GL2GL3StrokeLineVisitor.java

/*
 * Copyright 2015 Brandon Borkholder
 *
 * 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.
 */
package org.jogamp.glg2d.impl.shader;


import java.awt.BasicStroke;
import java.nio.FloatBuffer;

import com.jogamp.opengl.GL;
import com.jogamp.opengl.GL2ES2;

import org.jogamp.glg2d.VertexBuffer;
import org.jogamp.glg2d.impl.SimplePathVisitor;

public class GL2GL3StrokeLineVisitor extends SimplePathVisitor implements ShaderPathVisitor {
  protected VertexBuffer buffer = new VertexBuffer(1024);

  protected BasicStroke stroke;

  protected float[] lastV = new float[2];

  protected GL2ES2 gl;
  protected UniformBufferObject uniforms;

  protected GeometryShaderStrokePipeline pipeline;

  public GL2GL3StrokeLineVisitor() {
    this(new GeometryShaderStrokePipeline());
  }

  public GL2GL3StrokeLineVisitor(GeometryShaderStrokePipeline pipeline) {
    this.pipeline = pipeline;
  }

  @Override
  public void setGLContext(GL context) {
    gl = context.getGL2ES2();

    if (!pipeline.isSetup()) {
      pipeline.setup(gl);
    }
  }

  @Override
  public void setGLContext(GL glContext, UniformBufferObject uniforms) {
    setGLContext(glContext);
    this.uniforms = uniforms;
  }

  @Override
  public void setStroke(BasicStroke stroke) {
    this.stroke = stroke;
  }

  @Override
  public void moveTo(float[] vertex) {
    draw(false);

    lastV[0] = vertex[0];
    lastV[1] = vertex[1];
    buffer.addVertex(vertex[0], vertex[1]);
  }

  @Override
  public void lineTo(float[] vertex) {
    // no 0-length lines
    if (vertex[0] == lastV[0] && vertex[1] == lastV[1]) {
      return;
    }

    buffer.addVertex(vertex, 0, 1);
    lastV[0] = vertex[0];
    lastV[1] = vertex[1];
  }

  @Override
  public void closeLine() {
    /*
     * Sometimes shapes will set the last point to be the same as the first and
     * then close the line. That can be confusing. So we discard the last point
     * if it's the same as the first. Now no 2 consecutive points are the same.
     */
    FloatBuffer buf = buffer.getBuffer();
    if (buf.get(0) == lastV[0] && buf.get(1) == lastV[1]) {
      buf.position(buf.position() - 2);
    }

    draw(true);
  }

  @Override
  public void beginPoly(int windingRule) {
    pipeline.use(gl, true);

    pipeline.setColor(gl, uniforms.colorHook.getRGBA());
    pipeline.setTransform(gl, uniforms.transformHook.getGLMatrixData());
    pipeline.setStroke(gl, stroke);

    buffer.clear();
  }

  @Override
  public void endPoly() {
    draw(false);
    pipeline.use(gl, false);
  }

  protected void draw(boolean close) {
    FloatBuffer buf = buffer.getBuffer();
    if (buf.position() == 0) {
      return;
    }

    buf.flip();
    pipeline.draw(gl, buf, close);

    buffer.clear();
  }
}