0
我的問題是關於使一些頂點/三角形在bufferGeometry中不可見。我從another question複製這個shader:製作隱藏在bufferGeometry中的隨機頂點/ traingles
<script type="x-shader/x-vertex" id="vertexshader">
attribute float visible;
varying float vVisible;
attribute vec3 color;
varying vec3 vColor;
void main() {
gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
vColor = color;
vVisible = visible;
}
</script>
<script type="x-shader/x-fragment" id="fragmentshader">
varying float vVisible;
varying vec3 vColor;
void main() {
if (vVisible > 0.0) {
gl_FragColor = vec4(vColor, 1.0);
}else
discard;
}
</script>
,然後這是我所定義的緩衝區幾何:
var geometry = new THREE.BufferGeometry();
var sides = 4;
var heightSegments = 1;
var height = 20;
var radius = 10;
var indices= [];
var vertices;
function vertexes(){
for (var j=0; j <=height; j = j + (height/heightSegments)) {
for (var i=0;i<=sides;i++) {
vertex.push([radius*Math.cos(2*Math.PI*i/sides),j,radius*Math.sin(2*Math.PI*i/sides)]);
}
}
for (var j = 0; j<sides; j++) {
for (var i = 0 ; i <sides*heightSegments; i+=sides) {
indices.push(i + j);
indices.push(i + j + 1);
indices.push(i + sides + j + 1);
indices.push(i + j + 1);
indices.push(i + sides + j + 1 + 1);
indices.push(i + sides + j + 1);
}
}
} // three components per vertex
function updatePositions() {
for (var k=0; k<(sides+1)*(heightSegments+1) ; k++)
{
vertices[ k*3 + 0 ] = vertex[k][0];
vertices[ k*3 + 1 ] = vertex[k][1];
vertices[ k*3 + 2 ] = vertex[k][2];
line_visible[k] = 1;
line_colors[ k*3 + 0 ] = color.r;
line_colors[ k*3 + 1 ] = color.g;
line_colors[ k*3 + 2 ] = color.b;
}
}
vertexes();
vertices = new Float32Array(vertex.length*3);
line_visible = new Float32Array(vertex.length);
var color = new THREE.Color(0xffff00);
var line_colors = new Float32Array(vertex.length*3);
updatePositions();
geometry.setIndex(indices);
geometry.addAttribute('position', new THREE.BufferAttribute(vertices, 3));
geometry.addAttribute('color', new THREE.BufferAttribute(line_colors, 3));
geometry.addAttribute('visible', new THREE.BufferAttribute(line_visible, 1));
var shader_material = new THREE.ShaderMaterial({
vertexShader: document.getElementById('vertexshader').textContent,
fragmentShader: document.getElementById('fragmentshader').textContent
});
var mesh = new THREE.Mesh(geometry, shader_material);
scene.add(mesh);
所以當我做的這行代碼隱藏一些頂點或三角形:
geometry.attributes.visible.array[0]=0;
我還添加這行代碼的代碼上面的行之後:
geometry.attributes.visible.needsUpdate = true;
沒有什麼改變!只是爲了補充一點,我隨機想讓它們隱藏起來,所以我不認爲setDrawRange
會起作用!
謝謝TheJim01。我剛剛編輯了這個問題,並補充說我之前已經包含了這一行代碼。三角形/頂點也不會變得不可見。我只是想知道是不是因爲渲染只能做到臉的一面。換句話說,我不知道如何在着色器中添加雙面材質。它是否必須做任何事情,這種隱形不起作用? – Hesamoy
我剛剛在JavaScript中做了雙面,但仍然沒有顯示爲隱藏。 – Hesamoy
它剛剛工作!我應該更多地玩。我打開線框,看到線條隱藏起來,而我正在使頂點不可見,這在線框選項關閉時不可見。所以我做了三個三角形的頂點不可見,並且相應的三角形變得不可見。謝謝TheJim01。 – Hesamoy