py: Add cam.py

Add cam.py, which mimics the 'cam' tool. Four rendering backends are
added:

* null - Do nothing
* kms - Use KMS with dmabufs
* qt - SW render on a Qt window
* qtgl - OpenGL render on a Qt window

All the renderers handle only a few pixel formats, and especially the GL
renderer is just a prototype.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 74 insertions, 0 deletions

diff --git a/src/py/cam/gl_helpers.py b/src/py/cam/gl_helpers.py
new file mode 100644
index 00000000..ac5e6889
--- /dev/null
+++ b/src/py/cam/gl_helpers.py
@@ -0,0 +1,74 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (C) 2022, Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
+
+from OpenGL.EGL.VERSION.EGL_1_0 import EGLNativeDisplayType, eglGetProcAddress, eglQueryString, EGL_EXTENSIONS
+
+from OpenGL.raw.GLES2 import _types as _cs
+from OpenGL.GLES2.VERSION.GLES2_2_0 import *
+from OpenGL.GLES3.VERSION.GLES3_3_0 import *
+from OpenGL import GL as gl
+
+from ctypes import c_int, c_char_p, c_void_p, cdll, POINTER, util, \
+    pointer, CFUNCTYPE, c_bool
+
+
+def getEGLNativeDisplay():
+    _x11lib = cdll.LoadLibrary(util.find_library('X11'))
+    XOpenDisplay = _x11lib.XOpenDisplay
+    XOpenDisplay.argtypes = [c_char_p]
+    XOpenDisplay.restype = POINTER(EGLNativeDisplayType)
+
+    return XOpenDisplay(None)
+
+
+# Hack. PyOpenGL doesn't seem to manage to find glEGLImageTargetTexture2DOES.
+def getglEGLImageTargetTexture2DOES():
+    funcptr = eglGetProcAddress('glEGLImageTargetTexture2DOES')
+    prototype = CFUNCTYPE(None, _cs.GLenum, _cs.GLeglImageOES)
+    return prototype(funcptr)
+
+
+glEGLImageTargetTexture2DOES = getglEGLImageTargetTexture2DOES()
+
+# \todo This can be dropped when we have proper PixelFormat bindings
+def str_to_fourcc(str):
+    assert(len(str) == 4)
+    fourcc = 0
+    for i, v in enumerate([ord(c) for c in str]):
+        fourcc |= v << (i * 8)
+    return fourcc
+
+
+def get_gl_extensions():
+    n = GLint()
+    glGetIntegerv(GL_NUM_EXTENSIONS, n)
+    gl_extensions = []
+    for i in range(n.value):
+        gl_extensions.append(gl.glGetStringi(GL_EXTENSIONS, i).decode())
+    return gl_extensions
+
+
+def check_gl_extensions(required_extensions):
+    extensions = get_gl_extensions()
+
+    if False:
+        print('GL EXTENSIONS: ', ' '.join(extensions))
+
+    for ext in required_extensions:
+        if ext not in extensions:
+            raise Exception(ext + ' missing')
+
+
+def get_egl_extensions(egl_display):
+    return eglQueryString(egl_display, EGL_EXTENSIONS).decode().split(' ')
+
+
+def check_egl_extensions(egl_display, required_extensions):
+    extensions = get_egl_extensions(egl_display)
+
+    if False:
+        print('EGL EXTENSIONS: ', ' '.join(extensions))
+
+    for ext in required_extensions:
+        if ext not in extensions:
+            raise Exception(ext + ' missing')