting, but the object always gives a black output,
The vertex and the fragment normals are defined as:
float vertices[] = {
-0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-0.5f, 0.5f, 0.5f, -1.0f, 0.0f, 0.0f,
-0.5f, 0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, 0.5f, -1.0f, 0.0f, 0.0f,
-0.5f, 0.5f, 0.5f, -1.0f, 0.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f,
0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f,
-0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f,
0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f
};
The relevant VAO is defined as:
unsigned int VAO, lightVAO, VBO;
glGenVertexArrays(1, &VAO);
glBindVertexArray(VAO);
glGenBuffers(1, &VBO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER,sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0,3, GL_FLOAT,GL_FALSE, 6*sizeof(float),(const void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6*sizeof(float), (const void*)3);
glEnableVertexAttribArray(1);
The relavant uniform are set as:
mShader.use();//activate the shader, already compiled
mShader.setMat4fv("model", model1);//model matrix
mShader.setMat4fv("view", view1);//view matrix
mShader.setMat4fv("projection", projection1);//projection matrix
mShader.setVec3f("lightPosition", 1.2f, 1.0f, 2.0f);//light source position
mShader.setVec3f("objectColor", 1.0f, 0.0f, 0.0f);//our object's base color
mShader.setVec3f("lightColor", 1.0f, 1.0f, 1.0f);//light source color
glBindVertexArray(VAO);
glDrawArrays(GL_TRIANGLES, 0, 36);
//glSwapBuffers is also performed, which I've double checked
The vertex shader for the object is this:
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aNormal;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
out vec3 mPos;
out vec3 mNormal;
uniform vec3 lightPosition;
uniform vec3 lightColor;
uniform vec3 objectColor;
out vec3 FragColor;
void main(){
gl_Position = projection * view * model * vec4(aPos, 1.0f);
vec3 norm = normalize(aNormal);
vec3 Fragpos = vec3(model*vec4(aPos, 1.0f));
vec3 lightDir = normalize(lightPosition-Fragpos);
float diff = max(dot(norm, lightDir), 0.0f);
vec3 diffuse = diff*lightColor;
FragColor = diffuse;
}
The fragment shader is this:
#version 330
in vec3 FragColor;
out vec4 outFragColor;
void main(){
outFragColor = vec4(FragColor, 1.0f);
}
Yet the output is:
What could be the possible cause for this. The source code is almost exactly same to the one given in learnopenGL
The full code for reference is:
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include "Libs/glm/glm.hpp"
#include "Libs/glm/gtc/matrix_transform.hpp"
#include "Libs/glm/gtc/type_ptr.hpp"
#include <iostream>
#include "mLibs/camera.hpp"
#ifndef STB_IMAGE_IMPLEMENTATION
#define STB_IMAGE_IMPLEMENTATION //must define to use the library
#endif
#include "Libs/stb_image.h"
#ifdef WINDOWS
#include <direct.h>//for windows
#define getcwd _getcwd
#else
#include <unistd.h>//for unix
#endif
#include "mLibs/window.hpp"
#include "mLibs/shaderClass.hpp"
void mouse_callback(GLFWwindow* window, double xpos, double ypos);
void scroll_callback(GLFWwindow* window, double xOffset, double yOffset);
void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow *window);
Camera camera(glm::vec3(0.0f, 0.0f, 3.0f));
float deltaTime = 0.0f;
float lastFrame = 0.0f;
// settings
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;
bool firstMouse = true;
float lastX = SCR_WIDTH/2.0f;
float lastY = SCR_HEIGHT/2.0f;
std::string objVShader = "objVShader.vs";
std::string objFShader = "objFShader.fs";
std::string lightVShader = "lightVShader.vs";
std::string lightFShader = "lightFShader.fs";
void framebuffer_size_callback(GLFWwindow* window, int width, int height){
glViewport(0, 0, width, height);
}
int main(){
GLFWwindow* mainWindow = static_cast<GLFWwindow*>(window::getWindow());
if(glewInit() != GLEW_OK){
util::LogUtil::Log("GLEW: ", "GlewInitialization failed");
window::DestroyAndTerminate(mainWindow);
}
glfwSetFramebufferSizeCallback(mainWindow, framebuffer_size_callback);
glfwSetFramebufferSizeCallback(mainWindow, framebuffer_size_callback);
glfwSetCursorPosCallback(mainWindow, mouse_callback);
glfwSetScrollCallback(mainWindow, scroll_callback);
glEnable(GL_DEPTH_TEST);
float vertices[] = {
-0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-0.5f, 0.5f, 0.5f, -1.0f, 0.0f, 0.0f,
-0.5f, 0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, 0.5f, -1.0f, 0.0f, 0.0f,
-0.5f, 0.5f, 0.5f, -1.0f, 0.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f,
0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f,
-0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f,
0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f
};
unsigned int VAO, lightVAO, VBO;
glGenVertexArrays(1, &VAO);
glBindVertexArray(VAO);
glGenBuffers(1, &VBO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER,sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0,3, GL_FLOAT,GL_FALSE, 6*sizeof(float),(const void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6*sizeof(float), (const void*)3);
glEnableVertexAttribArray(1);
glGenVertexArrays(1, &lightVAO);
glBindVertexArray(lightVAO);
//select lightVAO and bind the same VBO to this VAO
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glVertexAttribPointer(0,3, GL_FLOAT,GL_FALSE,6*sizeof(float),(const void*)0);
glEnableVertexAttribArray(0);
glm::mat4 model1 = glm::mat4(1.0f);
glm::mat4 view1 = glm::mat4(1.0f);
glm::mat4 projection1 = glm::mat4(1.0f);
glm::mat4 model2 = glm::mat4(1.0f);
glm::mat4 view2 = glm::mat4(1.0f);
glm::mat4 projection2 = glm::mat4(1.0f);
Shader mShader(objVShader.c_str(), objFShader.c_str());
Shader lightCubeShader(lightVShader.c_str(), lightFShader.c_str());
mShader.CompileShaders();
lightCubeShader.CompileShaders();
model2 = glm::translate(model2, glm::vec3(.3f, .4f, .5f));
projection1 = glm::perspective(camera.Zoom, static_cast<float>(SCR_WIDTH/SCR_HEIGHT), 0.1f, 100.0f);
float currentFrame;
while(!window::WindowShouldClose(mainWindow)){
glfwPollEvents();
currentFrame = glfwGetTime();
deltaTime = currentFrame - lastFrame;
lastFrame = currentFrame;
processInput(mainWindow);
view1 = camera.GetViewMatrix();
glClearColor(1, 0, 1, 1);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
mShader.use();
mShader.setMat4fv("model", model1);
mShader.setMat4fv("view", view1);
mShader.setMat4fv("projection", projection1);
mShader.setVec3f("lightPosition", 1.2f, 1.0f, 2.0f);
mShader.setVec3f("objectColor", 1.0f, 0.0f, 0.0f);
mShader.setVec3f("lightColor", 1.0f, 1.0f, 1.0f);
glBindVertexArray(VAO);
glDrawArrays(GL_TRIANGLES,0, 36);
lightCubeShader.use();
model2 = glm::mat4(1.0f);
model2 = glm::translate(model2, glm::vec3(1, 1, 1));
model2 = glm::scale(model2, glm::vec3(0.5f, 0.5f, 0.5f));
lightCubeShader.setMat4fv("model", model2);
lightCubeShader.setMat4fv("view", view1);
lightCubeShader.setMat4fv("projection", projection1);
glBindVertexArray(lightVAO);
glDrawArrays(GL_TRIANGLES,0, 36);
glfwSwapBuffers(mainWindow);
}
glDeleteVertexArrays(1,&VAO);
glDeleteVertexArrays(1,&lightVAO);
glDeleteBuffers(1, &VBO);
return 0;
}
void mouse_callback(GLFWwindow* window, double xpos, double ypos){
if(firstMouse){
lastX = xpos;
lastY = ypos;
firstMouse = false;
}
float xOffset = xpos-lastX;
float yOffset = lastY - ypos;
lastX = xpos;
lastY = ypos;
camera.ProcessMouseMovement(xOffset, yOffset);
}
void scroll_callback(GLFWwindow* window, double xOffset, double yOffset){
camera.ProcessMouseScroll(yOffset);
}
void processInput(GLFWwindow *window)
{
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
glfwSetWindowShouldClose(window, true);
if(glfwGetKey(window, GLFW_KEY_W)==GLFW_PRESS)
camera.ProcessKeyboard(FORWARD, deltaTime);
if(glfwGetKey(window, GLFW_KEY_S)==GLFW_PRESS)
camera.ProcessKeyboard(BACKWARD, deltaTime);
if(glfwGetKey(window, GLFW_KEY_A)==GLFW_PRESS)
camera.ProcessKeyboard(LEFT, deltaTime);
if(glfwGetKey(window, GLFW_KEY_D)==GLFW_PRESS)
camera.ProcessKeyboard(RIGHT, deltaTime);
if(glfwGetKey(window, GLFW_KEY_Q)==GLFW_PRESS)
camera.ProcessKeyboard(UP, deltaTime);
if(glfwGetKey(window, GLFW_KEY_E)==GLFW_PRESS)
camera.ProcessKeyboard(DOWN, deltaTime);
}

Answer 1

If a named buffer object is bound, then the last parameter of glVertexAttribPointer is treated as a byte offset into the buffer object's data store. The offset of the normal vector attribute are 3*4 bytes, thus (const void*)3 has to be (const void*)(3*sizeof(float)):
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6*sizeof(float), (const void*)3);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6*sizeof(float),
(const void*)(3*sizeof(float));