diff --git a/rendergl.rs b/rendergl.rs
index 6ad0705..48b4035 100755
--- a/rendergl.rs
+++ b/rendergl.rs
@@ -64,6 +64,10 @@ static FRAGMENT_RECTANGLE_SHADER_SOURCE: &'static str = "
 ";
 
 static SOLID_COLOR_FRAGMENT_SHADER_SOURCE: &'static str = "
+    #ifdef GL_ES
+        precision mediump float;
+    #endif
+
     uniform vec4 uColor;
     void main(void) {
         gl_FragColor = uColor;