Nightmare with tangent space and tbnMatrix

100

Author

April 02, 2012 09:18 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

marx_86

100

Author

April 02, 2012 09:20 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;



}

marx_86

100

Author

April 02, 2012 09:22 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...

Ashaman73

13,718

April 02, 2012 11:21 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.

Ashaman

Gnoblins: Website - Facebook - Twitter - Youtube - Steam Greenlit - IndieDB - Gamedev Log

marx_86

100

Author

April 02, 2012 06:53 PM

I've used:



gl_FragColor=vec4(vec3(col.xyz)*0.5+0.7,1.0);

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

Nightmare with tangent space and tbnMatrix

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