Skip to content

Commit

Permalink
Added BroadPhaseCastResult::Reset
Browse files Browse the repository at this point in the history 
And using it in the heighfield demo instead of overriding the fraction to 1000, this makes a really long ray cast and (when using this construct in a world with multiple objects) is inefficient as it does more work than needed.
  • Loading branch information
@jrouwe
jrouwe committed Feb 21, 2024
1 parent 9f39028 commit 26ac07e
Show file tree
Hide file tree
Showing 3 changed files with 24 additions and 26 deletions.
2 changes: 1 addition & 1 deletion CMakeLists.txt
View file
Original file line number Diff line number Diff line change
Expand Up @@ -34,7 +34,7 @@ include(FetchContent)
FetchContent_Declare(
JoltPhysics
GIT_REPOSITORY "https://github.com/jrouwe/JoltPhysics"
GIT_TAG "20b1492288f6f0a5b12567ed1ea1db315914bd72"
GIT_TAG "733af810249191c49c6e3d61ceba97918249ff5b"
SOURCE_SUBDIR "Build"
)
FetchContent_MakeAvailable(JoltPhysics)
Expand Down
47 changes: 22 additions & 25 deletions Examples/heightfield.html
View file
Original file line number Diff line number Diff line change
Expand Up @@ -116,12 +116,12 @@
const overlayMap = new THREE.CanvasTexture(visibleTextureCanvas);

// Creating the THREE JS plane with displacement
// Note: Jolt HeightField maps each pixel to a vertex, so actual terrain is a SIZE-1 grid
// Note: Jolt HeightField maps each pixel to a vertex, so actual terrain is a SIZE-1 grid
const planeMesh = new THREE.Mesh(
new THREE.PlaneGeometry(img.width * mapScale, img.width * mapScale, IMAGE_SIZE, IMAGE_SIZE),
new THREE.MeshPhongMaterial({
displacementMap: displacementMap,
map: overlayMap,
map: overlayMap,
displacementScale: 256 * 0.1, // This should match the Y multiplier used on the ShapeSettings inScale.
flatShading: true
})
Expand All @@ -144,19 +144,19 @@
position.Set(px, 20, py);
createSphere(position, 1, Jolt.EMotionType_Dynamic, LAYER_MOVING, 0xFF0000);
}


// Allocate an 8x8 floating point array in memory, and map it against Jolt's HEAP for raw access
const READ_SIZE = 8;
const float32MemPointer = Jolt._webidl_malloc(READ_SIZE * READ_SIZE * 4);
const float32MemoryBuffer = new Float32Array(Jolt.HEAPF32.buffer, float32MemPointer, READ_SIZE*READ_SIZE);
const float32MemoryBuffer = new Float32Array(Jolt.HEAPF32.buffer, float32MemPointer, READ_SIZE * READ_SIZE);

// Update the THREE JS heightmap based on the current Float32 buffer
function updateThreeHeightMap(offsetX, offsetY) {
const textureImageData = displacementContext2D.getImageData(offsetX, offsetY, READ_SIZE, READ_SIZE);
float32MemoryBuffer.forEach((_o, i) => {
for(let j=0;j<3;j++) {
textureImageData.data[i*4+j] = float32MemoryBuffer[i] * 10;
for (let j = 0; j < 3; j++) {
textureImageData.data[i * 4 + j] = float32MemoryBuffer[i] * 10;
}
});
displacementContext2D.putImageData(textureImageData, offsetX, offsetY);
Expand All @@ -166,18 +166,18 @@

const terrainHeightFieldShape = Jolt.castObject(terrain.GetShape(), Jolt.HeightFieldShape);
// Given a percentage X,Y, alter the HeightField by a fixed float amount
function changeTerrainShape( fractionX, fractionY, amount) {
function changeTerrainShape(fractionX, fractionY, amount) {
// offset left of click and make multiple of block size
const offsetX = Math.min(Math.max((Math.floor( fractionX * IMAGE_SIZE) - 3) & -BLOCK_SIZE, 0), img.width - READ_SIZE);
const offsetX = Math.min(Math.max((Math.floor(fractionX * IMAGE_SIZE) - 3) & -BLOCK_SIZE, 0), img.width - READ_SIZE);
// offset up from click and make multiple of block size.
const offsetY = Math.min(Math.max((Math.floor( fractionY * IMAGE_SIZE) - 3) & -BLOCK_SIZE, 0), img.height - READ_SIZE);
const offsetY = Math.min(Math.max((Math.floor(fractionY * IMAGE_SIZE) - 3) & -BLOCK_SIZE, 0), img.height - READ_SIZE);
// Note: the bounding logic above will cause artifacts clicking along the terrain edges

terrainHeightFieldShape.GetHeights(offsetX, offsetY, READ_SIZE, READ_SIZE, float32MemPointer, READ_SIZE)

// Apply a flat amount of modification to all pixels in the selected region
float32MemoryBuffer.forEach((_o, f32Index) => {
float32MemoryBuffer[f32Index] += amount;
float32MemoryBuffer[f32Index] += amount;
})

const centerOfMass = terrain.GetCenterOfMassPosition();
Expand All @@ -203,38 +203,35 @@
cursorIndicator.visible = false;

function mouseEventToTerrainCoords(mouseEvt) {
pointerV2_3js.x = ( mouseEvt.clientX / window.innerWidth ) * 2 - 1;
pointerV2_3js.y = - ( mouseEvt.clientY / window.innerHeight ) * 2 + 1;
pointerV2_3js.x = (mouseEvt.clientX / window.innerWidth) * 2 - 1;
pointerV2_3js.y = - (mouseEvt.clientY / window.innerHeight) * 2 + 1;
// This is the stock Three JS picker logic
rayCaster_3js.setFromCamera( pointerV2_3js, camera );
rayCaster_3js.setFromCamera(pointerV2_3js, camera);
const { origin, direction } = rayCaster_3js.ray;
// Jolt Ray casts use the 'direction' vector length to limit our search, so use something sure to hit our target for this demo
direction.multiplyScalar(1000)
jRay.mOrigin.Set(origin.x, origin.y, origin.z)
jRay.mDirection.Set(direction.x, direction.y, direction.z);

// Failure to pick using a Ray will keep this mFraction value as-is
// CastRay in C++ would return a boolean on-hit, but WebIDL does not allow 2 calls of same name to have different return values
jRayResult.mFraction = 1000;
// Reset the result so we can check if there was a hit by checking if the fraction <= 1
jRayResult.Reset();
transformedShape.CastRay(jRay, jRayResult);
// Instead we check that the response is reasonable
// Hits will have a value between 0 and 1. Failures will keep the 1000 above
if(jRayResult.mFraction <= 1) {
if (jRayResult.mFraction <= 1) {
// mFraction is between 0 and 1. By multiplying the direction ray scalar, we turn it into a true offset of the hit, relative to the origin.
const intersectThreeVector = origin.add(direction.multiplyScalar(jRayResult.mFraction));
cursorIndicator.position.copy(intersectThreeVector);
cursorIndicator.visible = true;
// Using the Plane's world-matrix we can convert to local-space coordinates
// Three JS uses in-place modifications, so clone the matrix and vector so we do not disrupt their data.
// Three JS uses in-place modifications, so clone the matrix and vector so we do not disrupt their data.
const localPosition = intersectThreeVector.clone().applyMatrix4(planeMesh.matrixWorld.clone().invert());
// X and Y correspond to image UV. The original Z corresponds to world-space elevation
localPosition.multiplyScalar(1.0/(img.width * mapScale));
localPosition.multiplyScalar(1.0 / (img.width * mapScale));
// Transformed results are -0.5 to 0.5 in both X and Y direction, mappable to our texture/HeightField
const { x, y } = localPosition;
// preserve the true world-space vector for re-activating nearby Bodies
// invert the Y value, because the texture space coordinates use a different origin
// https://threejs.org/docs/#api/en/textures/Texture.flipY
return { mapSpace: { x: x + 0.5, y: -y + 0.5}, worldSpace: intersectThreeVector };
return { mapSpace: { x: x + 0.5, y: -y + 0.5 }, worldSpace: intersectThreeVector };
}
// On a failed hit, return null
return null;
Expand All @@ -243,7 +240,7 @@
visibleCanvasContext2d.fillStyle = 'rgba(0,0,0,.4)';
controls.domElement.addEventListener('mousemove', (mouseEvt) => {
const coords = mouseEventToTerrainCoords(mouseEvt);
if(coords) {
if (coords) {
// remove any previous texture overlay
visibleCanvasContext2d.drawImage(img, 0, 0);
// Values between 0 and 1 in the height-field/texture space
Expand All @@ -268,7 +265,7 @@
const raiseLower = document.getElementById('raise-lower');
controls.domElement.addEventListener('click', (mouseEvt) => {
const coords = mouseEventToTerrainCoords(mouseEvt);
if(coords) {
if (coords) {
// Mobile devices will not have mouse-over, so draw the indicator here as well
visibleCanvasContext2d.drawImage(img, 0, 0);
// Values between 0 and 1 in the height-field/texture space
Expand All @@ -281,7 +278,7 @@
// Alter the terrain by this amount
changeTerrainShape(x, y, delta);

// select a region sure to encompass all changed spheres. This could be smaller with demo's values.
// select a region sure to encompass all changed spheres. This could be smaller with demo's values.
aaboxMin.Set(coords.worldSpace.x - 6, coords.worldSpace.y - 6, coords.worldSpace.z - 6);
aaboxMax.Set(coords.worldSpace.x + 6, coords.worldSpace.y + 6, coords.worldSpace.z + 6);
// AABox does not support easy modification, so we are re-generating one per click
Expand Down
1 change: 1 addition & 0 deletions JoltJS.idl
View file
Original file line number Diff line number Diff line change
Expand Up @@ -506,6 +506,7 @@ interface RRayCast {

interface BroadPhaseCastResult {
void BroadPhaseCastResult();
void Reset();

[Value] attribute BodyID mBodyID;
attribute float mFraction;
Expand Down

0 comments on commit 26ac07e

Please sign in to comment.