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<title>WebGL OVR_multiview2 Conformance Tests</title>
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"use strict";

let wtu = WebGLTestUtils;
let gl = wtu.create3DContext(null, null, 2);
let ext = null;

function runDrawBuffersClearTest()
{
    debug("");
    debug("Testing that calling clear() clears all views in all draw buffers");

    let width = 256;
    let height = 256;

    let views = gl.getParameter(ext.MAX_VIEWS_OVR);

    let fb = gl.createFramebuffer();
    gl.bindFramebuffer(gl.FRAMEBUFFER, fb);
    let colorTex = [null, null, null];
    let drawBuffers = [0, 0, 0];
    for (let texIndex = 0; texIndex < colorTex.length; ++texIndex) {
        colorTex[texIndex] = createTextureWithNearestFiltering(gl.TEXTURE_2D_ARRAY);
        gl.texStorage3D(gl.TEXTURE_2D_ARRAY, 1, gl.RGBA8, width, height, views);
        ext.framebufferTextureMultiviewOVR(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0 + texIndex, colorTex[texIndex], 0, 0, views);
        drawBuffers[texIndex] = gl.COLOR_ATTACHMENT0 + texIndex;
    }

    gl.viewport(0, 0, width, height);
    gl.drawBuffers(drawBuffers);

    gl.clearColor(0, 1, 1, 1);
    gl.clear(gl.COLOR_BUFFER_BIT);
    wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors from clear");

    let readFb = gl.createFramebuffer();
    gl.bindFramebuffer(gl.READ_FRAMEBUFFER, readFb);
    for (let texIndex = 0; texIndex < colorTex.length; ++texIndex) {
        for (let viewIndex = 0; viewIndex < views; ++viewIndex) {
            gl.framebufferTextureLayer(gl.READ_FRAMEBUFFER, gl.COLOR_ATTACHMENT0, colorTex[texIndex], 0, viewIndex);
            let expectedColor = [0, 255, 255, 255];
            wtu.checkCanvasRect(gl, 0, 0, width, height, expectedColor, 'view ' + viewIndex + ' of color attachment ' + texIndex + ' should be cyan');
        }
        debug("");
    }
}

function runDrawBuffersRenderTest()
{
    debug("");
    debug("Testing rendering into multiple draw buffers with a different transformation matrix chosen from a uniform array according to ViewID");

    let width = 256;
    let height = 256;

    let views = gl.getParameter(ext.MAX_VIEWS_OVR);

    let fb = gl.createFramebuffer();
    gl.bindFramebuffer(gl.FRAMEBUFFER, fb);
    let colorTex = [null, null, null];
    let drawBuffers = [0, 0, 0];
    for (let texIndex = 0; texIndex < colorTex.length; ++texIndex) {
        colorTex[texIndex] = createTextureWithNearestFiltering(gl.TEXTURE_2D_ARRAY);
        gl.texStorage3D(gl.TEXTURE_2D_ARRAY, 1, gl.RGBA8, width, height, views);
        ext.framebufferTextureMultiviewOVR(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0 + texIndex, colorTex[texIndex], 0, 0, views);
        drawBuffers[texIndex] = gl.COLOR_ATTACHMENT0 + texIndex;
    }

    let multiviewShaders = [
      getMultiviewRealisticUseCaseVertexShader(views),
      getMultiviewColorFragmentShaderForDrawBuffers(colorTex.length)
    ];

    let testProgram = wtu.setupProgram(gl, multiviewShaders, ['a_position'], [0], true);
    if (!testProgram) {
        testFailed("Compilation with extension enabled failed.");
        return;
    }

    gl.viewport(0, 0, width, height);
    gl.drawBuffers(drawBuffers);

    let transformLocation = gl.getUniformLocation(testProgram, 'transform');
    let transformData = new Float32Array (views * 16);
    for (let viewIndex = 0; viewIndex < views; ++viewIndex) {
        let scaleX = 1.0 / views;
        // offsetX is the position of the left edge of the quad we want to get in normalized device coordinates
        let offsetX = viewIndex / views * 2.0 - 1.0;

        setupTranslateAndScaleXMatrix(transformData, viewIndex * 16, scaleX, offsetX);
    }
    gl.uniformMatrix4fv(transformLocation, false, transformData);

    wtu.drawUnitQuad(gl);
    wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors from draw");

    let readFb = gl.createFramebuffer();
    gl.bindFramebuffer(gl.READ_FRAMEBUFFER, readFb);
    for (let texIndex = 0; texIndex < colorTex.length; ++texIndex) {
        for (let viewIndex = 0; viewIndex < views; ++viewIndex) {
            gl.framebufferTextureLayer(gl.READ_FRAMEBUFFER, gl.COLOR_ATTACHMENT0, colorTex[texIndex], 0, viewIndex);
            let expectedColor = getExpectedColor(viewIndex + texIndex);

            checkVerticalStrip(width, height, views, viewIndex, expectedColor, 'view ' + viewIndex + ' of color attachment ' + texIndex);
        }
        debug("");
    }
}

description("This test verifies the functionality of the OVR_multiview2 extension when used with multiple draw buffers, if it is available.");

debug("");

if (!gl) {
  testFailed("WebGL context does not exist");
} else {
  testPassed("WebGL context exists");

  if (!gl.getExtension("OVR_multiview2")) {
      testPassed("No OVR_multiview2 support -- this is legal");
  } else {
      testPassed("Successfully enabled OVR_multiview2 extension");
      ext = gl.getExtension('OVR_multiview2');

      runDrawBuffersClearTest();

      wtu.setupUnitQuad(gl, 0, 1);

      runDrawBuffersRenderTest();
  }
}

debug("");
var successfullyParsed = true;
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