Tesselation-related shader types.

Not used anywhere yet, just like geometry shader.

src/Shader.cpp

@@ -85,6 +85,8 @@ GLuint Shader::compile() {
             case Vertex:    err << "vertex";        break;
             case Geometry:  err << "geometry";      break;
             case Fragment:  err << "fragment";      break;
+            case TesselationControl: err << "tesselation control"; break;
+            case TesselationEvaluation: err << "tesselation evaluation"; break;
         }
 
         /* Show error log and delete shader */

src/Shader.h

@@ -51,7 +51,21 @@ class MAGNUM_EXPORT Shader {
              */
             Geometry = GL_GEOMETRY_SHADER,
 
-            Fragment = GL_FRAGMENT_SHADER   /**< Fragment shader */
+            Fragment = GL_FRAGMENT_SHADER,  /**< Fragment shader */
+
+            /**
+             * Tesselation control shader
+             *
+             * @requires_gl40 Extension <tt>ARB_tesselation_shader</tt>
+             */
+            TesselationControl = GL_TESS_CONTROL_SHADER,
+
+            /**
+             * Tesselation evaluation shader
+             *
+             * @requires_gl40 Extension <tt>ARB_tesselation_shader</tt>
+             */
+            TesselationEvaluation = GL_TESS_EVALUATION_SHADER
         };
 
         /** @brief %Shader state */