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<title>WebGL vertexAttribPointer Conformance Tests</title>
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<script>
"use strict";
description("This test checks vertexAttribPointer behaviors in WebGL.");

debug("");
debug("Canvas.getContext");

var wtu = WebGLTestUtils;
var gl = wtu.create3DContext("canvas");
if (!gl) {
  testFailed("context does not exist");
} else {
  testPassed("context exists");

  debug("");
  debug("Checking gl.vertexAttribPointer.");

  if (!gl.FIXED) {
    gl.FIXED = 0x140C;
  }

  var vertexObject = gl.createBuffer();
  gl.bindBuffer(gl.ARRAY_BUFFER, vertexObject);
  gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(0), gl.STATIC_DRAW);


  gl.bindBuffer(gl.ARRAY_BUFFER, null);
  gl.vertexAttribPointer(0, 1, gl.FLOAT, false, 0, 4);
  wtu.glErrorShouldBe(gl, gl.INVALID_OPERATION,
      "vertexAttribPointer should fail if no buffer is bound and `offset` is non-zero.");

  gl.bindBuffer(gl.ARRAY_BUFFER, vertexObject);
  gl.vertexAttribPointer(0, 1, gl.FLOAT, false, 0, 0);
  wtu.glErrorShouldBe(gl, gl.NO_ERROR);

  gl.bindBuffer(gl.ARRAY_BUFFER, null);
  gl.vertexAttribPointer(0, 1, gl.FLOAT, false, 0, 0);
  wtu.glErrorShouldBe(gl, gl.NO_ERROR,
      "vertexAttribPointer should succeed if no buffer is bound and `offset` is zero.");

  gl.bindBuffer(gl.ARRAY_BUFFER, vertexObject);


  if (wtu.getDefault3DContextVersion() < 2) {
    gl.vertexAttribPointer(0, 1, gl.INT, 0, 0, 0);
    wtu.glErrorShouldBe(gl, gl.INVALID_ENUM,
            "vertexAttribPointer should not support INT");
    gl.vertexAttribPointer(0, 1, gl.UNSIGNED_INT, 0, 0, 0);
    wtu.glErrorShouldBe(gl, gl.INVALID_ENUM,
            "vertexAttribPointer should not support UNSIGNED_INT");
  }
  gl.vertexAttribPointer(0, 1, gl.FIXED, 0, 0, 0);
  wtu.glErrorShouldBe(gl, gl.INVALID_ENUM,
          "vertexAttribPointer should not support FIXED");

  var checkVertexAttribPointer = function(
      gl, err, reason, size, type, normalize, stride, offset) {
    gl.vertexAttribPointer(0, size, type, normalize, stride, offset);
    var succeeded = (err == gl.NO_ERROR);
    wtu.glErrorShouldBe(gl, err,
        "gl.vertexAttribPointer(0, " + size +
        ", gl." + wtu.glEnumToString(gl, type) +
        ", " + normalize +
        ", " + stride +
        ", " + offset +
        ") should " + (succeeded ? "succeed " : "fail ") + reason);
    if (succeeded) {
      shouldBe('gl.getVertexAttrib(0, gl.VERTEX_ATTRIB_ARRAY_SIZE)', size.toString());
      shouldBe('gl.getVertexAttrib(0, gl.VERTEX_ATTRIB_ARRAY_TYPE)', 'gl.' + wtu.glEnumToString(gl, type));
      shouldBe('gl.getVertexAttrib(0, gl.VERTEX_ATTRIB_ARRAY_NORMALIZED)', normalize.toString());
      shouldBe('gl.getVertexAttrib(0, gl.VERTEX_ATTRIB_ARRAY_STRIDE)', stride.toString());
      shouldBe('gl.getVertexAttribOffset(0, gl.VERTEX_ATTRIB_ARRAY_POINTER)', offset.toString());
    }
  }

  var types = [
    { type:gl.BYTE,           bytesPerComponent: 1 },
    { type:gl.UNSIGNED_BYTE,  bytesPerComponent: 1 },
    { type:gl.SHORT,          bytesPerComponent: 2 },
    { type:gl.UNSIGNED_SHORT, bytesPerComponent: 2 },
    { type:gl.FLOAT,          bytesPerComponent: 4 },
  ];

  if (wtu.getDefault3DContextVersion() >= 2) {
    types.push(...[
        { type:gl.INT,                         bytesPerComponent: 4 },
        { type:gl.UNSIGNED_INT,                bytesPerComponent: 4 },
        { type:gl.HALF_FLOAT,                  bytesPerComponent: 2 },
        { type:gl.INT_2_10_10_10_REV,          bytesPerComponent: 4, minSize: 4 },
        { type:gl.UNSIGNED_INT_2_10_10_10_REV, bytesPerComponent: 4, minSize: 4 },
      ]);
  }

  for (var ii = 0; ii < types.length; ++ii) {
    var info = types[ii];
    debug("");
    for (var size = 1; size <= 4; ++size) {
      debug("");
      debug("checking: " + wtu.glEnumToString(gl, info.type) + " with size " + size);
      var bytesPerElement = size * info.bytesPerComponent;
      var offsetSet = [
          0,
          1,
          info.bytesPerComponent - 1,
          info.bytesPerComponent,
          info.bytesPerComponent + 1,
          info.bytesPerComponent * 2];
      for (var jj = 0; jj < offsetSet.length; ++jj) {
        var offset = offsetSet[jj];
        for (var kk = 0; kk < offsetSet.length; ++kk) {
          var stride = offsetSet[kk];
          var err = gl.NO_ERROR;
          var reason = ""
          if (offset % info.bytesPerComponent != 0) {
            reason = "because offset is bad";
            err = gl.INVALID_OPERATION;
          }
          if (stride % info.bytesPerComponent != 0) {
            reason = "because stride is bad";
            err = gl.INVALID_OPERATION;
          }
          if (size < info.minSize) {
            reason = "because size < minSize";
            err = gl.INVALID_OPERATION;
          }
          checkVertexAttribPointer(
              gl, err, reason, size, info.type, false, stride, offset);
        }
        var stride = Math.floor(255 / info.bytesPerComponent) * info.bytesPerComponent;

        if (offset == 0) {
          checkVertexAttribPointer(
              gl, size < info.minSize ? gl.INVALID_OPERATION : gl.NO_ERROR, "at stride limit",
              size, info.type, false, stride, offset);
          checkVertexAttribPointer(
              gl, size < info.minSize ? [gl.INVALID_OPERATION, gl.INVALID_VALUE] : gl.INVALID_VALUE, "over stride limit",
              size, info.type, false,
              stride + info.bytesPerComponent, offset);
        }
      }
    }
  }
}

debug("");
var successfullyParsed = true;

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