Write a GLSL equivalent for overlay_solid.

Fixes #6403
Patch by: z0rg
Reviewed by: @vladislavbelov
Differential Revision: https://code.wildfiregames.com/D4406
This was SVN commit r26168.

binaries/data/mods/public/gui/credits/texts/programming.json

@@ -288,6 +288,7 @@
 				{ "nick": "yashi", "name": "Yasushi Shoji" },
 				{ "nick": "Ykkrosh", "name": "Philip Taylor" },
 				{ "nick": "Yves" },
+				{ "nick": "z0rg", "name": "Sébastien Maire" },
 				{ "nick": "Zeusthor", "name": "Jeffrey Tavares" },
 				{ "nick": "zoot" },
 				{ "nick": "zsol", "name": "Zsolt Dollenstein" },

binaries/data/mods/public/shaders/effects/overlay_solid.xml

@@ -1,9 +1,11 @@
 <?xml version="1.0" encoding="utf-8"?>
 <effect>
-
     <technique>
         <require shaders="arb"/>
         <pass shader="arb/overlay_solid"/>
     </technique>
-
+    <technique>
+        <require shaders="glsl"/>
+        <pass shader="glsl/overlay_solid"/>
+    </technique>
 </effect>

binaries/data/mods/public/shaders/glsl/overlay_solid.fs

@@ -0,0 +1,8 @@
+#version 120
+
+uniform vec4 color;
+
+void main()
+{
+	gl_FragColor = color;
+}

binaries/data/mods/public/shaders/glsl/overlay_solid.vs

@@ -0,0 +1,12 @@
+#version 120
+
+uniform mat4 transform;
+uniform mat4 instancingTransform;
+
+attribute vec3 a_vertex;
+
+void main()
+{
+	vec4 worldPos = instancingTransform * vec4(a_vertex, 1.0);
+	gl_Position = transform * worldPos;
+}

binaries/data/mods/public/shaders/glsl/overlay_solid.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<program type="glsl">
+    <vertex file="glsl/overlay_solid.vs">
+        <attrib name="a_vertex" semantics="gl_Vertex"/>
+    </vertex>
+    <fragment file="glsl/overlay_solid.fs"/>
+</program>