GRK-Projekt/grafika_projekt/shaders/bubble.vert

#version 330 core
layout(location = 0) in vec3 vertexPosition;
layout(location = 1) in vec3 vertexNormal;

out vec3 interpNormal;
out vec3 fragPos;
out vec3 incident;
out float deep;
out vec3 v_reflection;
out vec3 v_refraction;
out float v_fresnel;

uniform mat4 modelMatrix;
uniform mat4 modelViewProjectionMatrix;
uniform vec3 viewPos;

// Indices of refraction
const float Air = 1.0;
const float Glass = 4; //1.51714;//4
// Air to glass ratio of the indices of refraction (Eta)
const float Eta = Air / Glass;
// see http://en.wikipedia.org/wiki/Refractive_index Reflectivity
const float R0 = ((Air - Glass) * (Air - Glass)) / ((Air + Glass) * (Air + Glass));



void main()
{
	vec4 vertex = modelMatrix * vec4( vertexPosition, 1.0 );
	vec4 camera = vec4( viewPos, 1.0 );
	incident = normalize( vec3( vertex - camera ) );
	
	vec3 norm = mat3(transpose(inverse(modelMatrix))) * vertexNormal;
	v_refraction = refract( incident, norm, Eta );
    v_reflection = reflect( incident, norm );
    
    v_fresnel = R0 + (1.0 - R0) * pow( (1.0 - dot( -incident, vertexNormal ) ), 5.0);


	interpNormal = vertexNormal;

	fragPos = vec3(modelMatrix * vec4(vertexPosition, 1.0));
	gl_Position = modelViewProjectionMatrix * vec4(vertexPosition, 1.0);
	deep = vertexPosition.y;
}