Minimap Re-draw enhancement

I've encountered a situation with the project I'm working on that requires the minimap to be re-drawn occasionally in order to update it with respect to certain game environment changes.

Currently, forcing a re-draw after a game session has started often results in artifacts being created on the mini-map due to the units selection circles being rendered to the mini-map.

Fortunately, it only requires a few engine changes to disable the selection circle rendering during mini-map re-draws.

firstly, we need to add a static member variable to the terrainRender struct that defines whether the selections should be rendered, and create 2 functions to turn the selection rendering on/off.

At the end of the terrainRender struct in engine\terrain\terrrender.h add:

// enable / disable the rendering of the unit selection indicators  
   // to allow for minimap re-draws without selection circle artifacts
   static bool mRenderSelections;
   static void enableSelectionRender() { mRenderSelections = true; }
   static void disableSelectionRender() {mRenderSelections = false; }

and at the top of engine\terrain\terrrender.cc, add the following line at the end of the variable declarations (before the line that begins: namespace { )

bool TerrainRender::mRenderSelections;

then add the following line to the end of the terrainRender::init() function

mRenderSelections = true;

Now, in the renderBlock function in terrRender.cc, change:

//selections...
   if (sgCurrSelectionTris) {

to

//selections...
   if (sgCurrSelectionTris  && TerrainRender::mRenderSelections) {

so that the selection indicators will only be drawn if mRenderSelections is true.


Finally, we need to disable the selection rendering before a minimap re-draw, and re-enable the selection rendering after the minimap re-draw.
In engine\game\RTS\GuiMapHudGen.cc, change the function GuiMapHud::renderWorld
from

void GuiMapHud::renderWorld(const RectI &updateRect)
{
   setupRender();

   gClientSceneGraph->renderScene(TerrainObjectType | WaterObjectType);

   cleanupRender();
}

to

void GuiMapHud::renderWorld(const RectI &updateRect)
{
   setupRender();

   // turn off selection circle rendering so they don't show on the minimap
   TerrainRender::disableSelectionRender();
   
   gClientSceneGraph->renderScene(TerrainObjectType | WaterObjectType);

   // re-enable selection circle rendering
   TerrainRender::enableSelectionRender();
   
   cleanupRender();
}

And hopefully, that's it!
Courtesy of the Sixth Extinction RTS demo team