Please look at my code example. There is no math to do. I have two
images the same size (50 x 50). Each image has a shape with A=255.
The rest of the image A = 0.
I want to draw one image on the other. So I convert one image into a
texture and blit_into with the other image. I should be able to see
through the transparent parts of the top image and see the opaque
parts of the bottom image. But I can't. It won't work.
On Thursday, March 12, 2020 at 12:30:32 PM UTC-4, Charles M wrote:
Blend modes themselves aren't going to help you with combining
textures into one. That's only for things like sprites and other
things in the framebuffer.
It's not OpenGL at this point, it's the data you are providing it.
You need to use math to change your pixel data with the blend mode
formula equation in the link I provided in the last post.
On Thursday, March 12, 2020 at 11:04:21 AM UTC-5, Jonathon Parker
wrote:
I need them as one image. I have tried many different blend
function things and if they don't throw an error they all do
the same things. Namely, only display rect.
Something has to be wrong somewhere else. I tried
pyglet.gl.glBlendFunc(pyglet.gl.GL_ZERO,pyglet.gl.GL_ONE)
If I understand it right, it should only display the
destination image (the triangle) and set the source image to
have a zero factor. But that is not what it does. It still
displays the thin rectangle.
On Thursday, March 12, 2020 at 10:53:58 AM UTC-4, Charles M
wrote:
Ah I see you want to blend them together in the same data.
In your examples you are still overwriting the image data.
If you have a red channel that's at 100 bytes and you
replace the data with another pixel that's 100 bytes, it's
still 100. If you are looking to blend two images together
you have a few options:
1) Create separate ImageData, put them into
pyglet.sprite.Sprite objects and draw them where you want.
By default Sprites should blend, and it should be easier
to keep track of things/move them when they are separate.
I'm curious why the need to combine the data instead of
treating them separate but move them where you want?
2) If you actually *need *them combined into one image
data for some reason, then you can combine the pixels
together with math based on blending formulas.
https://learnopengl.com/Advanced-OpenGL/Blending
<https://learnopengl.com/Advanced-OpenGL/Blending> Here is
the formula and an example.
On Thursday, March 12, 2020 at 7:49:36 AM UTC-5, Jonathon
Parker wrote:
I tried that and it did not work. I have verified
that if I draw a smaller image on top of the new, I
can see that. But even with using RGBA, I only see the
last image if the sizes are the same. Here is a more
expanded example of what I am trying to do.
---
import pyglet
import pyglet.gl <http://pyglet.gl>
import ctypes
import itertools
import numpy as np
import cv2
pyglet.gl.glEnable(pyglet.gl.GL_BLEND)
pyglet.gl.glBlendFunc(pyglet.gl.GL_SRC_ALPHA,pyglet.gl.GL_ONE_MINUS_SRC_ALPHA)
image = np.zeros((50, 50, 4), np.uint8) # type(image)
= numpy.ndarray
pt1 = (12, 1)
pt2 = (48, 24)
pt3 = (12, 48)
pt4 = (1, 24)
pt5 = (1, 26)
pt6 = (48, 26)
pt7 = (48, 24)
triangle_cnt = np.array([pt1, pt2, pt3])
cv2.drawContours(image, [triangle_cnt], 0, (100, 255,
100, 255), -1)
image = image.tolist()
px = list(itertools.chain(*list(itertools.chain(*image))))
rawData = (ctypes.c_ubyte * len(px))(*px)
player_image = pyglet.image.ImageData(50, 50, 'RGBA',
rawData).get_texture()
image2 = np.zeros((50, 50, 4), np.uint8)
rect_cnt = np.array([pt4, pt5, pt6, pt7])
cv2.drawContours(image2, [rect_cnt], 0, (100, 255,
100, 255), -1)
image2 = image2.tolist()
px2 =
list(itertools.chain(*list(itertools.chain(*image2))))
rawData2 = (ctypes.c_ubyte * len(px2))(*px2)
rect = pyglet.image.ImageData(50, 50, 'RGBA', rawData2)
player_image.blit_into(rect, 0, 0, 0)
---
When I display player_image, I only see the thin
rectangle. What am I doing wrong?
My goal is to change images for sprites during a
simulation depending on simulation events. If you
know a better way to accomplish this, I would like to
hear it.
On Wednesday, March 11, 2020 at 7:49:46 PM UTC-4,
Charles M wrote:
Your images have no transparency (RGB). You need
will need to specify an alpha channel to do
transparency: RGBA and a fourth value for each pixel.
On Wednesday, March 11, 2020 at 5:57:27 PM UTC-5,
Jonathon Parker wrote:
In my test the images are the same size, but I
thought the background was transparent. Any
way to specify a background color is
transparent? Or is there a better way to
layer images?
On Wednesday, March 11, 2020 at 6:44:00 PM
UTC-4, Charles M wrote:
This is normal behavior, blit overwrites
the pixel data with new data you are
providing. Which in this case is an
entirely new image.
On Wednesday, March 11, 2020 at 2:34:15 PM
UTC-5, 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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