OpenGL normalMap

参考zwqxin的博客  http://www.zwqxin.com/

shader 来自zwqxin，稍作修改

<-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;

}

c++代码（用自己的框架不方便全部放出来）

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);

-------------------------------------------分界线

2016年12月1日

重新增加了VAO渲染，改写材质