Support for anisotropic filtering.

src/AbstractTexture.cpp

@@ -46,6 +46,12 @@ static_assert((filter_or(NearestNeighbor, BaseLevel) == GL_NEAREST) &&
 #undef filter_or
 #endif
 
+GLfloat AbstractTexture::maxSupportedAnisotropy() {
+    GLfloat value;
+    glGetFloatv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &value);
+    return value;
+}
+
 void AbstractTexture::setMinificationFilter(Filter filter, Mipmap mipmap) {
     CORRADE_ASSERT(_target != GL_TEXTURE_RECTANGLE || mipmap == Mipmap::BaseLevel, "AbstractTexture: rectangle textures cannot have mipmaps", )
 

src/AbstractTexture.h

@@ -29,7 +29,6 @@ namespace Magnum {
 See Texture, CubeMapTexture and CubeMapTextureArray documentation for more
 information.
 @todo Add glPixelStore encapsulation
-@todo Anisotropic filtering
 */
 class MAGNUM_EXPORT AbstractTexture {
     AbstractTexture(const AbstractTexture& other) = delete;
@@ -419,6 +418,14 @@ class MAGNUM_EXPORT AbstractTexture {
 
         /*@}*/
 
+        /**
+         * @brief Max supported anisotropy
+         *
+         * @see setMaxAnisotropy()
+         * @requires_extension <tt>EXT_texture_filter_anisotropic</tt>
+         */
+        static GLfloat maxSupportedAnisotropy();
+
         /**
          * @brief Constructor
          * @param layer     %Texture layer (number between 0 and 31)
@@ -498,6 +505,20 @@ class MAGNUM_EXPORT AbstractTexture {
             glTexParameterfv(_target, GL_TEXTURE_BORDER_COLOR, color.data());
         }
 
+        /**
+         * @brief Set max anisotropy
+         *
+         * Default value is `1.0`, which means no anisotropy. Set to value
+         * greater than `1.0` for anisotropic filtering.
+         *
+         * @see maxSupportedAnisotropy()
+         * @requires_extension <tt>EXT_texture_filter_anisotropic</tt>
+         */
+        inline void setMaxAnisotropy(GLfloat anisotropy) {
+            bind();
+            glTexParameterf(_target, GL_TEXTURE_MAX_ANISOTROPY_EXT, anisotropy);
+        }
+
         /**
          * @brief Generate mipmap
          *