readd select shaders.

Removing them was just for an experiment, I didn't intent to push the
change.

src/gfx/shaders.js

@@ -86,7 +86,46 @@ void main(void) {\n\
   gl_PointSize = pointSize * 200.0 / abs(distToCamera); \n\
   vertSelect = attrSelect;\n\
 }',
+
+SELECT_VS : '\n\
+precision ${PRECISION} float;\n\
+uniform mat4 projectionMat;\n\
+uniform mat4 modelviewMat;\n\
+uniform float pointSize;\n\
+attribute vec3 attrPos;\n\
+attribute float attrObjId;\n\
+\n\
+varying float objId;\n\
+\n\
+void main(void) {\n\
+  gl_Position = projectionMat * modelviewMat * vec4(attrPos, 1.0);\n\
+  float distToCamera = vec4(modelviewMat * vec4(attrPos, 1.0)).z;\n\
+  gl_PointSize = pointSize * 200.0 / abs(distToCamera); \n\
+  objId = attrObjId;\n\
+}',
 
+SELECT_FS : '\n\
+precision ${PRECISION} float;\n\
+\n\
+varying float objId;\n\
+uniform int symId;\n\
+\n\
+int intMod(int x, int y) { \n\
+  int z = x/y;\n\
+  return x-y*z;\n\
+}\n\
+void main(void) {\n\
+  // ints are only required to be 7bit...\n\
+  int integralObjId = int(objId+0.5);\n\
+  int red = intMod(integralObjId, 256);\n\
+  integralObjId/=256;\n\
+  int green = intMod(integralObjId, 256);\n\
+  integralObjId/=256;\n\
+  int blue = intMod(integralObjId, 256);\n\
+  int alpha = symId;\n\
+  gl_FragColor = vec4(float(red), float(green), \n\
+                      float(blue), float(alpha))/255.0;\n\
+}',
 // hemilight vertex shader
 LINES_VS : '\n\
 attribute vec3 attrPos;\n\

src/viewer.js

@@ -378,7 +378,8 @@ Viewer.prototype = {
       lines : c.initShader(shaders.LINES_VS, shaders.LINES_FS, p),
       text : c.initShader(shaders.TEXT_VS, shaders.TEXT_FS, p),
       selectLines : c.initShader(shaders.SELECT_LINES_VS, 
-                                 shaders.SELECT_LINES_FS, p)
+                                 shaders.SELECT_LINES_FS, p),
+      select : c.initShader(shaders.SELECT_VS, shaders.SELECT_FS, p)
     };
 
     this._boundDraw = utils.bind(this, this._draw);