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/// <reference path="mat4.js" />
/// <reference path="vec2.js" />
const BYTES_PER_FLOAT = 4;
/**
* Initializes a new circle object for the WebGL context.
*
* @param {WebGLRenderingContext} pGl
* @param {number} pRadius
* @param {number} pSegments
* @param {Array<Vector4>} pColorList
* @param {vec2} pInitialPosition
* @param {number} pMass
*/
function circle(pGl, pRadius, pSegments, pColorList, pInitialPosition, pMass) {
const lBuffer = pGl.createBuffer();
pGl.bindBuffer(pGl.ARRAY_BUFFER, lBuffer);
var lBufferedData = [];
vertexCount = 0;
const lAngleIncrements = (360.0 / pSegments) * (Math.PI / 180.0);
for (let lSegIdx = 0; lSegIdx < pSegments; lSegIdx++) {
const lAngle = lAngleIncrements * lSegIdx,
lNextAngle = lAngleIncrements * (lSegIdx + 1),
lColorIndex = Math.floor(pColorList.length * (lSegIdx / pSegments)),
lColor = pColorList[lColorIndex]; // TODO: Calculate which one to use
lBufferedData = lBufferedData.concat([
0, 0, lColor.x, lColor.y, lColor.z, lColor.w,
pRadius * Math.sin(lAngle), pRadius * Math.cos(lAngle), lColor.x, lColor.y, lColor.z, lColor.w,
pRadius * Math.sin(lNextAngle), pRadius * Math.cos(lNextAngle), lColor.x, lColor.y, lColor.z, lColor.w
]);
vertexCount += 3;
}
pGl.bufferData(pGl.ARRAY_BUFFER, new Float32Array(lBufferedData), pGl.STATIC_DRAW)
pGl.bindBuffer(pGl.ARRAY_BUFFER, undefined);
return {
buffer: lBuffer,
vertexCount: vertexCount,
prevPos: vec2(),
position: pInitialPosition || vec2(),
prevVelocity: vec2(),
velocity: vec2(),
force: vec2(),
torque: 0,
mass: pMass === undefined ? 1 : pMass,
rotationVelocity: 0,
rotationRadians: 0,
model: translateMatrix(mat4(), pInitialPosition ? pInitialPosition.x : 0, pInitialPosition ? pInitialPosition.y : 0, 0),
radius: pRadius
};
}
function renderCircle(pGl, pProgramInfo, pCircle) {
pGl.uniformMatrix4fv(pProgramInfo.uniformLocations.model, false, pCircle.model);
pGl.bindBuffer(pGl.ARRAY_BUFFER, pCircle.buffer);
{
pGl.enableVertexAttribArray(pProgramInfo.attributeLocations.position);
pGl.vertexAttribPointer(pProgramInfo.attributeLocations.position, 2, pGl.FLOAT, false, BYTES_PER_FLOAT * 6, 0);
pGl.enableVertexAttribArray(pProgramInfo.attributeLocations.color);
pGl.vertexAttribPointer(pProgramInfo.attributeLocations.color, 4, pGl.FLOAT, false, BYTES_PER_FLOAT * 6, BYTES_PER_FLOAT * 2);
}
pGl.drawArrays(pGl.TRIANGLE_STRIP, 0, pCircle.vertexCount);
}
function getMomentOfInertia(pCircle) {
return (Math.PI * Math.pow(pCircle.radius, 4)) / 4;
}
function doCirclesIntersect(pFirst, pSecond) {
const lDistanceBetween = Math.pow(pFirst.position.x - pSecond.position.x, 2)
+ Math.pow(pFirst.position.y - pSecond.position.y, 2)
return lDistanceBetween <= Math.pow(pFirst.radius + pSecond.radius, 2);
}
/**
* Returns intersection information about the intersecting circles.
*
* Warning! Only use this if doCirclesIntersect returned true for these circles.
*
* @param {circle} pFirst
* @param {circle} pSecond
*/
function getIntersectionDataForCircles(pFirst, pSecond) {
// The collision normal is simply the difference between the two current positions
const lCollisionNormal = normalize2(subVec2(pFirst.position, pSecond.position));
const lCollisionPoint = vec2(
((pFirst.position.x * pSecond.radius) + (pSecond.position.x * pFirst.radius)) / (pFirst.radius + pSecond.radius),
((pFirst.position.y * pSecond.radius) + (pSecond.position.y * pFirst.radius)) / (pFirst.radius + pSecond.radius)
);
return {
relativeVelocity: subVec2(pFirst.velocity, pSecond.velocity),
collisionNormal: lCollisionNormal,
//firstPointOfApplication: addVec2(scaleVec2(normalize2(pFirst.velocity), pFirst.radius), pFirst.position),
//secondPointOfApplication: addVec2(scaleVec2(normalize2(pSecond.velocity), pSecond.radius), pSecond.position)
firstPointOfApplication: subVec2(lCollisionPoint, pFirst.position),
secondPointOfApplication: subVec2(lCollisionPoint, pSecond.position)
}
}
function freeCircle(pGl, pCircle) {
pGl.deleteBuffer(pCircle.buffer);
}
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