GL_TEXTURE_2D_ARRAY in OpenFrameworks

ofApp.cpp

void ofApp::setup(){

    textures[0].load("Rhythmus01.jpg");    
    textures[1].load("Rhythmus02.jpg");
    
    textureShader.load("TextureArrayShader");
    
    GLsizei width = 480;
    GLsizei height = 360;
    GLsizei layerCount = 2;
    GLsizei mipLevelCount = 1;
 
    
    glGenTextures(1,&texture);
    glBindTexture(GL_TEXTURE_2D_ARRAY,texture);
    //Allocate the storage.
    glTexStorage3D(GL_TEXTURE_2D_ARRAY, mipLevelCount, GL_RGB8, width, height, layerCount);
    //Upload pixel data.
    //The first 0 refers to the mipmap level (level 0, since there's only 1)
    //The following 2 zeroes refers to the x and y offsets in case you only want to specify a subrectangle.
    //The final 0 refers to the layer index offset (we start from index 0 and have 2 levels).
    //Altogether you can specify a 3D box subset of the overall texture, but only one mip level at a time.
    
    glTexSubImage3D(GL_TEXTURE_2D_ARRAY, 0, 0, 0, 0, width, height, 1, GL_RGB, GL_UNSIGNED_BYTE, textures[0].getPixels());
    
    glTexSubImage3D(GL_TEXTURE_2D_ARRAY, 0, 0, 0, 1, width, height, 1, GL_RGB, GL_UNSIGNED_BYTE, textures[1].getPixels());
    
    //Always set reasonable texture parameters
    glTexParameteri(GL_TEXTURE_2D_ARRAY,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D_ARRAY,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D_ARRAY,GL_TEXTURE_WRAP_S,GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D_ARRAY,GL_TEXTURE_WRAP_T,GL_CLAMP_TO_EDGE);
    
    glBindTexture(GL_TEXTURE_2D_ARRAY,0);   
}

void ofApp::draw(){

	ofBackground(50);
    
    ofSetColor(255);
    
    glActiveTexture(GL_TEXTURE0+texture);
    glClientActiveTexture(GL_TEXTURE0+texture);
    
    glEnable(GL_TEXTURE_2D_ARRAY);
    glBindTexture(GL_TEXTURE_2D_ARRAY, texture);
    
    int w = textures[0].getWidth();
    int h = textures[0].getHeight();
    
    ofMesh m;
    m.setMode(OF_PRIMITIVE_TRIANGLE_STRIP);
    m.addVertex(ofVec2f(0, 0));
    m.addVertex(ofVec2f(w, 0));
    m.addVertex(ofVec2f(0, h));
    m.addVertex(ofVec2f(w, h));
    
    w = 1.0;
    h = 1.0;
    
    m.addTexCoord(ofVec2f(0, 0));
    m.addTexCoord(ofVec2f(w, 0));
    m.addTexCoord(ofVec2f(0, h));
    m.addTexCoord(ofVec2f(w, h));
    
    textureShader.begin();
    textureShader.setUniformTexture("texture", GL_TEXTURE_2D_ARRAY, texture, 0);
    textureShader.setUniform1i("texID", ofGetMousePressed() ? 1: 0);
    
    m.draw();

    textureShader.end();
    
    glActiveTexture(GL_TEXTURE0+texture);
    
    glBindTexture(GL_TEXTURE_2D_ARRAY, 0);
    glDisable(GL_TEXTURE_2D_ARRAY);
    
    glActiveTexture(GL_TEXTURE0);
}

TextureArrayShader.frag

#version 150

#define MAX_TEXTURES 2

uniform sampler2DArray textures;
uniform int texID;

in vec2 vTexCoord;

out vec4 fragColor;

void main(){

    vec4 color = texture(textures, vec3(vTexCoord, texID));
    fragColor = vec4(color.rgb, 1.0);
}

TextureArrayShader.vert

#version 150

#define MAX_TEXTURES 2

uniform mat4 modelMatrix;
uniform mat4 modelViewMatrix;
uniform mat4 textureMatrix;
uniform mat4 normalMatrix;
uniform mat4 modelViewProjectionMatrix;

in vec4 position;
in vec4 color;
in vec4 normal;
in vec2 texcoord;

out vec2 vTexCoord; 

void main(){

    vTexCoord = (textureMatrix*vec4(texcoord.x,texcoord.y,0,1)).xy;
    gl_Position = modelViewProjectionMatrix * position;
}

This example toggles between two textures loaded from ofImage. Click the mouse to toggle between texture 1 and 2.
Note that this example uses non ARB texture coordinates, which range from 0.0 to 1.0 not from 0.0 to image width/height.