/*******************************************************************************************
*
*   rPBR [shader] - Physically based rendering vertex shader
*
*   Copyright (c) 2017 Victor Fisac
*
**********************************************************************************************/

#version 330

# Input vertex attributes
in vec3 vertexPosition
in vec2 vertexTexCoord
in vec3 vertexNormal
in vec4 vertexTangent

# Input uniform values
uniform mat4 mvp
uniform mat4 matModel

# Output vertex attributes (to fragment shader)
out vec3 fragPosition
out vec2 fragTexCoord
out vec3 fragNormal
out vec3 fragTangent
out vec3 fragBinormal

void main()
[
    # Calculate binormal from vertex normal and tangent
    vec3 vertexBinormal = cross(vertexNormal, vec3(vertexTangent))

    # Calculate fragment normal based on normal transformations
    mat3 normalMatrix = transpose(inverse(mat3(matModel)))

    # Calculate fragment position based on model transformations
    fragPosition = vec3(matModel*vec4(vertexPosition, 1.0))

    # Send vertex attributes to fragment shader
    fragTexCoord = vertexTexCoord
    fragNormal = normalize(normalMatrix*vertexNormal)
    fragTangent = normalize(normalMatrix*vec3(vertexTangent))
    fragTangent = normalize(fragTangent - dot(fragTangent, fragNormal)*fragNormal)
    fragBinormal = normalize(normalMatrix*vertexBinormal)
    fragBinormal = cross(fragNormal, fragTangent)

    # Calculate final vertex position
    gl_Position = mvp*vec4(vertexPosition, 1.0)
]