Parallax Mapping - GLSL- OpenGL - c++

Question

In the past few days I been trying to implement parallax mapping in my engine, but it doesn't seem to work, I have seen at least 15 examples, and I'm still not being able to get it to work
Here is an Image:
As you can see, all you can see is the base color, the height map is not there
Here are my shaders:
Fragment Shader
#version 330 core
uniform sampler2D DiffuseTextureSampler;
uniform sampler2D HeightTextureSampler;
vec2 scaleBias = vec2(0.5,0.5);
in vec3 EyeDirection_tangentspace;
in vec2 UV;
void main()
{
float height = texture2D(HeightTextureSampler, vec2 (UV.x, -UV.y)).r;
//Our heightmap only has one color channel.
float v = height * scaleBias.r - scaleBias.g;
vec3 eye = EyeDirection_tangentspace;
vec2 newCoords = UV + (eye.xy * v);
vec3 rgb = texture2D(DiffuseTextureSampler, vec2 (newCoords.x, -newCoords.y)).rgb;
gl_FragColor = vec4(rgb, 1.0);
}
Vertex Shader
#version 330 core
// Input vertex data, different for all executions of this shader.
layout(location = 0) in vec3 vertexPosition_modelspace;
layout(location = 1) in vec2 vertexUV;
layout(location = 2) in vec3 vertexNormal_modelspace;
layout(location = 3) in vec3 vertexTangent_modelspace;
layout(location = 4) in vec3 vertexBitangent_modelspace;
// Output data ; will be interpolated for each fragment.
out vec2 UV;
out vec3 Position_worldspace;
out vec3 EyeDirection_cameraspace;
out vec3 LightDirection_cameraspace;
out vec3 LightDirection_tangentspace;
out vec3 EyeDirection_tangentspace;
// Values that stay constant for the whole mesh.
uniform mat4 MVP;
uniform mat4 V;
uniform mat4 M;
uniform mat3 MV3x3;
uniform vec3 LightPosition_worldspace;
void main()
{
gl_Position = MVP * vec4(vertexPosition_modelspace,1);
Position_worldspace = (M * vec4(vertexPosition_modelspace,1)).xyz;
// Vector that goes from the vertex to the camera, in camera space.
// In camera space, the camera is at the origin (0,0,0).
vec3 vertexPosition_cameraspace = ( V * M * vec4(vertexPosition_modelspace,1)).xyz;
EyeDirection_cameraspace = vec3(0,0,0) - vertexPosition_cameraspace;
UV = vertexUV;
vec3 vertexTangent_cameraspace = MV3x3 * vertexTangent_modelspace;
vec3 vertexBitangent_cameraspace = MV3x3 * vertexBitangent_modelspace;
vec3 vertexNormal_cameraspace = MV3x3 * vertexNormal_modelspace;
mat3 TBNMatrix = transpose(mat3(vertexTangent_cameraspace, vertexBitangent_cameraspace, vertexNormal_cameraspace));
EyeDirection_tangentspace = Position_worldspace - vertexPosition_modelspace.xyz;
EyeDirection_tangentspace *= TBNMatrix;
}

Answer 1

couple things
set your scale to 1. no point in halving your hightscale if you cant see it at all.
(YOUR CURRENT PROBLEM) you are getting your texture coordinates with -UV.y Opengl does not have negative texture coordinates. getting negative will pull nothing from the texture, or worse a mirrored textured if you have tiling on.
(YOUR NEXT PROBLEM) normalize your eye vector before calculating new coordinates in the fragment. if you don't normalize, the XY coords of the vector are going to be HUGE so your new texture coordinates are MASSIVE offsets.
try these shaders. they are very simple and work. you will have to add lighting after you get the parallax working
Vertex shader
attribute vec3 tangent;
attribute vec3 binormal;
uniform vec3 CAMERA_POSITION;
varying vec3 eyeVec;
void main()
{
gl_Position = ftransform();
gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
mat3 TBNMatrix = mat3(tangent, binormal, gl_Normal);
eyeVec = CAMERA_POSITION - gl_Vertex.xyz;
eyeVec *= TBNMatrix;
}
fragment shader
uniform sampler2D basetex;
uniform sampler2D heightMap;
uniform vec2 scaleBias;
varying vec3 eyeVec;
void main()
{
float height = texture2D(heightMap, gl_TexCoord[0].st).r;
float v = height * scaleBias.r - scaleBias.g;
vec3 eye = normalize(eyeVec);
vec2 newCoords = texCoord + (eye.xy * v);
vec3 rgb = texture2D(basetex, newCoords).rgb;
gl_FragColor = vec4(rgb, 1.0);
}