Refactor texture caps

src/celengine/glsupport.cpp

@@ -18,7 +18,9 @@ bool EXT_texture_compression_s3tc   = false;
 bool EXT_texture_filter_anisotropic = false;
 bool MESA_pack_invert               = false;
 GLint maxPointSize                  = 0;
+GLint maxTextureSize                = 0;
 GLfloat maxLineWidth                = 0.0f;
+GLint maxTextureAnisotropy          = 0;
 
 namespace
 {
@@ -59,6 +61,13 @@ bool init(util::array_view<std::string> ignore) noexcept
     maxPointSize = pointSizeRange[1];
     maxLineWidth = lineWidthRange[1];
 
+    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &maxTextureSize);
+
+#ifndef GL_ES
+    if (gl::EXT_texture_filter_anisotropic)
+        glGetIntegerv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &maxTextureAnisotropy);
+#endif
+
     return true;
 }
 

src/celengine/glsupport.h

@@ -49,7 +49,9 @@ extern bool ARB_vertex_array_object;
 extern bool EXT_framebuffer_object;
 #endif
 extern GLint maxPointSize;
+extern GLint maxTextureSize;
 extern GLfloat maxLineWidth;
+extern GLint maxTextureAnisotropy;
 
 bool init(util::array_view<std::string> = {}) noexcept;
 bool checkVersion(int) noexcept;

src/celengine/texture.cpp

@@ -30,12 +30,8 @@ using namespace celestia;
 using namespace Eigen;
 using namespace std;
 
-static bool texCapsInitialized = false;
-
 struct TextureCaps
 {
-    bool maxLevelSupported;
-    GLint maxTextureSize;
     GLint preferredAnisotropy;
 };
 
@@ -92,23 +88,19 @@ static bool testMaxLevel()
 
 static const TextureCaps& GetTextureCaps()
 {
+    static bool texCapsInitialized = false;
+
     if (!texCapsInitialized)
     {
         texCapsInitialized = true;
 
-        texCaps.maxLevelSupported = testMaxLevel();
-        glGetIntegerv(GL_MAX_TEXTURE_SIZE, &texCaps.maxTextureSize);
-
         texCaps.preferredAnisotropy = 1;
 #ifndef GL_ES
         if (gl::EXT_texture_filter_anisotropic)
         {
-            GLint maxAnisotropy = 1;
-            glGetIntegerv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &maxAnisotropy);
-
             // Cap the preferred level texture anisotropy to 8; eventually, we should allow
             // the user to control this.
-            texCaps.preferredAnisotropy = min(8, maxAnisotropy);
+            texCaps.preferredAnisotropy = min(8, gl::maxTextureAnisotropy);
         }
 #endif
     }
@@ -1006,8 +998,8 @@ static Texture* CreateTextureFromImage(Image& img,
     bool splittingAllowed = true;
     Texture* tex = nullptr;
 
-    int maxDim = GetTextureCaps().maxTextureSize;
-    if ((img.getWidth() > maxDim || img.getHeight() > maxDim) &&
+    const int maxDim = gl::maxTextureSize;
+    if ((img.getWidth() > maxDim || img.getHeight() > maxDim)
         splittingAllowed)
     {
         // The texture is too large; we need to split it.