初次提交

第10章 混合与雾/Sample10_2/assets/frag_earth.sh

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+//地球着色器
+precision mediump float;
+varying vec2 vTextureCoord;//接收从顶点着色器过来的参数
+varying vec4 vAmbient;
+varying vec4 vDiffuse;
+varying vec4 vSpecular;
+uniform sampler2D sTextureDay;//纹理内容数据
+uniform sampler2D sTextureNight;//纹理内容数据
+void main()                         
+{  
+  //给此片元从纹理中采样出颜色值   
+  vec4 finalColorDay;   
+  vec4 finalColorNight;   
+  
+  finalColorDay= texture2D(sTextureDay, vTextureCoord);
+  finalColorDay = finalColorDay*vAmbient+finalColorDay*vSpecular+finalColorDay*vDiffuse;
+  finalColorNight = texture2D(sTextureNight, vTextureCoord); 
+  finalColorNight = finalColorNight*vec4(0.5,0.5,0.5,1.0);
+  
+  if(vDiffuse.x>0.21)
+  {
+    gl_FragColor=finalColorDay;    
+  } 
+  else if(vDiffuse.x<0.05)
+  {     
+     gl_FragColor=finalColorNight;
+  }
+  else
+  {
+     float t=(vDiffuse.x-0.05)/0.16;
+     gl_FragColor=t*finalColorDay+(1.0-t)*finalColorNight;
+  }  
+}