[drape] use max precision for all data expect final color. In future it can be optimized, but now lowp on old devices leads to:

- wrong texel fetch
- performance degradation

11 files changed, 157 insertions, 145 deletions

diff --git a/drape/shader.cpp b/drape/shader.cpp
index 9a0f40a4d3..8af53238de 100644
--- a/drape/shader.cpp
+++ b/drape/shader.cpp
@@ -4,8 +4,6 @@
 #include "../base/assert.hpp"
 #include "../base/string_utils.hpp"
 
-
-
 namespace dp
 {
 
@@ -40,11 +38,11 @@ void ResolveGetTexel(string & result, string const & sampler, int count)
   result.append("uniform sampler2D u_textures[").append(to_string(count)).append("];\n");
 
   // Function signature
-  result.append(MEDIUM_P).append(" vec4 getTexel(int ").append(texIndex).append(", ")
-        .append(LOW_P).append(" vec2 ").append(texCoord).append("){ \n");
+  result.append(LOW_P).append(" vec4 getTexel(int ").append(texIndex).append(", ")
+        .append(MAXPREC_P).append(" vec2 ").append(texCoord).append("){ \n");
 
   // Declare result var;
-  result.append(MEDIUM_P).append(" vec4 ").append(answer).append(";\n");
+  result.append(LOW_P).append(" vec4 ").append(answer).append(";\n");
 
   for (uint32_t i = 0; i < count; ++i)
   {
diff --git a/drape/shaders/font_fragment_shader.fsh b/drape/shaders/font_fragment_shader.fsh
index 2213132d7f..044d66f2ce 100755
--- a/drape/shaders/font_fragment_shader.fsh
+++ b/drape/shaders/font_fragment_shader.fsh
@@ -1,6 +1,14 @@
-varying lowp vec3 v_texcoord;
-varying lowp vec4 v_colors;
-varying mediump float v_index;
+#ifdef GL_FRAGMENT_PRECISION_HIGH
+  #define MAXPREC highp
+#else
+  #define MAXPREC mediump
+#endif
+
+precision MAXPREC float;
+
+varying vec3 v_texcoord;
+varying vec4 v_colors;
+varying float v_index;
 
 ~getTexel~
 
@@ -11,13 +19,13 @@ const lowp float OUTLINE_MAX_VALUE1 = 0.95;
 const lowp float GLYPH_MIN_VALUE = 0.45;
 const lowp float GLYPH_MAX_VALUE = 0.6;
 
-lowp vec4 colorize(lowp vec4 base, lowp vec4 outline, lowp float alpha)
+vec4 colorize(vec4 base, vec4 outline, float alpha)
 {
   if (alpha > OUTLINE_MAX_VALUE1)
     return vec4(outline.rgb, 0);
   if (alpha > OUTLINE_MAX_VALUE0)
   {
-    lowp float oFactor = smoothstep(OUTLINE_MAX_VALUE1, OUTLINE_MAX_VALUE0, alpha );
+    float oFactor = smoothstep(OUTLINE_MAX_VALUE1, OUTLINE_MAX_VALUE0, alpha );
     return mix(vec4(outline.rgb,0), outline, oFactor);
   }
   if (alpha > OUTLINE_MIN_VALUE1)
@@ -26,17 +34,17 @@ lowp vec4 colorize(lowp vec4 base, lowp vec4 outline, lowp float alpha)
   }
   if (alpha > OUTLINE_MIN_VALUE0)
   {
-    lowp float oFactor = smoothstep(OUTLINE_MIN_VALUE0, OUTLINE_MIN_VALUE1, alpha );
+    float oFactor = smoothstep(OUTLINE_MIN_VALUE0, OUTLINE_MIN_VALUE1, alpha );
     return mix(base, outline, oFactor);
   }
   return base;
 }
 
-lowp vec4 without_outline(lowp vec4 base, lowp float alpha)
+vec4 without_outline(vec4 base, float alpha)
 {
   if (alpha > GLYPH_MIN_VALUE)
   {
-    lowp float oFactor = smoothstep(GLYPH_MIN_VALUE, GLYPH_MAX_VALUE, alpha );
+    float oFactor = smoothstep(GLYPH_MIN_VALUE, GLYPH_MAX_VALUE, alpha );
     return mix(base, vec4(1, 1, 1, 0), oFactor);
   }
   return base;
@@ -46,13 +54,16 @@ void main (void)
 {
   int shapeIndex = int(v_texcoord.z / 2.0);
   int colorIndex = int(v_index);
-  lowp vec4 base = getTexel(colorIndex, v_colors.xy);
-  lowp vec4 outline = getTexel(colorIndex, v_colors.zw);
-  mediump float alpha = getTexel(shapeIndex, v_texcoord.xy).a;
+  vec4 base = getTexel(colorIndex, v_colors.xy);;
+  vec4 outline = getTexel(colorIndex, v_colors.zw);
+  float alpha = getTexel(shapeIndex, v_texcoord.xy).a;
 
-  lowp float needOutline = (fract(v_texcoord.z / 2.0)) * 2.0;
+  float needOutline = (fract(v_texcoord.z / 2.0)) * 2.0;
+  vec4 finalColor;
   if (needOutline > 0.5)
-    gl_FragColor = colorize(base, outline, 1.0 - base.a*alpha);
+    finalColor = colorize(base, outline, 1.0 - base.a*alpha);
   else
-    gl_FragColor = without_outline(base, 1.0 - base.a*alpha);
-}                    
+    finalColor = without_outline(base, 1.0 - base.a*alpha);
+
+  gl_FragColor = finalColor;
+}
diff --git a/drape/shaders/font_vertex_shader.vsh b/drape/shaders/font_vertex_shader.vsh
index d7ddece594..d21867074a 100755
--- a/drape/shaders/font_vertex_shader.vsh
+++ b/drape/shaders/font_vertex_shader.vsh
@@ -1,14 +1,22 @@
-attribute highp vec4 a_position;
-attribute lowp vec4 a_texcoord;
-attribute lowp vec4 a_color;
-attribute mediump float a_index;
+#ifdef GL_FRAGMENT_PRECISION_HIGH
+  #define MAXPREC highp
+#else
+  #define MAXPREC mediump
+#endif
 
-uniform highp mat4 modelView;
-uniform highp mat4 projection;
+precision MAXPREC float;
 
-varying lowp vec3 v_texcoord;
-varying lowp vec4 v_colors;
-varying mediump float v_index;
+attribute vec4 a_position;
+attribute vec4 a_texcoord;
+attribute vec4 a_color;
+attribute float a_index;
+
+uniform mat4 modelView;
+uniform mat4 projection;
+
+varying vec3 v_texcoord;
+varying vec4 v_colors;
+varying float v_index;
 
 void main()
 {
diff --git a/drape/shaders/line_fragment_shader.fsh b/drape/shaders/line_fragment_shader.fsh
index f4f4cbc42c..49be8f77af 100644
--- a/drape/shaders/line_fragment_shader.fsh
+++ b/drape/shaders/line_fragment_shader.fsh
@@ -3,106 +3,45 @@
 #else
   #define MAXPREC mediump
 #endif
-varying MAXPREC float v_dx;
-varying MAXPREC vec4 v_radius;
-varying MAXPREC vec2 v_type;
 
-varying lowp vec3 v_color;
-varying lowp vec3 v_mask;
+precision MAXPREC float;
 
-~getTexel~
+varying float v_dx;
+varying vec4 v_radius;
+varying vec2 v_type;
 
-void sphere_join(MAXPREC float gip2, lowp vec4 baseColor, lowp vec4 outlineColor)
-{
-  MAXPREC float r = v_radius.y;
-  if (gip2 > v_radius.w * v_radius.w)
-  {
-    gl_FragColor = vec4(outlineColor.rgb, outlineColor.a * (v_radius.y - sqrt(gip2)) / (v_radius.y - v_radius.w));
-    if (v_type.x > 0.6)
-      gl_FragColor = vec4(outlineColor.rgb, outlineColor.a * (v_radius.z - abs(v_dx * v_radius.z)) / r * 2.0);
-  }
-  else
-  {
-    if (v_type.x > 0.6)
-    {
-      if (abs(v_dx*v_radius.z) / 2.0 >= v_radius.z / 2.0 - r + v_radius.w)
-        gl_FragColor = vec4(outlineColor.rgb, outlineColor.a * (v_radius.z - abs(v_dx * v_radius.z)) / (r-v_radius.w));
-    }
-  }
-}
+varying vec3 v_color;
+varying vec3 v_mask;
+
+~getTexel~
 
 void main(void)
 {
-  lowp float alfa = getTexel(int(v_mask.z), v_mask.xy).a;
-  lowp vec4 color = getTexel(int(v_color.z), v_color.xy) * alfa;
-  lowp vec4 outlineColor = vec4(0.0, 0.0, 0.0, 0.0);
-  MAXPREC float r = v_radius.y;
-  MAXPREC float dist = abs(v_radius.x);
-  gl_FragColor = color;
-  if (v_type.x > 0.5)
-  {
-    MAXPREC float coord = (v_dx + 1.0) * v_radius.y / 2.0;
-    if (v_type.y > 0.5)
-    {
-      if (coord > v_radius.w)
-        gl_FragColor = vec4(outlineColor.rgb, outlineColor.a * (1.0 - (coord - v_radius.w) / (v_radius.y - v_radius.w)));
-
-      if (dist > v_radius.w)
-      {
-        lowp float alpha = min((1.0 - (coord - v_radius.w) / (v_radius.y - v_radius.w)), (v_radius.y - dist) / (v_radius.y - v_radius.w));
-        gl_FragColor = vec4(outlineColor.rgb, outlineColor.a * alpha);
-      }
-
-    }
-    else
-    {
-      if (coord < v_radius.y - v_radius.w)
-        gl_FragColor = vec4(outlineColor.rgb, outlineColor.a * coord / (v_radius.y - v_radius.w));
+  float r = v_radius.y;
+  float dist = abs(v_radius.x);
 
-      if (dist > v_radius.w)
-      {
-        lowp float alpha = min(coord / (v_radius.y - v_radius.w), (v_radius.y - dist) / (v_radius.y - v_radius.w));
-        gl_FragColor = vec4(outlineColor.rgb, outlineColor.a * alpha);
-      }
-    }
-  }
-  else if (v_type.x < -0.5)
+  if (v_type.x < -0.5)
   {
-    MAXPREC float y = (v_dx + 1.0) * v_radius.y / 2.0;
+    float y = (v_dx + 1.0) * v_radius.y / 2.0;
     if (v_type.y < 0.5)
       y = v_radius.y - (v_dx + 1.0) * v_radius.y / 2.0;
 
-    MAXPREC float sq = dist*dist + y*y;
+    float sq = dist * dist + y * y;
     if (sq >= v_radius.y * v_radius.y)
       discard;
-    if (sq > v_radius.w * v_radius.w)
-      gl_FragColor = vec4(outlineColor.rgb, outlineColor.a * (v_radius.y - sqrt(sq)) / (v_radius.y - v_radius.w));
   }
   else
   {
-    if (dist > v_radius.w)
-      gl_FragColor = vec4(outlineColor.rgb, outlineColor.a * (v_radius.y - dist) / (v_radius.y - v_radius.w));
-
-    if (v_type.y>0.1)
+    if (v_type.y > 0.1 && abs(v_dx) >= 1.0)
     {
-      if (v_dx >= 1.0)
-      {
-        MAXPREC float y = (v_dx - 1.0) * v_radius.z / 2.0;
-        MAXPREC float gip2 = dist*dist + y*y;
-        if(gip2 > v_radius.y * v_radius.y)
-          discard;
-        else
-          sphere_join(gip2, color, outlineColor);
-      }
-      else if (v_dx <= -1.0)
-      {
-        MAXPREC float y = (v_dx + 1.0) * v_radius.z / 2.0;
-        MAXPREC float gip2 = dist*dist + y*y;
-        if(gip2 > v_radius.y * v_radius.y)
-          discard;
-        else
-          sphere_join(gip2, color, outlineColor);
-      }
+      float y = (v_dx + 1.0 * sign(v_dx)) * v_radius.z / 2.0;
+      float gip2 = dist * dist + y * y;
+      if(gip2 > v_radius.y * v_radius.y)
+        discard;
     }
   }
+
+  vec4 color = getTexel(int(v_color.z), v_color.xy);
+  color.a = getTexel(int(v_mask.z), v_mask.xy).a;
+  gl_FragColor = color;
 }
diff --git a/drape/shaders/line_vertex_shader.vsh b/drape/shaders/line_vertex_shader.vsh
index 2a1741f5fb..ce49980ef1 100644
--- a/drape/shaders/line_vertex_shader.vsh
+++ b/drape/shaders/line_vertex_shader.vsh
@@ -1,19 +1,27 @@
-attribute highp vec4 a_position;
-attribute highp vec4 a_deltas;
-attribute highp vec4 a_width_type;
-attribute highp vec4 a_centres;
-attribute lowp vec3 a_color;
-attribute lowp vec3 a_mask;
-
-varying highp float v_dx;
-varying highp vec4 v_radius;
-varying highp vec2 v_type;
-
-varying lowp vec3 v_color;
-varying lowp vec3 v_mask;
-
-uniform highp mat4 modelView;
-uniform highp mat4 projection;
+#ifdef GL_FRAGMENT_PRECISION_HIGH
+  #define MAXPREC highp
+#else
+  #define MAXPREC mediump
+#endif
+
+precision MAXPREC float;
+
+attribute vec4 a_position;
+attribute vec4 a_deltas;
+attribute vec4 a_width_type;
+attribute vec4 a_centres;
+attribute vec3 a_color;
+attribute vec3 a_mask;
+
+varying float v_dx;
+varying vec4 v_radius;
+varying vec2 v_type;
+
+varying vec3 v_color;
+varying vec3 v_mask;
+
+uniform mat4 modelView;
+uniform mat4 projection;
 
 void main(void)
 {
diff --git a/drape/shaders/normalize_vertex_shader.vsh b/drape/shaders/normalize_vertex_shader.vsh
index 972d02f2d0..e01042715e 100644
--- a/drape/shaders/normalize_vertex_shader.vsh
+++ b/drape/shaders/normalize_vertex_shader.vsh
@@ -1,3 +1,11 @@
+#ifdef GL_FRAGMENT_PRECISION_HIGH
+  #define MAXPREC highp
+#else
+  #define MAXPREC mediump
+#endif
+
+precision MAXPREC float;
+
 attribute vec4 a_position;
 attribute vec4 a_normal;
 attribute vec3 a_color_index;
@@ -5,7 +13,7 @@ attribute vec3 a_color_index;
 uniform mat4 modelView;
 uniform mat4 projection;
 
-varying mediump vec3 v_color_index;
+varying vec3 v_color_index;
 
 void main(void)
 {
diff --git a/drape/shaders/path_font_vertex_shader.vsh b/drape/shaders/path_font_vertex_shader.vsh
index 9fbfb7802d..9fdfda5781 100755
--- a/drape/shaders/path_font_vertex_shader.vsh
+++ b/drape/shaders/path_font_vertex_shader.vsh
@@ -1,19 +1,27 @@
+#ifdef GL_FRAGMENT_PRECISION_HIGH
+  #define MAXPREC highp
+#else
+  #define MAXPREC mediump
+#endif
+
+precision MAXPREC float;
+
 attribute vec2 a_position;
 attribute vec4 a_texcoord;
 attribute vec4 a_color;
 attribute float a_index;
 
-uniform highp mat4 modelView;
-uniform highp mat4 projection;
+uniform mat4 modelView;
+uniform mat4 projection;
 
 varying vec3 v_texcoord;
-varying lowp vec4 v_colors;
-varying mediump float v_index;
+varying vec4 v_colors;
+varying float v_index;
 
 void main()
 {
   gl_Position = vec4(a_position, a_texcoord.w, 1) * modelView * projection;
-    
+
   v_texcoord = a_texcoord.xyz;
   v_colors = a_color;
   v_index = a_index;
diff --git a/drape/shaders/simple_vertex_shader.vsh b/drape/shaders/simple_vertex_shader.vsh
index e9fa036e28..6a93085bdf 100644
--- a/drape/shaders/simple_vertex_shader.vsh
+++ b/drape/shaders/simple_vertex_shader.vsh
@@ -1,10 +1,18 @@
+#ifdef GL_FRAGMENT_PRECISION_HIGH
+  #define MAXPREC highp
+#else
+  #define MAXPREC mediump
+#endif
+
+precision MAXPREC float;
+
 attribute vec4 a_position;
 attribute vec3 a_color_index;
 
 uniform mat4 modelView;
 uniform mat4 projection;
 
-varying mediump vec3 v_color_index;
+varying vec3 v_color_index;
 
 void main(void)
 {
diff --git a/drape/shaders/solid_color_fragment_shader.fsh b/drape/shaders/solid_color_fragment_shader.fsh
index 31935ad7ef..7995a6d7de 100644
--- a/drape/shaders/solid_color_fragment_shader.fsh
+++ b/drape/shaders/solid_color_fragment_shader.fsh
@@ -1,4 +1,12 @@
-varying mediump vec3 v_color_index;
+#ifdef GL_FRAGMENT_PRECISION_HIGH
+  #define MAXPREC highp
+#else
+  #define MAXPREC mediump
+#endif
+
+precision MAXPREC float;
+
+varying vec3 v_color_index;
 
 ~getTexel~
 
diff --git a/drape/shaders/texturing_fragment_shader.fsh b/drape/shaders/texturing_fragment_shader.fsh
index 3a62a3d95a..279e5cf599 100644
--- a/drape/shaders/texturing_fragment_shader.fsh
+++ b/drape/shaders/texturing_fragment_shader.fsh
@@ -1,5 +1,13 @@
-varying lowp vec2 v_texCoords;
-varying lowp float v_textureIndex;
+#ifdef GL_FRAGMENT_PRECISION_HIGH
+  #define MAXPREC highp
+#else
+  #define MAXPREC mediump
+#endif
+
+precision MAXPREC float;
+
+varying vec2 v_texCoords;
+varying float v_textureIndex;
 
 ~getTexel~
 
diff --git a/drape/shaders/texturing_vertex_shader.vsh b/drape/shaders/texturing_vertex_shader.vsh
index 45ac865d60..97fc691f19 100644
--- a/drape/shaders/texturing_vertex_shader.vsh
+++ b/drape/shaders/texturing_vertex_shader.vsh
@@ -1,12 +1,20 @@
-attribute lowp vec4 a_position;
-attribute lowp vec2 a_normal;
-attribute lowp vec3 a_texCoords;
+#ifdef GL_FRAGMENT_PRECISION_HIGH
+  #define MAXPREC highp
+#else
+  #define MAXPREC mediump
+#endif
 
-uniform highp mat4 modelView;
-uniform highp mat4 projection;
+precision MAXPREC float;
 
-varying lowp vec2 v_texCoords;
-varying lowp float v_textureIndex;
+attribute vec4 a_position;
+attribute vec2 a_normal;
+attribute vec3 a_texCoords;
+
+uniform mat4 modelView;
+uniform mat4 projection;
+
+varying vec2 v_texCoords;
+varying float v_textureIndex;
 
 void main(void)
 {