gl: use Glew if available.

configure.ac

@@ -104,6 +104,15 @@ if test "${ac_cv_my_have_gl}" = "no"; then
   AC_MSG_ERROR([[No OpenGL or OpenGL ES implementation found]])
 fi
 
+dnl Use Glew?
+ac_cv_my_have_glew="no"
+PKG_CHECK_MODULES(GLEW, glew, [ac_cv_my_have_glew="yes"], [:])
+if test "${ac_cv_my_have_glew}" != "no"; then
+  AC_DEFINE(HAVE_GLES_2X, 1, Define to 1 if GLES 2.x is available)
+  AC_DEFINE(USE_GLEW, 1, Define to 1 to use libglew)
+fi
+AM_CONDITIONAL(USE_GLEW, test "${ac_cv_my_have_glew}" != "no")
+
 dnl Poor man's GL feature detection.
 save_LIBS="${LIBS}"
 LIBS="${LIBS} ${GL_LIBS} ${GLES2_LIBS}"
@@ -194,8 +203,9 @@ AM_CONDITIONAL(USE_CPPUNIT, test "$CPPUNIT" = "yes")
 
 
 dnl How to use the Lol Engine inside this tree
-LOL_CFLAGS="$LOL_CFLAGS -I \$(top_srcdir)/src $SDL_CFLAGS $EGL_CFLAGS $LIBPNG_CFLAGS"
-LOL_LIBS="$LOL_LIBS $SDL_LIBS $EGL_LIBS $LIBPNG_LIBS"
+LOL_CFLAGS="$LOL_CFLAGS -I \$(top_srcdir)/src"
+LOL_CFLAGS="$LOL_CFLAGS $SDL_CFLAGS $EGL_CFLAGS $GLEW_CFLAGS $LIBPNG_CFLAGS"
+LOL_LIBS="$LOL_LIBS $SDL_LIBS $EGL_LIBS $GLEW_LIBS $LIBPNG_LIBS"
 
 AC_SUBST(MATH_LIBS)
 AC_SUBST(LOL_CFLAGS)

src/lolgl.h

@@ -24,7 +24,9 @@
 #endif
 
 /* Include GL */
-#if defined HAVE_GL_2X
+#if defined USE_GLEW
+#   include <GL/glew.h>
+#elif defined HAVE_GL_2X
 #   if defined __APPLE__ && defined __MACH__
 #       include <OpenGL/gl.h>
 #   else
@@ -46,8 +48,8 @@
 
 /* Redefine some function names */
 #if defined HAVE_GL_2X
-#   define glClearDepthf glClearDepth
 #elif defined HAVE_GLES_2X
+#   define glClearDepth glClearDepthf
 #   define glGenVertexArrays glGenVertexArraysOES
 #   define glDeleteVertexArrays glDeleteVertexArraysOES
 #   define glBindVertexArray glBindVertexArrayOES

src/sdlapp.cpp

@@ -17,6 +17,7 @@
 #endif
 
 #include "core.h"
+#include "lolgl.h"
 #include "sdlapp.h"
 
 namespace lol
@@ -58,6 +59,15 @@ SdlApp::SdlApp(char const *title, vec2i res, float fps) :
         SDL_Quit();
         exit(EXIT_FAILURE);
     }
+#if defined USE_GLEW
+    GLenum glerr = glewInit();
+    if (glerr != GLEW_OK)
+    {
+        Log::Error("cannot initialise GLEW: %s\n", glewGetErrorString(glerr));
+        SDL_Quit();
+        exit(EXIT_FAILURE);
+    }
+#endif
 
     SDL_WM_SetCaption(title, NULL);
     SDL_ShowCursor(0);

src/video.cpp

@@ -59,7 +59,7 @@ void Video::Setup(vec2i size)
 #endif
 
     glClearColor(0.1f, 0.2f, 0.3f, 0.0f);
-    glClearDepthf(1.0);
+    glClearDepth(1.0);
 
 #if defined HAVE_GL_2X
     glShadeModel(GL_SMOOTH);