我在这个寒假里度过,试图学习一些有关着色器的知识,但我坚持进行以下几次练习:
y = sin(x);
尝试以下练习并注意会发生什么:
我该如何实施?
您将需要2个统一变量,以秒为单位的视口分辨率(u_resolution
)和时间(u_time
):
uniform vec2 u_resolution;
uniform float u_time;
x
可以通过片段的x坐标获得。将x坐标映射到范围[0,2 * PI]:
vec2 st = gl_FragCoord.xy/u_resolution.xy;
float x = st.x * 2.0 * 3.141529;
计算y
。 sin
是sin
功能:
Sine
通过float y = sin(x + u_time);
设置片段的颜色通道。 y
必须从[-1,1]范围映射到[0,1]:
y
结果是正弦渐变,从右向左移动:
gl_FragColor = vec4(vec3(y*0.5+0.5), 1.0);
var container, camera, scene, renderer, uniforms;
init();
animate();
function init() {
container = document.getElementById( 'container' );
camera = new THREE.Camera();
camera.position.z = 1;
scene = new THREE.Scene();
var geometry = new THREE.PlaneBufferGeometry( 2, 2 );
uniforms = {
u_time: { type: "f", value: 1.0 },
u_resolution: { type: "v2", value: new THREE.Vector2() }
};
var material = new THREE.ShaderMaterial( {
uniforms: uniforms,
vertexShader: document.getElementById( 'vertexShader' ).textContent,
fragmentShader: document.getElementById( 'fragmentShader' ).textContent
} );
var mesh = new THREE.Mesh( geometry, material );
scene.add( mesh );
renderer = new THREE.WebGLRenderer();
renderer.setPixelRatio( window.devicePixelRatio );
container.appendChild( renderer.domElement );
onWindowResize();
window.addEventListener( 'resize', onWindowResize, false );
}
function onWindowResize( event ) {
renderer.setSize( window.innerWidth, window.innerHeight );
uniforms.u_resolution.value.x = renderer.domElement.width;
uniforms.u_resolution.value.y = renderer.domElement.height;
}
function animate(delta_ms) {
requestAnimationFrame( animate );
uniforms.u_time.value = delta_ms / 1000.0;
renderer.render( scene, camera );
}