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• passes: 1
• failures: 0
• duration: 0.04s

• buffer overflow tests

  • test buffer overflow with drawArraysInstanced32ms ‣

    const {gl, tagObject} = createContext();
    const vs = `
    attribute vec4 position;
    attribute vec2 texcoord;
    attribute vec4 color;
    varying vec4 v_color;
    varying vec2 v_texcoord;
    void main() {
      gl_Position = position;
      v_color = color;
      v_texcoord = texcoord;
    }
    `;
    const fs = `
    precision mediump float;
    varying vec4 v_color;
    varying vec2 v_texcoord;
    uniform sampler2D u_diffuse;
    void main() {
      gl_FragColor = texture2D(u_diffuse, v_texcoord) * v_color;
    }
    `;
    const ext = gl.getExtension('ANGLE_instanced_arrays');
    if (!ext) {
      throw new Error('drawArraysInstancedProg "color", attribute \'color\'');
    }
    const prg = twgl.createProgram(gl, [vs, fs]);
    tagObject(prg, 'drawArraysInstancedPrg');
    const tex = gl.createTexture();
    tagObject(tex, 'drawArraysInstancedTex');
    gl.bindTexture(gl.TEXTURE_2D, tex);
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 1, 1, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
    function makeBuffer(gl, name, data, target = gl.ARRAY_BUFFER) {
      const buf = gl.createBuffer();
      tagObject(buf, name);
      gl.bindBuffer(target, buf);
      gl.bufferData(target, data, gl.STATIC_DRAW);
    }
    function makeBufferAndSetAttrib(gl, prg, name, size, data, divisor = 0) {
      makeBuffer(gl, name, data);
      const loc = gl.getAttribLocation(prg, name);
      gl.enableVertexAttribArray(loc);
      gl.vertexAttribPointer(loc, size, gl.FLOAT, false, 0, 0);
      ext.vertexAttribDivisorANGLE(loc, divisor);
    }
    const positions = new Float32Array([0, 0, 1, 0, 0, 1]);
    const texcoords = new Float32Array([0, 0, 1, 0, 0, 1]);
    const colors = new Float32Array([1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1]);  // 1 short
    makeBufferAndSetAttrib(gl, prg, 'position', 2, positions);
    makeBufferAndSetAttrib(gl, prg, 'texcoord', 2, texcoords);
    makeBufferAndSetAttrib(gl, prg, 'color', 4, colors, 1);
    gl.useProgram(prg);
    // an implementation is allowed to not generate an error
    // for out of bounds access if the guarantees that out of bounds
    // access is safe. In other words if the out of bound access is
    // either limited internally (eg. `ndx = clamp(ndx, 0, maxIndex)`)
    // or if the out of bounds access only accesses data provided by
    // the page itself. (eg. `ndx = ndx % bufferLength`)
    assertThrowsWith(() => {
      ext.drawArraysInstancedANGLE(gl.TRIANGLES, 0, 3, 4); // 1 too many instances
    }, [/drawArraysInstancedPrg/, /"color"/, /attribute 'color'/]);