<vertex>
uniform vec3 camPosition;

attribute vec3 rm_Tangent;   

varying vec2 v2TexCoord;
varying vec3 v3TanLightDir;
varying vec3 v3TanViewDir;

void main(void)
{
	// compute worldspace eye and light vectors
	vec3 v3TempLightDir = vec3(1.0, -1.0, 0.0);
	vec3 v3TempViewDir = camPosition - gl_Vertex.xyz;

	// matrix operation to transform 
	// both vectors into tangent space
	vec3 v3Binormal = cross( gl_Normal, rm_Tangent );

	v3TanLightDir.x = dot(rm_Tangent, v3TempLightDir);
	v3TanLightDir.y = dot(v3Binormal, v3TempLightDir);
	v3TanLightDir.z = dot(gl_Normal, v3TempLightDir);

	v3TanViewDir.x = dot(rm_Tangent, v3TempViewDir);
	v3TanViewDir.y = dot(v3Binormal, v3TempViewDir);
	v3TanViewDir.z = dot(gl_Normal, v3TempViewDir);

	// fetch tex coord
	v2TexCoord = (gl_MultiTexCoord0 * gl_TextureMatrix[0]).xy;

	// mvt
	gl_Position = ftransform();
}

<fragment>
uniform sampler2D TextureColor;
uniform sampler2D TextureNormBump;

varying vec2 v2TexCoord;
varying vec3 v3TanLightDir;
varying vec3 v3TanViewDir;

const float BUMP_HEIGHT_SCALE = 4.0;
const float BUMP_HEIGHT_BIAS = -2.0;

const float PARALLAX_SCALE = 0.08;
const float PARALLAX_BIAS = -0.04;

void main(void)
{
	// normalize the interpolated tangent space light vector and eye vector
	vec3 v3NormLightDir = normalize(v3TanLightDir);
	vec3 v3NormViewDir = normalize(v3TanViewDir);

	// calculate a suitable height value for this texel
	float fHeight = texture2D(TextureNormBump, v2TexCoord).w * PARALLAX_SCALE + PARALLAX_BIAS;

	// perturb the texture coordinate
	vec2 v2NewTexCoord = v2TexCoord + (fHeight * v3NormViewDir.xy) * texture2D(TextureNormBump, v2TexCoord).z;

	// retrieve the surface normal at this new texture coordinate
	vec3 v3BumpNormal = texture2D(TextureNormBump, v2NewTexCoord).xyz * BUMP_HEIGHT_SCALE + BUMP_HEIGHT_BIAS;

	// the dot3 operation - calculate diffuse intensity
	float fDiffuseIntensity = clamp( dot( v3NormLightDir, v3BumpNormal ), 0.0, 1.0);
	
	// fetch the color
	gl_FragColor = fDiffuseIntensity * texture2D( TextureColor, v2NewTexCoord );
	gl_FragColor.a = 1.0;
}

	// retrieve the surface normal at this new texture coordinate	vec3 v3BumpNormal = texture2D(TextureNormBump, v2NewTexCoord).xyz * BUMP_HEIGHT_SCALE + BUMP_HEIGHT_BIAS;	// the dot3 operation - calculate diffuse intensity	float fDiffuseIntensity = clamp( dot( v3NormLightDir, v3BumpNormal ), 0.0, 1.0);