#version 330 core

// Matrices
uniform mat4 modelViewMatrix;
uniform mat4 MVP;
uniform mat4 normalMatrix;
uniform mat4 viewMatrix;

uniform vec3 dirLight[2];
uniform int nbPointLights;
uniform vec3 pointLights[8];

layout(location = 0)in vec3 inPosition;
layout(location = 1)in vec3 inNormal;
layout(location = 2)in vec4 inTexCoord;

out vec3 lightDirInView[5];
out vec3 halfVecInView[5];

out vec3 varNormal;
out vec2 varTexCoord;

void computeDirectionnalLightingVectorsInView(in vec3 posInView, in vec3 lightDirInWorld, out vec3 lightDir, out vec3 halfVec){
	lightDir = mat3(viewMatrix)*lightDirInWorld;
	halfVec = normalize(normalize(lightDir) - normalize(posInView));
	lightDir = normalize(lightDir);
}

void computePointLightingVectorsInView(in vec3 posInView, in vec3 lightPosition, out vec3 lightDir, out vec3 halfVec){
	lightDir = vec3(viewMatrix*vec4(lightPosition, 1.0)) - posInView;
	halfVec = normalize(lightDir - posInView);
	lightDir = normalize(lightDir);
}

void main(void) {
	int i;
	computeDirectionnalLightingVectorsInView(vec3(modelViewMatrix*vec4(inPosition, 1.0)), dirLight[0], lightDirInView[0], halfVecInView[0]);
	for(i=1; i<nbPointLights+1; ++i)
		computePointLightingVectorsInView(vec3(modelViewMatrix*vec4(inPosition, 1.0)),
										  pointLights[i*2 - 2],
										  lightDirInView[i],
										  halfVecInView[i]);

	// normales corrigees (en fonction de la vue)
	varNormal = normalize(vec3(normalMatrix*vec4(inNormal,0)));

    // coordonnees de texture
	varTexCoord = inTexCoord.xy;

	// position du vertex
	gl_Position = MVP * vec4(inPosition, 1.0);
}