light bugs on 3D model [duplicate] - c++

Question

This question already has an answer here:
light source is not set correctly
(1 answer)
Closed 1 year ago.
I have this picture below that shows the 3D model and the light is not as I expected, I've already tried many ways but I can't figure out how to fix it. my normal vectors are fine
the goemetry:
glGenVertexArrays(1, &VAOArray);
glBindVertexArray(VAOArray);
/* GENERATE THE BUFFERS */
glGenBuffers(1, &bufferArray);
/* SELECT THAT BUFFER TO WORK WITH */
glBindBuffer(GL_ARRAY_BUFFER, bufferArray);
glBufferData(GL_ARRAY_BUFFER, myMeshes.at(j).realPositions.size() * sizeof(float), (GLfloat*)RealPos, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
glEnableVertexAttribArray(0);
glGenBuffers(1, &normalArray);
glBindBuffer(GL_ARRAY_BUFFER, normalArray);
glBufferData(GL_ARRAY_BUFFER, myMeshes.at(j).realNormals.size()*sizeof(float), (GLfloat*)RealNor, GL_STATIC_DRAW);
glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE, 0, 0);
glEnableVertexAttribArray(3);
this is my code:
while (!glfwWindowShouldClose(window))
{
/* Render here */
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glm::mat4 view = glm::mat4(1.0f);
glm::mat4 projection = glm::mat4(1.0f);
projection = glm::perspective(glm::radians(45.0f), (float)width / (float)heigh, 0.1f, 100.0f);
view = glm::translate(view, glm::vec3(0.0f, 0.0f, transZ)); //this is for scroll mouse
view = glm::translate(view, glm::vec3(0.0f, 0.0f, -2.0f));
view = glm::translate(view, glm::vec3(0.0f, 0.0f, -5.0f));
glUseProgram(programT);
int lightColorLoc = glGetUniformLocation(programT, "lightColor");
glUniformMatrix4fv(lightColorLoc, 1, GL_FALSE, glm::value_ptr(glm::vec3(1.0f, 0.0f, 0.0f)));
int objectColorLoc = glGetUniformLocation(programT, "objectColor");
glUniformMatrix4fv(objectColorLoc, 1, GL_FALSE, glm::value_ptr(glm::vec3(1.0f, 0.5f, 0.31f)));
glm::vec3 lightPos(2.0f, 4.0f, 5.0f);
int lightPosLoc = glGetUniformLocation(programT, "lightPos");
glUniformMatrix4fv(lightPosLoc, 1, GL_FALSE, glm::value_ptr(lightPos));
int projectionLocLight = glGetUniformLocation(programT, "projection");
glUniformMatrix4fv(projectionLocLight, 1, GL_FALSE, glm::value_ptr(projection));
glm::mat4 modelLight = glm::mat4(1.0f);
int modelLocLight = glGetUniformLocation(programT, "model");
glUniformMatrix4fv(modelLocLight, 1, GL_FALSE, glm::value_ptr(modelLight));
glm::mat4 viewLight = glm::mat4(1.0f);
int viewLocLight = glGetUniformLocation(programT, "view");
glUniformMatrix4fv(viewLocLight, 1, GL_FALSE, glm::value_ptr(viewLight));
int viewLoc = glGetUniformLocation(programT, "view");
glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
int projectionLoc = glGetUniformLocation(programT, "projection");
glUniformMatrix4fv(projectionLoc, 1, GL_FALSE, glm::value_ptr(projection));
model = glm::rotate(model, glm::radians(rotX), glm::vec3(1.0f, 0.0f, 0.0f));
model = glm::rotate(model, glm::radians(rotY), glm::vec3(.0f, 1.0f, .0f));
model = glm::rotate(model, glm::radians(rotZ), glm::vec3(.0f, 0.0f, 1.0f));
int modelLoc = glGetUniformLocation(programT, "model");
glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
glGenerateMipmap(GL_TEXTURE_2D);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, textureArray[0]);
glUniform1i(glGetUniformLocation(programT, "ourTexture"), 0);
glBindVertexArray(VAOArray[0]);
glDrawArrays(GL_TRIANGLES, 0, myMeshes.at(0).Indices.size());
/* Swap front and back buffers */
glfwSwapBuffers(window);
/* Poll for and process events */
glfwPollEvents();
glfwSetKeyCallback(window, key_callback);
glfwSetScrollCallback(window, scroll_callback);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
}
vertex shader used for this project:
#version 330 core
layout (location = 0) in vec3 RealPos;
layout (location = 1) in vec3 vertex_color;
layout (location = 2) in vec2 vertex_textcoord;
layout (location = 3) in vec3 RealNor;
out vec3 vs_pos;
out vec3 vs_color;
out vec2 vs_text;
out vec3 normal;
out vec3 FragPos;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
vs_pos = RealPos;
vs_color = vertex_color;
vs_text=vertex_textcoord;
FragPos = vec3(model * vec4(vs_pos, 1.0));
mat3 normalMat = mat3(inverse(transpose(model)));
normal = RealNor * normalMat;
gl_Position = projection * view * model * vec4(vs_pos, 1.0);
}
fragment shader used:
#version 330 core
in vec2 vs_text;
in vec3 normal;
in vec3 FragPos;
uniform vec3 lightPos;
out vec4 gl_FragColor;
uniform vec3 objectColor;
uniform vec3 lightColor;
uniform sampler2D ourTexture;
void main()
{
vec3 norm = normalize(normal);
vec3 lightDir = normalize(lightPos - FragPos);
float ambientStrength = 0.1;
vec3 ambient = ambientStrength * lightColor;
float diff = max(abs(dot(norm, lightDir)), 0.0);
vec3 diffuse = diff * lightColor;
vec3 result = (ambient + diffuse) * objectColor;
gl_FragColor = texture(ourTexture, vs_text) * diff;
}
can someone help me to fix this or maybe guide me to solve it?
thanks

Answer 1

It applies that matrix * vector == vector * (matrix)^T
You are calculating normals via normal = RealNor * normalMat;
This is not equal to normalMat * RealNor which results in wrong normals. So kommutate the expression to normalMat * RealNor and see if it fixes the issue.