Question

以前有一个颜色顶点用于渲染这个小方块，现在我想使用一个图像。我正在使用一个图像精灵，我躺在64x128宽。

我没有收到任何错误，但也没有出现任何错误。首先是着色器：

<script id="shader-fs" type="x-shader/x-fragment">
  precision mediump float;

  varying vec2 vTextureCoord;

  uniform sampler2D uSampler;

  void main(void) {
    gl_FragColor = texture2D(uSampler, vec2(vTextureCoord.s, vTextureCoord.t));
  }
</script>

<script id="shader-vs" type="x-shader/x-vertex">
  attribute vec3 aVertexPosition;
  attribute vec2 aTextureCoord;

  uniform mat4 uMVMatrix;
  uniform mat4 uPMatrix;

  varying vec2 vTextureCoord;

  void main(void) {
    gl_Position = uPMatrix * uMVMatrix * vec4(aVertexPosition, 1.0);
    vTextureCoord = aTextureCoord;
  }
</script>

对于缓冲区：

initBuffers: function () {
  this.planePositionBuffer = gl.createBuffer();
  gl.bindBuffer(gl.ARRAY_BUFFER, this.planePositionBuffer);

  var vertices = [
    1.0, 1.0, 0.0,
    -1.0, 1.0, 0.0,
    1.0, -1.0, 0.0,
    -1.0, -1.0, 0.0
  ];

  gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);
  this.planePositionBuffer.itemSize = 3;
  this.planePositionBuffer.numItems = 4;

  this.textureBuffer = gl.createBuffer();
  gl.bindBuffer(gl.ARRAY_BUFFER, this.textureBuffer);
  var textureCoords = [
    0.0, 1.0,
    0.0, 0.0,
    1.0, 1.0,
    1.0, 0.0
  ];

  gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(textureCoords), gl.STATIC_DRAW);
  this.textureBuffer.itemSize = 2;
  this.textureBuffer.numItems = 4;
}

初始化着色器：

initShaders: function () {
  this.shader = new Shader("shader");
  var shaderProgram = this.shader.shaderProgram;
  shaderProgram.vertexPositionAttribute = gl.getAttribLocation(shaderProgram, "aVertexPosition");
  gl.enableVertexAttribArray(shaderProgram.vertexPositionAttribute);

  shaderProgram.textureCoordAttribute = gl.getAttribLocation(shaderProgram, "aTextureCoord");
  gl.enableVertexAttribArray(shaderProgram.textureCoordAttribute);

  shaderProgram.pMatrixUniform = gl.getUniformLocation(shaderProgram, "uPMatrix");
  shaderProgram.mvMatrixUniform = gl.getUniformLocation(shaderProgram, "uMVMatrix");
  shaderProgram.samplerUniform = gl.getUniformLocation(shaderProgram, "uSampler");
}

抽奖电话。

draw: function () {
  this.resize();
  var delta = this.getDeltaTime();

  gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
  gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

  mat4.identity(this.mvMatrix);
  mat4.identity(this.pMatrix);

  mat4.perspective(this.pMatrix, 45 * Math.PI / 180, gl.canvas.clientWidth / gl.canvas.clientHeight, 0.1, 100.0);
  mat4.translate(this.pMatrix, this.pMatrix, [0.0, 0.0, -50.0]);

  var shaderProgram = this.shader.shaderProgram;

  for (var i = 0; i < this.objects.length; i++) {
    this.objects[i].update(delta, this.mvMatrix);
  }

  gl.bindBuffer(gl.ARRAY_BUFFER, this.planePositionBuffer);
  gl.vertexAttribPointer(shaderProgram.vertexPositionAttribute, this.planePositionBuffer.itemSize, gl.FLOAT, false, 0, 0);

  gl.bindBuffer(gl.ARRAY_BUFFER, this.textureBuffer);
  gl.vertexAttribPointer(shaderProgram.textureCoordAttribute, this.textureBuffer.itemSize, gl.FLOAT, false, 0, 0);

  gl.activeTexture(gl.TEXTURE0);
  gl.bindTexture(gl.TEXTURE_2D, me.loader.getImage('test'));
  gl.uniform1i(shaderProgram.samplerUniform, 0);

  this.setMatrixUniforms();
  gl.drawArrays(gl.TRIANGLE_STRIP, 0, this.planePositionBuffer.numItems);
  requestAnimationFrame(this.draw.bind(this));
},

我根据在android上绘制的opengles上找到的文章来设置纹理坐标。想法是坐标应该按左下方顺序 - ＆gt;左上角 - ＆gt;右下角 - ＆gt;右上角。

除了上面的代码段之外，还可以在此处找到其已损坏状态的完整源代码：https://github.com/agmcleod/webgl-2dexperiment/tree/13f31f70037fdd4515c1336423337a1e82ab4e89

Answer 1

看起来好像WebGL代码都是正确的。但是，我从来没有调用函数bindAllTextures来实际设置webgl的纹理以进行渲染。

WebGL渲染2d精灵的纹理。没有出现

1 个答案: