Loading the Game Scene - WebGL Game Development - page 91

Finally, we are left with our drawScene function. Since we are rendering a single
object, we only referenced the first object of the stageObjects array. We activated
its buffers using the vertexAttribPointer API call for vertices and normals. Then,
we initialized the material's color (diffuse, specular, and ambient) uniforms. Now,
instead of using the global JavaScript variables vertexBuffer and indexBuffer , we
use the stageObject array's buffer objects such as stageObject.ibo , stageObject.
vbo , and stageObject.nbo . The following is the code for the drawScene function:
function drawScene() {
gl.viewport(0, 0, gl.viewportWidth, gl.viewportHeight);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
mat4.perspective(pMatrix,degToRadian(55), gl.viewportWidth /
gl.viewportHeight, 0.1, 1000.0);
setLightUniform();
var i=0;
mat4.translate(mvMatrix,mvMatrix,
stage.stageObjects[i].location);
mat4.rotateX(mvMatrix,mvMatrix,stage.stageObjects[i].rotationX);
mat4.rotateY(mvMatrix,mvMatrix,stage.stageObjects[i].rotationY);
mat4.rotateZ(mvMatrix,mvMatrix,stage.stageObjects[i].rotationZ);
setMatrixUniforms();
gl.bindBuffer(gl.ARRAY_BUFFER, stage.stageObjects[i].vbo);
gl.vertexAttribPointer(shaderProgram.vertexPositionAttribute,
stage.stageObjects[i].vbo.itemSize, gl.FLOAT, false, 0, 0);
gl.bindBuffer(gl.ARRAY_BUFFER,stage.stageObjects[i].nbo);
gl.vertexAttribPointer(shaderProgram.vertexNormalAttribute,
stage.stageObjects[i].nbo.itemSize, gl.FLOAT, false, 0, 0);
gl.uniform3f(shaderProgram.materialDiffuseColor,
stage.stageObjects[i].diffuseColor[0],
stage.stageObjects[i].diffuseColor[1],
stage.stageObjects[i].diffuseColor[2]);
gl.uniform3f(shaderProgram.materialAmbientColor,
stage.stageObjects[i].ambientColor[0],
stage.stageObjects[i].ambientColor[1],
stage.stageObjects[i].ambientColor[2]);
gl.uniform3f(shaderProgram.materialSpecularColor,
stage.stageObjects[i].specularColor[0],
stage.stageObjects[i].specularColor[1],
stage.stageObjects[i].specularColor[2]);
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER,
stage.stageObjects[i].ibo);
gl.drawElements(gl.TRIANGLES,
stage.stageObjects[i].geometry.indices.length,
gl.UNSIGNED_SHORT,0);
}