Diffuse lighting artifacts (OpenGL 4) - macos

Question

I'm trying to implement simplest possible diffuse lighting after reading a few tutorials, but fail miserably.
I load 3d mesh from Wavefront obj file and if I don't apply lighting, it looks just fine. But, when I do apply lighting, the animal looks like a chessboard and the cube is messed up even more:
animal comparison (with normals)
cube comparison (with normals)
Here is the vertex shader:
#version 400
layout (location = 0) in vec4 a_position;
layout (location = 1) in vec3 a_texCoords;
layout (location = 2) in vec3 a_normal;
uniform mat4 u_viewProjection;
uniform mat4 u_model;
out vec3 v_fragPos;
out vec3 v_fragNormal;
void main() {
v_fragPos = a_position.xyz;
v_fragNormal = a_normal;
gl_Position = u_viewProjection * a_position;
}
I pass fragment position and normals to the fragment shader as-is because I'm not applying any model transformations, I simply assume that a model already has world coordinates after loading it from file (forget about u_model uniform, it's not used for now).
Then, the fragment shader:
#version 400
uniform vec3 u_lightPos;
uniform vec3 u_lightColor;
uniform vec3 u_diffuseColor;
uniform vec3 u_specularColor;
uniform vec3 u_ambientColor;
in vec3 v_fragPos;
in vec3 v_fragNormal;
out vec4 o_fragColor;
void main() {
vec3 lightDir = u_lightPos - v_fragPos;
float cosTheta = max(dot(normalize(v_fragNormal), normalize(lightDir)), 0.0);
vec3 diffuseContribution = cosTheta * u_lightColor;
o_fragColor = vec4(u_diffuseColor * diffuseContribution, 1.0);
}
No model or normal matrices used, because no rotations (or scale) are applied to model for now.
I thought about incorrect normals, but at least a simple cube should have correct ones, right?
Also, maybe I should mention that I'm using NSOpenGLView under MacOS.
Any help will be appreciated.
Thank you!
UPDATE:
Adding VBO setup.
This is how single vertex looks like:
struct Vertex1P1N1UV {
glm::vec4 mPosition;
glm::vec3 mTextureCoords;
glm::vec3 mNormal;
Vertex1P1N1UV();
Vertex1P1N1UV(glm::vec4 position, glm::vec3 texcoords, glm::vec3 normal);
};
I initialize my VAO like this
auto* VAO = new GLVertexArray<Vertex1P1N1UV>();
VAO->initialize(subMesh.vertices(), GLVertexArrayLayoutDescription({
static_cast<int>(glm::vec4::length() * sizeof(GLfloat)),
static_cast<int>(glm::vec3::length() * sizeof(GLfloat)),
static_cast<int>(glm::vec3::length() * sizeof(GLfloat)) }));
VAO initialize method
void initialize(const std::vector<Vertex>& vertices, const GLVertexArrayLayoutDescription& layoutDescription) {
bind();
mVertexBuffer.initialize(vertices);
GLuint offset = 0;
for (GLuint location = 0; location < layoutDescription.getAttributeSizes().size(); location++) {
glEnableVertexAttribArray(location);
GLsizei attributeSize = layoutDescription.getAttributeSizes()[location];
glVertexAttribPointer(location, attributeSize / sizeof(GLfloat), GL_FLOAT, GL_FALSE, sizeof(Vertex), reinterpret_cast<void *>(offset));
offset += attributeSize;
}
}
And buffer initialize method
void initialize(const std::vector<Vertex>& data) override {
bind();
glBufferData(GL_ARRAY_BUFFER, data.size() * sizeof(Vertex), data.data(), GL_STATIC_DRAW);
}
Vertex will become Vertex1P1N1UV in this case
UPDATE:
Implemented normal visualization (reuploaded screenshots, scroll to top).
What bothers me is that I can see normals through the mesh, like it's transparent despite opaque color. Is this a depth testing problem?

Answer 1

After 2 days of struggling I found the problem.
I did not enable depth buffer on NSOpenGLView. That is one line of code.
If someone stumbles upon this, he can look here OpenGL GL_DEPTH_TEST not working
for a solution.