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-rw-r--r--frontend/2d/_collisions/rectangle_rectangle/main.cpp447
1 files changed, 0 insertions, 447 deletions
diff --git a/frontend/2d/_collisions/rectangle_rectangle/main.cpp b/frontend/2d/_collisions/rectangle_rectangle/main.cpp
deleted file mode 100644
index 99dafe5..0000000
--- a/frontend/2d/_collisions/rectangle_rectangle/main.cpp
+++ /dev/null
@@ -1,447 +0,0 @@
-#include "../../../shared_cpp/OrthographicRenderer.h"
-#include "../../../shared_cpp/types.h"
-#include "../../../shared_cpp/WebglContext.h"
-#include "../../../shared_cpp/mathlib.h"
-#include "../../../shared_cpp/MainLoop.h"
-#include <cstdio>
-#include <cmath>
-#include <emscripten/html5.h>
-#include <unistd.h>
-#include <pthread.h>
-#include <cmath>
-#include <cfloat>
-
-struct Rigidbody {
- Vector2 force = { 0, 0 };
- Vector2 velocity = { 0, 0 };
- Vector2 position = { 0, 0 };
- float32 rotationalVelocity = 0.f;
- float32 rotation = 0.f;
- float32 mass = 1.f;
- float32 cofOfRestition = 1.f;
- float32 momentOfInertia = 0.f;
-
- void reset() {
- force = { 0, 0 };
- velocity = { 0, 0 };
- rotationalVelocity = 0.f;
- rotation = 0.f;
- }
-
- void applyForce(Vector2 f) {
- force += f;
- }
-
- void applyGravity(float32 deltaTimeSeconds) {
- velocity += (Vector2 { 0.f, -50.f } * deltaTimeSeconds);
- }
-
- void update(float32 deltaTimeSeconds) {
- applyGravity(deltaTimeSeconds);
-
- Vector2 acceleration = force / mass;
- velocity += (acceleration * deltaTimeSeconds);
- position += (velocity * deltaTimeSeconds);
- force = Vector2 { 0.f, 0.f };
-
- rotation += (rotationalVelocity * deltaTimeSeconds);
- }
-
- void setMomentOfInertia(float32 moi) {
- momentOfInertia = moi;
- }
-};
-
-struct IntersectionResult {
- bool intersect = false;
- Vector2 collisionNormal;
- Vector2 relativeVelocity;
- Vector2 firstPointOfApplication;
- Vector2 secondPointOfApplication;
-};
-
-struct Edge {
- Vector2 normal;
- Vector2 start;
- Vector2 end;
-};
-
-struct Rectangle {
- OrthographicShape shape;
- Rigidbody body;
- Rigidbody previousBody;
- Vector4 color;
- float32 width = 0.f;
- float32 height = 0.f;
-
- void load(OrthographicRenderer* renderer, Vector4 inColor, float32 inWidth, float32 inHeight) {
- color = inColor.toNormalizedColor();
- width = inWidth;;
- height = inHeight;
-
- float32 halfWidth = width / 2.f;
- float32 halfHeight = height / 2.f;
-
- OrthographicVertex vertices[6];
- vertices[0].position = Vector2 { -halfWidth, -halfHeight };
- vertices[1].position = Vector2 { -halfWidth, halfHeight };
- vertices[2].position = Vector2 { halfWidth, halfHeight };
- vertices[3].position = Vector2 { -halfWidth, -halfHeight };
- vertices[4].position = Vector2 { halfWidth, -halfHeight };
- vertices[5].position = Vector2 { halfWidth, halfHeight };
-
- for (int32 i = 0; i < 6; i++) {
- vertices[i].color = color;
- }
-
- shape.load(vertices, 6, renderer);
- body.reset();
- body.momentOfInertia = (1.f / 12.f) * body.mass * (width + height * height * height);
- }
-
- void update(float32 dtSeconds) {
- previousBody = body;
-
- body.update(dtSeconds);
- shape.model = Mat4x4().translateByVec2(body.position).rotate2D(body.rotation);
- }
-
- void render(OrthographicRenderer* renderer) {
- shape.render(renderer);
- }
-
- void unload() {
- shape.unload();
- }
-
- void restorePreviousBody() {
- body = previousBody;
- }
-
- Vector2 getPoint(int index) {
- switch (index) {
- case 0: return shape.model * Vector2 { -width / 2.f, -height / 2.f };
- case 1: return shape.model * Vector2 { -width / 2.f, height / 2.f };
- case 2: return shape.model * Vector2 { width / 2.f, height / 2.f };
- case 3: return shape.model * Vector2 { width / 2.f, -height / 2.f };
- default: {
- printf("Unable to find point: index=%d", index);
- return Vector2();
- }
- }
- }
-
- // Note that these getters are needlessly verbose for demonstration's sake
- void getPoints(Vector2* pointList) {
- Vector2 botLeft = shape.model * Vector2 { -width / 2.f, -height / 2.f };
- Vector2 topLeft = shape.model * Vector2 { -width / 2.f, height / 2.f };
- Vector2 topRight = shape.model * Vector2 { width / 2.f, height / 2.f };
- Vector2 botRight = shape.model * Vector2 { width / 2.f, -height / 2.f };
-
- pointList[0] = botLeft;
- pointList[1] = topLeft;
- pointList[2] = topRight;
- pointList[3] = botRight;
- }
-
- void getEdges(Edge* edgeList) {
- Vector2 pointsList[4];
- getPoints(pointsList);
-
- for (int i = 0; i < 4; i++) {
- edgeList[i].start = pointsList[i];
- if (i + 1 == 4) {
- edgeList[i].end = pointsList[0];
- } else {
- edgeList[i].end = pointsList[i + 1];
- }
-
- edgeList[i].normal = (edgeList[i].end - edgeList[i].start).getPerp().normalize();
- }
- }
-};
-
-EM_BOOL onPlayClicked(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData);
-EM_BOOL onStopClicked(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData);
-
-void load();
-void update(float32 time, void* userData);
-void unload();
-
-WebglContext context;
-OrthographicRenderer renderer;
-MainLoop mainLoop;
-Rectangle rectangleList[4];
-
-int main() {
- context.init("#gl_canvas");
- emscripten_set_click_callback("#gl_canvas_play", NULL, false, onPlayClicked);
- emscripten_set_click_callback("#gl_canvas_stop", NULL, false, onStopClicked);
- return 0;
-}
-
-void load() {
- renderer.load(&context);
-
- rectangleList[0].load(&renderer, Vector4 { 235.f, 35.f, 35.f, 255.f }, 24.f, 32.f);
- rectangleList[0].body.position = Vector2 { context.width / 3.f, context.height / 3.f };
- rectangleList[0].body.velocity = Vector2 { 100.f, 250.f };
- rectangleList[0].body.rotation = 0.2f;
-
- rectangleList[1].load(&renderer, Vector4 { 35.f, 235.f, 35.f, 255.f }, 64.f, 96.f);
- rectangleList[1].body.position = Vector2 { context.width / 3.f, context.height * (2.f / 3.f) };
- rectangleList[1].body.rotation = 1.3f;
-
- rectangleList[2].load(&renderer, Vector4 { 235.f, 35.f, 235.f, 255.f }, 64.f, 32.f);
- rectangleList[2].body.position = Vector2 { context.width * (2.f / 3.f), context.height / 3.f };
- rectangleList[2].body.velocity = Vector2 { -100.f, 250.f };
- rectangleList[2].body.rotation = -0.5f;
-
- rectangleList[3].load(&renderer, Vector4 { 35.f, 235.f, 235.f, 255.f }, 8.f, 16.f);
- rectangleList[3].body.position = Vector2 { context.width * (2.f / 3.f), context.height * (2.f / 3.f) };
- rectangleList[3].body.rotation = -3.23f;
-
- mainLoop.run(update);
-}
-
-Vector2 getProjection(Vector2* vertices, Vector2 axis) {
- float32 min = axis.dot(vertices[0]);
- float32 max = min;
-
- for (int v = 1; v < 4; v++) {
- float32 d = axis.dot(vertices[v]);
-
- if (d < min) {
- min = d;
- } else if (d > max) {
- max = d;
- }
- }
-
- return Vector2 { min, max };
-}
-
-bool projectionsOverlap(Vector2 first, Vector2 second) {
- return first.x <= second.y && second.x <= first.y;
-}
-
-float32 getProjectionOverlap(Vector2 first, Vector2 second) {
- float32 firstOverlap = fabs(first.x - second.y);
- float32 secondOverlap = fabs(second.x - first.y);
- return firstOverlap > secondOverlap ? secondOverlap : firstOverlap;
-}
-
-const float32 EPSILON = 1.f;
-IntersectionResult getIntersection(Rectangle* first, Rectangle* second) {
- IntersectionResult ir;
-
- // For two rectangles to overlap, it means that at least one of the corners of one is inside of the other
- Edge firstEdges[4];
- first->getEdges(firstEdges);
- Vector2 firstPoints[4];
- first->getPoints(firstPoints);
-
- Edge secondEdges[4];
- second->getEdges(secondEdges);
- Vector2 secondPoints[4];
- second->getPoints(secondPoints);
-
- float32 minOverlap = FLT_MAX;
- Vector2 minOverlapAxis;
- Edge* minOverlapEdge = NULL;
- bool minOverlapWasFirstRect = false;
-
- for (int i = 0; i < 4; i++) {
- Vector2 normal = firstEdges[i].normal;
-
- Vector2 firstProj = getProjection(firstPoints, normal);
- Vector2 secondProj = getProjection(secondPoints, normal);
-
- if (!projectionsOverlap(firstProj, secondProj)) {
- return ir;
- }
-
- float32 overlap = getProjectionOverlap(firstProj, secondProj);
- if (overlap < minOverlap) {
- minOverlap = overlap;
- minOverlapAxis = normal;
- minOverlapEdge = &firstEdges[i];
- minOverlapWasFirstRect = true;
- }
- }
-
- for (int i = 0; i < 4; i++) {
- Vector2 normal = secondEdges[i].normal;
-
- Vector2 firstProj = getProjection(firstPoints, normal);
- Vector2 secondProj = getProjection(secondPoints, normal);
-
- if (!projectionsOverlap(firstProj, secondProj)) {
- return ir;
- }
-
- float32 overlap = getProjectionOverlap(firstProj, secondProj);
- if (overlap < minOverlap) {
- minOverlap = overlap;
- minOverlapAxis = normal;
- minOverlapEdge = &secondEdges[i];
- }
- }
-
- ir.intersect = true;
- ir.relativeVelocity = first->body.velocity - second->body.velocity;
- ir.collisionNormal = minOverlapAxis;
-
- // Find the point of collision, this is kind of tricky, and it is just an approximation for now.
- // At this point, we know that we intersected along the minOverlapAxis, but we do not know where
- // that exactly happened. To remedy this will, we create two parallel lines: one at the top of the
- // normal area, and one at the bottom. For point on both of the Rectangles, we will check:
- // (1) if it is between these two planes
- // (2) if, for that rectangle, it is the closest point to the original normal vector
- // (3) or if it is equally distant from normal vector as another point (then this is a "flat" collision)
- //
- // The collision point MUST be between these two planes. We can then say the corner/face of the non-monoverlapAxis
- // Rectangle is the collision point. This enables us to then solve for their respective points of application fairly
- // easily. If the collision "point" is an entire face, we make the collision point be the center point.
- //
-
- Vector2 closestPoint;
- float32 minDistance = FLT_MAX;
-
- for (int p = 0; p < 4; p++) {
- Vector2 point = minOverlapWasFirstRect ? secondPoints[p] : firstPoints[p];
-
- float32 distFromPointToStart = (minOverlapEdge->start - point).length();
- float32 distFromPointToEnd = (minOverlapEdge->end - point).length();
- float32 potentialMin = MIN(distFromPointToStart, distFromPointToEnd);
-
- if (potentialMin < minDistance) {
- closestPoint = point;
- minDistance = potentialMin;
- }
- }
-
- ir.firstPointOfApplication = closestPoint - first->body.position;
- ir.secondPointOfApplication = closestPoint - second->body.position;;
-
- return ir;
-}
-
-void resolveCollision(Rigidbody* first, Rigidbody* second, IntersectionResult* ir) {
- Vector2 relativeVelocity = ir->relativeVelocity;
- Vector2 collisionNormal = ir->collisionNormal;
- Vector2 firstPerp = ir->firstPointOfApplication.getPerp();
- Vector2 secondPerp = ir->secondPointOfApplication.getPerp();
- float32 firstPerpNorm = firstPerp.dot(collisionNormal);
- float32 sndPerpNorm = secondPerp.dot(collisionNormal);
-
- float32 cofOfRestition = (first->cofOfRestition + second->cofOfRestition) / 2.f;
- float32 numerator = (relativeVelocity * (-1 * (1.f + cofOfRestition))).dot(collisionNormal);
- float32 linearDenomPart = collisionNormal.dot(collisionNormal * (1.f / first->mass + 1.f / second->mass));
- float32 rotationalDenomPart = (firstPerpNorm * firstPerpNorm) / first->momentOfInertia + (sndPerpNorm * sndPerpNorm) / second->momentOfInertia;
-
- float32 impulseMagnitude = numerator / (linearDenomPart + rotationalDenomPart);
- first->velocity = first->velocity + (collisionNormal * (impulseMagnitude / first->mass));
- second->velocity = second->velocity - (collisionNormal * (impulseMagnitude / second->mass));
-
- first->rotationalVelocity = first->rotationalVelocity + firstPerp.dot(collisionNormal * impulseMagnitude) / first->momentOfInertia;
- second->rotationalVelocity = second->rotationalVelocity - secondPerp.dot(collisionNormal * impulseMagnitude) / second->momentOfInertia;
-}
-
-void update(float32 deltaTimeSeconds, void* userData) {
- // Update
- for (int r = 0; r < 4; r++) {
- rectangleList[r].update(deltaTimeSeconds);
- }
-
- // Check collisions with other rectangles
- for (int i = 0; i < 4; i++) {
- Rectangle* first = &rectangleList[i];
- for (int j = i + 1; j < 4; j++) {
- Rectangle* second = &rectangleList[j];
-
- IntersectionResult ir = getIntersection(first, second);
- if (!ir.intersect) {
- continue;
- }
-
- // Handle collison here
- IntersectionResult irCopy = ir;
- float32 copyDt = deltaTimeSeconds;
-
- do {
- first->restorePreviousBody();
- second->restorePreviousBody();
-
- ir = irCopy;
- copyDt = copyDt /= 2.f;
-
- first->update(copyDt);
- second->update(copyDt);
-
- irCopy = getIntersection(first, second);
-
- if (copyDt <= 0.f) {
- printf("Error: Should not be happening.\n");
- break;
- }
-
- } while (irCopy.intersect);
-
- printf("Found intersection at timestamp: %f\n", copyDt);
-
- resolveCollision(&first->body, &second->body, &ir);
- float32 frameTimeRemaining = deltaTimeSeconds - copyDt;
-
- first->update(frameTimeRemaining);
- second->update(frameTimeRemaining);
- }
- }
-
- // Check collisions with walls
- for (int r = 0; r < 4; r++) {
- Rectangle* rect = &rectangleList[r];
- if (rect->body.position.x <= 0.f) {
- rect->body.velocity = rect->body.velocity - Vector2 { 1.f, 0.f } * (2 * (rect->body.velocity.dot(Vector2 { 1.f, 0.f })));
- }
- if (rect->body.position.y <= 0.f) {
- rect->body.velocity = rect->body.velocity - Vector2 { 0.f, 1.f } * (2 * (rect->body.velocity.dot(Vector2 { 0.f, 1.f })));
- }
- if (rect->body.position.x >= 640.f) {
- rect->body.velocity = rect->body.velocity - Vector2 { -1.f, 0.f } * (2 * (rect->body.velocity.dot(Vector2{ -1.f, 0.f })));
- }
- if (rect->body.position.y >= 480.f) {
- rect->body.velocity = rect->body.velocity - Vector2 { 0.f, -1.f } * (2 * (rect->body.velocity.dot(Vector2 { 0.f, -1.f }))) ;
- }
- }
-
- // Renderer
- renderer.render();
- for (int r = 0; r < 4; r++) {
- rectangleList[r].render(&renderer);
- }
-}
-
-void unload() {
- mainLoop.stop();
- renderer.unload();
- for (int r = 0; r < 4; r++) {
- rectangleList[r].unload();
- }
-}
-
-//
-// Interactions with DOM handled below
-//
-EM_BOOL onPlayClicked(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData) {
- printf("Play clicked\n");
-
- load();
- return true;
-}
-
-EM_BOOL onStopClicked(int eventType, const EmscriptenMouseEvent* mouseEvent, void* userData) {
- printf("Stop clicked\n");
- unload();
- return true;
-}
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