[libgdx] SSAO shader black screen

Engines, Libraries and Tools
#1

Hello everyone, I’ve been trying to implement the SSAO shader for several days without success. Maybe someone can help me.

I am using this fragment shader:



uniform sampler2D texture0;
uniform sampler2D texture1;

uniform vec2 camerarange;
uniform vec2 screensize;

float readDepth( in vec2 coord ) {
    return (2.0 * camerarange.x) / (camerarange.y + camerarange.x - texture2D( texture0, coord ).x * (camerarange.y - camerarange.x));
}


void main(void)
{
    vec2 texCoord = gl_TexCoord[0].st;
    //vec2 texCoord = texture2D(texture0, gl_TexCoord[0].st).xy;
    //vec3 texColor = texture2D(texture1, gl_TexCoord[0].st).rgb;

    float depth = readDepth( texCoord );
    float d;

    float pw = 1.0 / screensize.x;
    float ph = 1.0 / screensize.y;

    float aoCap = 0.45;

    float ao = 0.0;

    float aoMultiplier=1000.0;

    float depthTolerance = 0.00001;

    d=readDepth( vec2(texCoord.x+pw,texCoord.y+ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    d=readDepth( vec2(texCoord.x-pw,texCoord.y+ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    d=readDepth( vec2(texCoord.x+pw,texCoord.y-ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    d=readDepth( vec2(texCoord.x-pw,texCoord.y-ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    pw*=2.0;
    ph*=2.0;
    aoMultiplier/=2.0;

    d=readDepth( vec2(texCoord.x+pw,texCoord.y+ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    d=readDepth( vec2(texCoord.x-pw,texCoord.y+ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    d=readDepth( vec2(texCoord.x+pw,texCoord.y-ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    d=readDepth( vec2(texCoord.x-pw,texCoord.y-ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    pw*=2.0;
    ph*=2.0;
    aoMultiplier/=2.0;

    d=readDepth( vec2(texCoord.x+pw,texCoord.y+ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    d=readDepth( vec2(texCoord.x-pw,texCoord.y+ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    d=readDepth( vec2(texCoord.x+pw,texCoord.y-ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    d=readDepth( vec2(texCoord.x-pw,texCoord.y-ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    pw*=2.0;
    ph*=2.0;
    aoMultiplier/=2.0;

    d=readDepth( vec2(texCoord.x+pw,texCoord.y+ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    d=readDepth( vec2(texCoord.x-pw,texCoord.y+ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    d=readDepth( vec2(texCoord.x+pw,texCoord.y-ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    d=readDepth( vec2(texCoord.x-pw,texCoord.y-ph));
    ao+=min(aoCap,max(0.0,depth-d-depthTolerance) * aoMultiplier);

    ao/=16.0;

    gl_FragColor = vec4(1.2-ao) * texture2D(texture1, texCoord);
}

And this vertex :


#version 110

void main(){
	gl_Position = ftransform();
	gl_TexCoord[0] = gl_MultiTexCoord0;
}

RENDER:

First I get the depthmap and scene textures from a framebuffer. And this is the result


        fbo.begin();
        Gdx.gl.glClearColor(0.1f, 0.1f, 0.1f, 1);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT | GL20.GL_DEPTH_BUFFER_BIT);
        modelBatch.begin(cam);
        modelBatch.render(models);
        modelBatch.end();
        fbo.end();
        Texture diffuseText = fbo.getTextureAttachments().get(DIFFUSE_ATTACHMENT);
        Texture depthText = fbo.getTextureAttachments().get(DEPTH_ATTACHMENT);

diffuse : https://i.imgur.com/fj2oPmT.png
depthMap: https://i.imgur.com/1Q9Zf3n.png

Next step, I apply the ssao shader and render it in a full screen quad


        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT | GL20.GL_DEPTH_BUFFER_BIT);
        depthText .bind(0);
        diffuseText .bind(1);
        shaderProgramSSAO.begin();
        shaderProgramSSAO.setUniformi("texture0", 0);
        shaderProgramSSAO.setUniformi("texture1", 1);
        shaderProgramSSAO.setUniformf("camerarange", new Vector2(cam.near, cam.far)); // near=1, far=20
        shaderProgramSSAO.setUniformf("screensize", new Vector2(Gdx.graphics.getWidth(), Gdx.graphics.getHeight()));
        mesh.render(shaderProgramSSAO, GL20.GL_TRIANGLES);
        shaderProgramSSAO.end();

But the only result I get is a black screen.

Any suggestions? What am I doing wrong?
Thanks in advance