Difference between OpenGLES and OpenGL 3.0

@edapx wrote:

Hello, I'm moving a shader from openGLES to OpenGL 3.0.
The shaders are almost identical, but that one for OpenGL 3.0 does not show the texture. This is the OpenGLES version

const int MAX_MARCHING_STEPS = 64;
const float EPSILON = 0.0011;
const float NEAR_CLIP = 0.0;
const float FAR_CLIP = 100.00;

float sdfSphere(vec3 pos, float radius){
    return length(pos) - radius;
}

float map(vec3 pos){
    return sdfSphere(pos, 2.4);
}

vec3 computeNormal(vec3 pos){
    vec2 eps = vec2(0.01, 0.);
    return normalize(vec3(
        map(pos + eps.xyy) - map(pos - eps.xyy),
        map(pos + eps.yxy) - map(pos - eps.yxy),
        map(pos + eps.yyx) - map(pos - eps.yyx)
    ));
}

float raymarching(vec3 eye, vec3 marchingDirection){
    float depth = NEAR_CLIP;
    for (int i = 0; i < MAX_MARCHING_STEPS; i++) {
        float dist = map(eye + depth * marchingDirection);
        if (dist < EPSILON){
            return depth;
        }

        depth += dist;

        if (depth >= FAR_CLIP) {
            return FAR_CLIP;
        }
    }
    return FAR_CLIP;
}

vec3 getRefTexture(vec3 normal, vec3 dir) {
    vec3 eye = -dir;
    vec3 r = reflect( eye, normal );
    vec4 color = texture2D(iChannel1, (0.5 * (r.xy) + .5));
    return color.xyz;
}

void main(){
    vec2 uv = 2.0 * gl_FragCoord.xy / iResolution.xy - 1.0;
    uv.x *= iResolution.x / iResolution.y;

    vec3 eye = vec3(0.0, 0.0, -10);
    float fov = 2.;
    vec3 dir = normalize(vec3(uv, fov));

    float shortestDistanceToScene = raymarching(eye, dir);

    vec3 color;
    vec3 bgColor = vec3(0.1, 0.35, 0.75);

    if (shortestDistanceToScene < FAR_CLIP - EPSILON) {
        vec3 collision = (eye += (shortestDistanceToScene*0.995) * dir );
        vec3 normal = computeNormal(collision);
        color = getRefTexture(normal, dir);
    } else {
        color = bgColor;
    }
    gl_FragColor = vec4(color , 1.0);
}

That gives me this:

Screen Shot 2018-02-13 at 10.05.40.png1226x1354 564 KB

And this is the openGL 3.0 version:

#version 150
uniform sampler2DRect tex0;
uniform vec2 resolution;

in vec2 vTexCoord; //used just for debugging purpose
out vec4 fragColor;

int MAX_MARCHING_STEPS = 64;
const float EPSILON = 0.0011;
const float NEAR_CLIP = 0.0;
const float FAR_CLIP = 100.00;

float sdfSphere(vec3 pos, float radius){
    return length(pos) - radius;
}

float map(vec3 pos){
    return sdfSphere(pos, 2.4);
}

float raymarching(vec3 eye, vec3 marchingDirection){
    float depth = NEAR_CLIP;
    for (int i = 0; i < MAX_MARCHING_STEPS; i++) {
        float dist = map(eye + depth * marchingDirection);
        if (dist < EPSILON){
            return depth;
        }

        depth += dist;

        if (depth >= FAR_CLIP) {
            return FAR_CLIP;
        }
    }
    return FAR_CLIP;
}

vec3 computeNormal(vec3 pos){
    vec2 eps = vec2(0.01, 0.);
    return normalize(vec3(
                          map(pos + eps.xyy) - map(pos - eps.xyy),
                          map(pos + eps.yxy) - map(pos - eps.yxy),
                          map(pos + eps.yyx) - map(pos - eps.yyx)
                          ));
}

vec3 getRefTexture(vec3 normal, vec3 dir) {
    vec3 eye = -dir;
    vec3 r = reflect( eye, normal );
    vec4 color = texture(tex0, (0.5 * (r.xy) + .5));
    return color.xyz;
}

void main(){
    vec2 uv = 2.0 * gl_FragCoord.xy / resolution.xy - 1.0;
    uv.x *= resolution.x / resolution.y;

    vec3 eye = vec3(0.0, 0.0, -10);
    float fov = 2.;
    vec3 dir = normalize(vec3(uv, fov));

    float shortestDistanceToScene = raymarching(eye, dir);

    vec3 color;
    vec3 bgColor = vec3(0.1, 0.35, 0.75);

    if (shortestDistanceToScene < FAR_CLIP - EPSILON) {
        vec3 collision = (eye += (shortestDistanceToScene*0.995) * dir );
        vec3 normal = computeNormal(collision);
        color = getRefTexture(normal, dir);
    } else {
        color = bgColor;
    }

    // if I uncomment this, the texture is displayed as expected. That means the texture is available to the shader
    // color = texture(tex0, (0.5 * (vTexCoord.xy) + .5));
    fragColor = vec4(color , 1.0);
}

And it gives me this result:

Screen Shot 2018-02-13 at 10.06.06.png1660x1228 15.3 KB

Did I miss something?
The texture is passed correctly to the shader in the ofApp.cpp file, and I can print it on screen.

myShader.setUniformTexture("tex0", image0, 1);

The only difference that I see is the way the sampler is defined

Screen Shot 2018-02-13 at 10.19.07.png1980x238 34.7 KB

And this is my ofApp.cpp file

void ofApp::draw(){
    cam.begin();
    tex0.bind();
    plane.mapTexCoordsFromTexture(image0.getTexture());
    myShader.begin();
    setUniforms();
    plane.draw();
    myShader.end();
    tex0.unbind();
    cam.end();
}

void ofApp::setUniforms(){
    float resolution[] = {float(ofGetWidth()), float(ofGetHeight())};
    myShader.setUniform2fv("resolution",resolution);
    myShader.setUniformTexture("tex0", image0, 1);
}

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