added RGBA8toA1RGB5

inc/hgl/color/ColorFormat.h

@@ -25,6 +25,28 @@ namespace hgl
         }
     }
 
+    constexpr uint16 RGBA8toA1RGB5(const uint8 r,const uint8 g,const uint8 b,const uint8 a)
+    {
+           return ((a>>7)<<15)
+                 |((r<<7)&0x7C00)
+                 |((g<<2)&0x3E0)
+                 | (b>>3);
+    }
+
+    inline void RGBA8toA1RGB5(uint16 *target,uint8 *src,uint size)
+    {
+        for(uint i=0;i<size;i++)
+        {
+            *target=( (src[3]>>7)<<15)
+                    |((src[0]<<7)&0x7C00)
+                    |((src[1]<<2)&0x3E0)
+                    | (src[2]>>3);
+           
+            ++target;
+            src+=4;
+        }
+    }
+
     // Bit depth    Sign bit present    Exponent bits   Mantissa bits
     //  32              Yes                 8               23
     //  16              Yes                 5               10