diff --git a/res/CMakeLists.txt b/res/CMakeLists.txt
index 1913c065..b91f2165 100644
--- a/res/CMakeLists.txt
+++ b/res/CMakeLists.txt
@@ -211,7 +211,6 @@ add_resources(
     shaders/imesh_point.vert
     shaders/imesh_tex.frag
     shaders/imesh_texa.frag
-    shaders/imesh_texr.frag
     shaders/imesh_tex.vert
     shaders/mesh.frag
     shaders/mesh.vert
diff --git a/res/shaders/imesh_texa.frag b/res/shaders/imesh_texa.frag
index db2934ea..ed21a86d 100644
--- a/res/shaders/imesh_texa.frag
+++ b/res/shaders/imesh_texa.frag
@@ -9,5 +9,5 @@ uniform sampler2D texture;
 varying vec2 fragTex;
 
 void main() {
-    gl_FragColor = vec4(color.rgb, color.a * texture2D(texture, fragTex).a);
+    gl_FragColor = vec4(color.rgb, color.a * texture2D(texture, fragTex).TEX_ALPHA);
 }
diff --git a/res/shaders/imesh_texr.frag b/res/shaders/imesh_texr.frag
deleted file mode 100644
index 5d7bc68c..00000000
--- a/res/shaders/imesh_texr.frag
+++ /dev/null
@@ -1,13 +0,0 @@
-//-----------------------------------------------------------------------------
-// Indexed Mesh rendering shader
-//
-// Copyright 2016 Aleksey Egorov
-//-----------------------------------------------------------------------------
-uniform vec4 color;
-uniform sampler2D texture;
-
-varying vec2 fragTex;
-
-void main() {
-    gl_FragColor = vec4(color.rgb, color.a * texture2D(texture, fragTex).r);
-}
diff --git a/res/shaders/mesh_fill.frag b/res/shaders/mesh_fill.frag
index 4521ca96..74b38603 100644
--- a/res/shaders/mesh_fill.frag
+++ b/res/shaders/mesh_fill.frag
@@ -7,6 +7,6 @@ uniform vec4 color;
 uniform sampler2D texture;
 
 void main() {
-    if(texture2D(texture, gl_FragCoord.xy / 32.0).a < 0.5) discard;
+    if(texture2D(texture, gl_FragCoord.xy / 32.0).TEX_ALPHA < 0.5) discard;
     gl_FragColor = color;
 }
diff --git a/src/render/gl2shader.cpp b/src/render/gl2shader.cpp
index 786a6a99..828808ca 100644
--- a/src/render/gl2shader.cpp
+++ b/src/render/gl2shader.cpp
@@ -84,12 +84,21 @@ static GLuint CompileShader(const std::string &res, GLenum type) {
     // the `precision` keyword entirely, because that's clearly how minor versions work.
     // Christ, what a trash fire.
 
-    std::string src(resData, size);
+    const char *prelude;
 #if defined(HAVE_GLES)
-    src = "#version 100\nprecision highp float;\n" + src;
+    prelude = R"(
+#version 100
+#define TEX_ALPHA a
+precision highp float;
+)";
 #else
-    src = "#version 120\n" + src;
+    prelude = R"(
+#version 120
+#define TEX_ALPHA r
+)";
 #endif
+    std::string src(resData, size);
+    src = prelude + src;
 
     GLuint shader = glCreateShader(type);
     ssassert(shader != 0, "glCreateShader failed");