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Spherical
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Code Issues Releases Wiki Activity

Fix #5

This commit is contained in:
Simon Leistikow 2017-09-15 12:45:56 +02:00
parent 94c7d8c540
commit 89da0239f3
1 changed files with 36 additions and 56 deletions
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92
app/src/main/java/de/trac/spherical/rendering/Sphere.java
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@ -18,13 +18,15 @@ public class Sphere {
public Sphere(float radius, int polyCountX, int polyCountY) { public Sphere(float radius, int polyCountX, int polyCountY) {
final int polyCountXPitch = polyCountX + 1;
// Setup vertex buffer. // Setup vertex buffer.
ByteBuffer buffer = ByteBuffer.allocateDirect((polyCountX*polyCountY+2)*2*3*4); ByteBuffer buffer = ByteBuffer.allocateDirect((polyCountXPitch*polyCountY+2)*3*4);
buffer.order(ByteOrder.nativeOrder()); buffer.order(ByteOrder.nativeOrder());
vertexBuffer = buffer.asFloatBuffer(); vertexBuffer = buffer.asFloatBuffer();
// Setup texture coordinate buffer. // Setup texture coordinate buffer.
buffer = ByteBuffer.allocateDirect((polyCountX*polyCountY+2)*2*2*4); buffer = ByteBuffer.allocateDirect((polyCountXPitch*polyCountY+2)*2*4);
buffer.order(ByteOrder.nativeOrder()); buffer.order(ByteOrder.nativeOrder());
textureCoordinatesBuffer = buffer.asFloatBuffer(); textureCoordinatesBuffer = buffer.asFloatBuffer();
@ -32,25 +34,19 @@ public class Sphere {
buffer = ByteBuffer.allocateDirect(polyCountX*polyCountY*6*2); buffer = ByteBuffer.allocateDirect(polyCountX*polyCountY*6*2);
buffer.order(ByteOrder.nativeOrder()); buffer.order(ByteOrder.nativeOrder());
indexBuffer = buffer.asShortBuffer(); indexBuffer = buffer.asShortBuffer();
int polyCountXPitch = polyCountX+1; // get to same vertex on next level
int level = 0;
for (int p1 = 0; p1 < polyCountY-1; p1++) { for (int p1 = 0, level = 0; p1 < polyCountY-1; p1++) {
//main quads, top to bottom for (int p2 = 0; p2 < polyCountX-1; p2++) {
for (int p2 = 0; p2 < polyCountX - 1; p2++)
{
final int curr = level + p2; final int curr = level + p2;
indexBuffer.put((short)(curr + polyCountXPitch)); indexBuffer.put((short)(curr + polyCountXPitch));
indexBuffer.put((short)(curr)); indexBuffer.put((short)(curr));
indexBuffer.put((short)(curr + 1)); indexBuffer.put((short)(curr + 1));
indexBuffer.put((short)(curr + polyCountXPitch)); indexBuffer.put((short)(curr + polyCountXPitch));
indexBuffer.put((short)(curr+1)); indexBuffer.put((short)(curr + 1));
indexBuffer.put((short)(curr + 1 + polyCountXPitch)); indexBuffer.put((short)(curr + 1 + polyCountXPitch));
} }
// the connectors from front to end
indexBuffer.put((short)(level + polyCountX - 1 + polyCountXPitch)); indexBuffer.put((short)(level + polyCountX - 1 + polyCountXPitch));
indexBuffer.put((short)(level + polyCountX - 1)); indexBuffer.put((short)(level + polyCountX - 1));
indexBuffer.put((short)(level + polyCountX)); indexBuffer.put((short)(level + polyCountX));
@ -65,28 +61,20 @@ public class Sphere {
final int polyCountSq1 = polyCountSq + 1; // bottom point final int polyCountSq1 = polyCountSq + 1; // bottom point
final int polyCountSqM1 = (polyCountY - 1) * polyCountXPitch; // last row's first vertex final int polyCountSqM1 = (polyCountY - 1) * polyCountXPitch; // last row's first vertex
for (int p2 = 0; p2 < polyCountX - 1; p2++) { for (int p2 = 0; p2 < polyCountX-1; p2++) {
// create triangles which are at the top of the sphere
indexBuffer.put((short)(polyCountSq)); indexBuffer.put((short)(polyCountSq));
indexBuffer.put((short)(p2 + 1)); indexBuffer.put((short)(p2 + 1));
indexBuffer.put((short)(p2)); indexBuffer.put((short)(p2));
// create triangles which are at the bottom of the sphere
indexBuffer.put((short)(polyCountSqM1 + p2)); indexBuffer.put((short)(polyCountSqM1 + p2));
indexBuffer.put((short)(polyCountSqM1 + p2 + 1)); indexBuffer.put((short)(polyCountSqM1 + p2 + 1));
indexBuffer.put((short)(polyCountSq1)); indexBuffer.put((short)(polyCountSq1));
} }
// create final triangle which is at the top of the sphere
indexBuffer.put((short)(polyCountSq)); indexBuffer.put((short)(polyCountSq));
indexBuffer.put((short)(polyCountX)); indexBuffer.put((short)(polyCountX));
indexBuffer.put((short)(polyCountX-1)); indexBuffer.put((short)(polyCountX-1));
// create final triangle which is at the bottom of the sphere
indexBuffer.put((short)(polyCountSqM1 + polyCountX - 1)); indexBuffer.put((short)(polyCountSqM1 + polyCountX - 1));
indexBuffer.put((short)(polyCountSqM1)); indexBuffer.put((short)(polyCountSqM1));
indexBuffer.put((short)(polyCountSq1)); indexBuffer.put((short)(polyCountSq1));
@ -94,55 +82,47 @@ public class Sphere {
// calculate the angle which separates all points in a circle // calculate the angle which separates all points in a circle
final double AngleX = 2.0 * Math.PI / polyCountX; final double AngleX = 2.0 * Math.PI / polyCountX;
final double AngleY = Math.PI / polyCountY; final double AngleY = Math.PI / polyCountY;
final double InvPI = 1.0 / Math.PI;
int i=0;
double axz;
// we don't start at 0.
double ay = 0;//AngleY / 2; double ay = 0;//AngleY / 2;
for (int y = 0; y < polyCountY; y++) { for (int y = 0; y < polyCountY; y++) {
ay += AngleY;
final double sinay = Math.sin(ay);
axz = 0;
// calculate the necessary vertices without the doubled one ay += AngleY;
for (int xz = 0; xz < polyCountX; xz++) double axz = 0;
{ final double sinay = Math.sin(ay);
float rx = (float) (radius * Math.cos(axz) * sinay); final float tv = (float) (ay*InvPI);
float ry = (float) (radius * Math.cos(ay));
float rz = (float) (radius * Math.sin(axz) * sinay); for (int xz = 0; xz < polyCountX; xz++) {
double nx = Math.cos(axz) * sinay;
double ny = Math.cos(ay);
double nz = Math.sin(axz) * sinay;
// calculate texture coordinates via sphere mapping // calculate texture coordinates via sphere mapping
// tu is the same on each level, so only calculate once // tu is the same on each level, so only calculate once
float tu = 0.5f; float tu = 0.5f;
if (y==0) if (y == 0) {
{ if (ny != -1.0 && ny != 1.0)
if (ry != -1.0f && ry != 1.0f) { tu = (float) (Math.acos(Math.max(Math.min(nx / sinay, 1.0), -1.0)) * 0.5 * InvPI);
float len = (float) Math.sqrt(rx*rx + ry*ry + rz*rz); if (nz < 0.0)
tu = (float) (Math.acos(Math.max(Math.min(rx / len / sinay, 1.0), -1.0)) * 0.5 / Math.PI); tu = 1.0f - tu;
} } else
if (rz < 0.0f) tu = textureCoordinatesBuffer.get(xz*2);
tu=1-tu;
}
else
tu = textureCoordinatesBuffer.get((i-polyCountXPitch)*2);
vertexBuffer.put(rx); vertexBuffer.put((float) (radius * nx));
vertexBuffer.put(ry); vertexBuffer.put((float) (radius * ny));
vertexBuffer.put(rz); vertexBuffer.put((float) (radius * nz));
textureCoordinatesBuffer.put(tu); textureCoordinatesBuffer.put(tu);
textureCoordinatesBuffer.put((float)(ay/Math.PI)); textureCoordinatesBuffer.put(tv);
i++;
axz += AngleX; axz += AngleX;
} }
// This is the doubled vertex on the initial position
vertexBuffer.put(vertexBuffer.get((i-polyCountX)*3 + 0)); vertexBuffer.put(vertexBuffer.get((y*polyCountXPitch)*3 + 0));
vertexBuffer.put(vertexBuffer.get((i-polyCountX)*3 + 1)); vertexBuffer.put(vertexBuffer.get((y*polyCountXPitch)*3 + 1));
vertexBuffer.put(vertexBuffer.get((i-polyCountX)*3 + 2)); vertexBuffer.put(vertexBuffer.get((y*polyCountXPitch)*3 + 2));
textureCoordinatesBuffer.put(1.0f); textureCoordinatesBuffer.put(1.0f);
textureCoordinatesBuffer.put(0.0f); textureCoordinatesBuffer.put(tv);
i++;
} }
// Add the vertex at the top of the sphere. // Add the vertex at the top of the sphere.