Vertex shader makes GUI disappear

Question

I have some code to render GUI's, and if I dont use a vertex shader then it renders exactly where its meant to :

However, as soon as I use a vertex shader, even simply one that calls

gl_position = vec4(position,1.0);

It hides, or moves, or otherwise makes my GUI disappear

Whats the correct way to have a shader for GUIs in OpenGL?

GUI render :

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    glOrtho(0, width, 0, height, -10, 10);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    glDisable(GL_CULL_FACE);
    glDisable(GL_DEPTH_TEST);
    RendererUtils.setWireframeMode(false);
    for (Interface i : interfaces)
    {
        i.updateShaderForThisB();
        if (i instanceof InterfaceContainer)
        {
            ((InterfaceContainer) i).draw();
        }
        else
        {
            ((InterfaceControl) i).draw();
        }           
    }
    InterfaceShader.getInstance().unbind();
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_CULL_FACE);

InterfaceContainer and InterfaceControl's draw call is largely the same, so I'll only add one of them.

InterfaceControl.draw()

public void draw()
{
    this.updateShaderForThisB();
    this.getMesh().draw();
    if (this.hasText)
    {
        //this.updateShaderForThisF();
        //drawText();
    }

}

InterfaceControl.updateShaderForThisB()

public void updateShaderForThisB()
{
    InterfaceShader shader = InterfaceShader.getInstance();
    shader.bind();
    shader.setColour(this.getActingColour());
    shader.setLocation(this.getLocation());
    shader.setSize(this.getBounds());
    shader.setGradient(this.getShouldGradient());
    shader.updateUniforms();
}

Mesh.draw()

public void draw()
{
    glEnableVertexAttribArray(0); //Vertices
    glEnableVertexAttribArray(1); //Tex coords
    glEnableVertexAttribArray(2); //Normals

    glBindBuffer(GL_ARRAY_BUFFER,vbo);
    glVertexAttribPointer(0, 3, GL_FLOAT, false, Vertex.SIZE * 4, 0);
    glVertexAttribPointer(1, 2, GL_FLOAT, false, Vertex.SIZE * 4, 12);
    glVertexAttribPointer(2, 3, GL_FLOAT, false, Vertex.SIZE * 4, 20);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
    glDrawElements(GL_TRIANGLES, size, GL_UNSIGNED_INT,0);

    glDisableVertexAttribArray(0);
    glDisableVertexAttribArray(1);
    glDisableVertexAttribArray(2);
}

InterfaceShader.vs

#version 330

layout(location = 0) in vec3 position;
layout(location = 1) in vec2 texCoord;
uniform mat4 viewMatrix;

out vec2 texCoord0;

void main()
{
    gl_Position = viewMatrix * vec4(position,1.0);
    texCoord0 = texCoord;
}

Can anyone see an obvious problem that i've overlooked? My first thought was that the shader was translating my interface-oriented coordinates (ie 50,50,1) into real world coordinates, but I dont know

Edit : As requested, updated shader code and added matrix projection code

https://pastebin.com/gKdewDVi

pastebin for Transform class, for getting the view matrix and such, and how it's related back to the shader

Knew it would be something simple, my other shader works fine but i thought i wouldnt need any matrices in this one because i didnt want any transformations to happen on the vertices — DuskFall, Nov 22 '17 at 18:51
The first step is to replace with "#version 130\n\n gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;", which should give the same result as without vertex shader; and then to change to a higher version and uniform parameters instead of the matrices stacks. — Sebastian, Nov 26 '21 at 09:56

score 2 · Answer 1 · edited Mar 14 '18 at 16:54

2

The fixed function vertex processing pipeline multiplies the vertex positions by the current matrix given by GL_PROJECTION * GL_MODELVIEW. You have to do the same thing in your vertex shader like so:

gl_Position = gl_ModelViewProjectionMatrix * vec4(position,1.0);

Please note that you are using outdated OpenGL programming practices by using the fixed-function processing. This has been deprecated for a while now.

edited Mar 14 '18 at 16:54

Rabbid76

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answered Nov 22 '17 at 19:09

bernie

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I'm passing in the transformed view matrix and now its rendering in worldspace rather than in your face, do I need to apply a transform to each individual part of the interface and bind that per draw, or can I specify a single transformation, send that to the shader, and then have that applied until I change it? – DuskFall Nov 22 '17 at 19:20
please update your question with your vertex shader code – bernie Nov 22 '17 at 20:16

Vertex shader makes GUI disappear

1 Answers1