From 2368cde54675f39e9b5a99880124503b3ae391e1 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sun, 21 Jan 2024 03:01:44 +0000
Subject: Replace tokens found with values from getIntegerv

---
 gfx/gl/shader.cpp | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/gfx/gl/shader.cpp b/gfx/gl/shader.cpp
index b57dcd4..0f75817 100644
--- a/gfx/gl/shader.cpp
+++ b/gfx/gl/shader.cpp
@@ -1,8 +1,24 @@
 #include "shader.h"
+#include <algorithm>
 #include <array>
 #include <stdexcept>
 #include <string>
 
+namespace {
+	auto
+	getInt(GLenum e)
+	{
+		GLint i {};
+		glGetIntegerv(e, &i);
+		return std::to_string(i);
+	}
+
+	using LookUpFunction = std::string (*)(GLenum);
+	constexpr std::array<std::tuple<std::string_view, GLenum, LookUpFunction>, 1> LOOKUPS {{
+			{"GL_MAX_GEOMETRY_OUTPUT_VERTICES", GL_MAX_GEOMETRY_OUTPUT_VERTICES, getInt},
+	}};
+}
+
 Shader::ShaderRef
 Shader::compile() const
 {
@@ -13,7 +29,14 @@ Shader::compile() const
 	if (lookups) {
 		std::basic_string<GLchar> textMod {text};
 		for (const auto & match : ctre::range<R"(\bGL_[A-Z_]+\b)">(textMod)) {
-			textMod.replace(match.begin(), match.end(), "255");
+			if (const auto lookup = std::find_if(LOOKUPS.begin(), LOOKUPS.end(),
+						[&match](const auto & lookup) {
+							return std::get<std::string_view>(lookup) == match;
+						});
+					lookup != LOOKUPS.end()) {
+				const auto & [name, pname, getFunction] = *lookup;
+				textMod.replace(match.begin(), match.end(), getFunction(pname));
+			}
 		}
 		source(textMod.c_str(), static_cast<GLint>(textMod.length()));
 	}
-- 
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