{"id":104,"date":"2015-04-30T20:56:40","date_gmt":"2015-04-30T20:56:40","guid":{"rendered":"http:\/\/visualgdb.com\/w\/?p=104"},"modified":"2015-04-30T20:56:40","modified_gmt":"2015-04-30T20:56:40","slug":"android-vs-android-codemap","status":"publish","type":"post","link":"https:\/\/visualgdb.com\/tutorials\/android\/vs-android\/codemap\/","title":{"rendered":"Using Code Map to understand C++ Android code"},"content":{"rendered":"\n

This tutorial shows how to use the CodeMap feature of Visual Studio to understand the structure of complex C++ code. We will show it based on the san-angeles demo built using vs-android, however it will also work for all other VisualGDB project types.<\/p>\n

    \n
  1. Install VisualGDB<\/a> 5.0 or later (ensure that “Android Edition” is checked in the installer). This will add support for debugging and Clang-based IntelliSense to vs-android projects.<\/li>\n
  2. Ensure you can build and debug the san-angeles project by following this tutorial<\/a>. <\/li>\n
  3. Open the san-angeles project and go to the drawModels <\/strong>function in demo.c<\/strong>:\"01-drawmodels\"<\/a><\/li>\n
  4. The first thing we will investigate using code map is that drawModels()<\/strong> function that appears to be called repeatedly is calling seedRandom()<\/strong> each time with the same value. That supposedly resets the state of the random number generator. Let’s use the code map to understand what is affected by this. Right-click on seedRandom()<\/strong> and select “show on code map”:\"02-map\"<\/a><\/li>\n
  5. A new Code Map window will appear. Right-click on seedRandom in that window and select “show referenced data”:\"03-data\"<\/a><\/li>\n
  6. You will see that seedRandom accesses the sRandomSeed variable. Right-click on it and select “Show functions referencing this”:\"04-randomseed\"<\/a><\/li>\n
  7. Now you will see that sRandomSeed is also accessed by randomUInt()<\/strong>:\"05-2calls\"<\/a><\/li>\n
  8. Now we need to figure out the context in which both functions are called. Select both of them by holding the ctrl key, right-click and select “Show functions calling this”: \"06-callers\"<\/a><\/li>\n
  9. Now you will see all functions in the project that call the two random number functions we found. However, this is not enough to see the big picture:\"07-4callers\"<\/a><\/li>\n
  10. Repeat the previous step (selecting newly found functions) twice more until you see the functions called by the Java framework (starting with Java_<\/strong>):\"08-jnifuncs\"<\/a>Now the big picture is clear: the random functions are mainly involved during app initialization and the only other place that calls them is the drawModels()<\/strong> function itself. Hence, resetting the random seed inside drawModels()<\/strong> does not affect the behavior of other functions.<\/li>\n
  11. Now let’s use Code Map to quickly find functions related to the GLObject struct. First of all, select any of the GLObject’s fields and select “Show on Code Map”:\"09-globject\"<\/a><\/li>\n
  12. Then right-click on it and select “Show containing type”:\"10-showtype\"<\/a><\/li>\n
  13. Right-click on the type, select “Show type contents”, then select all fields, right-click select “Show functions referencing this”:\"11-showrefs\"<\/a><\/li>\n
  14. You will now see all functions that directly reference fields of GLObject:\"12-objectfuncs\"<\/a><\/li>\n
  15. By highlighting all objects and repeatedly selecting “Show functions calling this” you can easily see the big picture:\"13-objlifetime\"<\/a>The Code Map now clearly shows how the objects are created during initialization, used during the render calls and destroyed during the de-initialization. You can double-click on any of the functions or fields to quickly jump to the code and examine the function contents.<\/li>\n<\/ol>\n

    <\/root><\/p>\n","protected":false},"excerpt":{"rendered":"

    This tutorial shows how to use the CodeMap feature of Visual Studio to understand the structure of complex C++ code.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[31,51,48],"_links":{"self":[{"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/posts\/104"}],"collection":[{"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/comments?post=104"}],"version-history":[{"count":0,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/posts\/104\/revisions"}],"wp:attachment":[{"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/media?parent=104"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/categories?post=104"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/visualgdb.com\/w\/wp-json\/wp\/v2\/tags?post=104"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}