android - OpenGL ES 3.0/GLSL 不呈现数据 (Kotlin)

Question

我正在尝试使用 OpenGL ES 3.0 实现一个基本的着色程序，并从各种教程中拼凑了这段代码。对我来说一切看起来都是正确的，编译也很好，但我的屏幕上没有任何显示。

在我添加 Normal 和 Light Position 数据之前，它呈现良好，然后它坏了，我一直无法找到修复它的方法。

谁能看出这里出了什么问题？

import android.opengl.GLES30.*
import android.opengl.GLSurfaceView.Renderer
import android.opengl.Matrix.*
import java.nio.*
import java.nio.ByteBuffer.allocateDirect
import java.nio.ByteOrder.nativeOrder
import javax.microedition.khronos.egl.EGLConfig
import javax.microedition.khronos.opengles.GL10

class GLRenderer:Renderer{
    lateinit var vBuf: FloatBuffer
    lateinit var nBuf: FloatBuffer
    var glProgram = -1
    var uMV       = -1
    var uMVP      = -1
    var uLightPos = -1
    val aPosition =  0
    val aNormal   =  1
    val aColor    =  2
    val modelM = FloatArray(16)
    val viewM  = FloatArray(16)
    val projM  = FloatArray(16)
    val mvM    = FloatArray(16)
    val mvpM   = FloatArray(16)
    val lPos   = FloatArray(4)
    val lightPos = floatArrayOf(0f,10f,0f,1f)

    override fun onSurfaceCreated(g:GL10,c:EGLConfig) {
        glClearColor(0f,0f,0f,1f)
        setLookAtM(viewM,0,0f,0f,5f,0f,0f,0f,0f,1f,0f)

        val vShader = glCreateShader(GL_VERTEX_SHADER)
        val fShader = glCreateShader(GL_FRAGMENT_SHADER)
        glShaderSource(vShader,"#version 300 es\n" +
            " uniform mat4 u_mvpM;                              " +
            " uniform mat4 u_mvM;                               " +
            " layout(location=0) in vec4 aPos;                  " +
            " layout(location=1) in vec4 aCol;                  " +
            " layout(location=2) in vec3 aNorm;                 " +
            " out vec3 vPos;                                    " +
            " out vec4 vCol;                                    " +
            " out vec3 vNorm;                                   " +
            " void main(){                                      " +
            "   vPos        = vec3(u_mvM * aPos);               " +
            "   vCol        = aCol;                             " +
            "   vNorm       = vec3(u_mvM * vec4(aNorm,0.0));    " +
            "   gl_Position = u_mvpM * aPos;}                   " )
        glShaderSource(fShader,"#version 300 es\n" +
            " precision mediump float;                          " +
            " uniform vec3 u_LightPos;                          " +
            " in  vec3 vPos;                                    " +
            " in  vec4 vCol;                                    " +
            " in  vec3 vNorm;                                   " +
            " out vec4 fColor;                                  " +
            " void main(){                                      " +
            "   float distance = length(u_LightPos - vPos);     " +
            "   vec3  lightPos = normalize(u_LightPos - vPos);  " +
            "   float diffuse  = max(dot(vNorm,lightPos),0.1)/  " +
            "                    (distance*distance/4.0 + 1.0); " +
            "   fColor         = vCol * diffuse;}               " )
        glCompileShader(vShader)
        glCompileShader(fShader)
        glProgram = glCreateProgram()
        glAttachShader(glProgram,vShader)
        glAttachShader(glProgram,fShader)
        glLinkProgram(glProgram)
        glUseProgram(glProgram)
        uMV       = glGetUniformLocation(glProgram,"u_mvM")
        uMVP      = glGetUniformLocation(glProgram,"u_mvpM")
        uLightPos = glGetUniformLocation(glProgram,"u_LightPos")

        vBuf = allocateDirect(9*4).order(nativeOrder()).asFloatBuffer().put(floatArrayOf(
               0f,1f,0f, -1f,0f,0f, 1f,0f,0f))
        nBuf = allocateDirect(9*4).order(nativeOrder()).asFloatBuffer().put(floatArrayOf(
               0f,0f,-1f, 0f,0f,-1f, 0f,0f,-1f))
        vBuf.position(0)
        nBuf.position(0)
    }
    override fun onSurfaceChanged(g:GL10,w:Int,h:Int) {
        glViewport(0,0,w,h)
        val ratio = (w/h).toFloat()
        frustumM(projM,0,-ratio,ratio,1f,-1f,1f,10f)
    }
    override fun onDrawFrame(g:GL10){
        glClear(GL_COLOR_BUFFER_BIT)
        setIdentityM(modelM,0)
        multiplyMM(mvM, 0,viewM,0,modelM,0)
        multiplyMM(mvpM,0,projM,0,mvM,0)
        multiplyMV(lPos,0,mvpM,0,lightPos,0)

        glUniformMatrix4fv(uMV, 1,false,mvM, 0)
        glUniformMatrix4fv(uMVP,1,false,mvpM,0)
        glUniform3f(uLightPos,lPos[0],lPos[1],lPos[2])
        glVertexAttribPointer(aPosition,3,GL_FLOAT,false,0,vBuf)
        glVertexAttribPointer(aNormal,  3,GL_FLOAT,false,0,nBuf)
        glVertexAttrib4f(aColor,1f,1f,1f,1f)
        glEnableVertexAttribArray(aPosition)
        glEnableVertexAttribArray(aNormal)
        glDrawArrays(GL_TRIANGLES,0,vBuf.capacity()/4)
    }
}

Answer 1

layout qualifiers 之间不匹配在着色器程序中和应用程序中的资源索引:

aPos、aCol 和aNorm 的布局位置是 0, 1, 2

layout(location=0) in vec4 aPos;
layout(location=1) in vec4 aCol;
layout(location=2) in vec3 aNorm;

但是应用中对应的变量(aPosition、aColor、aNormal)初始化为0、2、1:

val aPosition =  0
val aNormal   =  1
val aColor    =  2