Hello list.
2 quick questions.
- Is there a way to enable an alpha channel for the [color ( message
to gemwin? I ask because jitters [erase_color] attribute with an alpha between 0 and 1 allows for interesting trailing effects when geometry is moved, and leaves a gradated trail behind it. Quite nice.
- Is there a way to change blend mode attributes for gemhead objects?
Ie force a renderchain to render with one of the 7 source and 7 alpha blending modes that should be available?
forgive me if this is in the docs somewhere, but I havent seen it mentioned.
Thanks,
- { v a d e } / /
On Apr 3, 2005, at 11:43 PM, vade wrote:
Hello list.
2 quick questions.
- Is there a way to enable an alpha channel for the [color ( message
to gemwin? I ask because jitters [erase_color] attribute with an alpha between 0 and 1 allows for interesting trailing effects when geometry is moved, and leaves a gradated trail behind it. Quite nice.
Looks like the alpha is set to 0.0 after the message is received, which is an oversight. You can use GEMglClearColor to set an new color and it does handle alpha.
- Is there a way to change blend mode attributes for gemhead objects?
Ie force a renderchain to render with one of the 7 source and 7 alpha blending modes that should be available?
The [alpha] object has the basic transparency function. Rolling your own around GEMglBlendFunc might work although the messages for src and dst are floats, which might require looking at the GL headers to get those values.
chris clepper wrote:
On Apr 3, 2005, at 11:43 PM, vade wrote:
- Is there a way to change blend mode attributes for gemhead objects?
Ie force a renderchain to render with one of the 7 source and 7 alpha blending modes that should be available?
The [alpha] object has the basic transparency function. Rolling your own around GEMglBlendFunc might work although the messages for src and dst are floats, which might require looking at the GL headers to get those values.
that is what we have the [GLdefine] object for: convert GL-preprocessor definitions into their values, eg: GL_ONE_MINUS_SRC_ALPHA into 0x0303 (which is then output as float "771.0").
mfg,.asd. IOhannes
IOhannes m zmoelnig wrote:
that is what we have the [GLdefine] object for: convert GL-preprocessor definitions into their values, eg: GL_ONE_MINUS_SRC_ALPHA into 0x0303 (which is then output as float "771.0").
since people start bothering me about documentation, please note that there is an example patch gem/examples/09.openGL/01.primQuad.pd that shows the basic idea of how to use the openGL-wrapper.
btw, it has been there since the official release of 0.90 (so you don't need the hottest cvs)
mfg,.asd. IOhannes
-
chris clepper -
IOhannes m zmoelnig -
vade