check float texture extension, use float32 or float16 if available, show extension on title bar, add thread and render task for lightmap rendering

src/app_shaders.cpp

@@ -15,10 +15,18 @@ void App::initShaders()
         for (int i = 0; i < n_exts; i++)
         {
             std::string ext = (const char*)glGetStringi(GL_EXTENSIONS, i);
-            if (ext.find("shader_framebuffer_fetch") != std::string::npos)
+            if (GLAD_GL_EXT_shader_framebuffer_fetch || GLAD_GL_EXT_shader_framebuffer_fetch_non_coherent)
             {
                 ShaderManager::ext_framebuffer_fetch = true;
             }
+            else if (GLAD_GL_ARB_texture_float || GLAD_GL_ATI_texture_float)
+            {
+                ShaderManager::ext_texture_float = true;
+            }
+            else if (GLAD_GL_NV_half_float || GLAD_GL_ARB_half_float_pixel)
+            {
+                ShaderManager::ext_half_float_pixel = true;
+            }
         }
     });