engine.render.LightArea.java Source code

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Here is the source code for engine.render.LightArea.java

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package engine.render;

import java.nio.FloatBuffer;
import java.nio.IntBuffer;
import java.util.ArrayList;
import math.Vector2f;
import org.lwjgl.BufferUtils;
import static org.lwjgl.opengl.ARBVertexArrayObject.*;
import static org.lwjgl.opengl.GL11.GL_FLOAT;
import org.lwjgl.opengl.GL15;
import static org.lwjgl.opengl.GL15.GL_ARRAY_BUFFER;
import static org.lwjgl.opengl.GL15.GL_DYNAMIC_DRAW;
import static org.lwjgl.opengl.GL15.GL_ELEMENT_ARRAY_BUFFER;
import static org.lwjgl.opengl.GL15.glBindBuffer;
import static org.lwjgl.opengl.GL15.glDeleteBuffers;
import static org.lwjgl.opengl.GL15.glGenBuffers;
import static org.lwjgl.opengl.GL20.glVertexAttribPointer;

/**
 *
 * @author Zeus
 */
public class LightArea {
    private int vao;
    private ArrayList<Integer> vbos;
    private Vector2f lightCenter;
    private int numVertices;
    private int positionsVboId;
    private int indicesVboId;
    //TODO make static flaot array with indices

    public LightArea() {
        vao = createVao();
        vbos = new ArrayList<>();
        positionsVboId = glGenBuffers();
        indicesVboId = glGenBuffers();
        numVertices = 0;
    }

    public void generateTriangles(ArrayList<Vector2f> points, Vector2f lightCenter) {
        prepare();
        if (points.size() < 2) {
            numVertices = 0;
            return;
        }
        this.lightCenter = lightCenter;
        vao = createVao();
        vbos = new ArrayList<>();
        IntBuffer indicesBuffer = generateIndices(points);
        bindIndices(indicesBuffer);

        FloatBuffer positionsBuffer = generatePositions(points);
        bindPositions(positionsBuffer, 0);
        unBindVao();
        numVertices = points.size() * 3;
    }

    private void bindIndices(IntBuffer indicesBuffer) {
        vbos.add(indicesVboId);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indicesVboId);
        GL15.glBufferData(GL_ELEMENT_ARRAY_BUFFER, indicesBuffer, GL_DYNAMIC_DRAW);
    }

    private void bindPositions(FloatBuffer positions, int attributeNumber) {
        vbos.add(positionsVboId);
        glBindBuffer(GL_ARRAY_BUFFER, positionsVboId);
        GL15.glBufferData(GL_ARRAY_BUFFER, positions, GL_DYNAMIC_DRAW);
        glVertexAttribPointer(attributeNumber, 2, GL_FLOAT, false, 0, 0);
        glBindBuffer(GL15.GL_ARRAY_BUFFER, 0);
    }

    private void prepare() {
        glDeleteVertexArrays(vao);
        for (Integer vbo : vbos)
            glDeleteBuffers(vbo);
        //vao = createVao();
        //vbos = new ArrayList<>();
    }

    private FloatBuffer generatePositions(ArrayList<Vector2f> points) {
        FloatBuffer buffer = BufferUtils.createFloatBuffer(2 * points.size() + 2);
        buffer.put(lightCenter.x);
        buffer.put(lightCenter.y);

        for (int i = 0; i < points.size(); i++) {
            buffer.put(points.get(i).x);
            buffer.put(points.get(i).y);
        }
        buffer.flip();
        return buffer;
    }

    private IntBuffer generateIndices(ArrayList<Vector2f> points) {

        IntBuffer indices = BufferUtils.createIntBuffer(3 * points.size());
        for (int i = 1; i < points.size() - 1; i++) {
            indices.put(0);
            indices.put(i);
            indices.put(i + 1);

        }
        indices.put(0);
        indices.put(points.size() - 1);
        indices.put(1);

        indices.flip();
        return indices;

    }

    private void unBindVao() {
        glBindVertexArray(0);
    }

    private int createVao() {
        int vao = glGenVertexArrays();
        glBindVertexArray(vao);
        return vao;
    }

    public int getVao() {
        return vao;
    }

    @Override
    public void finalize() {
        glDeleteVertexArrays(vao);
        for (Integer vbo : vbos)
            glDeleteBuffers(vbo);
    }

    public int getNumVertices() {
        return numVertices;
    }

}