Missing core GL features

arcade/gl/context.py

@@ -211,6 +211,17 @@ def __init__(self, window: pyglet.window.Window, gc_mode: str = "context_gc", gl
         self._point_size = 1.0
         self._flags: Set[int] = set()
         self._wireframe = False
+        # Options for cull_face
+        self._cull_face_options = {
+            "front": gl.GL_FRONT,
+            "back": gl.GL_BACK,
+            "front_and_back": gl.GL_FRONT_AND_BACK,
+        }
+        self._cull_face_options_reverse = {
+            gl.GL_FRONT: "front",
+            gl.GL_BACK: "back",
+            gl.GL_FRONT_AND_BACK: "front_and_back",
+        }
 
         # Context GC as default. We need to call Context.gc() to free opengl resources
         self._gc_mode = "context_gc"
@@ -618,8 +629,50 @@ def blend_func(self, value: Union[Tuple[int, int], Tuple[int, int, int, int]]):
             ValueError("blend_func takes a tuple of 2 or 4 values")
 
     # def blend_equation(self)
-    # def front_face(self)
-    # def cull_face(self)
+
+    @property
+    def front_face(self) -> str:
+        """
+        Configure front face winding order of triangles.
+
+        By default the counter-clockwise winding side is the front face.
+        This can be set set to clockwise or counter-clockwise::
+
+            ctx.front_face = "cw"
+            ctx.front_face = "ccw"
+        """
+        value = c_int()
+        gl.glGetIntegerv(gl.GL_FRONT_FACE, value)
+        return "cw" if value.value == gl.GL_CW else "ccw"
+
+    @front_face.setter
+    def front_face(self, value: str):
+        if value not in ["cw", "ccw"]:
+            raise ValueError("front_face must be 'cw' or 'ccw'")
+        gl.glFrontFace(gl.GL_CW if value == "cw" else gl.GL_CCW)
+
+    @property
+    def cull_face(self) -> str:
+        """
+        The face side to cull when face culling is enabled.
+
+        By default the back face is culled. This can be set to
+        front, back or front_and_back::
+
+            ctx.cull_face = "front"
+            ctx.cull_face = "back"
+            ctx.cull_face = "front_and_back"
+        """
+        value = c_int()
+        gl.glGetIntegerv(gl.GL_CULL_FACE_MODE, value)
+        return self._cull_face_options_reverse[value.value]
+
+    @cull_face.setter
+    def cull_face(self, value):
+        if value not in self._cull_face_options:
+            raise ValueError("cull_face must be", list(self._cull_face_options.keys()))
+
+        gl.glCullFace(self._cull_face_options[value])
 
     @property
     def wireframe(self) -> bool:

doc/programming_guide/release_notes.rst

@@ -187,6 +187,8 @@ Changes
   * Uniforms are now set using ``glProgramUniform`` instead of ``glUniform``
     when the extension is available.
   * Fixed many implicit type conversions in the shader code for wider support.
+  * Added ``front_face`` property on the context for configuring front face winding order of triangles
+  * Added ``cull_face`` property on the context for configuring what triangle face to cull
 
 * :py:class:`~arcade.tilemap.TileMap`
 

tests/unit/gl/test_opengl_context.py

@@ -149,3 +149,35 @@ def test_shader_include_fail(ctx):
     """
     with pytest.raises(FileNotFoundError):
         ctx.shader_inc(src)
+
+
+def test_front_face(ctx):
+    """Test front face"""
+    # Default
+    assert ctx.front_face == "ccw"
+
+    # Set valid values
+    ctx.front_face = "cw"
+    assert ctx.front_face == "cw"
+    ctx.front_face = "ccw"
+    assert ctx.front_face == "ccw"
+
+    # Set invalid value
+    with pytest.raises(ValueError):
+        ctx.front_face = "moo"
+
+
+def test_cull_face(ctx):
+    assert ctx.cull_face == "back"
+
+    # Set valid values
+    ctx.cull_face = "front"
+    assert ctx.cull_face == "front"
+    ctx.cull_face = "back"
+    assert ctx.cull_face == "back"
+    ctx.cull_face = "front_and_back"
+    assert ctx.cull_face == "front_and_back"
+
+    # Set invalid value
+    with pytest.raises(ValueError):
+        ctx.cull_face = "moo"