第一个是最容易“发明”的车轮:x射线效果,不过按这个做法实现真正透明的话还要逐个物体渲染到纹理,再叠加:
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uniform vec3 LightPos;
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uniform float specularContribution;
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varying vec3 normal;
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varying float LightIntensity;
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void main(void)
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{
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vec3 ecPosition = vec3(gl_ModelViewMatrix * gl_Vertex);
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normal = normalize(gl_NormalMatrix * gl_Normal);
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vec3 lightVec = normalize(LightPos - ecPosition);
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vec3 reflectVec = reflect(-lightVec, normal);
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vec3 viewVec = normalize(-ecPosition);
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float spec = clamp(dot(reflectVec, viewVec), 0.0, 1.0);
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spec = pow(spec, 6.0);
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LightIntensity = (1.0-specularContribution) * max(dot(lightVec, normal), 0.0)
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+ specularContribution * spec;
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LightIntensity=max(LightIntensity,0.0);
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gl_Position = ftransform();
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}
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uniform vec4 myColor;
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uniform vec4 InnerColor;
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uniform float RayTransmittance;
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varying vec3 normal;
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varying float LightIntensity;
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void main(void)
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{
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if(normal.z<=0.0)
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normal.z=1.0;
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float alpha=1.0-normal.z;
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alpha=pow(alpha,RayTransmittance);
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gl_FragColor =mix(myColor,InnerColor,alpha)+LightIntensity;//vec4( myColor.r, myColor.g, myColor.b, alpha );
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}
第二个是per pixel lighting,也简单,把vs中的东西搬到ps中就完了:
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uniform vec3 LightPos;
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varying vec3 Normal_eyeSpace;
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varying vec3 Pos_eyeSpace;
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void main(void)
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{
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gl_Position = ftransform();
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Normal_eyeSpace=gl_NormalMatrix * gl_Normal;
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Pos_eyeSpace=gl_ModelViewMatrix * gl_Vertex;
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}
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uniform vec3 LightPos;
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varying vec3 Normal_eyeSpace;
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varying vec3 Pos_eyeSpace;
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void main(void)
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{
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Normal_eyeSpace=normalize(Normal_eyeSpace);
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vec3 LightDir_eyeSpace=normalize(Pos_eyeSpace-LightPos);
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float diffuse=max(dot(-LightDir_eyeSpace,Normal_eyeSpace),0.0);
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float spec = 0.0;
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if (diffuse > 0.0)
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{
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vec3 reflectVec = reflect(LightDir_eyeSpace, Normal_eyeSpace);
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reflectVec=normalize(reflectVec);
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vec3 viewVec=normalize(-Pos_eyeSpace);
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spec = max(dot(reflectVec, viewVec), 0.0);//反射光
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spec = pow(spec, 4.0);
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}
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float color=min(1.0,diffuse+spec);
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gl_FragColor = vec4( color, spec, spec, 1.0 );
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}
第三个是normal mapping,比较难理解些,在vs中把点的空间位置弄清楚,然后ps中直接拿normal map的贴图当法线用。
但是看过别人实现的normal mapping是可以控制凹凸的强度的,这里好像控制不了,那位高手能说一说思路?
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uniform vec3 LightPosition;
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varying vec3 EyePos_pointTanSpace;
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varying vec3 LightPos_pointTanSpace;
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attribute vec3 Tangent;
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//uniform vec3 Tangent;
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void main()
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{
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gl_Position = ftransform();
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gl_TexCoord[0] = gl_MultiTexCoord0;
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vec3 Pos_eyeSpace = vec3(gl_ModelViewMatrix * gl_Vertex);
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// 眼坐标系下的TBN
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vec3 n = normalize(gl_NormalMatrix * gl_Normal);
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vec3 t = normalize(gl_NormalMatrix * Tangent);
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vec3 b = cross(n, t);
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mat3 TBN = mat3(t, b, n);
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vec3 pointLightPos=LightPosition-Pos_eyeSpace;//光相对于点,在眼空间的位置
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LightPos_pointTanSpace=TBN*pointLightPos;//光相对于点,在点的tangent坐标系下的位置
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vec3 eyePos=Pos_eyeSpace*-1.0; //眼睛相对于点,在眼空间的位置
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EyePos_pointTanSpace=TBN*eyePos;//眼睛相对于点,在点的tangent坐标系下的点位置
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}
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uniform sampler2D BumpTex;
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uniform float bumpFactor;
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varying vec3 EyePos_pointTanSpace;
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varying vec3 LightPos_pointTanSpace;
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void main()
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{
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float dist=length(LightPos_pointTanSpace);//光距离
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vec3 BumpNorm = vec3(texture2D(BumpTex, gl_TexCoord[0].xy));//获得法向量
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BumpNorm = (BumpNorm -0.5)* bumpFactor;
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vec3 LightDir=normalize(LightPos_pointTanSpace);//光方向
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vec3 viewVec=normalize(EyePos_pointTanSpace);//眼睛方向
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float diffuse = max(dot(BumpNorm, LightDir), 0.0);
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//diffuse=1.0/(pow(2.0,dist));//距离衰减
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vec3 reflectVec=reflect(-LightDir,BumpNorm);
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float spec = max(dot(reflectVec, viewVec), 0.0);//反射光
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spec = pow(spec, 16.0);
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float color=spec+diffuse;
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gl_FragColor = vec4(color,spec,0.0, 1.0);
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}
posted on 2009-10-17 22:50
陈昱(CY) 阅读(1355)
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