My GLSL vertex shader works fine, but you if put a for loop inside or rename the uniform xxx to something else, it says the follwoing:

Exception in thread "main" org.lwjgl.opengl.OpenGLException: Invalid operation (1282) at org.lwjgl.opengl.Util.checkGLError( at org.lwjgl.opengl.GL20.glGetUniformLocation(

this is the method causing the problem:

protected void getAllUniformLocations()

        location_transformationMatrix   = super.getUniformLocation("transformationMatrix");
        location_diffuseColor           = super.getUniformLocation("in_color");
        location_projectionMatrix       = super.getUniformLocation("projectionMatrix");
        location_lightPos               = super.getUniformLocation("lightPosition");
        location_lightColor             = super.getUniformLocation("lightColor");
        location_viewMatrix             = super.getUniformLocation("viewMatrix");
        location_specular               = super.getUniformLocation("specularLevel");
        location_boneTransformations    = new int[32]; 
        for(int i = 0; i < location_boneTransformations.length; i++)
            location_boneTransformations[i] = super.getUniformLocation("xxx["+i+"]");

this is my vertex shader:

#version 400 core

//data from VBO
in vec3 position;
in vec2 texture_coordinates;
in vec3 normal;
//bone data
in int bone_pointer;
in float bone_intensity;
//vertex color output
out vec4 color;
//texture coordinates
out vec2 pass_texcoords;
out vec2 texCoord0;
out vec3 surface_normal;
//vector pointing towards the light
out vec3 to_light_vector;

//position, rotation, scale
uniform mat4 transformationMatrix;
//perspective projection
uniform mat4 projectionMatrix;
//TODO: material color
uniform vec3 in_color;
//camera viewmatrix
uniform mat4 viewMatrix;
uniform vec3 lightPosition;
uniform vec3 lightColor;
//skeleton data xxx = bone transformations
uniform mat4 xxx[];
uniform int group_indices[];
uniform float group_values[];
void main()
    for(int i = 0; i < group_indices.length(); i++)

    mat4 total_transform =  transformationMatrix;
    total_transform = total_transform * xxx[0];

    vec4 worldPosition;

    worldPosition =  total_transform * (vec4(position, 1)) ; // 

    vec4 pos =  projectionMatrix * viewMatrix * worldPosition;
    gl_Position = pos;

    pass_texcoords = texture_coordinates;

    surface_normal = (total_transform *  vec4(normal, 0)).xyz;
    to_light_vector = lightPosition *; 

     texCoord0 = texture_coordinates;

  • 1
    What is the question part of your question? – david van brink Mar 1 '15 at 23:52
  • for-loops in shader initialisation aren't even allowed, i think, so that makes perfect sense. – Timothy Groote Mar 2 '15 at 14:01

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