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Nightmare with tangent space and tbnMatrix


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#1 marx_86   Members   -  Reputation: 100

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Posted 02 April 2012 - 03:18 AM

Hello everybody,
I have a huge problem that I can't fix alone.
I've tested a normal mapping shader with shader designer and here is everything working.
But I have problems when I try to supply the T and B vectors to my shader. I don't even know if the calculation of my T and B vector is correct.

Here's the code.

the render function for every model

void objModel::draw(float cp[3]){
if(NormalMapping()||BlinnPhong()){
glUseProgram(buf->program.progName);
}

else
glUseProgramObjectARB(0);

glBindBuffer(GL_ARRAY_BUFFER,getVertexBuffer());
glVertexPointer(3,GL_FLOAT,sizeof(Vertex),(void*)0);
glEnableClientState(GL_VERTEX_ARRAY);
if(applyNormalToObj()){//normal mapping shader
glBindBuffer(GL_ARRAY_BUFFER,getNormalBuffer());
glNormalPointer(GL_FLOAT,sizeof(Vertex),(void*)0);
glEnableClientState(GL_NORMAL_ARRAY);
}
if(NormalMapping()){
glEnableVertexAttribArrayARB(getTangentBuffer());  
glEnableVertexAttribArrayARB(getBinormalBuffer());
glVertexAttribPointerARB(getTangentBuffer(),3,GL_FLOAT,0,0,&par.Tangent[0]);
		glVertexAttribPointerARB(getBinormalBuffer(),3,GL_FLOAT,0,0,&par.Binormal[0]);
glUniform1i(buf->uniforms.textures[0],0);

glUniform1i(buf->uniforms.textures[1],1);//i don't use this in the shader

glUniform1i(buf->uniforms.textures[2],2);//I don't use this in the shader
glUniform1i(buf->uniforms.textures[3],3);
glUniform1f(buf->uniforms.mat.shininess,kShi);
glUniform4fv(buf->uniforms.mat.diffuse,1,kDiff);

}
//this works well
if(BlinnPhong()){

glUniform4fv(buf->uniforms.mat.ambient,1,kAmb);
glUniform4fv(buf->uniforms.mat.diffuse,1,kDiff);
glUniform4fv(buf->uniforms.mat.specular,1,kSpec);
glUniform1f(buf->uniforms.mat.shininess,kShi);
glUniform3fv(buf->uniforms.campos,1,cp);
}

if(applyTextureToObj()){//se devo applicare le texture al modello...
//diffuse texture
glActiveTexture(GL_TEXTURE0);

glBindTexture ( GL_TEXTURE_2D, getTextureNameDiffuse() );


glBindBuffer(GL_ARRAY_BUFFER,getTextureBuffer());

glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glClientActiveTexture(GL_TEXTURE0);
if(apply3CoordTexture())
glTexCoordPointer(3,GL_FLOAT,sizeof(Texel),(void*)0);
else
glTexCoordPointer(2,GL_FLOAT,sizeof(GLfloat)*2,(void*)0);//sizeof(Texeluv)

//_________________________________________________________________________________


//specular texture
glActiveTexture(GL_TEXTURE1);
glBindTexture ( GL_TEXTURE_2D, getTextureNameSpecular() );
glTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_MODULATE);
glBindBuffer(GL_ARRAY_BUFFER,getTextureBuffer());

glEnableClientState(GL_TEXTURE_COORD_ARRAY);
if(apply3CoordTexture())
glTexCoordPointer(3,GL_FLOAT,sizeof(Texel),(void*)0);
else
glTexCoordPointer(2,GL_FLOAT,sizeof(GLfloat)*2,(void*)0);//sizeof(Texeluv)
//__________________________________________________________________________
//gloss or normal texture
glEnable(GL_TEXTURE_2D);
glBindTexture ( GL_TEXTURE_2D, getTextureNameGloss( ));
glTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_MODULATE);

glBindBuffer(GL_ARRAY_BUFFER,getTextureBuffer());

glEnableClientState(GL_TEXTURE_COORD_ARRAY);
if(apply3CoordTexture())
glTexCoordPointer(3,GL_FLOAT,sizeof(Texel),(void*)0);
else
glTexCoordPointer(2,GL_FLOAT,sizeof(GLfloat)*2,(void*)0);//sizeof(Texeluv)

if(NormalMapping()){
//__________________________________________________________________________
//normal map texture
glEnable(GL_TEXTURE_2D);
glBindTexture ( GL_TEXTURE_2D, getTextureNameNormal( ));
glTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_MODULATE);

glBindBuffer(GL_ARRAY_BUFFER,getTextureBuffer());

glEnableClientState(GL_TEXTURE_COORD_ARRAY);
if(apply3CoordTexture())
glTexCoordPointer(3,GL_FLOAT,sizeof(Texel),(void*)0);
else
glTexCoordPointer(2,GL_FLOAT,sizeof(GLfloat)*2,(void*)0);//sizeof(Texeluv)
}


}

if(getCullBack()){
glEnable(GL_CULL_FACE);
glCullFace(GL_BACK);
}
if(getCullFront()){
glEnable(GL_CULL_FACE);
glCullFace(GL_FRONT);
}
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,getTIndeces());
glDrawElements(GL_TRIANGLES,getTIndecesSize(),GL_UNSIGNED_INT,(void*)0);
//glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,getQIndeces());
//glDrawElements(GL_QUADS,getQIndecesSize(),GL_UNSIGNED_INT,(void*)0);

if(NormalMapping()){
glDisableVertexAttribArrayARB(getTangentBuffer());
		glDisableVertexAttribArrayARB(getBinormalBuffer());
}

if(getCullBack()|| getCullFront())
glDisable(GL_CULL_FACE);
if(applyNormalToObj())
glDisableClientState(GL_NORMAL_ARRAY);
if(applyTextureToObj()){
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
//glDisable(GL_TEXTURE_2D);
}
glDisableClientState(GL_VERTEX_ARRAY);
}



here I have the setup of the normal map shader

if(par.NormalMapping()){
createNormalMappingVShader1(nmvs);//these are two funcions that create the text files with the shader source code
createNormalMappingFShader1(nmfs);
cout << " normal mapping shader creati " << endl;

buffer->vertex_shader = make_shader(GL_VERTEX_SHADER,nmvs.c_str());
if (buffer->vertex_shader == 0)
return 0;
buffer->fragment_shader = make_shader(GL_FRAGMENT_SHADER,nmfs.c_str());
if (buffer->fragment_shader == 0)
return 0;
buffer->program.progName = make_program(buffer->vertex_shader, buffer->fragment_shader);
if (buffer->program.progName == 0)
return 0;
buffer->uniforms.textures[0]=glGetUniformLocation(buffer->program.progName,"base");
buffer->uniforms.textures[1]=glGetUniformLocation(buffer->program.progName,"specularTexture");
buffer->uniforms.textures[2]=glGetUniformLocation(buffer->program.progName,"glossTexture");
buffer->uniforms.textures[3]=glGetUniformLocation(buffer->program.progName,"normalMap");

buffer->uniforms.mat.diffuse=glGetUniformLocation(buffer->program.progName,"kdiff");
buffer->uniforms.mat.shininess=glGetUniformLocation(buffer->program.progName,"kshi");
buffer->attributes.tangent=glGetAttribLocation(buffer->program.progName, "tangent");
glBindAttribLocation(buffer->program.progName,buffer->attributes.tangent,"tangent");
buffer->attributes.binormal=glGetAttribLocation(buffer->program.progName, "binormal");
glBindAttribLocation(buffer->program.progName,buffer->attributes.binormal,"binormal");


tangent space calculation



std::vector <int> nTimes;
if(NormalMapping()){





//init tantent
Vertex zero;
zero.x=zero.y=zero.z=0.0;

for(int a=0;a<NewVertex.size();a++) {
Tangent.push_back(zero);
Binormal.push_back(zero);
nTimes.push_back(0);
}


for(int a=0;a<triangle_elements.size();a++){

if((a%3)==0){


int i1,i2,i3;
i1=triangle_elements.at(a);
i2=triangle_elements.at(a+1);
i3=triangle_elements.at(a+2);

Vertex v1,v2,v3;
Texeluv t1,t2,t3;


v1.x=NewVertex[i1].x;
v1.y=NewVertex[i1].y;
v1.z=NewVertex[i1].z;
t1.u=NewTexeluv[i1].u;
t1.v=NewTexeluv[i1].v;

v2.x=NewVertex[i2].x;
v2.y=NewVertex[i2].y;
v2.z=NewVertex[i2].z;
t2.u=NewTexeluv[i2].u;
t2.v=NewTexeluv[i2].v;

v3.x=NewVertex[i3].x;
v3.y=NewVertex[i3].y;
v3.z=NewVertex[i3].z;
t3.u=NewTexeluv[i3].u;
t3.v=NewTexeluv[i3].v;


Tangent.at(i1)=somma(Tangent.at(i1),(generateTangent(v1,v2,v3,t1,t2,t3)));
Tangent.at(i2)=somma(Tangent.at(i2),(generateTangent(v1,v2,v3,t1,t2,t3)));
Tangent.at(i3)=somma(Tangent.at(i3),(generateTangent(v1,v2,v3,t1,t2,t3)));
Binormal.at(i1)=somma(Binormal.at(i1),(generateBinormal(v1,v2,v3,t1,t2,t3)));
Binormal.at(i2)=somma(Binormal.at(i2),(generateBinormal(v1,v2,v3,t1,t2,t3)));
Binormal.at(i3)=somma(Binormal.at(i3),(generateBinormal(v1,v2,v3,t1,t2,t3)));


nTimes.at(i1)++;
nTimes.at(i2)++;
nTimes.at(i3)++;







}



}



}

if(NormalMapping()){
for(int v=0;v<NewVertex.size();v++){
if(nTimes.at(v)!=0){
Tangent.at(v).x=Tangent.at(v).x/nTimes.at(v);
Tangent.at(v).y=Tangent.at(v).y/nTimes.at(v);
Tangent.at(v).z=Tangent.at(v).z/nTimes.at(v);
Binormal.at(v).x=Binormal.at(v).x/nTimes.at(v);
Binormal.at(v).y=Binormal.at(v).y/nTimes.at(v);
Binormal.at(v).z=Binormal.at(v).z/nTimes.at(v);

}

}

}


if(NormalMapping()){


for(int v=0;v<NewVertex.size();v++){
// Gram-Schmidt orthogonalize

Tangent.at(v).x=Tangent.at(v).x- NewNormal.at(v).x*(NewNormal.at(v).x*Tangent.at(v).x+NewNormal.at(v).y*Tangent.at(v).y+NewNormal.at(v).z*Tangent.at(v).z);
Tangent.at(v).y=Tangent.at(v).y- NewNormal.at(v).y*(NewNormal.at(v).x*Tangent.at(v).x+NewNormal.at(v).y*Tangent.at(v).y+NewNormal.at(v).z*Tangent.at(v).z);
Tangent.at(v).z=Tangent.at(v).z- NewNormal.at(v).z*(NewNormal.at(v).x*Tangent.at(v).x+NewNormal.at(v).y*Tangent.at(v).y+NewNormal.at(v).z*Tangent.at(v).z);

Tangent.at(v)=normalize(Tangent.at(v));

if((Tangent.at(v).x*Tangent.at(v).x)!=0)
Binormal.at(v).x=Binormal.at(v).x- NewNormal.at(v).x*(NewNormal.at(v).x*Binormal.at(v).x+NewNormal.at(v).y*Binormal.at(v).y+NewNormal.at(v).z*Binormal.at(v).z)-((Tangent.at(v).x*Binormal.at(v).x+Tangent.at(v).y*Binormal.at(v).y+Tangent.at(v).z*Binormal.at(v).z)*Tangent.at(v).x)/(Tangent.at(v).x*Tangent.at(v).x);
else
Binormal.at(v).x=Binormal.at(v).x- NewNormal.at(v).x*(NewNormal.at(v).x*Binormal.at(v).x+NewNormal.at(v).y*Binormal.at(v).y+NewNormal.at(v).z*Binormal.at(v).z)-((Tangent.at(v).x*Binormal.at(v).x+Tangent.at(v).y*Binormal.at(v).y+Tangent.at(v).z*Binormal.at(v).z)*Tangent.at(v).x);

if((Tangent.at(v).y*Tangent.at(v).y)!=0)
Binormal.at(v).y=Binormal.at(v).y- NewNormal.at(v).y*(NewNormal.at(v).x*Binormal.at(v).x+NewNormal.at(v).y*Binormal.at(v).y+NewNormal.at(v).z*Binormal.at(v).z)-((Tangent.at(v).x*Binormal.at(v).x+Tangent.at(v).y*Binormal.at(v).y+Tangent.at(v).z*Binormal.at(v).z)*Tangent.at(v).y)/(Tangent.at(v).y*Tangent.at(v).y);
else
Binormal.at(v).y=Binormal.at(v).y- NewNormal.at(v).y*(NewNormal.at(v).x*Binormal.at(v).x+NewNormal.at(v).y*Binormal.at(v).y+NewNormal.at(v).z*Binormal.at(v).z)-((Tangent.at(v).x*Binormal.at(v).x+Tangent.at(v).y*Binormal.at(v).y+Tangent.at(v).z*Binormal.at(v).z)*Tangent.at(v).y);
if((Binormal.at(v).z*Binormal.at(v).z)!=0)
Binormal.at(v).z=Binormal.at(v).z- NewNormal.at(v).z*(NewNormal.at(v).x*Binormal.at(v).x+NewNormal.at(v).y*Binormal.at(v).y+NewNormal.at(v).z*Binormal.at(v).z)-((Tangent.at(v).x*Binormal.at(v).x+Tangent.at(v).y*Binormal.at(v).y+Tangent.at(v).z*Binormal.at(v).z)*Tangent.at(v).z)/(Tangent.at(v).z*Tangent.at(v).z);
else
Binormal.at(v).z=Binormal.at(v).z- NewNormal.at(v).z*(NewNormal.at(v).x*Binormal.at(v).x+NewNormal.at(v).y*Binormal.at(v).y+NewNormal.at(v).z*Binormal.at(v).z)-((Tangent.at(v).x*Binormal.at(v).x+Tangent.at(v).y*Binormal.at(v).y+Tangent.at(v).z*Binormal.at(v).z)*Tangent.at(v).z);

Binormal.at(v)=normalize(Binormal.at(v));
}

}





Vertex  parser::generateTangent(Vertex v1, Vertex v2, Vertex v3, Texeluv tex1, Texeluv tex2,Texeluv tex3)
{
Vertex Q1,Q2;
Q1.x=v2.x-v1.x;
Q1.y=v2.y-v1.y;
Q1.z=v2.z-v1.z;
Q2.x=v3.x-v1.x;
Q2.y=v3.y-v1.y;
Q2.z=v3.z-v1.z;
float u1=tex2.u-tex1.u;
float vi1=tex2.v-tex1.v;
float u2=tex3.u-tex1.u;
float vi2=tex3.v-tex1.v;


float coef = 0.0f;
if(fabsf(u1* vi2 - u2 * vi1)<= 0.0001f)
coef=1.0;
else
coef = 1/ (u1* vi2 - u2 * vi1);

Vertex tangent;

tangent.x=coef*(vi2*Q1.x-vi1*Q2.x);
tangent.y=coef*(vi2*Q1.y-vi1*Q1.y);
tangent.z=coef*(vi2+Q1.x-vi1*Q1.z);



return normalize(tangent);


}


Vertex  parser::generateBinormal(Vertex v1, Vertex v2, Vertex v3, Texeluv tex1, Texeluv tex2,Texeluv tex3)
{
Vertex Q1,Q2;
Q1.x=v2.x-v1.x;
Q1.y=v2.y-v1.y;
Q1.z=v2.z-v1.z;
Q2.x=v3.x-v1.x;
Q2.y=v3.y-v1.y;
Q2.z=v3.z-v1.z;
float u1=tex2.u-tex1.u;
float vi1=tex2.v-tex1.v;
float u2=tex3.u-tex1.u;
float vi2=tex3.v-tex1.v;
float coef;

if(fabsf(u1* vi2 - u2 * vi1)<= 0.0001f)
coef=1.0;
else
coef = 1/ (u1* vi2 - u2 * vi1);

Vertex binormal;


binormal.x=coef*(-u2*Q1.x-u1*Q2.x);
binormal.y=coef*(-u2*Q1.y-u1*Q1.y);
binormal.z=coef*(-u2+Q1.x-u1*Q1.z);




return normalize(binormal);

}

that's should be everything... thanks

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#2 marx_86   Members   -  Reputation: 100

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Posted 02 April 2012 - 03:20 AM

I forgot the shader source code...
normal mapping vertex shader


#version 110
  attribute vec3 tangent;
attribute vec3 binormal;
varying vec3 position;
varying vec3 lightvec;
uniform vec3 CAMERA_POSITION;
void main( )
  { 
  gl_Position=ftransform();
gl_TexCoord[0]=gl_MultiTexCoord0;
  position=gl_Vertex.xyz;
vec3 t=normalize(tangent);
  vec3 b=normalize(binormal);
  vec3 n=normalize(gl_Normal);
  mat3 TBNMatrix=mat3(t.x,b.x,gl_Normal.x,t.y,b.y,gl_Normal.y,t.z,b.z,gl_Normal.z);
  lightvec=gl_LightSource[0].position.xyz-position;
  lightvec*=TBNMatrix;

 } 


normal mapping fragment shader


#version 110
  #pragma debug(on)
  uniform sampler2D base;
uniform sampler2D specular;
uniform sampler2D gloss;
uniform sampler2D normalMap;
uniform float kshi;
uniform vec4 kdiff;
uniform vec3 CAMERA_POSITION;
varying vec3 position;
varying vec3 lightvec;
void main()
  {
vec3 norm=texture2D(normalMap,gl_TexCoord[0].st).rgb*2.0-1.0;
vec3 baseColor=texture2D(base,gl_TexCoord[0].st).rgb;
float dist=length(lightvec);
vec3 lightVector=normalize(lightvec);
float nxDir=max(0.0,dot(norm,lightVector));
vec4 diffuse=gl_LightSource[0].diffuse*nxDir;
float specularPower=0.0;
if(nxDir!=0.0)
{
vec3 cameraVector=normalize(CAMERA_POSITION-position.xyz);
vec3 halfVector=normalize(lightVector+cameraVector);
float nxHalf=max(0.0,dot(norm,halfVector));
specularPower=pow(nxHalf,kshi);

}
vec4 specular=gl_LightSource[0].specular*specularPower;
gl_FragColor=gl_LightSource[0].ambient+(diffuse*vec4(baseColor.rgb,1.0))+specular;

}


#3 marx_86   Members   -  Reputation: 100

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Posted 02 April 2012 - 03:22 AM

the problem is that if I try to apply the normal mapping shader to a cube I see a black cube... but the light has a totaly different color. The problem dipends on everything that comes from lightVec, that is incorrect because the tbn matrix is not working properly I think...

#4 Ashaman73   Crossbones+   -  Reputation: 7416

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Posted 02 April 2012 - 05:21 AM

Getting the tangent space matrix calculation running is always somewhat tricky. I can only sugguest to do some testing of your tangent space generation code first (unit tests). Here's a nice article about tanget space normals: clicky

For debugging purpose try to render the normal (color = normal*0.5+0.5) and post some images of the results.

#5 marx_86   Members   -  Reputation: 100

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Posted 02 April 2012 - 12:53 PM

I've used:

gl_FragColor=vec4(vec3(col.xyz)*0.5+0.7,1.0);
Posted Image
where col is gl_Vertex form the vertex shader and the cube is colored.
But if I use the normal from the normal map, or the tangent or the binormal the cube is black.. so their value is 0.. so the problem is in my opengl application that doesen't feed the shader with the correct datas

but I can't properly find where is the problem




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