orxVECTOR colorVec;
colorVec.fX = 1.0; //full red
colorVec.fY = 0.5; //half green
colorVec.fZ = 0;   //no blue = orange
 
orxCOLOR color;
color.vRGB = colorVec;
color.fAlpha = orxFLOAT_1; //set alpha (required) to stop your object from becoming fully transparent.
 
orxObject_SetColor(MyObject, &color);