source: data/data_extern/programs/GLSL/DepthShadowmapNormalMapReceiverVp.glsl

#version 120

uniform mat4 world;
uniform mat4 worldViewProj;
uniform mat4 texViewProj;
uniform vec4 lightPosition; // object space

attribute vec4 vertex;
attribute vec3 normal;
attribute vec3 tangent;
attribute vec4 uv0;

varying vec3 tangentLightDir;
varying vec4 oUv;
varying vec2 oUv2;

void main()
{
        vec4 worldPos = world * vertex;

        // Get object space light direction 
    vec3 lightDir = normalize(lightPosition.xyz -  (vertex.xyz * lightPosition.w));

        // calculate shadow map coords
        oUv = texViewProj * worldPos;

        // pass the main uvs straight through unchanged 
        oUv2 = uv0.xy;

        // Calculate the binormal (NB we assume both normal and tangent are 
        // already normalised) 
        vec3 binormal = cross(normal, tangent); 

        // Form a rotation matrix out of the vectors 
        mat3 rotation = mat3(tangent, binormal, normal); 
    
        // Transform the light vector according to this matrix 
        tangentLightDir = normalize(rotation * lightDir); 
        
        gl_Position = worldViewProj * vertex;
}