# Shader issue when converted from Java

**URL:** <https://discourse.processing.org/t/shader-issue-when-converted-from-java/13589>\
**Category:** Processing.py\
**Created:** [August 25, 2019, 12:09pm UTC](https://discourse.processing.org/t/shader-issue-when-converted-from-java/13589 "2019-08-25T12:09:09Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![lnp](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/lnp/32/4911_2.png) [@lnp](https://discourse.processing.org/u/lnp)\
**Post date:** [August 25, 2019, 12:09pm UTC](https://discourse.processing.org/t/shader-issue-when-converted-from-java/13589/1 "2019-08-25T12:09:09Z")

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I converted a very simple Java example in to Python and I get a black screen instead. Just started tinkering with shaders so this is not a good start! Is there something obvious I’ve missed here? The shader seems to exist when I print myshader out.

```auto

def setup():

	global myshader
	size(640, 360, P2D)
	noStroke()

	# Load and compile shader
	myshader = loadShader("wood-1566731901444.frag")
	#print myshader
	

def draw():

	# Set uniforms
	myshader.set("u_resolution", width, height)
	#myshader.set("u_mouse", float(mouseX), float(mouseY))
	#myshader.set("u_time", millis() / 1000.0);

	# Replace the default pipeline programs with our shader
	shader(myshader)

	# Draw a billboard
	rect(0,0,width,height)

def keyPressed():
	print "keypressed"
	# Reload shader everytime a key is pressed
	myshader = loadShader("wood-1566731901444.frag");

```

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<div class="post-metadata">

**Author:** ![lnp](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/lnp/32/4911_2.png) [@lnp](https://discourse.processing.org/u/lnp)\
**Post date:** [August 25, 2019, 12:23pm UTC](https://discourse.processing.org/t/shader-issue-when-converted-from-java/13589/2 "2019-08-25T12:23:23Z")

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I needed to set width and height as floats.

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<div class="post-metadata">

**Author:** ![jeremydouglass](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/jeremydouglass/32/20_2.png) [@jeremydouglass](https://discourse.processing.org/u/jeremydouglass)\
**Post date:** [August 26, 2019, 10:16pm UTC](https://discourse.processing.org/t/shader-issue-when-converted-from-java/13589/3 "2019-08-26T22:16:48Z")

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> [@lnp](#):
>
> set width and height as floats

Do you mean like this?:

```
myshader.set("u_resolution", float(width), float(height))

```

Did that change to your above sketch solve your problem?

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<div class="post-metadata">

**Author:** ![lnp](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/lnp/32/4911_2.png) [@lnp](https://discourse.processing.org/u/lnp)\
**Post date:** [August 28, 2019, 11:51am UTC](https://discourse.processing.org/t/shader-issue-when-converted-from-java/13589/4 "2019-08-28T11:51:35Z")

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That’s exactly right!