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<title>WebGL OES_fbo_render_mipmap Conformance Tests</title>
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"use strict";
description("This test verifies the functionality of the OES_fbo_render_mipmap extension, if it is available.");

var wtu = WebGLTestUtils;
var canvas = document.getElementById("canvas");
var gl = wtu.create3DContext(canvas);
var ext = null;

(function(){

    const oesFboRenderMipmap = gl.getExtension("OES_fbo_render_mipmap");
    if (!oesFboRenderMipmap) {
        testPassed("OES_fbo_render_mipmap is allowed to be missing.");
        return;
    }

    let texture = gl.createTexture();
    gl.bindTexture(gl.TEXTURE_2D, texture);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST_MIPMAP_NEAREST);

    let colors = [
        [255, 0, 0, 255],
        [255, 127, 0, 255],
        [255, 255, 0, 255],
        [0, 255, 0, 255],
        [0, 255, 255, 255],
        [0, 127, 255, 255],
        [0, 0, 255, 255],
        [255, 0, 255, 255],
    ];

    let fbos = [];
    let maxLevel = 7;
    for (let level = 0; level <= maxLevel; level++) {
        let size = Math.pow(2, maxLevel - level);
        gl.texImage2D(gl.TEXTURE_2D, level, gl.RGBA, size, size, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
        let fbo = gl.createFramebuffer();
        gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
        gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture, level);
        fbos.push(fbo);

        wtu.glErrorShouldBe(gl, gl.NO_ERROR, "Any level of a texture can be attached to a framebuffer object.");
    }

    for (let level = 0; level <= maxLevel; level++) {
        gl.bindFramebuffer(gl.FRAMEBUFFER, fbos[level]);
        shouldBe("gl.checkFramebufferStatus(gl.FRAMEBUFFER)", "gl.FRAMEBUFFER_COMPLETE");
        gl.clearColor(colors[level][0] / 255, colors[level][1] / 255, colors[level][2] / 255, colors[level][3] / 255);
        gl.clear(gl.COLOR_BUFFER_BIT);
    }

    gl.bindFramebuffer(gl.FRAMEBUFFER, null);

    let program = wtu.setupTexturedQuad(gl);

    for (let level = 0; level <= maxLevel; level++) {
        let size = Math.pow(2, maxLevel - level);
        // We use differrent viewport sizes to affect which miplevel is fetched from the texture.
        gl.viewport(0, 0, size, size);
        gl.drawArrays(gl.TRIANGLES, 0, 6);
        wtu.checkCanvasRect(gl, 0, 0, 1, 1, colors[level]);
    }

})();

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