package com.example.liyuanjing.object;
import android.opengl.GLES20;
import android.util.FloatMath;
import com.example.liyuanjing.util.Genmetry;
import java.util.ArrayList;
import java.util.List;
class ObjectBuilder {
private static final int FLOATS_PER_VERTEX = 3;
static interface DrawCommand {
void draw();
}
static class GeneratedData {
final float[] vertexData;
final List<DrawCommand> drawList;
GeneratedData(float[] vertexData, List<DrawCommand> drawList) {
this.vertexData = vertexData;
this.drawList = drawList;
}
}
static GeneratedData createCylindrical(Genmetry.Cylinder cylinder, int numPoints) {
int size = sizeOfCircleInVertices(numPoints)
+ sizeOfOpenCylinderInVertices(numPoints);
ObjectBuilder builder = new ObjectBuilder(size);
Genmetry.Circle circle = new Genmetry.Circle(
puck.center.translateY(puck.height / 2f),
puck.radius);
builder.appendCircle(circle, numPoints);
builder.appendOpenCylinder(cylinder, numPoints);
return builder.build();
}
private static int sizeOfCircleInVertices(int numPoints) {
return 1 + (numPoints + 1);
}
private static int sizeOfOpenCylinderInVertices(int numPoints) {
return (numPoints + 1) * 2;
}
private final float[] vertexData;
private final List<DrawCommand> drawList = new ArrayList<DrawCommand>();
private int offset = 0;
private ObjectBuilder(int sizeInVertices) {
vertexData = new float[sizeInVertices * FLOATS_PER_VERTEX];
}
private void appendCircle(Genmetry.Circle circle, int numPoints) {
final int startVertex = offset / FLOATS_PER_VERTEX;
final int numVertices = sizeOfCircleInVertices(numPoints);
vertexData[offset++] = circle.center.x;
vertexData[offset++] = circle.center.y;
vertexData[offset++] = circle.center.z;
for (int i = 0; i <= numPoints; i++) {
float angleInRadians =
((float) i / (float) numPoints)
* ((float) Math.PI * 2f);
vertexData[offset++] =
circle.center.x
+ circle.radius * FloatMath.cos(angleInRadians);
vertexData[offset++] = circle.center.y;
vertexData[offset++] =
circle.center.z
+ circle.radius * FloatMath.sin(angleInRadians);
}
drawList.add(new DrawCommand() {
@Override
public void draw() {
GLES20.glDrawArrays(GLES20.GL_TRIANGLE_FAN, startVertex, numVertices);
}
});
}
private void appendOpenCylinder(Genmetry.Cylinder cylinder, int numPoints) {
final int startVertex = offset / FLOATS_PER_VERTEX;
final int numVertices = sizeOfOpenCylinderInVertices(numPoints);
final float yStart = cylinder.center.y - (cylinder.height / 2f);
final float yEnd = cylinder.center.y + (cylinder.height / 2f);
for (int i = 0; i <= numPoints; i++) {
float angleInRadians =
((float) i / (float) numPoints)
* ((float) Math.PI * 2f);
float xPosition =
cylinder.center.x
+ cylinder.radius * FloatMath.cos(angleInRadians);
float zPosition =
cylinder.center.z
+ cylinder.radius * FloatMath.sin(angleInRadians);
vertexData[offset++] = xPosition;
vertexData[offset++] = yStart;
vertexData[offset++] = zPosition;
vertexData[offset++] = xPosition;
vertexData[offset++] = yEnd;
vertexData[offset++] = zPosition;
}
drawList.add(new DrawCommand() {
@Override
public void draw() {
GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, startVertex, numVertices);
}
});
}
private GeneratedData build() {
return new GeneratedData(vertexData, drawList);
}
}
