Vulkan diffuse shading doesn't change with object transformation - graphics

Question

System:
GPU: Intel(R) UHD Graphics
Here is my shader code:
vertex shader:
#version 450
layout(location = 0) in vec3 position;
layout(location = 1) in vec3 color;
layout(location = 2) in vec3 normal;
layout(location = 3) in vec2 uv;
layout(location = 0) out vec3 fragCol;
layout(push_constant) uniform Push {
mat4 transform; // projection * view * model
mat4 modelMatrix;
} push;
vec3 DIRECTION_TO_LIGHT = normalize(vec3(1.0, -10.0, -1.0));
void main() {
gl_Position = push.transform * vec4(position, 1.0);
vec3 normalWorldSpace = normalize(mat3(push.modelMatrix) * normal);
float lightIntensity = max(dot(normalWorldSpace, DIRECTION_TO_LIGHT), 0);
fragCol = lightIntensity * vec3(1.0);
}
fragment shader:
#version 450 core
layout(location = 0) in vec3 fragCol;
layout(location = 0) out vec4 outColor;
layout(push_constant) uniform Push{
mat4 transform;
mat4 modelMatrix;
}push;
void main(){
outColor = vec4(fragCol, 1.0);
}
The dark parts of the model remain dark even while rotating on the z-axis. It is like the color is baked into the model which isn't the case.
I tried calculating the color on the fragment shader but that didn't work either.
Code calculating the transform matrix:
auto projectionMatrix = camera.getProjection() * camera.getView();
for (auto& obj : gameObjects) {
//rotating doesn't change the dark pixels.
obj.transform.rotation.y += glm::radians(45.0f) * deltaTime;
SimplePushConstantData push{};
auto modelMatrix = obj.transform.mat4();
push.transform = projectionMatrix * modelMatrix;
push.modelMatrix = modelMatrix;
vkCmdPushConstants(commandBuffer, pipelineLayout,
VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT,
0, sizeof(SimplePushConstantData), &push);
obj.model->bind(commandBuffer);
obj.model->draw(commandBuffer);
}