Hey Jonathon, I tried to explain it to you earlier (math), but I think you
still have a fundamental misunderstanding of how blending and blit_into
works. Blending is combining pixels using the blending formula. That
formula determines the output of the resulting pixel. Normally this is done
automatically in the framebuffer of drawn images, but you aren't doing;
that you have two separate sets of data. With blitting you are writing your
data to the texture. Writing data twice doesn't mean they combine
automatically, even if they are different data sets.
Example: If you take two text files A and B, and output a file [not in
append] and write file A to the same output, then write the file B to the
same output. It doesn't become an intertwined mix of A and B, it just
becomes B, since you are REPLACING the data. They don't just combine on
their own in the data. This is the same as what you are doing, you are just
replacing the data in those spots. It doesn't matter about alpha or colors;
it's all data and you are replacing it. You need to COMBINE the data using
the formula I linked you.
It's a slow day for me, but I made you an example using two images of the
same size:
import pyglet
import ctypes
image_one = pyglet.image.load("one.png")
image_two = pyglet.image.load("two.png")
window = pyglet.window.Window()
def blend_color(color_src, color_dst, src_factor, dst_factor):
# Blending Formula = source * src_factor + dst * dst_factor. Make sure
they are int on return
return int((color_src * src_factor + color_dst * dst_factor) * 255)
def blend_alpha(alpha_src, alpha_dst, src_factor, dst_factor):
# Blend alpha, no source factor, can change if you want.
return int((alpha_src + alpha_dst * dst_factor) * 255)
def combine_pixels(source, dst):
""" source and dst are pixels of RGBA
This demonstarates formula for glBlendFunc(GL_SRC_ALPHA,
GL_ONE_MINUS_SRC_ALPHA)
"""
converted_src = [px / 255 for px in source] # From bytes to values in
relation to 1.
converted_dst = [px / 255 for px in dst]
# blend mode
src_factor = converted_src[3] # Source Factor: Source alpha. AKA
GL_SRC_ALPHA
dst_factor = (1 - converted_src[3]) # Dst Factor: 1 minus source alpha
AKA GL_ONE_MINUS_SRC_ALPHA
r = blend_color(converted_src[0], converted_dst[0], src_factor,
dst_factor)
g = blend_color(converted_src[1], converted_dst[1], src_factor,
dst_factor)
b = blend_color(converted_src[2], converted_dst[2], src_factor,
dst_factor)
a = blend_alpha(converted_src[3], converted_dst[3], src_factor,
dst_factor)
return r, g, b, a
# Turn both images in a list of RGBA int values.
pixel_data_one = list(image_one.get_image_data().get_data('RGBA',
image_one.width
* 4))
pixel_data_two = list(image_two.get_image_data().get_data('RGBA',
image_two.width
* 4))
combined_image = []
for i in range(0, len(pixel_data_one), 4):
pixel_one = pixel_data_one[i:i + 4]
pixel_two = pixel_data_two[i:i + 4]
# Pixel_two (source) on top of pixel_one (destination)
combined_image.extend(combine_pixels(pixel_one, pixel_two))
data = (ctypes.c_ubyte * len(pixel_data_one))(*combined_image)
new_image = pyglet.image.ImageData(image_one.width, image_two.height, "RGBA"
, data)
new_image.save("combined_image.png")
# draw new image.
sprite = pyglet.sprite.Sprite(new_image, x=0, y=0)
@window.event
def on_draw():
window.clear()
sprite.draw()
pyglet.app.run()
On Thursday, March 19, 2020 at 11:18:32 AM UTC-5, Jonathon Parker wrote:
>
> So there is no solution for this? All I want to do is:
>
> # imgA, imgB are identically sized instances of pyglet.image.ImageData in
> RGBA format
>
> imgC = imgA + imgB
>
> # imgC is now imgA with imgB superimposed on top of it. Transparent pixels
> in imgB allow *opaque* pixels in imgA to be visible
>
> I never thought something so simple would be so hard!
>
> On Wednesday, March 11, 2020 at 3:34:15 PM UTC-4, Jonathon Parker wrote:
>>
>> A minimal example
>>
>> # rawdata1 and rawdata2 are a list of c_ubytes
>>
>> my_texture_region = pyglet.image.ImageData(x, y, 'RGB',
>> rawdata1).get_texture()
>> my_image = pyglet.image.ImageData(x, y, 'RGB', rawdata2)
>> my_texture_region.blit_into(my_image, 0, 0, 0)
>>
>> When I create a sprite using my_texture region, I only see my_image.
>> What I want is my_image on top of my_texture_region.
>>
>> What am I doing wrong?
>>
>>
>>
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