Initial commit: OpenRA game engine

Fork from OpenRA/OpenRA with one-click launch script (start-ra.cmd)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

glsl/postprocess_textured_sonic.frag

@@ -0,0 +1,18 @@
+#version {VERSION}
+#ifdef GL_ES
+precision mediump float;
+#endif
+
+uniform sampler2D SourceTexture;
+uniform float Scale;
+
+in vec2 vTexCoord;
+out vec4 fragColor;
+
+void main()
+{
+    if (dot(vTexCoord, vTexCoord) >= 1.0)
+	    discard;
+
+	fragColor = texelFetch(SourceTexture, ivec2(gl_FragCoord.xy + Scale * vTexCoord), 0);
+}