Veretelnikov_lab2

package com.example.myapplication

import android.content.Context
import android.opengl.GLES20
import android.opengl.GLSurfaceView
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import java.nio.ByteBuffer
import java.nio.ByteOrder
import java.nio.FloatBuffer
import javax.microedition.khronos.egl.EGLConfig
import javax.microedition.khronos.opengles.GL10
import android.opengl.Matrix

class MainActivity : AppCompatActivity() {
    private lateinit var glSurfaceView: MyGLSurfaceView

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        glSurfaceView = MyGLSurfaceView(this)
        setContentView(glSurfaceView)
    }
}

class MyGLSurfaceView(context: Context) : GLSurfaceView(context) {
    private val renderer: MyGLRenderer

    init {
        setEGLContextClientVersion(2)
        renderer = MyGLRenderer()
        setRenderer(renderer)
    }
}

class MyGLRenderer : GLSurfaceView.Renderer {
    private lateinit var square: Square
    private lateinit var triangle: Triangle
    private val vPMatrix = FloatArray(16)
    private val projectionMatrix = FloatArray(16)
    private val viewMatrix = FloatArray(16)

    override fun onSurfaceCreated(unused: GL10?, config: EGLConfig?) {
        GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f)
        square = Square()
        triangle = Triangle()
    }

    override fun onDrawFrame(unused: GL10?) {
        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT)

        // Set the camera position (View matrix)
        Matrix.setLookAtM(viewMatrix, 0, 0f, 0f, 3f, 0f, 0f, 0f, 0f, 1.0f, 0.0f)
        // Calculate the projection and view transformation
        Matrix.multiplyMM(vPMatrix, 0, projectionMatrix, 0, viewMatrix, 0)

        square.draw(vPMatrix)
        triangle.draw(vPMatrix)


    }

    override fun onSurfaceChanged(unused: GL10?, width: Int, height: Int) {
        GLES20.glViewport(0, 0, width, height)
        val ratio: Float = width.toFloat() / height.toFloat()

        // this projection matrix is applied to object coordinates
        // in the onDrawFrame() method
        Matrix.frustumM(projectionMatrix, 0, -ratio, ratio, -1f, 1f, 3f, 7f)
    }
}

class Square {
    private val squareCoords = floatArrayOf(
        -0.4f,  0.0f, 0.0f,   // Верхний левый угол
        -0.4f, -0.8f, 0.0f,   // Нижний левый угол
        0.4f, -0.8f, 0.0f,   // Нижний правый угол
        0.4f,  0.0f, 0.0f    // Верхний правый угол
    )

    private val vertexShaderCode =
        "uniform mat4 uMVPMatrix;" +
                "attribute vec4 vPosition;" +
                "void main() {" +
                "  gl_Position = uMVPMatrix * vPosition;" +
                "}"

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

    private var mProgram: Int = 0

    private val vertexBuffer: FloatBuffer = ByteBuffer.allocateDirect(squareCoords.size * 4)
        .order(ByteOrder.nativeOrder())
        .asFloatBuffer()
        .put(squareCoords)
        .apply { position(0) }

    init {
        val vertexShader: Int = loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode)
        val fragmentShader: Int = loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode)

        mProgram = GLES20.glCreateProgram().also {
            GLES20.glAttachShader(it, vertexShader)
            GLES20.glAttachShader(it, fragmentShader)
            GLES20.glLinkProgram(it)
        }
    }

    fun draw(mvpMatrix: FloatArray) {
        GLES20.glUseProgram(mProgram)
        val positionHandle: Int = GLES20.glGetAttribLocation(mProgram, "vPosition")
        GLES20.glEnableVertexAttribArray(positionHandle)
        GLES20.glVertexAttribPointer(positionHandle, 3, GLES20.GL_FLOAT, false, 12, vertexBuffer)

        val mvpMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix")
        GLES20.glUniformMatrix4fv(mvpMatrixHandle, 1, false, mvpMatrix, 0)

        val mColorHandle: Int = GLES20.glGetUniformLocation(mProgram, "vColor")
        GLES20.glUniform4fv(mColorHandle, 1, floatArrayOf(0.63671875f, 0.76953125f, 0.22265625f, 1.0f), 0)

        GLES20.glDrawArrays(GLES20.GL_TRIANGLE_FAN, 0, 4)

        GLES20.glDisableVertexAttribArray(positionHandle)
    }
}

class Triangle {
    private val triangleCoords = floatArrayOf(
        0.0f,  0.9f, 0.0f,  // Верхняя точка
        -0.5f, 0.1f, 0.0f, // Левая нижняя точка
        0.5f, 0.1f, 0.0f   // Правая нижняя точка
    )

    private val vertexShaderCode =
        "uniform mat4 uMVPMatrix;" +
                "attribute vec4 vPosition;" +
                "void main() {" +
                "  gl_Position = uMVPMatrix * vPosition;" +
                "}"

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

    private var mProgram: Int = 0

    private val vertexBuffer: FloatBuffer = ByteBuffer.allocateDirect(triangleCoords.size * 4)
        .order(ByteOrder.nativeOrder())
        .asFloatBuffer()
        .put(triangleCoords)
        .apply { position(0) }

    init {
        val vertexShader: Int = loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode)
        val fragmentShader: Int = loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode)

        mProgram = GLES20.glCreateProgram().also {
            GLES20.glAttachShader(it, vertexShader)
            GLES20.glAttachShader(it, fragmentShader)
            GLES20.glLinkProgram(it)
        }
    }

    fun draw(mvpMatrix: FloatArray) {
        GLES20.glUseProgram(mProgram)

        val positionHandle: Int = GLES20.glGetAttribLocation(mProgram, "vPosition")
        GLES20.glEnableVertexAttribArray(positionHandle)
        GLES20.glVertexAttribPointer(positionHandle, 3, GLES20.GL_FLOAT, false, 12, vertexBuffer)

        val mvpMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix")
        GLES20.glUniformMatrix4fv(mvpMatrixHandle, 1, false, mvpMatrix, 0)

        val mColorHandle: Int = GLES20.glGetUniformLocation(mProgram, "vColor")
        GLES20.glUniform4fv(mColorHandle, 1, floatArrayOf(0.63671875f, 0.76953125f, 0.22265625f, 1.0f), 0)

        GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, 3)

        GLES20.glDisableVertexAttribArray(positionHandle)
    }
}

fun loadShader(type: Int, shaderCode: String): Int {
    return GLES20.glCreateShader(type).also { shader ->
        GLES20.glShaderSource(shader, shaderCode)
        GLES20.glCompileShader(shader)
    }
}