"PShape::attrib()" and "PShape::setAttrib()" are not working. #5560
Description
Description
PShape::attrib() and PShape::setAttrib() are not working.
As discussed on the forum:
https://discourse.processing.org/t/pshape-attrib-and-pshape-setattrib-dont-work-proprely/845
Expected Behavior
Make Shape::attrib() and PShape::setAttrib() assign some attributes in glsl shaders and make processing not crash.
Current Behavior
When using PShape::attrib() it works fine.
Meanwhile, when using Shape::attrib() on a shape then added as a child in a GROUP PShape, it throws error like : java.lang.NullPointerException and crashes. Also when using PShape::setAttrib() it does not work in any case.
Steps to Reproduce
3 following Exemples to demonstrate the problem.
- Working Exemple
//
// Working Exemple
//
PShape shape;
PShader shader;
public void setup() {
size(500, 500, P2D);
shape = createShape();
shape.beginShape();
// Visual
shape.noStroke();
shape.fill(255, 0, 0); // Not supposed to be Red
// Custom Attribute
shape.attrib("vert_color", 1.0, 0.5, 0.0, 1.0); // Supposed to be Orange
shape.vertex(-100, -100);
shape.vertex(100, -100);
shape.vertex(100, 100);
shape.vertex(-100, 100);
shape.endShape();
// Exemple shader
shader = createShader();
}
public void draw() {
background(255);
shader(shader);
translate(width/2, height/2);
shape(shape);
}
public PShader createShader() {
String[] vert = new String[] {
"#version 110",
"uniform mat4 transform;",
"",
"attribute vec4 position;",
"attribute vec4 vert_color;",
"",
"varying vec4 vertColor;",
"",
"void main() {",
" gl_Position = transform * position;",
" vertColor = vert_color;",
"}"
};
String[] frag = new String[] {
"varying vec4 vertColor;",
"",
"void main() {",
" gl_FragColor = vertColor;",
"}"
};
return new PShader(this, vert, frag);
}
- PShape::attrib() in GROUP PShape crash
//
// Does not work when shape is GROUP
// ERROR : java.lang.NullPointerException
//
PShape shape;
PShape child;
PShader shader;
public void setup() {
size(500, 500, P2D);
child = createShape();
child.beginShape();
// Visual
child.noStroke();
child.fill(255, 0, 0); // Not supposed to be Red
// Custom Attribute
child.attrib("vert_color", 1.0, 0.5, 0.0, 1.0); // Supposed to be Orange
child.vertex(-100, -100);
child.vertex(100, -100);
child.vertex(100, 100);
child.vertex(-100, 100);
child.endShape();
shape = createShape(GROUP);
shape.addChild(child);
// Exemple shader
shader = createShader();
}
public void draw() {
background(255);
shader(shader);
translate(width/2, height/2);
shape(shape);
}
public PShader createShader() {
String[] vert = new String[] {
"#version 110",
"uniform mat4 transform;",
"",
"attribute vec4 position;",
"attribute vec4 vert_color;",
"",
"varying vec4 vertColor;",
"",
"void main() {",
" gl_Position = transform * position;",
" vertColor = vert_color;",
"}"
};
String[] frag = new String[] {
"varying vec4 vertColor;",
"",
"void main() {",
" gl_FragColor = vertColor;",
"}"
};
return new PShader(this, vert, frag);
}
- PShape::setAttrib() crash
//
// Does not work when using PShape::setAttrib() later
// ERROR : java.lang.NullPointerException
//
PShape shape;
PShader shader;
public void setup() {
size(500, 500, P2D);
shape = createShape();
shape.beginShape();
// Visual
shape.noStroke();
shape.fill(255, 0, 0); // Not supposed to be Red
// Custom Attribute
//shape.attrib("vert_color", 1.0, 0.5, 0.0, 1.0); // Not yet
shape.vertex(-100, -100);
shape.vertex(100, -100);
shape.vertex(100, 100);
shape.vertex(-100, 100);
shape.endShape();
// Set Custom Attributes
for(int i=0; i<shape.getVertexCount(); i++) {
shape.setAttrib("vert_color", i, 1.0, 0.5, 0.0, 1.0); // java.lang.NullPointerException, huh
}
// Exemple shader
shader = createShader();
}
public void draw() {
background(255);
shader(shader);
translate(width/2, height/2);
shape(shape);
}
public PShader createShader() {
String[] vert = new String[] {
"#version 110",
"uniform mat4 transform;",
"",
"attribute vec4 position;",
"attribute vec4 vert_color;",
"",
"varying vec4 vertColor;",
"",
"void main() {",
" gl_Position = transform * position;",
" vertColor = vert_color;",
"}"
};
String[] frag = new String[] {
"varying vec4 vertColor;",
"",
"void main() {",
" gl_FragColor = vertColor;",
"}"
};
return new PShader(this, vert, frag);
}
Your Environment
- Processing version: 3.3.7
- Operating System and OS version: Mac OS 10.12.6
Possible Causes / Solutions
The functions PShape::attrib() and PShape::setAttrib() are located in : processing/opengl/PShapeOpenGL.java