From d7d24ca36ac16055d2a4d2cf50674d125487fcd3 Mon Sep 17 00:00:00 2001
From: Armin Burgmeier <armin@arbur.net>
Date: Sat, 2 Jan 2016 19:15:38 -0800
Subject: [PATCH] Enable OGL core profile for linux

---
 src/graphics/C4DrawGL.cpp           | 10 +++-------
 src/graphics/C4DrawGLCtx.cpp        |  5 +++++
 src/landscape/C4LandscapeRender.cpp |  7 -------
 3 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/src/graphics/C4DrawGL.cpp b/src/graphics/C4DrawGL.cpp
index 104a17340..bad5bcb2d 100644
--- a/src/graphics/C4DrawGL.cpp
+++ b/src/graphics/C4DrawGL.cpp
@@ -382,14 +382,10 @@ bool CStdGL::CreatePrimarySurfaces(unsigned int, unsigned int, int iColorDepth,
 	// store options
 	bool ok = RestoreDeviceObjects();
 
-	// - AMD GPUs have supported OpenGL 2.1 since 2007
-	// - nVidia GPUs have supported OpenGL 2.1 since 2005
-	// - Intel integrated GPUs have supported OpenGL 2.1 since Clarkdale (maybe earlier).
-	// And we've already been using features from OpenGL 2.1. Nobody has complained yet.
-	// So checking for 2.1 support should be fine.
-	if (!GLEW_VERSION_2_1)
+	// We need at least OpenGL 3.0
+	if (!GLEW_VERSION_3_0)
 	{
-		return Error("  gl: OpenGL Version 2.1 or higher required. A better graphics driver will probably help.");
+		return Error("  gl: OpenGL Version 3.0 or higher required. A better graphics driver will probably help.");
 	}
 	return ok;
 }
diff --git a/src/graphics/C4DrawGLCtx.cpp b/src/graphics/C4DrawGLCtx.cpp
index 4052e23e1..522641fa3 100644
--- a/src/graphics/C4DrawGLCtx.cpp
+++ b/src/graphics/C4DrawGLCtx.cpp
@@ -480,6 +480,7 @@ bool CStdGLCtx::Init(C4Window * pWindow, C4AbstractApp *)
 	GLXContext dummy_ctx = glXCreateContext(dpy, vis_info, 0, True);
 	XFree(vis_info);
 	glXMakeCurrent(dpy, pWindow->renderwnd, dummy_ctx);
+	glewExperimental = GL_TRUE;
 	GLenum err = glewInit();
 	if (err != GLEW_OK)
 	{
@@ -488,7 +489,10 @@ bool CStdGLCtx::Init(C4Window * pWindow, C4AbstractApp *)
 
 	// Create Context with sharing (if this is the main context, our ctx will be 0, so no sharing)
 	const int attribs[] = {
+		GLX_CONTEXT_MAJOR_VERSION_ARB, 3,
+		GLX_CONTEXT_MINOR_VERSION_ARB, 1,
 		GLX_CONTEXT_FLAGS_ARB, (Config.Graphics.DebugOpenGL ? GLX_CONTEXT_DEBUG_BIT_ARB : 0),
+		GLX_CONTEXT_PROFILE_MASK_ARB, GLX_CONTEXT_CORE_PROFILE_BIT_ARB,
 		None
 	};
 	GLXContext share_context = (pGL->pMainCtx != this) ? static_cast<GLXContext>(pGL->pMainCtx->ctx) : 0;
@@ -511,6 +515,7 @@ bool CStdGLCtx::Init(C4Window * pWindow, C4AbstractApp *)
 	if (!ctx) return pGL->Error("  gl: Unable to create context");
 	if (!Select(true)) return pGL->Error("  gl: Unable to select context");
 	// init extensions
+	glewExperimental = GL_TRUE;
 	err = glewInit();
 	if (GLEW_OK != err)
 	{
diff --git a/src/landscape/C4LandscapeRender.cpp b/src/landscape/C4LandscapeRender.cpp
index 91d3bc8f3..703f4e29b 100644
--- a/src/landscape/C4LandscapeRender.cpp
+++ b/src/landscape/C4LandscapeRender.cpp
@@ -612,13 +612,6 @@ bool C4LandscapeRenderGL::LoadShader(C4GroupSet *pGroups, C4Shader& shader, cons
 
 bool C4LandscapeRenderGL::LoadShaders(C4GroupSet *pGroups)
 {
-	// No support?
-	if(!GLEW_ARB_fragment_program)
-	{
-		Log("  gl: no shader support!");
-		return false;
-	}
-
 	// First, clear out all existing shaders
 	ClearShaders();