First attempt at GLSL Heightmap > causing an error

Rhino Developer
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1

@stevebaer

Hi Steve,
I’m try to recreate the Linear Gradient as you’ve shared on Github repository, as that one unfortunately doesn’t work any more. I get prompted a "IO Read Error: Unknown data type encountered
Anyway, I want to make a heightmap shader. Basically a linear gradient between lowest and highest vertex of a mesh. Would you mind having a look where things go wrong? When I first compiled (saved the code) the first time it did show me a black/white display, but right after I tweaked a slider I get an error message: 1. Solution exception:Object reference not set to an instance of an object.

Heightmap.gh (6.3 KB)

Vertex

layout(location = 0) in vec3 _meshVertex;
layout(location = 1) in vec3 _meshNormal;

uniform mat4 _worldToClip;
out vec3 vertexPosition;

void main() 
{
  vertexPosition = _meshVertex;
  gl_Position = _worldToClip * vec4(_meshVertex, 1);
}

Fragment

in vec3 vertexPosition;
out vec4 FragColor;

uniform vec3 meshMin;
uniform vec3 meshMax;

float normalizeHeight(float height, float minHeight, float maxHeight)
{
  return (height - minHeight) / (maxHeight - minHeight);
}

void main()
{
  float normalizedHeight = normalizeHeight(vertexPosition.z, meshMin.z, meshMax.z);
  vec3 color = vec3(1.0 - normalizedHeight);
  FragColor = vec4(color, 1.0);
}

I want to use a shader for it’s speed. For an extremely dense mesh the computing time using normal components is +/- 1 minute, so loking for alternative

2

Odly enough the same examples as download form the wiki actually do work: https://github.com/mcneel/ghgl/wiki/Samples

So No need to tweak my weak attempt, I can not use yours.