package com.example.niclas.rouge_like;

import android.opengl.GLES31;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.ShortBuffer;

import static android.opengl.GLES20.GL_TRIANGLES;
import static android.opengl.GLES32.GL_QUADS;

public class Square {

    private FloatBuffer vertexBuffer;
    private ShortBuffer drawListBuffer;

    private final int mProgram;
    private int mPositionHandle;
    private int mColorHandle;

    private final String vertexShaderCode =
            "attribute vec4 vPosition;" +
                    "void main() {" +
                    "  gl_Position = vPosition;" +
                    "}";

    private final String fragmentShaderCode =
            "precision mediump float;" +
                    "uniform vec4 vColor;" +
                    "void main() {" +
                    "  gl_FragColor = vColor;" +
                    "}";


    static final int COORDS_PER_VERTEX = 3;
    static float squareCoords[] = {
            -0.5f,  0.5f, 0.0f,   // top left
            -0.5f, -0.5f, 0.0f,   // bottom left
            0.5f, -0.5f, 0.0f,   // bottom right
            0.5f,  0.5f, 0.0f }; // top right

    private short drawOrder[] ={ 0, 1, 2, 0, 2, 3};

    //  private final int vertexCount = squareCoords.length / COORDS_PER_VERTEX;
    private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex
    float color[] = {100f,0.0f,0.0f,1.0f};

    public Square() {

        ByteBuffer bb = ByteBuffer.allocateDirect(squareCoords.length*4);
        bb.order(ByteOrder.nativeOrder());
        vertexBuffer = bb.asFloatBuffer();
        vertexBuffer.put(squareCoords);
        vertexBuffer.position(0);

        ByteBuffer dlb = ByteBuffer.allocateDirect(drawOrder.length*2);
        dlb.order(ByteOrder.nativeOrder());
        drawListBuffer = dlb.asShortBuffer();
        drawListBuffer.put(drawOrder);
        drawListBuffer.position(0);

        int vertexShader = MyGLRenderer.loadShader(GLES31.GL_VERTEX_SHADER, vertexShaderCode);
        int fragmentShader = MyGLRenderer.loadShader(GLES31.GL_FRAGMENT_SHADER, fragmentShaderCode);

        mProgram = GLES31.glCreateProgram();
        GLES31.glAttachShader(mProgram, vertexShader);
        GLES31.glAttachShader(mProgram, fragmentShader);
        GLES31.glLinkProgram(mProgram);

    }



    public void draw(){

        GLES31.glUseProgram(mProgram);
        mPositionHandle = GLES31.glGetAttribLocation(mProgram, "vPosition");
        GLES31.glEnableVertexAttribArray(mPositionHandle);
        GLES31.glVertexAttribPointer(mPositionHandle,COORDS_PER_VERTEX,GLES31.GL_FLOAT,false,vertexStride,vertexBuffer);
        GLES31.glDrawElements(GLES31.GL_TRIANGLES,drawOrder.length,GLES31.GL_UNSIGNED_SHORT,drawListBuffer);
        //  GLES31.glDrawArrays(GL_TRIANGLES,0,6);

        mColorHandle = GLES31.glGetUniformLocation(mProgram, "vColor");
        GLES31.glUniform4fv(mColorHandle,1,color, 0);





        GLES31.glDisableVertexAttribArray(mPositionHandle);
    }
}