shader support

1 files changed, 50 insertions, 0 deletions

diff --git a/txtgameengine/shaders/shader.py b/txtgameengine/shaders/shader.py
new file mode 100644
index 0000000..61b6aaf
--- /dev/null
+++ b/txtgameengine/shaders/shader.py
@@ -0,0 +1,50 @@
+import typing
+
+if typing.TYPE_CHECKING:
+    from ..app import TxtGameApp
+
+
+class Shader:
+    """Wrapper class for a GL program"""
+
+    UNIFORMS: typing.Dict[str, str] = dict()
+    VERTEX_PATH: str
+    FRAGMENT_PATH: str
+
+    def __init__(self, app: 'TxtGameApp'):
+        self.app = app
+        self._prog_id = self.app.shaders.load_shaders(self.VERTEX_PATH, self.FRAGMENT_PATH)
+        self._is_bound = 0
+        self.uniform_locations = {}
+        self._fill_uniforms()
+
+    def _fill_uniforms(self):
+        with self:
+            for prop_name, shader_name in self.UNIFORMS.items():
+                self.uniform_locations[prop_name] = \
+                    self.app.shaders.get_uniform_location(self._prog_id, shader_name)
+
+    def __getattr__(self, item):
+        if item in self.uniform_locations:
+            return self.uniform_locations[item]
+        raise AttributeError("Shader '%s' has no attribute or uniform named %s" % (type(self).__name__, item))
+
+    def _require_bound(self, required=False):
+        assert self._is_bound > 0 or not required
+        return self
+
+    def get_uniform_location(self, name: str):
+        return self.uniform_locations[name]
+
+    def __enter__(self):
+        self._is_bound += 1
+        if self._is_bound == 1:
+            self.app.shaders.bind_shader(self._prog_id)
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self._is_bound -= 1
+        if self._is_bound == 0:
+            self.app.shaders.bind_shader(0)
+
+    def __repr__(self):
+        return '<Shader prog_id=%d uniforms=%r>' % (self._prog_id, self.uniform_locations)