use highp for all vertex shaders

vtm/resources/assets/shaders/base_shader.glsl

@@ -1,5 +1,5 @@
 #ifdef GLES
-precision mediump float;
+precision highp float;
 #endif
 uniform mat4 u_mvp;
 attribute vec4 a_pos;

vtm/resources/assets/shaders/extrusion_layer_ext.glsl

@@ -1,3 +1,6 @@
+#ifdef GLES
+precision highp float;
+#endif
 uniform mat4 u_mvp;
 uniform vec4 u_color[4];
 uniform int u_mode;

vtm/resources/assets/shaders/extrusion_layer_mesh.glsl

@@ -1,3 +1,6 @@
+#ifdef GLES
+precision highp float;
+#endif
 uniform mat4 u_mvp;
 uniform vec4 u_color;
 uniform float u_alpha;

vtm/resources/assets/shaders/linetex_layer.glsl

@@ -1,5 +1,5 @@
 #ifdef GLES
-precision mediump float;
+precision highp float;
 #endif
 uniform mat4 u_mvp;
 uniform vec4 u_color;

vtm/resources/assets/shaders/mesh_layer_2D.glsl

@@ -1,5 +1,5 @@
 #ifdef GLES
-precision mediump float;
+precision highp float;
 #endif
 uniform mat4 u_mvp;
 uniform float u_height;

vtm/resources/assets/shaders/poly_texture.glsl

@@ -1,4 +1,6 @@
-precision mediump float;
+#ifdef GLES
+precision highp float;
+#endif
 uniform mat4 u_mvp;
 uniform vec2 u_scale;
 attribute vec4 a_pos;
@@ -11,7 +13,9 @@ void main() {
 }
 
 §
+#ifdef GLES
 precision mediump float;
+#endif
 uniform vec4 u_color;
 uniform sampler2D tex;
 uniform vec2 u_scale;

vtm/resources/assets/shaders/polygon_layer_tex.glsl

@@ -1,5 +1,5 @@
 #ifdef GLES
-precision mediump float;
+precision highp float;
 #endif
 uniform mat4 u_mvp;
 uniform vec2 u_scale;

vtm/resources/assets/shaders/texture_alpha.glsl

@@ -1,5 +1,5 @@
 #ifdef GLES
-precision mediump float;
+precision highp float;
 #endif
 attribute vec2 vertex;
 attribute vec2 tex_coord;