package com.qboxus.tictic.activitesfragments.argear.rendering;

import android.opengl.GLES20;

import com.seerslab.argear.session.ARGFrame;

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

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;


public class ScreenRenderer {

    private final String vss =
            "attribute vec2 vPosition;\n" +
                    "attribute vec2 vTexCoord;\n" +
                    "varying vec2 texCoord;\n" +
                    "void main() {\n" +
                    "  texCoord = vTexCoord;\n" +
                    "  gl_Position = vec4 ( vPosition.x, vPosition.y, 0.0, 1.0 );\n" +
                    "}";
    private final String fss =
            "precision mediump float;\n" +
                    "uniform sampler2D sTexture;\n" +
                    "varying vec2 texCoord;\n" +
                    "void main() {\n" +
                    "  gl_FragColor = texture2D(sTexture,texCoord);\n" +
                    "}";
    private FloatBuffer pVertex;
    private FloatBuffer pTexCoord;
    private int hProgram;

    public void create(GL10 gl, EGLConfig config) {
        float[] vtmp = {1.0f, -1.0f, -1.0f, -1.0f, 1.0f, 1.0f, -1.0f, 1.0f};
        float[] ttmp = {1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f};

        pVertex = ByteBuffer.allocateDirect(8 * 4).order(ByteOrder.nativeOrder()).asFloatBuffer();
        pVertex.put(vtmp);
        pVertex.position(0);
        pTexCoord = ByteBuffer.allocateDirect(8 * 4).order(ByteOrder.nativeOrder()).asFloatBuffer();
        pTexCoord.put(ttmp);
        pTexCoord.position(0);

        hProgram = loadShader(vss, fss);
    }

    public void draw(ARGFrame frame, int viewWidth, int viewHeight) {

        GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);

        GLES20.glViewport(0, 0, viewWidth, viewHeight);
        GLES20.glUseProgram(hProgram);

        int ph = GLES20.glGetAttribLocation(hProgram, "vPosition");
        int tch = GLES20.glGetAttribLocation(hProgram, "vTexCoord");
        int th = GLES20.glGetUniformLocation(hProgram, "sTexture");

        GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, frame.getTextureId());
        GLES20.glUniform1i(th, 0);

        GLES20.glVertexAttribPointer(ph, 2, GLES20.GL_FLOAT, false, 4 * 2, pVertex);
        GLES20.glVertexAttribPointer(tch, 2, GLES20.GL_FLOAT, false, 4 * 2, pTexCoord);
        GLES20.glEnableVertexAttribArray(ph);
        GLES20.glEnableVertexAttribArray(tch);

        GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
        GLES20.glFlush();
    }

    private int loadShader(String vss, String fss) {
        int vshader = GLES20.glCreateShader(GLES20.GL_VERTEX_SHADER);
        GLES20.glShaderSource(vshader, vss);
        GLES20.glCompileShader(vshader);
        int[] compiled = new int[1];
        GLES20.glGetShaderiv(vshader, GLES20.GL_COMPILE_STATUS, compiled, 0);
        if (compiled[0] == 0) {
            GLES20.glDeleteShader(vshader);
            vshader = 0;
        }

        int fshader = GLES20.glCreateShader(GLES20.GL_FRAGMENT_SHADER);
        GLES20.glShaderSource(fshader, fss);
        GLES20.glCompileShader(fshader);
        GLES20.glGetShaderiv(fshader, GLES20.GL_COMPILE_STATUS, compiled, 0);
        if (compiled[0] == 0) {
            GLES20.glDeleteShader(fshader);
            fshader = 0;
        }

        int program = GLES20.glCreateProgram();
        GLES20.glAttachShader(program, vshader);
        GLES20.glAttachShader(program, fshader);
        GLES20.glLinkProgram(program);

        return program;
    }
}