OpenGL normalMap

<-vertex->

attribute vec3 v_Pos;
attribute vec3 v_Normal;
attribute vec2 v_TexCoord;
attribute vec3 v_tangent;

uniform vec3 lightpos; //传入光源的模型坐标吧
uniform vec4 eyepos;

varying vec3 lightdir;
varying vec3 halfvec;
varying vec3 norm;
varying vec3 eyedir;

void main(void)
{
vec4 pos = gl_ModelViewMatrix * vec4(v_Pos,1.0);
pos = pos / pos.w;

//把光源和眼睛从模型空间转换到视图空间
vec4 vlightPos = (gl_ModelViewMatrix * vec4(lightpos, 1.0));
vec4 veyePos   = (gl_ModelViewMatrix * eyepos);

lightdir = normalize(vlightPos.xyz - pos.xyz);
vec3 eyedir = normalize(veyePos.xyz - pos.xyz);

//模型空间下的TBN
norm = normalize(gl_NormalMatrix * v_Normal);

vec3 vtangent  = normalize(gl_NormalMatrix * v_tangent);

vec3 vbinormal = cross(norm,vtangent);

//将光源向量和视线向量转换到TBN切线空间
lightdir.x = dot(vtangent,  lightdir);
lightdir.y = dot(vbinormal, lightdir);
lightdir.z = dot(norm     , lightdir);
lightdir = normalize(lightdir);

eyedir.x = dot(vtangent,  eyedir);
eyedir.y = dot(vbinormal, eyedir);
eyedir.z = dot(norm     , eyedir);
eyedir = normalize(eyedir);

halfvec = normalize(lightdir + eyedir);

gl_TexCoord[0].st = v_TexCoord;

gl_Position = gl_ModelViewProjectionMatrix *vec4( v_Pos,1);
}

<-fragment->

uniform sampler2D bumptex;
uniform sampler2D basetex;

float amb = 0.2;
float diff = 0.2;
float spec = 0.6;

varying vec3 lightdir;
varying vec3 halfvec;
varying vec3 norm;
varying vec3 eyedir;

void main(void)
{
float shiness =4;
vec4 ambient = vec4(0.2,0.2,0.2,0.2);
vec4 diffuse = vec4(0.3,0.3,0.3,0.3);
vec4 specular = vec4(0.3,0.3,0.3,0.3);

vec3 vlightdir = normalize(lightdir);
vec3 veyedir = normalize(eyedir);

vec3 vnorm =   normalize(norm);
vec3 vhalfvec =  normalize(halfvec);

vec4 baseCol = texture2D(basetex, gl_TexCoord[0].xy);

//Normal Map里的像素normal定义于该像素的切线空间
vec3 tbnnorm = texture2D(bumptex, gl_TexCoord[0].xy).xyz;

tbnnorm = normalize((tbnnorm  - vec3(0.5))* 2.0);

float diffusefract =  max( dot(lightdir,tbnnorm) , 0.0);
float specularfract = max( dot(vhalfvec,tbnnorm) , 0.0);

if(specularfract > 0.0){
specularfract = pow(specularfract, shiness);
}

gl_FragColor = vec4(amb * ambient.xyz * baseCol.xyz
+ diff * diffuse.xyz * diffusefract * baseCol.xyz
+ spec * specular.xyz * specularfract ,1.0)*3.0;
}

glEnable(GL_TEXTURE_2D);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D,m_img.Getid());

glActiveTexture(GL_TEXTURE0+1);
glBindTexture(GL_TEXTURE_2D,m_NormalImg.Getid());

m_ShaderNormalMap.Enable();
m_ShaderNormalMap.uniform("bumptex",1);
m_ShaderNormalMap.uniform("basetex",0);
m_ShaderNormalMap.uniform("lightpos",vec3(100,100,100));
m_ShaderNormalMap.uniform("eyepos",vec3(0,0,10));
glPushMatrix();
glTranslatef(0,0,-100);

static float angleA =0.0f;
angleA +=0.02f;

glRotatef(angleA,1,1,1);

m_Mesh.RenderTest();

glActiveTexture( GL_TEXTURE0);