skycraft: can walk around the earth

skycraft/chunk.ts

@@ -329,7 +329,7 @@ export function getBodyGeometry(seed: number) {
     };
 }
 
-function blockLookup(chunkMap, x, y, z) {
+export function blockLookup(chunkMap, x, y, z) {
     const chunki = Math.floor((x + CHUNKSIZE / 2) / CHUNKSIZE);
     const chunkj = Math.floor((y + CHUNKSIZE / 2) / CHUNKSIZE);
     const chunkk = Math.floor((z + CHUNKSIZE / 2) / CHUNKSIZE);

skycraft/draw.ts

@@ -122,8 +122,7 @@ export async function initWorldGl(gl: WebGLRenderingContext) {
 
     const drawObject = (objectParams) => {
         const {
-            position,
-            orientation,
+            tf,
             glBuffer,
             numVertices,
             lightDirection,
@@ -131,8 +130,7 @@ export async function initWorldGl(gl: WebGLRenderingContext) {
             specularColor,
         } = objectParams;
 
-        gl.uniformMatrix4fv(modelLoc, false, new Float32Array(se3.product(
-            se3.translation(...position), orientation)));
+        gl.uniformMatrix4fv(modelLoc, false, new Float32Array(tf));
         gl.uniform3fv(lightDirectionLoc, lightDirection);
         gl.uniform3fv(glowColorLoc, glowColor);
         gl.uniform3fv(specularColorLoc, specularColor);
@@ -219,14 +217,12 @@ export function getOrbitDrawContext(gl: WebGLRenderingContext) {
 
     const drawObject = (objectParams) => {
         const {
-            position,
-            orientation,
+            tf,
             value,
             glBuffer,
         } = objectParams;
 
-        gl.uniformMatrix4fv(modelLoc, false, new Float32Array(se3.product(
-            se3.translation(...position), orientation)));
+        gl.uniformMatrix4fv(modelLoc, false, new Float32Array(tf));
 
         gl.bindBuffer(gl.ARRAY_BUFFER, glBuffer);
 
@@ -244,6 +240,16 @@ export function getOrbitDrawContext(gl: WebGLRenderingContext) {
     };
 }
 
+function getShipTf(context) {
+    if (context.landed) {
+        const body = context.landedBody;
+        const bodyTf = se3.product(se3.translation(...body.position), body.orientation);
+        return se3.product(bodyTf, context.shipTf);
+    }
+
+    return context.player.tf;
+}
+
 function getObjects(context, body, parentPosition = undefined) {
     const objects = [];
     const {gl, glContext, player} = context;
@@ -255,8 +261,7 @@ function getObjects(context, body, parentPosition = undefined) {
 
     objects.push({
         geometry: body.glBuffer,
-        orientation,
-        position,
+        tf: se3.product(se3.translation(...position), orientation),
         glContext,
         glowColor,
         specularColor,
@@ -265,23 +270,10 @@ function getObjects(context, body, parentPosition = undefined) {
         const orbitObject = makeOrbitObject(gl, context.orbitGlContext, body.orbit, parentPosition);
         //objects.push(orbitObject);
     } else {
-        const tfs = [player.tf];
-        if (context.landed) {
-            const body = context.landedBody;
-            const bodyTf = se3.product(se3.translation(...body.position), body.orientation);
-            tfs.splice(0, 0, bodyTf);
-        }
-        const tf = tfs.reduce(se3.product);
-        const shipOrientation = [
-            se3.rotationOnly(tf),
-            //se3.rotationOnly(context.camera.tf),
-            se3.rotxyz(-Math.PI / 2, Math.PI / 2, Math.PI / 2),
-        ].reduce(se3.product);
-        const shipPos = se3.apply(tf, [0, 0, 0, 1]);
+        const shipTf = se3.product(getShipTf(context), se3.rotxyz(-Math.PI / 2, Math.PI / 2, Math.PI / 2));
         objects.push({
             geometry: makeBufferFromFaces(gl, context.spaceship),
-            orientation: shipOrientation,
-            position: shipPos,
+            tf: shipTf,
             glContext,
             specularColor: [0.8, 0.8, 0.8],
         });
@@ -320,10 +312,12 @@ export function draw(context) {
 
     gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
 
+    const thirdPerson = context.landed ? se3.identity() : se3.translation(0, 1, 4);
+
     const playerView = [
         player.tf,  // player position & orientation
         camera.tf,  // camera orientation relative to player
-        se3.translation(0, 1, 4),  // step back from the player
+        thirdPerson,
     ];
     if (context.landed) {
         const body = context.landedBody;
@@ -334,7 +328,7 @@ export function draw(context) {
     const viewMatrix = se3.inverse(playerView.reduce(se3.product));
     let lastGlContext;
 
-    for (const {position, orientation, geometry, glContext, glowColor, specularColor} of objects) {
+    for (const {tf, geometry, glContext, glowColor, specularColor} of objects) {
         if (glContext !== lastGlContext) {
             glContext.setupScene({
                 projectionMatrix: projMatrix,
@@ -344,11 +338,11 @@ export function draw(context) {
         }
 
         lastGlContext = glContext;
+        const position = se3.apply(tf, [0, 0, 0, 1]);
         const lightDirection = sunDirection(position);
 
         glContext.drawObject({
-            position,
-            orientation,
+            tf,
             glBuffer: geometry.glBuffer,
             numVertices: geometry.numVertices,
             lightDirection,

skycraft/index.ts

@@ -4,7 +4,7 @@ import * as linalg from './linalg';
 import { loadObjModel } from './obj';
 import * as se3 from 'wmc-common/se3';
 import { computeOrbit, findSoi, getCartesianState, updateBodyPhysics, isInSoi } from './orbit';
-import { getBodyGeometry, castRay, BlockType } from './chunk';
+import { getBodyGeometry, castRay, blockLookup, BlockType } from './chunk';
 import { draw, getOrbitDrawContext, initWorldGl } from './draw';
 import * as quat from './quat';
 
@@ -159,19 +159,34 @@ function initUiListeners(canvas: HTMLCanvasElement, context) {
                     case 'KeyL':
                         context.landing = !context.landing;
                         return false;
-                    case 'Space':
+                    case 'KeyP':
                         context.pause = !context.pause;
                         return false;
+                    case 'Space':
+                        if (!context.flying) {
+                            jump(context);
+                        }
+                        return false;
                 }
             } else {
                 context.keys.delete(e.code);
             }
         };
         const moveListener = e => {
-//            context.camera.orientation[0] -= e.movementY / 500;
-//            context.camera.orientation[1] -= e.movementX / 500;
-            context.camera.tf =[
-                context.camera.tf,
+            const cam = context.camera;
+            if (context.landed) {
+                cam.orientation[1] -= e.movementX / 500;
+                cam.orientation[0] -= e.movementY / 500;
+                cam.tf = [
+                    se3.roty(cam.orientation[1]),
+                    se3.rotx(cam.orientation[0]),
+                ].reduce(se3.product);
+
+                return;
+            }
+
+            cam.tf =[
+                cam.tf,
                 se3.roty(-e.movementX / 500),
                 se3.rotx(-e.movementY / 500),
             ].reduce(se3.product);
@@ -204,29 +219,84 @@ function initUiListeners(canvas: HTMLCanvasElement, context) {
     });
 }
 
+function jump(context) {
+    if (context.jumpAmount > 0) {
+        const amount = context.jumpForce;
+        context.jumpAmount -= 1;
+
+        const gravity = landedGravity(context);
+        const up = linalg.normalize(linalg.scale(gravity, -1));
+        context.player.velocity = linalg.scale(up, amount);
+    }
+}
+
+function moveShip(context, forward, right) {
+    if (context.keys.has('ShiftLeft')) {
+        forward *= 10;
+        right *= 10;
+    }
+    const tf = se3.product(
+        se3.orientationOnly(context.player.tf),
+        context.camera.tf,
+    );
+    const dir = [right, 0, -forward, 10];
+    if (context.flying) {
+        context.player.tf = [
+            context.player.tf,
+            se3.translation(...dir),
+        ].reduce(se3.product);
+    } else {
+        const vel = context.player.velocity;
+        const dv = linalg.scale(se3.apply(tf, dir), 1/dir[3]);
+        context.player.velocity = linalg.add(vel, dv);
+        delete context.orbit;
+    }
+}
+
+function moveOnGround(context, forward, right) {
+    if (context.keys.has('ShiftLeft')) {
+        forward *= 2;
+        right *= 2;
+    }
+    const tf = se3.product(
+        se3.orientationOnly(context.player.tf),
+        context.camera.tf,
+    );
+    const dir = se3.apply(tf, [right, 0, -forward, 0]);
+    if (context.flying) {
+        context.player.tf = [
+            se3.translation(...dir),
+            context.player.tf,
+        ].reduce(se3.product);
+        return;
+    }
+
+    const dv = linalg.scale(dir, 10);
+
+    const maxSpeed = 8;
+    const airMovement = 0.08;
+
+    if (context.isOnGround) {
+        const up = upDirection(context);
+        const vertical = linalg.dot(dv, up);
+        const horizontal = linalg.diff(dv, linalg.scale(up, vertical));
+        context.player.velocity = horizontal;
+        return;
+    }
+
+    // steering in the air
+    context.player.velocity = linalg.add(context.player.velocity, linalg.scale(dv, airMovement));
+
+    const curVel = linalg.norm(context.player.velocity);
+
+    if (curVel > maxSpeed) {
+        context.player.velocity = linalg.scale(context.player.velocity, maxSpeed / curVel);
+    }
+}
+
+
 function handleInput(context) {
-    const move = (forward: number, right: number) => {
-        if (context.keys.has('ShiftLeft')) {
-            forward *= 10;
-            right *= 10;
-        }
-        const tf = se3.product(
-            se3.orientationOnly(context.player.tf),
-            context.camera.tf,
-        );
-        const dir = [right, 0, -forward, 10];
-        if (context.flying) {
-            context.player.tf = [
-                context.player.tf,
-                se3.translation(...dir),
-            ].reduce(se3.product);
-        } else {
-            const vel = context.player.velocity;
-            const dv = linalg.scale(se3.apply(tf, dir), 1/dir[3]);
-            context.player.velocity = linalg.add(vel, dv);
-            delete context.orbit;
-        }
-    };
+    const move = (f, r) => (context.landed ? moveOnGround : moveShip)(context, f, r);
 
     const roll = (amount: number) => {
         if (context.keys.has('ShiftLeft')) {
@@ -302,7 +372,48 @@ function distanceToGround(body: Body, position: number[], direction: number[]) :
     return {distance, normal};
 }
 
-function autoLand(context) {
+function finishLanding(context, body) {
+    const p = context.player;
+    context.landed = true;
+    context.landedBody = body;
+
+    p.tf = [
+        se3.inverse(body.orientation),
+        se3.inverse(se3.translation(...body.position)),
+        p.tf,
+    ].reduce(se3.product);
+
+    context.shipTf = p.tf;
+    p.tf = se3.product(p.tf, se3.translation(1, 1, 0));
+    p.velocity = [0, 0, 0];
+    p.position = se3.apply(p.tf, [0, 0, 0, 1]);
+}
+
+function alignUp(playerTf, surfaceNormal) {
+    const zaxis = se3.apply(playerTf, [0, 0, 1, 0]);
+    const ny = surfaceNormal;
+    const nx = linalg.normalize(linalg.cross(ny, zaxis));
+    const nz = linalg.normalize(linalg.cross(nx, ny));
+
+    return se3.fromBases(nx, ny, nz);
+}
+
+function calculateLandingDv(verticalSpeed, altitude, dt) {
+    // pretty crude logic, could be improved
+    const maxThrust = 2;
+    const final = verticalSpeed**2 / (2*(altitude - 1.0));
+
+    if (verticalSpeed > 0 || final < maxThrust * 0.8) {
+        // can still accelerate forward
+        return -maxThrust * dt;
+    } else if (final < maxThrust) {
+        // coast
+        return 0;
+    }
+    return final;
+}
+
+function autoLand(context, dt) {
     const p = context.player;
     // 0. check prereqs:
     //   - none
@@ -317,44 +428,32 @@ function autoLand(context) {
     const toBodyCenter = linalg.diff(body.position, p.position);
     const {distance: altitude, normal: surfaceNormal} = distanceToGround(body, p.position, linalg.normalize(toBodyCenter));
 
-    // figure out tangential speed
-    const spinSpeed = linalg.add(body.velocity, linalg.cross(body.spin, linalg.scale(toBodyCenter, -1)));
-    const dv = linalg.diff(spinSpeed, p.velocity);
-    // remove vertical component
-    const vertical = linalg.scale(surfaceNormal, -linalg.dot(dv, surfaceNormal));
-    const smallDv = linalg.scale(linalg.add(dv, vertical), 0.01);
-//    const smallDv = linalg.scale(dv, 0.05);
+    const surfaceVelocity = linalg.add(body.velocity, linalg.cross(body.spin, linalg.scale(toBodyCenter, -1)));
+    const relativeVelocity = linalg.diff(p.velocity, surfaceVelocity);
+    const upward = linalg.dot(relativeVelocity, surfaceNormal);
+    const vertical = linalg.scale(surfaceNormal, upward);
+    const horizontal = linalg.diff(relativeVelocity, vertical);
+    const smallDv = linalg.scale(horizontal, -0.01);
     p.velocity = linalg.add(p.velocity, smallDv);
 
     // up is up
-    const shipZ = se3.apply(p.tf, [0, 0, 1, 0]);
-    const ny = surfaceNormal;
-    const nx = linalg.normalize(linalg.cross(ny, shipZ));
-    const nz = linalg.normalize(linalg.cross(nx, ny));
-
-    const targetOrientation = se3.fromBases(nx, ny, nz);
-    const currentOrientation = slerp(p.tf, targetOrientation, kShipRotateSpeed);
+    const currentOrientation = slerp(p.tf, alignUp(p.tf, surfaceNormal), kShipRotateSpeed);
     p.tf = se3.setOrientation(p.tf, currentOrientation);
 
     if (altitude < 1.5) {
-        const upward = linalg.dot(linalg.diff(p.velocity, body.velocity), surfaceNormal);
         if (upward < -2) {
+            // going too fast, bounce
             p.velocity = linalg.add(p.velocity, linalg.scale(surfaceNormal, -2*upward));
             context.landing = false;
         } else if (upward < 0) {
-            context.landed = true;
-            context.landedBody = body;
-
-            p.tf = [
-                se3.inverse(body.orientation),
-                se3.inverse(se3.translation(...body.position)),
-                p.tf,
-            ].reduce(se3.product);
-            p.velocity = [0, 0, 0];
-            p.position = se3.apply(p.tf, [0, 0, 0, 1]);
+            finishLanding(context, body);
+            return;
         }
     }
-//    p.velocity = linalg.add(p.velocity, linalg.scale(surfaceNormal, dvup));
+
+    // accelerate towards the ground and then slow down to land
+    const dvup = calculateLandingDv(upward, altitude, dt);
+    p.velocity = linalg.add(p.velocity, linalg.scale(surfaceNormal, dvup));
 }
 
 function effectiveGravity(position: number[], rootBody: Body) : number[] {
@@ -381,6 +480,110 @@ function effectiveGravity(position: number[], rootBody: Body) : number[] {
     return acceleration;
 }
 
+function upDirection(context) {
+    const gravity = landedGravity(context);
+    return linalg.normalize(linalg.scale(gravity, -1));
+}
+
+function landedGravity(context) {
+    // just clamp "down" to one of our six directions
+    const pos = context.player.position;
+    const altitude2 = pos[0]**2 + pos[1]**2 + pos[2]**2;
+    const g = context.landedBody.mass / altitude2;
+    if (pos[0] > 0 && Math.abs(pos[1]) < pos[0] && Math.abs(pos[2]) < pos[0]) {
+        return [-g, 0, 0];
+    }
+    if (pos[0] < 0 && Math.abs(pos[1]) < -pos[0] && Math.abs(pos[2]) < -pos[0]) {
+        return [+g, 0, 0];
+    }
+    if (pos[1] > 0 && Math.abs(pos[0]) < pos[1] && Math.abs(pos[2]) < pos[1]) {
+        return [0, -g, 0];
+    }
+    if (pos[1] < 0 && Math.abs(pos[0]) < -pos[1] && Math.abs(pos[2]) < -pos[1]) {
+        return [0, +g, 0];
+    }
+    if (pos[2] > 0 && Math.abs(pos[1]) < pos[2] && Math.abs(pos[1]) < pos[2]) {
+        return [0, 0, -g];
+    }
+    if (pos[2] < 0 && Math.abs(pos[1]) < -pos[2] && Math.abs(pos[1]) < -pos[2]) {
+        return [0, 0, +g];
+    }
+    // blarg
+}
+
+function checkCollision(curPos, newPos, chunkMap, orientation) {
+    const upDir = se3.apply(orientation, [0, 1, 0, 0]);
+    // I guess Gaspard is about 1.7 m tall?
+    // he also has a 60x60 cm axis-aligned square section '^_^
+    // box is centered around the camera
+    const gaspardBB = [
+        [-0.3, 0.2, -0.3],
+        [-0.3, 0.2, 0.3],
+        [0.3, 0.2, -0.3],
+        [0.3, 0.2, 0.3],
+
+        [-0.3, -1.5, -0.3],
+        [-0.3, -1.5, 0.3],
+        [0.3, -1.5, -0.3],
+        [0.3, -1.5, 0.3],
+    ].map(v => se3.apply(orientation, v.concat([0])));
+
+    let dp = linalg.diff(newPos, curPos);
+    let isOnGround = false;
+
+    for (let i = 0; i < 3; i++) {
+        const newGaspard = v => v.map((x, j) => i === j ? x + newPos[j] : x + curPos[j]);
+        for (const point of gaspardBB.map(newGaspard)) {
+            const block = blockLookup(chunkMap, ...point);
+            if (block.type !== BlockType.AIR) {
+                const dir = [...Array(3).keys()].map(j => j === i ? 1 : 0);
+                if (Math.abs(linalg.dot(dir, upDir)) > 0.5) {
+                    isOnGround = true;
+                }
+                dp[i] = 0;
+            }
+        }
+    }
+    for (let i = 0; i < 3; i++) {
+        const newGaspard = v => linalg.add(linalg.add(curPos, v), dp);
+        for (const point of gaspardBB.map(newGaspard)) {
+            const block = blockLookup(chunkMap, ...point);
+            if (block.type !== BlockType.AIR) {
+                dp[i] = 0;
+            }
+        }
+    }
+
+    return {
+        newPos: linalg.add(curPos, dp),
+        isOnGround,
+    };
+}
+
+function updateLandedPhysics(context, dt) {
+    const gravity = landedGravity(context);
+    context.player.velocity = linalg.add(context.player.velocity, linalg.scale(gravity, dt));
+
+    const oldPos = context.player.position;
+    const taregtPos = linalg.add(context.player.position, linalg.scale(context.player.velocity, dt));
+
+    // from wmc
+    const {isOnGround, newPos} = checkCollision(oldPos, taregtPos, context.landedBody.geometry.chunkMap, se3.orientationOnly(context.player.tf));
+    context.player.position = newPos;
+    context.player.velocity = newPos.map((p, i) => (p - oldPos[i]) / dt);
+    if (isOnGround) {
+        context.jumpAmount = 2;
+        context.player.velocity = context.player.velocity.map(v => v * 0.7);
+    }
+    context.isOnGround = isOnGround;
+    context.player.tf = se3.setPosition(context.player.tf, newPos);
+
+    // up is up
+    const p = context.player;
+    const currentOrientation = slerp(p.tf, alignUp(p.tf, upDirection(context)), 0.1);
+    p.tf = se3.setOrientation(p.tf, currentOrientation);
+}
+
 function updatePhysics(time: number, context) {
     const {player} = context;
     const dt = time - (context.lastTime || 0);
@@ -395,13 +598,13 @@ function updatePhysics(time: number, context) {
     const kShipRotateSpeed = 0.1;
 
     if (context.landed) {
-        return; // TODO: implement
+        return updateLandedPhysics(context, dt);
     }
 
     if (context.landing) {
-        autoLand(context);
+        autoLand(context, dt);
     } else {
-        // allow acdjusting camera
+        // allow adjusting camera
         const dr = slerp(se3.identity(), context.camera.tf, kShipRotateSpeed);
         player.tf = se3.product(player.tf, dr);
         context.camera.tf = se3.product(context.camera.tf, se3.inverse(dr));
@@ -479,7 +682,7 @@ async function main() {
     // TODO
     // [ ] loading bar
     // [x] spaceship
-    // [ ] landing
+    // [x] landing
     // [ ] huge planets
     // [x] lighting
     // [x] better lighting

skycraft/orbit.ts

@@ -277,8 +277,7 @@ export function makeOrbitObject(gl: WebGLRenderingContext, glContext: any, orbit
 
     return {
         geometry,
-        orientation,
-        position,
+        tf: se3.product(se3.translation(...position), orientation),
         glContext,
     };
 }