From 2ac4ca33381de82f51b2fb8c605008268c5ca977 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Thu, 25 Jul 2019 19:27:20 +0200
Subject: [PATCH] python: expose basic Framebuffer.

---
 src/python/magnum/PyGL.h             |  7 +++++
 src/python/magnum/gl.cpp             | 39 ++++++++++++++++++++++++++++
 src/python/magnum/test/test_gl_gl.py | 17 ++++++++++++
 3 files changed, 63 insertions(+)

diff --git a/src/python/magnum/PyGL.h b/src/python/magnum/PyGL.h
index 144c517..49d8e25 100644
--- a/src/python/magnum/PyGL.h
+++ b/src/python/magnum/PyGL.h
@@ -28,6 +28,7 @@
 #include <pybind11/pybind11.h>
 #include <vector>
 #include <Magnum/GL/Mesh.h>
+#include <Magnum/GL/Framebuffer.h>
 
 #include "magnum/bootstrap.h"
 
@@ -41,6 +42,12 @@ struct PyMesh: GL::Mesh {
     std::vector<py::object> buffers;
 };
 
+struct PyFramebuffer: GL::Framebuffer {
+    explicit PyFramebuffer(const Range2Di& viewport): GL::Framebuffer{viewport} {}
+
+    std::vector<py::object> attached;
+};
+
 }
 
 #endif
diff --git a/src/python/magnum/gl.cpp b/src/python/magnum/gl.cpp
index 7f4be3f..cba85fa 100644
--- a/src/python/magnum/gl.cpp
+++ b/src/python/magnum/gl.cpp
@@ -31,6 +31,7 @@
 #include <Magnum/GL/Attribute.h>
 #include <Magnum/GL/Buffer.h>
 #include <Magnum/GL/DefaultFramebuffer.h>
+#include <Magnum/GL/Framebuffer.h>
 #include <Magnum/GL/Mesh.h>
 #include <Magnum/GL/Renderer.h>
 #include <Magnum/GL/Renderbuffer.h>
@@ -46,6 +47,13 @@
 namespace magnum {
 
 void gl(py::module& m) {
+    /*
+        Missing APIs:
+
+        GL object labels
+        limit queries
+    */
+
     m.doc() = "OpenGL wrapping layer";
 
     /* Abstract shader program */
@@ -292,6 +300,37 @@ void gl(py::module& m) {
     NonDestructibleBase<GL::DefaultFramebuffer, GL::AbstractFramebuffer> defaultFramebuffer{m,
         "DefaultFramebuffer", "Default framebuffer"};
 
+    NonDestructibleBase<PyFramebuffer, GL::AbstractFramebuffer> framebuffer{m,
+        "Framebuffer", "Framebuffer"};
+
+    py::class_<GL::Framebuffer::ColorAttachment>{framebuffer, "ColorAttachment", "Color attachment"}
+        .def(py::init<UnsignedByte>(), "Constructor");
+
+    py::class_<GL::Framebuffer::BufferAttachment>{framebuffer, "BufferAttachment", "Buffer attachment"}
+        .def(py::init<GL::Framebuffer::ColorAttachment>(), "Color buffer")
+        .def_readonly_static("DEPTH", &GL::Framebuffer::BufferAttachment::Depth, "Depth buffer")
+        .def_readonly_static("STENCIL", &GL::Framebuffer::BufferAttachment::Stencil, "Stencil buffer")
+        #if !defined(MAGNUM_TARGET_GLES2) || defined(MAGNUM_TARGET_WEBGL)
+        .def_readonly_static("DEPTH_STENCIL", &GL::Framebuffer::BufferAttachment::DepthStencil, "Both depth and stencil buffer")
+        #endif
+        ;
+
+    py::implicitly_convertible<GL::Framebuffer::ColorAttachment, GL::Framebuffer::BufferAttachment>();
+
+    framebuffer
+        .def(py::init<const Range2Di&>(), "Constructor")
+        .def_property_readonly("id", &GL::Framebuffer::id, "OpenGL framebuffer ID")
+        .def("attach_renderbuffer", [](PyFramebuffer& self, GL::Framebuffer::BufferAttachment attachment, GL::Renderbuffer& renderbuffer) {
+            self.attachRenderbuffer(attachment, renderbuffer);
+
+            /* Keep a reference to the renderbuffer to avoid it being deleted
+               before the framebuffer */
+            /** @todo isn't there an API for this? */
+            self.attached.emplace_back(py::detail::get_object_handle(&renderbuffer, py::detail::get_type_info(typeid(GL::Renderbuffer))), true);
+        }, "Attach renderbuffer to given buffer")
+
+        .def_readonly("attached", &PyFramebuffer::attached, "Renderbuffer and texture objects referenced by the framebuffer");
+
     /* An equivalent to this would be
         m.attr("default_framebuffer") = &GL::defaultFramebuffer;
        (have to use a & to make it choose return_value_policy::reference
diff --git a/src/python/magnum/test/test_gl_gl.py b/src/python/magnum/test/test_gl_gl.py
index c764738..b58c810 100644
--- a/src/python/magnum/test/test_gl_gl.py
+++ b/src/python/magnum/test/test_gl_gl.py
@@ -57,6 +57,23 @@ class DefaultFramebuffer(GLTestCase):
         # Using it should not crash, leak or cause double-free issues
         self.assertTrue(gl.default_framebuffer is not None)
 
+class Framebuffer(GLTestCase):
+    def test(self):
+        framebuffer = gl.Framebuffer(((0, 0), (4, 4)))
+        self.assertNotEqual(framebuffer.id, 0)
+        self.assertEqual(len(framebuffer.attached), 0)
+
+    def test_attach(self):
+        renderbuffer = gl.Renderbuffer()
+        renderbuffer.set_storage(gl.RenderbufferFormat.RGBA8, (4, 4))
+        renderbuffer_refcount = sys.getrefcount(renderbuffer)
+
+        framebuffer = gl.Framebuffer(((0, 0), (4, 4)))
+        framebuffer.attach_renderbuffer(gl.Framebuffer.ColorAttachment(0), renderbuffer)
+        self.assertEqual(len(framebuffer.attached), 1)
+        self.assertIs(framebuffer.attached[0], renderbuffer)
+        self.assertEqual(sys.getrefcount(renderbuffer), renderbuffer_refcount + 1)
+
 class Mesh(GLTestCase):
     def test_init(self):
         a = gl.Mesh()