opaque/alphatest/alphablend sort order (#819)

src/bgfx_p.h

@@ -1460,8 +1460,9 @@ namespace bgfx
 		void setState(uint64_t _state, uint32_t _rgba)
 		{
 			uint8_t blend = ( (_state&BGFX_STATE_BLEND_MASK)>>BGFX_STATE_BLEND_SHIFT)&0xff;
+			uint8_t alphaRef = ( (_state&BGFX_STATE_ALPHA_REF_MASK)>>BGFX_STATE_ALPHA_REF_SHIFT)&0xff;
 			// transparency sort order table
-			m_key.m_trans = "\x0\x1\x1\x2\x2\x1\x2\x1\x2\x1\x1\x1\x1\x1\x1\x1\x1\x1\x1"[( (blend)&0xf) + (!!blend)];
+			m_key.m_trans = "\x0\x2\x2\x3\x3\x2\x3\x2\x3\x2\x2\x2\x2\x2\x2\x2\x2\x2\x2"[( (blend)&0xf) + (!!blend)] + !!alphaRef;
 			m_draw.m_stateFlags = _state;
 			m_draw.m_rgba = _rgba;
 		}