GLSLGamma_GammaCorrect: clear the cached texture binding in GL_Bind properly, after the glBindTexture calls earlier in this function.

Fixes a obscure bug where:
 - a bsp with no textures (pink checkerboard displayed)
 - gamma != 1
 - nothing else on screen (sbar hidden, r_drawviewmodel 0)
would result in the screen turning to noise.

git-svn-id: svn+ssh://svn.code.sf.net/p/quakespasm/code/trunk@1263 af15c1b1-3010-417e-b628-4374ebc0bcbd

quakespasm/Quake/gl_rmain.c

@@ -251,7 +251,7 @@ void GLSLGamma_GammaCorrect (void)
 	GL_UseProgramFunc (0);
 	
 // clear cached binding
-	GL_Bind (notexture);
+	GL_ClearBindings ();
 }
 
 /*

quakespasm/Quake/gl_texmgr.c

@@ -1521,3 +1521,21 @@ static void GL_DeleteTexture (gltexture_t *texture)
 
 	texture->texnum = 0;
 }
+
+/*
+================
+GL_ClearBindings -- ericw
+ 
+Invalidates cached bindings, so the next GL_Bind calls for each TMU will
+make real glBindTexture calls.
+Call this after changing the binding outside of GL_Bind.
+================
+*/
+void GL_ClearBindings(void)
+{
+	int i;
+	for (i = 0; i < 3; i++)
+	{
+		currenttexture[i] = -1;
+	}
+}

quakespasm/Quake/gl_texmgr.h

@@ -104,6 +104,7 @@ void GL_SelectTexture (GLenum target);
 void GL_DisableMultitexture (void); //selects texture unit 0
 void GL_EnableMultitexture (void); //selects texture unit 1
 void GL_Bind (gltexture_t *texture);
+void GL_ClearBindings (void);
 
 #endif	/* _GL_TEXMAN_H */