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6502bench/SourceGen/WireframeObject.cs
Andy McFadden ea379fce18 Consolidate wireframe data validation
Some tests were duplicated between VisWireframe and the code that
consumed the data.  We now expose the Validate function as a public
interface, and invoke it from WireframeObject.  Failed validation
results in a null object being returned, which was previously allowed
but not actually checked for.
2020-04-23 11:25:45 -07:00

476 lines
19 KiB
C#

/*
* Copyright 2020 faddenSoft
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
using System;
using System.Collections.Generic;
using System.Diagnostics;
using PluginCommon;
namespace SourceGen {
/// <summary>
/// Renders a wireframe visualization, generating a collection of line segments in clip space.
/// </summary>
public class WireframeObject {
/// <summary>
/// Line segment.
/// </summary>
public class LineSeg {
public double X0 { get; private set; }
public double Y0 { get; private set; }
public double X1 { get; private set; }
public double Y1 { get; private set; }
public LineSeg(double x0, double y0, double x1, double y1) {
X0 = x0;
Y0 = y0;
X1 = x1;
Y1 = y1;
}
}
private class Vertex {
public Vector3 Vec { get; private set; }
public List<Face> Faces { get; private set; }
public bool IsExcluded { get; private set; }
public Vertex(double x, double y, double z, bool isExcluded) {
Vec = new Vector3(x, y, z);
Faces = new List<Face>();
IsExcluded = isExcluded;
}
public override string ToString() {
return Vec.ToString() + " + " + Faces.Count + " faces";
}
}
private class Edge {
public Vertex Vertex0 { get; private set; }
public Vertex Vertex1 { get; private set; }
public List<Face> Faces { get; private set; }
public bool IsExcluded { get; private set; }
public Edge(Vertex v0, Vertex v1, bool isExcluded) {
Vertex0 = v0;
Vertex1 = v1;
Faces = new List<Face>();
IsExcluded = isExcluded;
}
}
private class Face {
// Surface normal.
public Vector3 Normal { get; private set; }
// One vertex on the face, for BFC.
public Vertex Vert { get; set; }
// Flag set during BFC calculation.
public bool IsVisible { get; set; }
public Face(double x, double y, double z) {
Normal = new Vector3(x, y, z);
Normal.Normalize(); // not necessary, but easier to read in debug output
IsVisible = true;
}
}
public bool VerboseDebug { get; set; }
private bool mIs2d = false;
private List<Vertex> mVertices = new List<Vertex>();
private List<Vertex> mPoints = new List<Vertex>();
private List<Edge> mEdges = new List<Edge>();
private List<Face> mFaces = new List<Face>();
private double mBigMag = -1.0;
private double mBigMagRc = -1.0;
private double mCenterAdjX, mCenterAdjY;
// private constructor; use Create()
private WireframeObject() { }
/// <summary>
/// Creates a new object from a wireframe visualization.
/// </summary>
/// <param name="visWire">Visualization object.</param>
/// <returns>New object, or null if visualization data fails validation.</returns>
public static WireframeObject Create(IVisualizationWireframe visWire) {
if (!visWire.Validate(out string msg)) {
// Should not be here -- visualizer should have checked validation and
// reported an error.
Debug.WriteLine("Wireframe validation failed: " + msg);
return null;
}
WireframeObject wireObj = new WireframeObject();
wireObj.mIs2d = visWire.Is2d;
//
// Start by extracting data from the visualization object. Everything stored
// there is loaded into this object. The VisWireframe validator will have
// ensured that all the indices are in range.
//
// IMPORTANT: do not retain "visWire", as it may be a proxy for an object with a
// limited lifespan.
//
float[] normalsX = visWire.GetNormalsX();
if (normalsX.Length > 0) {
float[] normalsY = visWire.GetNormalsY();
float[] normalsZ = visWire.GetNormalsZ();
for (int i = 0; i < normalsX.Length; i++) {
wireObj.mFaces.Add(new Face(normalsX[i], normalsY[i], normalsZ[i]));
}
}
float[] verticesX = visWire.GetVerticesX();
float[] verticesY = visWire.GetVerticesY();
float[] verticesZ = visWire.GetVerticesZ();
int[] excludedVertices = visWire.GetExcludedVertices();
// Compute min/max for X/Y for 2d re-centering. The trick is that we only want
// to use vertices that are visible. If the shape starts with a huge move off to
// the left, we don't want to include (0,0).
double xmin, xmax, ymin, ymax;
xmin = ymin = 10e9;
xmax = ymax = -10e9;
for (int i = 0; i < verticesX.Length; i++) {
wireObj.mVertices.Add(new Vertex(verticesX[i], verticesY[i], verticesZ[i],
HasIndex(excludedVertices, i)));
}
int[] points = visWire.GetPoints();
for (int i = 0; i < points.Length; i++) {
Vertex vert = wireObj.mVertices[points[i]];
wireObj.mPoints.Add(vert);
UpdateMinMax(vert, ref xmin, ref xmax, ref ymin, ref ymax);
}
IntPair[] edges = visWire.GetEdges();
int[] excludedEdges = visWire.GetExcludedEdges();
for (int i = 0; i < edges.Length; i++) {
int v0index = edges[i].Val0;
int v1index = edges[i].Val1;
//if (v0index < 0 || v0index >= wireObj.mVertices.Count ||
// v1index < 0 || v1index >= wireObj.mVertices.Count) {
// Debug.Assert(false);
// return null;
//}
Vertex vert0 = wireObj.mVertices[v0index];
Vertex vert1 = wireObj.mVertices[v1index];
wireObj.mEdges.Add(new Edge(vert0, vert1, HasIndex(excludedEdges, i)));
UpdateMinMax(vert0, ref xmin, ref xmax, ref ymin, ref ymax);
UpdateMinMax(vert1, ref xmin, ref xmax, ref ymin, ref ymax);
}
IntPair[] vfaces = visWire.GetVertexFaces();
for (int i = 0; i < vfaces.Length; i++) {
int vindex = vfaces[i].Val0;
int findex = vfaces[i].Val1;
//if (vindex < 0 || vindex >= wireObj.mVertices.Count ||
// findex < 0 || findex >= wireObj.mFaces.Count) {
// Debug.Assert(false);
// return null;
//}
Face face = wireObj.mFaces[findex];
wireObj.mVertices[vindex].Faces.Add(face);
if (face.Vert == null) {
face.Vert = wireObj.mVertices[vindex];
}
}
IntPair[] efaces = visWire.GetEdgeFaces();
for (int i = 0; i < efaces.Length; i++) {
int eindex = efaces[i].Val0;
int findex = efaces[i].Val1;
//if (eindex < 0 || eindex >= wireObj.mEdges.Count ||
// findex < 0 || findex >= wireObj.mFaces.Count) {
// Debug.Assert(false);
// return null;
//}
Face face = wireObj.mFaces[findex];
wireObj.mEdges[eindex].Faces.Add(face);
if (face.Vert == null) {
face.Vert = wireObj.mEdges[eindex].Vertex0;
}
}
//
// All data has been loaded into friendly classes.
//
// Compute center of visible vertices.
wireObj.mCenterAdjX = -(xmin + xmax) / 2;
wireObj.mCenterAdjY = -(ymin + ymax / 2);
// Compute the magnitude of the largest vertex, for scaling.
double bigMag = -1.0;
double bigMagRc = -1.0;
for (int i = 0; i < wireObj.mVertices.Count; i++) {
Vector3 vec = wireObj.mVertices[i].Vec;
double mag = vec.Magnitude();
if (bigMag < mag) {
bigMag = mag;
}
// Repeat the operation with recentering. This isn't quite right as we're
// including all vertices, not just the visible ones.
mag = new Vector3(vec.X + wireObj.mCenterAdjX,
vec.Y + wireObj.mCenterAdjY, vec.Z).Magnitude();
if (bigMagRc < mag) {
bigMagRc = mag;
}
}
wireObj.mBigMag = bigMag;
wireObj.mBigMagRc = bigMagRc;
return wireObj;
}
private static void UpdateMinMax(Vertex vert, ref double xmin, ref double xmax,
ref double ymin, ref double ymax) {
if (vert.Vec.X < xmin) {
xmin = vert.Vec.X;
}
if (vert.Vec.X > xmax) {
xmax = vert.Vec.X;
}
if (vert.Vec.Y < ymin) {
ymin = vert.Vec.Y;
}
if (vert.Vec.Y > ymax) {
ymax = vert.Vec.Y;
}
}
private static bool HasIndex(int[] arr, int val) {
for (int i = 0; i < arr.Length; i++) {
if (arr[i] == val) {
return true;
}
}
return false;
}
/// <summary>
/// Generates a list of line segments for the wireframe data and the specified
/// parameters.
/// </summary>
/// <param name="eulerX">Rotation about X axis.</params>
/// <param name="eulerY">Rotation about Y axis.</params>
/// <param name="eulerZ">Rotation about Z axis.</params>
/// <param name="doPersp">Perspective or othographic projection?</param>
/// <param name="doBfc">Perform backface culling?</param>
/// <param name="doRecenter">Re-center 2D renderings?</param>
/// <returns>List a of line segments, which could be empty if backface culling
/// was especially successful. All segment coordinates are in the range
/// [-1,1].</returns>
public List<LineSeg> Generate(int eulerX, int eulerY, int eulerZ,
bool doPersp, bool doBfc, bool doRecenter) {
if (VerboseDebug) {
Debug.WriteLine("Found center=" + mCenterAdjX + "," + mCenterAdjY);
Debug.WriteLine(" bigMag=" + mBigMag + " / " + mBigMagRc);
}
// overrule flags that don't make sense
if (mIs2d) {
doPersp = doBfc = false;
} else {
doRecenter = false;
}
List<LineSeg> segs = new List<LineSeg>(mEdges.Count);
// Camera Z coordinate adjustment, used to control how perspective projections
// appear. The larger the value, the farther the object appears to be. Very
// large values approximate an orthographic projection.
const double zadj = 3.0;
// Scale coordinate values to [-1,1].
double scale;
if (doRecenter) {
scale = 1.0 / mBigMagRc;
} else {
scale = 1.0 / mBigMag;
}
if (doPersp) {
// objects closer to camera are bigger; reduce scale slightly
scale = (scale * zadj) / (zadj + 0.3);
}
// Configure X/Y translation for 2D wireframes.
double transX = 0;
double transY = 0;
if (doRecenter) {
transX = mCenterAdjX;
transY = mCenterAdjY;
}
// In a left-handed coordinate system, +Z is away from the viewer. The
// visualizer expects a left-handed system with the "nose" aimed toward +Z,
// which leaves us looking at the back end of things. We can add a 180 degree
// rotation about Y so we're looking at the front instead, though this
// effectively reverses the direction of rotation about X. We can compensate
// for it by reversing the handedness of the X rotation.
//eulerY = (eulerY + 180) % 360;
// Form rotation matrix.
Matrix33 rotMat = new Matrix33();
rotMat.SetRotationEuler(eulerX, eulerY, eulerZ, Matrix33.RotMode.ZYX_LLL);
//Debug.WriteLine("ROT: " + rotMat);
if (doBfc) {
// Mark faces as visible or not. This is determined with the surface normal,
// rather than by checking whether a transformed triangle is clockwise.
foreach (Face face in mFaces) {
// Transform the surface normal.
Vector3 rotNorm = rotMat.Multiply(face.Normal);
if (doPersp) {
// Transform one vertex to get a vector from the camera to the
// surface. We want (V0 - C), where C is the camera; since we're
// at the origin, we just need -C.
if (face.Vert == null) {
Debug.WriteLine("GLITCH: no vertex for face");
face.IsVisible = true;
continue;
}
Vector3 camVec = rotMat.Multiply(face.Vert.Vec); // transform
camVec = camVec.Multiply(-scale); // scale to [-1,1] and negate to get -C
camVec = camVec.Add(new Vector3(0, 0, -zadj)); // translate
// Now compute the dot product of the camera vector.
double dot = Vector3.Dot(camVec, rotNorm);
face.IsVisible = (dot >= 0);
//Debug.WriteLine(string.Format(
// "Face {0} vis={1,-5} dot={2,-8:N2}: camVec={3} rotNorm={4}",
// index++, face.IsVisible, dot, camVec, rotNorm));
} else {
// For orthographic projection, the camera is essentially looking
// down the Z axis at every X,Y, so we can trivially check the
// value of Z in the transformed normal.
face.IsVisible = (rotNorm.Z <= 0);
}
}
}
foreach (Vertex point in mPoints) {
// There are no "point faces" at the moment, so no BFC is applied.
Vector3 vec = point.Vec;
if (doRecenter) {
vec = new Vector3(vec.X + transX, vec.Y + transY, vec.Z);
}
Vector3 trv = rotMat.Multiply(vec);
double xc, yc;
if (doPersp) {
double zc = trv.Z * scale;
xc = (trv.X * scale * zadj) / (zadj + zc);
yc = (trv.Y * scale * zadj) / (zadj + zc);
} else {
xc = trv.X * scale;
yc = trv.Y * scale;
}
//Debug.WriteLine("POINT " + xc + "," + yc);
// Zero-length line segments don't do anything. Try a '+'.
const double dist = 1 / 64.0;
double x0 = Math.Max(-1.0, xc - dist);
double x1 = Math.Min(xc + dist, 1.0);
segs.Add(new LineSeg(x0, yc, x1, yc));
double y0 = Math.Max(-1.0, yc - dist);
double y1 = Math.Min(yc + dist, 1.0);
segs.Add(new LineSeg(xc, y0, xc, y1));
}
foreach (Edge edge in mEdges) {
if (doBfc) {
// To be visible, vertices and edges must either not specify any
// faces, or must specify a visible face. They can also be hidden
// by the level-of-detail exclusion mechanism.
if (!IsVertexVisible(edge.Vertex0) || edge.Vertex0.IsExcluded ||
!IsVertexVisible(edge.Vertex1) || edge.Vertex1.IsExcluded ||
!IsEdgeVisible(edge) || edge.IsExcluded) {
continue;
}
}
Vector3 vec0 = edge.Vertex0.Vec;
Vector3 vec1 = edge.Vertex1.Vec;
if (doRecenter) {
vec0 = new Vector3(vec0.X + transX, vec0.Y + transY, vec0.Z);
vec1 = new Vector3(vec1.X + transX, vec1.Y + transY, vec1.Z);
}
Vector3 trv0 = rotMat.Multiply(vec0);
Vector3 trv1 = rotMat.Multiply(vec1);
double x0, y0, x1, y1;
if (doPersp) {
// Left-handed system, so +Z is away from viewer.
double z0 = trv0.Z * scale;
double z1 = trv1.Z * scale;
x0 = (trv0.X * scale * zadj) / (zadj + z0);
y0 = (trv0.Y * scale * zadj) / (zadj + z0);
x1 = (trv1.X * scale * zadj) / (zadj + z1);
y1 = (trv1.Y * scale * zadj) / (zadj + z1);
} else {
x0 = trv0.X * scale;
y0 = trv0.Y * scale;
x1 = trv1.X * scale;
y1 = trv1.Y * scale;
}
segs.Add(new LineSeg(x0, y0, x1, y1));
}
return segs;
}
private bool IsVertexVisible(Vertex vert) {
if (vert.Faces.Count == 0) {
return true;
}
foreach (Face face in vert.Faces) {
if (face.IsVisible) {
return true;
}
}
return false;
}
private bool IsEdgeVisible(Edge edg) {
if (edg.Faces.Count == 0) {
return true;
}
foreach (Face face in edg.Faces) {
if (face.IsVisible) {
return true;
}
}
return false;
}
}
}