LWJGL 三角形未显示 kotlin

Question

我试图用 LWJGL 在 kotlin 中制作三角形着色器，但由于某种原因它不起作用并且我没有收到任何错误。调试起来真的很难，因为即使我故意在着色器代码中写错了东西，我仍然没有收到任何错误，所以我什至无法判断这段代码有什么问题。

三角形类代码：

class Triangle {
    private var vertexShaderCode: String = "" +
            "attribute vec4 vPosition; \n" +
            "void main() { \n" +
            "   gl_Position = vPosition; \n" +
            "}"
    private var fragmentShaderCode: String = "" +
            "precision mediump float; \n" +
            "uniform vec4 vColor; \n" +
            "void main() { \n" +
            "   gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0); \n" +
            "}"

    private lateinit var vertexBuffer: FloatBuffer

    private val COORDS_PER_VERTEX: Int = 3
    private val triangleCoords = floatArrayOf(
        0.0f, 0.0f, 0.0f,
        0.0f, 1.0f, 0.0f,
        1.0f, 0.0f, 0.0f
    )
    private val color = floatArrayOf(1.0f, 0.0f, 0.0f, 1.0f)

    private val mProgram: Int

    var VBO: Int
    var VAO: Int

    init {
        VBO = glGenBuffers()
        VAO = glGenVertexArrays()

        glBindVertexArray(0)

        val vertexShader: Int = Engine().loadShader(GL_VERTEX_SHADER, vertexShaderCode)
        val fragmentShader: Int = Engine().loadShader(GL_FRAGMENT_SHADER, fragmentShaderCode)

        mProgram = glCreateProgram()

        glAttachShader(mProgram, vertexShader)
        glAttachShader(mProgram, fragmentShader)

        glLinkProgram(mProgram)
    }

    fun draw() {
        glUseProgram(mProgram)

        VBO = glGenBuffers()
        VAO = glGenVertexArrays()

        glBindVertexArray(VAO)
        glBindBuffer(GL_ARRAY_BUFFER, VBO)

        GL15.glBufferData(GL_ARRAY_BUFFER, triangleCoords, GL_STATIC_DRAW)

        GL20.glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, 0)

        glBindVertexArray(VAO)

        glDrawArrays(GL_TRIANGLES, 0, 3)

        glDisableVertexAttribArray(0)
        glBindVertexArray(0)
    }
}

应用代码：

class Engine {
    private var window: Long = 0

     fun run() {
        println("Hello LWJGL " + Version.getVersion() + "!")

        init()
        loop()

        glfwFreeCallbacks(window)
        glfwDestroyWindow(window)

        glfwTerminate()
        glfwSetErrorCallback(null)?.free()
    }

    private fun init() {
        GLFWErrorCallback.createPrint(System.err).set()

        if(!glfwInit())
            throw IllegalStateException("Unable to initialize GLFW!")

        glfwDefaultWindowHints()
        glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE)
        glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE)
        glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3)
        glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0)

        window = glfwCreateWindow(600, 800, "Hello World!", NULL, NULL)
        if(window==NULL)
            throw RuntimeException("Failed to create the GLFW window!")

        stackPush().use { stack ->
            val pWidth = stack.mallocInt(1) // int*
            val pHeight = stack.mallocInt(1) // int*

            // Get the window size passed to glfwCreateWindow
            glfwGetWindowSize(window, pWidth, pHeight)

            // Get the resolution of the primary monitor
            val vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor())

            // Center the window
            glfwSetWindowPos(
                window,
                (vidmode!!.width() - pWidth[0]) / 2,
                (vidmode.height() - pHeight[0]) / 2
            )
        }


        glfwMakeContextCurrent(window)
        glfwSwapInterval(1)
        glfwShowWindow(window)
    }

    private fun loop(){
        GL.createCapabilities()

        var triangle = Triangle1()
        glClearColor(1.0f, 1.0f, 1.0f, 1.0f)

        while(!glfwWindowShouldClose(window)) {
            glClear(GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT)

            triangle.draw()

            glfwSwapBuffers(window)

            glfwPollEvents()
        }
    }

    fun loadShader(type: Int, shaderCode: String): Int {
        val shader = glCreateShader(type)
        glShaderSource(shader, shaderCode)
        glCompileShader(shader)
        return shader
    }
}

Answer 1

好的，所以这段代码有很多问题。我的问题下的评论真的很有帮助，所以谢谢！如果有人有类似的问题，我发布此代码的固定版本。

class Triangle {
    private var vertexShaderCode: String = "" +
            "#version 330\n" +
            "attribute vec4 vPosition; \n" +
            "void main() { \n" +
            "   gl_Position = vPosition; \n" +
            "}"
    private var fragmentShaderCode: String = "" +
            "#version 330 \n" +
            "precision mediump float; \n" +
            "uniform vec4 vColor; \n" +
            "void main() { \n" +
            "   gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0); \n" +
            "}"

    private val COORDS_PER_VERTEX: Int = 3
    private val triangleCoords = floatArrayOf(
        +0.0f, +0.8f,    // Top coordinate
        -0.8f, -0.8f,    // Bottom-left coordinate
        +0.8f, -0.8f     // Bottom-right coordinate
    )

    private var coordsBuffer: FloatBuffer = BufferUtils.createFloatBuffer(triangleCoords.size)

    private val color = floatArrayOf(1.0f, 0.0f, 0.0f, 1.0f)

    private val mProgram: Int

    var VBO: Int
    var VAO: Int

    var vertexShader: Int
    var fragmentShader: Int

    init {
        coordsBuffer.put(triangleCoords).flip()

        VAO = glGenVertexArrays()
        glBindVertexArray(VAO)

        VBO = glGenBuffers()
        glBindBuffer(GL_ARRAY_BUFFER, VBO)
        GL15.glBufferData(GL_ARRAY_BUFFER, coordsBuffer, GL_STATIC_DRAW)

        GL20.glVertexAttribPointer(0, 2, GL_FLOAT, false, 0, 0)

        vertexShader = Engine().loadShader(GL_VERTEX_SHADER, vertexShaderCode)
        fragmentShader = Engine().loadShader(GL_FRAGMENT_SHADER, fragmentShaderCode)

        mProgram = glCreateProgram()

        glAttachShader(mProgram, vertexShader)
        glAttachShader(mProgram, fragmentShader)

        glLinkProgram(mProgram)
        if (glGetProgrami(mProgram, GL_LINK_STATUS) == GL_FALSE)
            throw RuntimeException("Unable to link shader program:")
    }

    fun draw() {
        glUseProgram(mProgram)

        glBindVertexArray(VAO)
        glEnableVertexAttribArray(0)

        glDrawArrays(GL_TRIANGLES, 0, 3)

        glDisableVertexAttribArray(0)
        glBindVertexArray(0)
        glUseProgram(0)
    }