CODEWITHSUNDEEP
openglglsl
Felix King
Felix King

Reputation: 23

Opengl/GLSL Using SSBO in an array

I got an errro when I using SSBO in an array.

this is my source code in a vertex shader:

#version 430 compatibility
in int aID;
in int bID;
out vec4 vColor;
struct Vertex{  
    vec4 Position;  
    vec4 Color;
};
layout(std430) buffer shader_data{
    Vertex vertex[];
}mybuffers[4];      // using a fixed size
void main()
{
    vColor = mybuffers[bID].vertex[aID].Color;  // using bID to locate the ssbo. the error is here
    vec4 worldPos = mybuffers[0].vertex[aID].Position;
    gl_Position = gl_ModelViewProjectionMatrix * worldPos;
}

And then I got an error when I link the glsl program object.

The error is:

Link Error

0(17) : error C1306: cannot determine type of interface variable. Need to inline function

I don't understand the meaning, need to inline function

Upvotes: 2

Views: 1712

Answers (1)

João Magalhães
João Magalhães

Reputation: 26

GLSL is saying you must resolve at link time the buffer which you're using. Thus if you substitute mybuffers[bID] by mybuffers[0] (for example) it would link cleanly.

A solution to this problem is using an explicit if (since your universe of buffers is small - 4 only):

void main()
{
    // explicitly index the buffer so GLSL can see it at link time:
    if(bId == 0)
        vColor = mybuffers[0].vertex[aID].Color;
    else if(bId == 1)
        vColor = mybuffers[1].vertex[aID].Color;
    else if(bId == 2)
        vColor = mybuffers[2].vertex[aID].Color;
    else if(bId == 3)
        vColor = mybuffers[3].vertex[aID].Color;

    vec4 worldPos = mybuffers[0].vertex[aID].Position;
    gl_Position = gl_ModelViewProjectionMatrix * worldPos;
}

Upvotes: 1

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