Related
I can currently draw the triangle, set the background as Red, but I can't color the triangle. What obvious step am I missing here?
Current Progress - Red background and black triangle
const GLfloat vertices[] = {
vertex1_s, vertex1_t, 0,
vertex2_s, vertex2_t, 0,
vertex3_s, vertex3_t, 0
};
glClearColor(1,0,0,0);
glClear(GL_COLOR_BUFFER_BIT);
const GLfloat colors[] = {
0, 0, 1,
0, 0, 1,
0, 0, 1
};
glEnableClientState(GL_VERTEX_ARRAY);
glVertexPointer(3, GL_FLOAT, 0, vertices);
glEnableClientState(GL_COLOR_ARRAY);
glColorPointer(3, GL_FLOAT, 0, colors);
glDrawArrays(GL_TRIANGLES, 0, 3);
eglSwapBuffers(dpy, surface);
I have a simple object that draws a 3d gizmo at 0, 0, 0. If the camera is centered on 0, 0, 0, then it draws the gizmo at the center of the screen.
I would like to "lift" this gizmo and render it at the bottom right of the screen in screen coordinates, without rotating it. Basically, I want the gizmo to show the rotation of the center of the screen without blocking the view and without having to focus on a specific point. So I want to do away with the model matrix, or something.
I got the following to work by translating the projection matrix:
this.gl.uniformMatrix4fv(this.modelMatrixUniform, false, modelMatrix);
this.gl.uniformMatrix4fv(this.viewMatrixUniform, false, viewMatrix);
const bottomRightMat = mat4.create();
mat4.translate(bottomRightMat, projectionMatrix, [5, -3, 0]);
this.gl.uniformMatrix4fv(this.projectionMatrixUniform, false, bottomRightMat);
this.gl.drawElements(this.gl.LINES, this.indexBuffer.getLength(), this.gl.UNSIGNED_SHORT, 0);
But the gizmo has been rotated into its new position. The red line should still point down and to the left, since that's the direction of the positive X axis at the center of the screen. Also, the numbers 5 and 3 are arbitrary, and I don't think they would work at different zooms or camera locations.
Is there a way to specify a matrix transform that takes the center of the screen and translates it in screen space?
One way would be to change the viewport when rendering that object.
// size of area in bottom right
const miniWidth = 150;
const miniHeight = 100;
gl.viewport(gl.canvas.width - miniWidth, gl.canvas.height - miniHeight, miniWidth, miniHeight);
// now draw. you'll need to zoom in, like set the camera closer
// or move the object closer or add a scale matrix after the projection
// matrix as in projection * scale * view * ...
you'll need a projection matrix that matches the aspect ratio of the new viewport and you'll either need to scale the object, put the camera closer, or add a 2D scale between the projection and view matrices.
Remember to put the viewport back to the full canvas to render the rest of the scene.
const vs = `
attribute vec4 position;
uniform mat4 u_worldViewProjection;
void main() {
gl_Position = u_worldViewProjection * position;
}
`;
const fs = `
precision mediump float;
void main() {
gl_FragColor = vec4(vec3(0), 1);
}
`
const gl = document.querySelector("canvas").getContext("webgl");
const programInfo = twgl.createProgramInfo(gl, [vs, fs]);
const bufferInfo = twgl.createBufferInfoFromArrays(gl, {
position: [
-1, -1, -1,
1, -1, -1,
1, 1, -1,
-1, 1, -1,
-1, -1, 1,
1, -1, 1,
1, 1, 1,
-1, 1, 1,
],
indices: {
numComponents: 2,
data: [
0, 1,
1, 2,
2, 3,
3, 0,
4, 5,
5, 6,
6, 7,
7, 4,
0, 4,
1, 5,
2, 6,
3, 7,
],
},
});
function render(time) {
time *= 0.001;
twgl.resizeCanvasToDisplaySize(gl.canvas);
gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
const fov = 90 * Math.PI / 180;
const zNear = 0.5;
const zFar = 100;
const projection = mat4.perspective(mat4.create(),
fov, gl.canvas.clientWidth / gl.canvas.clientHeight, zNear, zFar);
const eye = [0, 0, 10];
const target = [0, 0, 0];
const up = [0, 1, 0];
const view = mat4.lookAt(mat4.create(), eye, target, up);
drawCube([-8, 0, 0], projection, view);
drawCube([-4, 0, 0], projection, view);
drawCube([ 0, 0, 0], projection, view);
drawCube([ 4, 0, 0], projection, view);
drawCube([ 8, 0, 0], projection, view);
const iconAreaWidth = 100;
const iconAreaHeight = 75;
gl.viewport(
gl.canvas.width - iconAreaWidth, 0,
iconAreaWidth, iconAreaHeight);
const iconProjection = mat4.perspective(mat4.create(),
fov, iconAreaWidth / iconAreaHeight, zNear, zFar);
// compute the zoom size need to make things the sngs
const scale = gl.canvas.clientHeight / iconAreaHeight;
mat4.scale(iconProjection, iconProjection, [scale, scale, 1]);
drawCube([ 0, 0, 0], iconProjection, view);
function drawCube(translation, projection, view) {
const viewProjection = mat4.multiply(mat4.create(), projection, view);
const world = mat4.multiply(
mat4.create(),
mat4.fromTranslation(mat4.create(), translation),
mat4.fromRotation(mat4.create(), time, [0.42, 0.56, 0.70]));
const worldViewProjection = mat4.multiply(mat4.create(), viewProjection, world);
gl.useProgram(programInfo.program);
twgl.setBuffersAndAttributes(gl, programInfo, bufferInfo);
twgl.setUniforms(programInfo, {
u_worldViewProjection: worldViewProjection,
});
twgl.drawBufferInfo(gl, bufferInfo, gl.LINES);
}
requestAnimationFrame(render);
}
requestAnimationFrame(render);
body { margin: 0; }
canvas { width: 100vw; height: 100vh; display: block; background: #CDE; }
<canvas></canvas>
<script src="https://twgljs.org/dist/4.x/twgl-full.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/gl-matrix/2.8.1/gl-matrix.js"></script>
Another is to compute an off center frustum projection matrix. Instead of mat4.perspective use mat4.frustum
function perspectiveWithCenter(
fieldOfView, width, height, near, far, centerX = 0, centerY = 0) {
const aspect = width / height;
// compute the top and bottom of the near plane of the view frustum
const top = Math.tan(fieldOfView * 0.5) * near;
const bottom = -top;
// compute the left and right of the near plane of the view frustum
const left = aspect * bottom;
const right = aspect * top;
// compute width and height of the near plane of the view frustum
const nearWidth = right - left;
const nearHeight = top - bottom;
// convert the offset from canvas units to near plane units
const offX = centerX * nearWidth / width;
const offY = centerY * nearHeight / height;
const m = mat4.create();
mat4.frustum(
m,
left + offX,
right + offX,
bottom + offY,
top + offY,
near,
far);
return m;
}
So to draw your gizmo set call something like
const gizmoCenterX = -gl.canvas.clientWidth / 2 + 50;
const gizmoCenterY = gl.canvas.clientHeight / 2 - 50;
const offsetProjection = perspectiveWithCenter(
fov, gl.canvas.clientWidth, gl.canvas.clientHeight, zNear, zFar,
gizmoCenterX, gizmoCenterY);
const vs = `
attribute vec4 position;
uniform mat4 u_worldViewProjection;
void main() {
gl_Position = u_worldViewProjection * position;
}
`;
const fs = `
precision mediump float;
void main() {
gl_FragColor = vec4(vec3(0), 1);
}
`
const gl = document.querySelector("canvas").getContext("webgl");
const programInfo = twgl.createProgramInfo(gl, [vs, fs]);
const bufferInfo = twgl.createBufferInfoFromArrays(gl, {
position: [
-1, -1, -1,
1, -1, -1,
1, 1, -1,
-1, 1, -1,
-1, -1, 1,
1, -1, 1,
1, 1, 1,
-1, 1, 1,
],
indices: {
numComponents: 2,
data: [
0, 1,
1, 2,
2, 3,
3, 0,
4, 5,
5, 6,
6, 7,
7, 4,
0, 4,
1, 5,
2, 6,
3, 7,
],
},
});
function perspectiveWithCenter(
fieldOfView, width, height, near, far, centerX = 0, centerY = 0) {
const aspect = width / height;
// compute the top and bottom of the near plane of the view frustum
const top = Math.tan(fieldOfView * 0.5) * near;
const bottom = -top;
// compute the left and right of the near plane of the view frustum
const left = aspect * bottom;
const right = aspect * top;
// compute width and height of the near plane of the view frustum
const nearWidth = right - left;
const nearHeight = top - bottom;
// convert the offset from canvas units to near plane units
const offX = centerX * nearWidth / width;
const offY = centerY * nearHeight / height;
const m = mat4.create();
mat4.frustum(
m,
left + offX,
right + offX,
bottom + offY,
top + offY,
near,
far);
return m;
}
function render(time) {
time *= 0.001;
twgl.resizeCanvasToDisplaySize(gl.canvas);
gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
const fov = 90 * Math.PI / 180;
const zNear = 0.5;
const zFar = 100;
const projection = perspectiveWithCenter(
fov, gl.canvas.clientWidth, gl.canvas.clientHeight, zNear, zFar);
const eye = [0, 0, 10];
const target = [0, 0, 0];
const up = [0, 1, 0];
const view = mat4.lookAt(mat4.create(), eye, target, up);
drawCube([-8, 0, 0], projection, view);
drawCube([-4, 0, 0], projection, view);
drawCube([ 0, 0, 0], projection, view);
drawCube([ 4, 0, 0], projection, view);
drawCube([ 8, 0, 0], projection, view);
const gizmoCenterX = -gl.canvas.clientWidth / 2 + 50;
const gizmoCenterY = gl.canvas.clientHeight / 2 - 50;
const offsetProjection = perspectiveWithCenter(
fov, gl.canvas.clientWidth, gl.canvas.clientHeight, zNear, zFar,
gizmoCenterX, gizmoCenterY);
drawCube([ 0, 0, 0], offsetProjection, view);
function drawCube(translation, projection, view) {
const viewProjection = mat4.multiply(mat4.create(), projection, view);
const world = mat4.multiply(
mat4.create(),
mat4.fromTranslation(mat4.create(), translation),
mat4.fromRotation(mat4.create(), time, [0.42, 0.56, 0.70]));
const worldViewProjection = mat4.multiply(mat4.create(), viewProjection, world);
gl.useProgram(programInfo.program);
twgl.setBuffersAndAttributes(gl, programInfo, bufferInfo);
twgl.setUniforms(programInfo, {
u_worldViewProjection: worldViewProjection,
});
twgl.drawBufferInfo(gl, bufferInfo, gl.LINES);
}
requestAnimationFrame(render);
}
requestAnimationFrame(render);
body { margin: 0; }
canvas { width: 100vw; height: 100vh; display: block; background: #CDE; }
<canvas></canvas>
<script src="https://twgljs.org/dist/4.x/twgl-full.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/gl-matrix/2.8.1/gl-matrix.js"></script>
I have a scene with a cube and a custom obj. I am attempting to apply a gradient as a texture to the cube via createGraphics, but every time I use createGraphics as a texture on the cube it flickers
The custom model does not have the same issue when using the createGraphics texture for it, it is exclusively a problem with the cube.
Here is my code:
var camy;
var camz;
var camoffset;
var horiZon;
var c1;
var c2;
function preload() {
fria = loadImage('nocity.png');
island = loadModel('untitled.obj');
}
function setup() {
canvas = createCanvas(windowWidth, windowHeight, WEBGL);
pixelDensity=1;
c1 = color(255, 255, 255);
c2 = color(0, 0, 0);
sunset = createGraphics(200, 200);
}
function windowResized() {
resizeCanvas(windowWidth,windowHeight);
}
function draw() {
background(0, 5, 100);
angleMode(DEGREES);
camoffset = 2500 - windowWidth;
horiZon = map(mouseY, 0, height, -35, -65);
camx = map(mouseX, 0, width, -500, 500);
camz = map(mouseY, height, 0, -1400 - camoffset, -2100 - camoffset);
camy = map(mouseY, height, 0, -1000 - camoffset, -400);
setGradient(0, 0, 200, 200, c1, c2);
perspective(PI / 3.0, width / height, 0.1, 10000);
camera(camx, camy, camz, 0, 0, 0, 0, 1, -0.25);
translate(-2.5, 6, 0);
rotateZ(180);
rotateY(180);
noStroke();
texture(fria);
model(island);
texture(sunset);
translate(0, 100, horiZon);
box(200, 200, 1);
}
function setGradient(x, y, w, h, c1, c2) {
noFill();
for (var i = y; i <= y + h; i++) {
var inter = map(i, y, y + h, 0, 1);
var c = lerpColor(c1, c2, inter);
sunset.stroke(c);
sunset.line(x, i, x + w, i);
}
}
I found a solution to this problem. When I removed the camera code, the flickering disappeared. So the solution I made was I instead used translation and rotation to emulate the camera motions that I wanted. It is quite hard to think of it this way, but you can figure out what translation you need to do with simple trig.
I am working on an animation of a simplified solar system and want to apply rotation to the Sun. It seems to be a simple task, but somehow it won't work. I try to write my program using object-oriented paradigm, so each planet, moon and the Sun is an object of the CelestialBody class.
I tried to put the rotate(angle) line in an following excerpt from the CelestialBody class, as follows:
if(Type == 4){
emissive(255, 255, 255);
pointLight(255, 255, 255, 0, 0, 0); //for the normal behaviour of the sun light
lightFalloff(0, 0, 0.00020); //light falls off right behind the surface of the sun
ambientLight(255, 255, 255, 0, 0, 0); //ambientLight in the center of the sun
rotate(angle);
}
Sadly, it does nothing. How to fix this and make the sun rotate, for example along the x-axis?
Here's my code:
Main file:
import peasy.*; //<>//
PImage bg;
float angle = 0;
CelestialBody planet1;
CelestialBody planet2;
CelestialBody planet3;
CelestialBody planet4;
CelestialBody planet5;
CelestialBody sun;
PImage sunTexture;
PImage rocketTexture;
PShape rocket;
PeasyCam cam;
void setup() {
fullScreen(P3D);
bg = loadImage("background.jpg");
sunTexture = loadImage("sun.jpg");
cam = new PeasyCam(this, 1200);
rocket = loadShape("rocket.obj");
noStroke();
sun = new CelestialBody(70, 0, 0, 255, 200, 50, 4);//4 - type: sun
sun.planet.setTexture(sunTexture);
//noStroke();
//emissive(0, 0, 0);
planet1 = new CelestialBody(16, 150, 0.01, 150, 50, 255, 1);
planet1.spawnMoon(2);
planet2 = new CelestialBody(25, 300, 0.014, 50, 100, 255, 1);
planet2.spawnMoon(3);
planet3 = new CelestialBody(35, 450, -0.015, 255, 100, 40, 2);
planet3.spawnMoon(1);
planet4 = new CelestialBody(50, 650, 0.011, 50, 200, 255, 1);
planet4.spawnMoon(2);
planet5 = new CelestialBody(65, 900, -0.014, 0, 100, 0, 1);
planet5.planet = rocket;
planet5.planet.scale(0.9);
}
void makeOrbit(int a, int r){
for(int i=0; i<a; i++){
stroke(255, 10);
ellipse(height/2,width/2,r,r);
r-=180;
}
noStroke();
}
void draw() {
background(bg);
//lights();
noFill();
//translate(width/2, height/2);
stroke(#FFFFFF);
//ellipse(0,0,300,300);
//ellipse(0,0,600,600);
//ellipse(0,0,900,900);
//ellipse(0,0,planet4.distance,planet4.distance
// int z = 100;
//for (int i = 0; i<2; i++){
// z = -z;
// pointLight(255, 255, 255, -100, -100, z);
// pointLight(255, 255, 255, 100, -100, z);
// pointLight(255, 255, 255, 100, 100, z);
// pointLight(255, 255, 255, -100, 100, z);
//}
//emissive(255, 255, 255);
//pointLight(255, 255, 255, 0, 0, 0); //for the normal behaviour of the sun light
//lightFalloff(0, 0, 0.00025); //light falls off right behind the surface of the sun
//ambientLight(255, 255, 255, 0, 0, 0); //ambientLight in the center of the sun
sun.show();
planet1.show();
planet1.orbit();
planet2.show();
planet2.orbit();
planet3.show();
planet3.orbit();
planet4.show();
planet4.orbit();
planet5.show();
planet5.orbit();
}
CelestialBody class:
class CelestialBody {
float radius;
float angle = random(TWO_PI);
float distance;
float orbitSpeed;
PShape planet;
CelestialBody[] moons;
int red;
int green;
int blue;
PVector v;
//PShape globe;
int Type;
CelestialBody(float _radius, float _distance, float _orbitSpeed, int _red, int _green, int _blue, int type) {
v = PVector.random3D();
radius = _radius;
distance = _distance;
v.mult(distance);
orbitSpeed = _orbitSpeed;
red = _red;
green = _green;
blue = _blue;
//stroke(red, green, blue);
fill(red, green, blue);
if(type == 1 || type == 4){
planet = createShape(SPHERE, _radius);
}
else if(type == 2){
planet = createShape(BOX, _radius);
}
Type = type;
}
void orbit() {
angle += orbitSpeed;
if (moons != null) {
for (int i = 0; i < moons.length; i++) {
moons[i].orbit();
}
}
}
void spawnMoon(int total){
moons = new CelestialBody[total];
for(int i = 0; i < moons.length; i++){
float r = radius / random(2,5);
float d = random((radius + r), (radius + r)*2);
float o = random(0.01, 0.05);
moons[i] = new CelestialBody(r, d, o, (int)random(0, 256), (int)random(0, 256), (int)random(0, 256), 1);
}
}
void show() {
pushMatrix();
PVector v2 = new PVector(1,0,1);
PVector p = v.cross(v2);
rotate(angle,p.x, p.y, p.z);
translate(v.x, v.y, v.z);
if(Type == 4){
emissive(255, 255, 255);
pointLight(255, 255, 255, 0, 0, 0); //for the normal behaviour of the sun light
lightFalloff(0, 0, 0.00020); //light falls off right behind the surface of the sun
ambientLight(255, 255, 255, 0, 0, 0); //ambientLight in the center of the sun
}
//shape(globe);
shape(planet);
if (moons != null) {
for (int i = 0; i < moons.length; i++) {
moons[i].show();
}
}
noStroke();
popMatrix();
}
}
Code: https://plnkr.co/edit/QNA31hMYnIJwotwbaDhT?p=preview
Question: How can I interpolate all properties of fromRotationTranslationScaleOrigin from gl-matrixin draw function of this cube?
Let's interpolate over 3 seconds:
from:
q = quat.create(),
translate =[-3, 0, -10],
scale = [1,1,1],
pivot = [0,0,0]
to:
q = quat.create(),
translate =[0, 0, -8],
scale = [3,3,3],
pivot = [1,1,1]
Program:
var gl,
shaderProgram,
vertices,
matrix = mat4.create(),
vertexCount,
indexCount,
q = quat.create(),
translate =[-3, 0, -10],
scale = [1,1,1],
pivot = [0,0,0];
initGL();
createShaders();
createVertices();
createIndices();
draw();
function initGL() {
var canvas = document.getElementById("canvas");
gl = canvas.getContext("webgl");
gl.enable(gl.DEPTH_TEST);
gl.viewport(0, 0, canvas.width, canvas.height);
gl.clearColor(1, 1, 1, 1);
}
function createShaders() {
var vertexShader = getShader(gl, "shader-vs");
var fragmentShader = getShader(gl, "shader-fs");
shaderProgram = gl.createProgram();
gl.attachShader(shaderProgram, vertexShader);
gl.attachShader(shaderProgram, fragmentShader);
gl.linkProgram(shaderProgram);
gl.useProgram(shaderProgram);
}
function createVertices() {
vertices = [
-1, -1, -1, 1, 0, 0, 1, // 0
1, -1, -1, 1, 1, 0, 1, // 1
-1, 1, -1, 0, 1, 1, 1, // 2
1, 1, -1, 0, 0, 1, 1, // 3
-1, 1, 1, 1, 0.5, 0, 1, // 4
1, 1, 1, 0.5, 1, 1, 1, // 5
-1, -1, 1, 1, 0, 0.5, 1, // 6
1, -1, 1, 0.5, 0, 1, 1, // 7
];
vertexCount = vertices.length / 7;
var buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);
var coords = gl.getAttribLocation(shaderProgram, "coords");
gl.vertexAttribPointer(coords, 3, gl.FLOAT, false, Float32Array.BYTES_PER_ELEMENT * 7, 0);
gl.enableVertexAttribArray(coords);
var colorsLocation = gl.getAttribLocation(shaderProgram, "colors");
gl.vertexAttribPointer(colorsLocation, 4, gl.FLOAT, false, Float32Array.BYTES_PER_ELEMENT * 7, Float32Array.BYTES_PER_ELEMENT * 3);
gl.enableVertexAttribArray(colorsLocation);
gl.bindBuffer(gl.ARRAY_BUFFER, null);
var pointSize = gl.getAttribLocation(shaderProgram, "pointSize");
gl.vertexAttrib1f(pointSize, 20);
// var color = gl.getUniformLocation(shaderProgram, "color");
// gl.uniform4f(color, 0, 0, 0, 1);
var perspectiveMatrix = mat4.create();
mat4.perspective(perspectiveMatrix, 1, canvas.width / canvas.height, 0.1, 11);
var perspectiveLoc = gl.getUniformLocation(shaderProgram, "perspectiveMatrix");
gl.uniformMatrix4fv(perspectiveLoc, false, perspectiveMatrix);
}
function createIndices() {
var indices = [
0, 1, 2, 1, 2, 3,
2, 3, 4, 3, 4, 5,
4, 5, 6, 5, 6, 7,
6, 7, 0, 7, 0, 1,
0, 2, 6, 2, 6, 4,
1, 3, 7, 3, 7, 5
];
indexCount = indices.length;
var indexBuffer = gl.createBuffer();
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexBuffer);
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint8Array(indices), gl.STATIC_DRAW);
}
function draw() {
mat4.fromRotationTranslationScaleOrigin(
matrix,
q,
translate,
scale,
pivot
);
var transformMatrix = gl.getUniformLocation(shaderProgram, "transformMatrix");
gl.uniformMatrix4fv(transformMatrix, false, matrix);
gl.clear(gl.COLOR_BUFFER_BIT);
gl.drawElements(gl.TRIANGLES, indexCount, gl.UNSIGNED_BYTE, 0);
requestAnimationFrame(draw);
}
/*
* https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/Tutorial/Adding_2D_content_to_a_WebGL_context
*/
function getShader(gl, id) {
var shaderScript, theSource, currentChild, shader;
shaderScript = document.getElementById(id);
if (!shaderScript) {
return null;
}
theSource = "";
currentChild = shaderScript.firstChild;
while (currentChild) {
if (currentChild.nodeType == currentChild.TEXT_NODE) {
theSource += currentChild.textContent;
}
currentChild = currentChild.nextSibling;
}
if (shaderScript.type == "x-shader/x-fragment") {
shader = gl.createShader(gl.FRAGMENT_SHADER);
} else if (shaderScript.type == "x-shader/x-vertex") {
shader = gl.createShader(gl.VERTEX_SHADER);
} else {
// Unknown shader type
return null;
}
gl.shaderSource(shader, theSource);
// Compile the shader program
gl.compileShader(shader);
// See if it compiled successfully
if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
alert("An error occurred compiling the shaders: " + gl.getShaderInfoLog(shader));
return null;
}
return shader;
}
<canvas id="canvas" width="600" height="600"></canvas>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/gl-matrix/2.3.2/gl-matrix-min.js"></script>
<script id="shader-vs" type="x-shader/x-vertex">
attribute vec4 coords;
attribute float pointSize;
uniform mat4 transformMatrix;
attribute vec4 colors;
varying vec4 varyingColors;
uniform mat4 perspectiveMatrix;
void main(void) {
gl_Position = perspectiveMatrix * transformMatrix * coords;
gl_PointSize = pointSize;
varyingColors = colors;
}
</script>
<script id="shader-fs" type="x-shader/x-fragment">
precision mediump float;
uniform vec4 color;
varying vec4 varyingColors;
void main(void) {
gl_FragColor = varyingColors;
}
</script>
To the call back function of requestAnimationFrame is passe one single argument, which is a time value.
This time can be used to calculate a matrix by a function of time.
function draw(timeMs) {
requestAnimationFrame(draw);
let interval = timeMs / 3000; // 3000 ms are 3 seconds
let t = interval - Math.floor(interval);
// [...]
}
Use vec3.lerp to interpolate the translation, pivot and scale, dependent on the time interval t:
function draw(timeMs) {
// [...]
let trans_t = vec3.lerp([], translate, translate2, t);
let scale_t = vec3.lerp([], scale, scale2, t);
let pivot_t = vec3.lerp([], pivot, pivot2, t);
mat4.fromRotationTranslationScaleOrigin(matrix, q, trans_t, scale_t, pivot_t);
// [...]
}
See the example, where I applied the suggestions to the code of the question:
var gl,
shaderProgram,
vertices,
matrix = mat4.create(),
vertexCount,
indexCount,
q = quat.create(),
translate =[-3, 0, -10],
scale = [1,1,1],
pivot = [0,0,0];
translate2 = [0, 0, -8],
scale2 = [3,3,3],
pivot2 = [1,1,1]
initGL();
createShaders();
createVertices();
createIndices();
draw();
function initGL() {
var canvas = document.getElementById("canvas");
gl = canvas.getContext("webgl");
gl.enable(gl.DEPTH_TEST);
gl.viewport(0, 0, canvas.width, canvas.height);
gl.clearColor(1, 1, 1, 1);
}
function createShaders() {
var vertexShader = getShader(gl, "shader-vs");
var fragmentShader = getShader(gl, "shader-fs");
shaderProgram = gl.createProgram();
gl.attachShader(shaderProgram, vertexShader);
gl.attachShader(shaderProgram, fragmentShader);
gl.linkProgram(shaderProgram);
gl.useProgram(shaderProgram);
}
function createVertices() {
vertices = [
-1, -1, -1, 1, 0, 0, 1, // 0
1, -1, -1, 1, 1, 0, 1, // 1
-1, 1, -1, 0, 1, 1, 1, // 2
1, 1, -1, 0, 0, 1, 1, // 3
-1, 1, 1, 1, 0.5, 0, 1, // 4
1, 1, 1, 0.5, 1, 1, 1, // 5
-1, -1, 1, 1, 0, 0.5, 1, // 6
1, -1, 1, 0.5, 0, 1, 1, // 7
];
vertexCount = vertices.length / 7;
var buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);
var coords = gl.getAttribLocation(shaderProgram, "coords");
gl.vertexAttribPointer(coords, 3, gl.FLOAT, false, Float32Array.BYTES_PER_ELEMENT * 7, 0);
gl.enableVertexAttribArray(coords);
var colorsLocation = gl.getAttribLocation(shaderProgram, "colors");
gl.vertexAttribPointer(colorsLocation, 4, gl.FLOAT, false, Float32Array.BYTES_PER_ELEMENT * 7, Float32Array.BYTES_PER_ELEMENT * 3);
gl.enableVertexAttribArray(colorsLocation);
gl.bindBuffer(gl.ARRAY_BUFFER, null);
var pointSize = gl.getAttribLocation(shaderProgram, "pointSize");
gl.vertexAttrib1f(pointSize, 20);
// var color = gl.getUniformLocation(shaderProgram, "color");
// gl.uniform4f(color, 0, 0, 0, 1);
var perspectiveMatrix = mat4.create();
mat4.perspective(perspectiveMatrix, 1, canvas.width / canvas.height, 0.1, 11);
var perspectiveLoc = gl.getUniformLocation(shaderProgram, "perspectiveMatrix");
gl.uniformMatrix4fv(perspectiveLoc, false, perspectiveMatrix);
}
function createIndices() {
var indices = [
0, 1, 2, 1, 2, 3,
2, 3, 4, 3, 4, 5,
4, 5, 6, 5, 6, 7,
6, 7, 0, 7, 0, 1,
0, 2, 6, 2, 6, 4,
1, 3, 7, 3, 7, 5
];
indexCount = indices.length;
var indexBuffer = gl.createBuffer();
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexBuffer);
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint8Array(indices), gl.STATIC_DRAW);
}
function draw(timeMs) {
requestAnimationFrame(draw);
let interval = timeMs / 3000
let t = interval - Math.floor(interval);
let trans_t = vec3.lerp([], translate, translate2, t);
let scale_t = vec3.lerp([], scale, scale2, t);
let pivot_t = vec3.lerp([], pivot, pivot2, t);
mat4.fromRotationTranslationScaleOrigin(matrix, q, trans_t, scale_t, pivot_t);
var transformMatrix = gl.getUniformLocation(shaderProgram, "transformMatrix");
gl.uniformMatrix4fv(transformMatrix, false, matrix);
gl.clear(gl.COLOR_BUFFER_BIT);
gl.drawElements(gl.TRIANGLES, indexCount, gl.UNSIGNED_BYTE, 0);
}
/*
* https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/Tutorial/Adding_2D_content_to_a_WebGL_context
*/
function getShader(gl, id) {
var shaderScript, theSource, currentChild, shader;
shaderScript = document.getElementById(id);
if (!shaderScript) {
return null;
}
theSource = "";
currentChild = shaderScript.firstChild;
while (currentChild) {
if (currentChild.nodeType == currentChild.TEXT_NODE) {
theSource += currentChild.textContent;
}
currentChild = currentChild.nextSibling;
}
if (shaderScript.type == "x-shader/x-fragment") {
shader = gl.createShader(gl.FRAGMENT_SHADER);
} else if (shaderScript.type == "x-shader/x-vertex") {
shader = gl.createShader(gl.VERTEX_SHADER);
} else {
// Unknown shader type
return null;
}
gl.shaderSource(shader, theSource);
// Compile the shader program
gl.compileShader(shader);
// See if it compiled successfully
if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
alert("An error occurred compiling the shaders: " + gl.getShaderInfoLog(shader));
return null;
}
return shader;
}
<script id="shader-vs" type="x-shader/x-vertex">
attribute vec4 coords;
attribute float pointSize;
uniform mat4 transformMatrix;
attribute vec4 colors;
varying vec4 varyingColors;
uniform mat4 perspectiveMatrix;
void main(void) {
gl_Position = perspectiveMatrix * transformMatrix * coords;
gl_PointSize = pointSize;
varyingColors = colors;
}
</script>
<script id="shader-fs" type="x-shader/x-fragment">
precision mediump float;
uniform vec4 color;
varying vec4 varyingColors;
void main(void) {
gl_FragColor = varyingColors;
}
</script>
<canvas id="canvas" width="600" height="600"></canvas>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/gl-matrix/2.3.2/gl-matrix-min.js"></script>