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* Added near and far plane clipping for THREE.Line rendering in CanvasRenderer.

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* Changed THREE.Vertex.positionScreen from a Vector3 to a Vector4 to support clipping.
This commit is contained in:
Julian Walker
2010-11-16 20:40:02 -08:00
parent 592ea71e48
commit 49f878c5a5
3 changed files with 96 additions and 24 deletions
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src/core/Vector4.js
+9 -1
View File
@@ -30,7 +30,7 @@ THREE.Vector4.prototype = {
this.x = v.x;
this.y = v.y;
this.z = v.z;
this.w = v.w;
this.w = v.w || 1.0;
return this;
@@ -101,6 +101,14 @@ THREE.Vector4.prototype = {
return this;
},
lerpSelf: function ( v, alpha ) {
this.x = this.x + (v.x - this.x) * alpha;
this.y = this.y + (v.y - this.y) * alpha;
this.z = this.z + (v.z - this.z) * alpha;
this.w = this.w + (v.w - this.w) * alpha;
}
clone: function () {
src/core/Vertex.js
+1 -1
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@@ -6,7 +6,7 @@ THREE.Vertex = function ( position, normal ) {
this.position = position || new THREE.Vector3();
this.positionWorld = new THREE.Vector3();
this.positionScreen = new THREE.Vector3();
this.positionScreen = new THREE.Vector4();
this.normal = normal || new THREE.Vector3();
this.normalWorld = new THREE.Vector3();
src/renderers/Projector.js
+86 -22
View File
@@ -14,15 +14,74 @@ THREE.Projector = function() {
_vector4 = new THREE.Vector4(),
_projScreenMatrix = new THREE.Matrix4(),
_projScreenObjectMatrix = new THREE.Matrix4();
function clipLineSegmentAgainstNearAndFarPlanes ( s0, s1 ) {
var visible,
alpha0 = 0, alpha1 = 1,
// Calculate the boundary coordinate of each vertex for the near and far clip planes,
// Z = -1 and Z = +1, respectively.
bc0near = s0.z + s0.w,
bc1near = s1.z + s1.w,
bc0far = -s0.z + s0.w,
bc1far = -s1.z + s1.w;
if (bc0near >= 0 && bc1near >= 0 && bc0far >= 0 && bc1far >= 0) {
// Both vertices lie entirely within all clip planes.
visible = true;
} else if ((bc0near < 0 && bc1near < 0) || (bc0far < 0 && bc1far < 0)) {
// Both vertices lie entirely outside one of the clip planes.
visible = false;
} else {
// The line segment spans at least one clip plane.
if (bc0near < 0) {
// vertex0 lies outside the near plane, vertex1 inside
alpha0 = Math.max(alpha0, bc0near / (bc0near - bc1near));
} else if (bc1near < 0) {
// vertex1 lies outside the near plane, vertex0 inside
alpha1 = Math.min(alpha1, bc0near / (bc0near - bc1near));
}
if (bc0far < 0) {
// vertex0 lies outside the far plane, vertex1 inside
alpha0 = Math.max(alpha0, bc0far / (bc0far - bc1far));
} else if (bc1far < 0) {
// vertex1 lies outside the far plane, vertex1 inside
alpha1 = Math.min(alpha1, bc0far / (bc0far - bc1far));
}
if (alpha1 < alpha0) {
// The line segment spans two boundaries, but is outside both of them.
// (This can't happen when we're only clipping against just near/far but good
// to leave the check here for future usage if other clip planes are added.)
visible = false;
} else {
// Update the s0 and s1 vertices to match the clipped line segment.
s0.lerpSelf(s1, alpha0);
s1.lerpSelf(s0, 1 - alpha1);
visible = true;
}
}
return visible;
}
this.projectScene = function ( scene, camera ) {
var o, ol, v, vl, f, fl, objects, object, objectMatrix,
vertices, vertex, vertexPositionScreen, vertex2,
vertices, vertex, vertex0, vertex1, vertexPositionScreen,
faces, face, v1, v2, v3, v4;
_renderList = [];
_face3Count = 0, _face4Count = 0, _lineCount = 0, _particleCount = 0;
_face3Count = 0;
_face4Count = 0;
_lineCount = 0;
_particleCount = 0;
if( camera.autoUpdateMatrix ) {
@@ -60,6 +119,11 @@ THREE.Projector = function() {
vertexPositionScreen = vertex.positionScreen;
vertexPositionScreen.copy( vertex.position );
_projScreenObjectMatrix.transform( vertexPositionScreen );
// Perform the perspective divide. TODO: This should be be performend
// post clipping (imagine if the vertex lies at the same location as
// the camera, causing a divide by w = 0).
vertexPositionScreen.multiplyScalar( 1.0 / vertexPositionScreen.w );
vertex.__visible = vertexPositionScreen.z > 0 && vertexPositionScreen.z < 1;
@@ -170,32 +234,33 @@ THREE.Projector = function() {
vertex = vertices[ v ];
vertexPositionScreen = vertex.positionScreen;
vertexPositionScreen.copy( vertex.position );
_projScreenObjectMatrix.transform( vertexPositionScreen );
vertex.positionScreen.copy( vertex.position );
_projScreenObjectMatrix.transform( vertex.positionScreen );
}
vertex.__visible = vertexPositionScreen.z > 0 && vertexPositionScreen.z < 1;
for ( v = 1, vl = vertices.length; v < vl; v++ ) {
if ( v > 0 ) {
vertex0 = vertices[ v ];
vertex1 = vertices[ v - 1 ];
if (clipLineSegmentAgainstNearAndFarPlanes(vertex0.positionScreen, vertex1.positionScreen)) {
// Perform the perspective divide
vertex0.positionScreen.multiplyScalar( 1.0 / vertex0.positionScreen.w );
vertex1.positionScreen.multiplyScalar( 1.0 / vertex1.positionScreen.w );
vertex2 = object.geometry.vertices[ v - 1 ];
_line = _linePool[ _lineCount ] = _linePool[ _lineCount ] || new THREE.RenderableLine();
_line.v1.copy( vertex0.positionScreen );
_line.v2.copy( vertex1.positionScreen );
if ( vertex.__visible && vertex2.__visible ) {
// TODO: Use centriums here too.
_line.z = Math.max( vertex0.positionScreen.z, vertex1.positionScreen.z );
_line = _linePool[ _lineCount ] = _linePool[ _lineCount ] || new THREE.RenderableLine();
_line.v1.copy( vertex.positionScreen );
_line.v2.copy( vertex2.positionScreen );
_line.material = object.material;
// TODO: Use centriums here too.
_line.z = Math.max( vertex.positionScreen.z, vertex2.positionScreen.z );
_renderList.push( _line );
_line.material = object.material;
_renderList.push( _line );
_lineCount ++;
}
_lineCount ++;
}
}
@@ -248,5 +313,4 @@ THREE.Projector = function() {
return vector;
};
};