Source

LWJGL Shader Tutorials / src / main / java / com / ra4king / opengl / arcsynthesis / gl33 / chapter9 / example1 / example9.1.VertexLighting_PCN.vert

#version 330

layout(location = 0) in vec3 position;
layout(location = 1) in vec4 diffuseColor;
layout(location = 2) in vec3 normal;

smooth out vec4 interpColor;

uniform vec3 dirToLight;
uniform vec4 lightIntensity;

uniform mat4 modelToCameraMatrix;
uniform mat3 normalModelToCameraMatrix;

layout(std140) uniform Projection
{
	mat4 cameraToClipMatrix;
};

void main()
{
	gl_Position = cameraToClipMatrix * (modelToCameraMatrix * vec4(position, 1.0));
	
	vec3 normCamSpace = normalize(normalModelToCameraMatrix * normal);
	
	float cosAngIncidence = dot(normCamSpace, dirToLight);
	cosAngIncidence = clamp(cosAngIncidence, 0.0, 1.0);
	
	interpColor = lightIntensity * diffuseColor * cosAngIncidence;
}