Tutorial1.java

package com.main;

import com.main.Main;
import com.main.ShaderProgram;
import org.lwjgl.BufferUtils;

import java.nio.FloatBuffer;

import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.opengl.GL15.*;
import static org.lwjgl.opengl.GL20.*;
import static org.lwjgl.opengl.GL30.*;


public class Tutorial1 extends Main {

    int vaoID;
    int vboID;
    int vboColID;
    ShaderProgram shaderProgram = new ShaderProgram();
    float x1,y1,x2,y2,x3,y3;

    public Tutorial1() {

    }

    public void initGame() {

        x1= +0f;
        x2= -1f;
        x3= +1f;
        y1= +1f;
        y2= -1f;
        y3= -1f;

        shaderProgram.attachVertexShader("com/utility/simply2D.vs");
        shaderProgram.attachFragmentShader("com/utility/blank.fs");
        shaderProgram.link();


    }

    int lastaction = 2;

    public void render(float delta)
    {
        // Clear the screen
        glClear(GL_COLOR_BUFFER_BIT);

        // Use our program
        shaderProgram.bind();

        // Bind the vertex array and enable our location
        glBindVertexArray(vaoID);
        glEnableVertexAttribArray(0);

        // Draw a triangle of 3 vertices
        glDrawArrays(GL_TRIANGLES, 0, 3);

        // Disable our location
        glDisableVertexAttribArray(0);
        glBindVertexArray(0);

        // Un-bind our program
        shaderProgram.unbind();



        if (lastaction==2 && y1>-1) {
            x2 += +0.004f;
            x3 += -0.004f;
            y1 += -0.004f;
            y2 += +0.004f;
            y3 += +0.004f;
            if (y1<-1 || y1==-1) {lastaction = 1;}
            }

        if (lastaction==1  && y1<1) {
            x2 += -0.004f;
            x3 += +0.004f;
            y1 += +0.004f;
            y2 += -0.004f;
            y3 += -0.004f;
            if (y1>1 || y1==1) {lastaction = 2;}
            }


        verticeSpecify(x1, y1, x2, y2, x3, y3);
        colorSpecify();

        glEnableVertexAttribArray(0);
        glEnableVertexAttribArray(1);
        glBindVertexArray(0);


    }


    public void dispose()
    {
        // Dispose the program
        shaderProgram.dispose();

        // Dispose the vertex array
        glBindVertexArray(0);
        glDeleteVertexArrays(vaoID);

        // Dispose the buffer object
        glBindBuffer(GL_ARRAY_BUFFER, 0);
        glBindBuffer(GL_ARRAY_BUFFER, 1);
        glDeleteBuffers(vboID);
        glDeleteBuffers(vboColID);
    }

    public void verticeSpecify(float x1, float y1, float x2, float y2, float x3, float y3) {

        // Generate and bind a Vertex Array
        vaoID = glGenVertexArrays();
        glBindVertexArray(vaoID);

        // The vertices of our Triangle
        float[] vertices = new float[]
        {
            x1, y1,    // Top coordinate
            x2, y2,    // Bottom-left coordinate
            x3, y3     // Bottom-right coordinate
        };

        // Create a FloatBuffer of vertices
        FloatBuffer verticesBuffer = BufferUtils.createFloatBuffer(vertices.length);
        verticesBuffer.put(vertices).flip();

        // Create a Buffer Object and upload the vertices buffer
        vboID = glGenBuffers();
        glBindBuffer(GL_ARRAY_BUFFER, vboID);
        glBufferData(GL_ARRAY_BUFFER, verticesBuffer, GL_STATIC_DRAW);

        // Point the buffer at location 0, the location we set
        // inside the vertex shader. You can use any location
        // but the locations should match
        glVertexAttribPointer(0, 2, GL_FLOAT, false, 0, 0);

    }

      public void colorSpecify() {


        // The vertices of our Triangle
        float[] colors = new float[]
                {
                    1, 0, 0, 1,  // Red color, for the first vertex
                    0, 1, 0, 1,  // Green color, for the second vertex
                    0, 0, 1, 1   // Blue color, for the third vertex
                };

        // Create a FloatBuffer of vertices
        FloatBuffer colorsBuffer = BufferUtils.createFloatBuffer(colors.length);
        colorsBuffer.put(colors).flip();

        // Create a Buffer Object and upload the vertices buffer
        vboColID = glGenBuffers();
        glBindBuffer(GL_ARRAY_BUFFER, vboColID);
        glBufferData(GL_ARRAY_BUFFER, colorsBuffer, GL_STATIC_DRAW);

        // Point the buffer at location 0, the location we set
        // inside the vertex shader. You can use any location
        // but the locations should match
        glVertexAttribPointer(1, 4, GL_FLOAT, false, 0, 0);

    }

    public static void main(String[] args) {
        new Tutorial1().start();
    }

}