Adding Features to Your Game - Learn HTML5 by Creating Fun Games - page 273

<script src="./glmatrix.js"></script>
…
function drawScene(gl, entityBuf, shader) {
// Step 1: Create the Model, View and
Projection matrices
var mvMat = mat4.create();
var pMat = mat4.create();
// Step 2: Initialize matrices
mat4.perspective(45, gl.viewportWidth /
gl.viewportHeight, 0.1,
100.0, pMat);
mat4.identity(mvMat);
mat4.translate(mvMat, [0.0, 0.5, -3.0]);
// Step 3: Set up the rendering viewport
gl.viewport(0, 0, gl.viewportWidth,
gl.viewportHeight);
gl.clear(gl.COLOR_BUFFER_BIT |
gl.DEPTH_BUFFER_BIT);
// Step 4: Send buffers to GPU
gl.bindBuffer(gl.ARRAY_BUFFER, entityBuf);
gl.vertexAttribPointer(shader.attribVertPos,
entityBuf.itemSize, gl.FLOAT, false, 0, 0);
gl.uniformMatrix4fv(shader.pMatrixUniform,
false, pMat);
gl.uniformMatrix4fv(shader.mvMatrixUniform,
false, mvMat);
// Step 5: Get this over with, and render the
triangle already!
gl.drawArrays(gl.TRIANGLES, 0,
entityBuf.numItems);
}