模型法线（或其他东西）的 GLES 2.0 错误

Question

这是我修改 Google CardBoard 示例的项目： https://github.com/MrCsabaToth/cardboard-java

（我基本上砍掉了一堆东西：我不需要 3D 音频反馈，我不生成立方体。我的 3D 模型中没有 "floor"（大表面下面呈现为网格），但我前面有一个表面（我称之为屏幕），我将 png 图像渲染为纹理。因此着色器（片段和顶点）也非常简单。）

不幸的是我在修改过程中做错了什么，我无法弄清楚它是什么。

如果我取消注释 MainActivity (https://github.com/MrCsabaToth/cardboard-java/blob/master/CardboardSample/src/main/java/com/google/vrtoolkit/cardboard/samples/treasurehunt/MainActivity.java#L289) 中的第 289 行 (GLES20.glEnableVertexAttribArray(screenNormalParam);)，应用程序会在启动后崩溃：

01-16 20:17:40.325 9167-9305/com.google.vrtoolkit.cardboard.samples.treasurehunt I/OpenGLRenderer: Initialized EGL, version 1.4
01-16 20:17:40.355 9167-9305/com.google.vrtoolkit.cardboard.samples.treasurehunt I/OpenGLRenderer: HWUI protection enabled for context ,  &this =0xaf440088 ,&mEglDisplay = 1 , &mEglConfig = 8 
01-16 20:17:40.355 9167-9305/com.google.vrtoolkit.cardboard.samples.treasurehunt D/OpenGLRenderer: Enabling debug mode 0
01-16 20:17:40.485 9167-9302/com.google.vrtoolkit.cardboard.samples.treasurehunt I/MainActivity: onSurfaceCreated
01-16 20:17:40.515 9167-9305/com.google.vrtoolkit.cardboard.samples.treasurehunt V/RenderScript: Application requested CPU execution
01-16 20:17:40.525 9167-9302/com.google.vrtoolkit.cardboard.samples.treasurehunt W/Adreno-ES20: <core_glEnableVertexAttribArray:193>: GL_INVALID_VALUE
01-16 20:17:40.525 9167-9302/com.google.vrtoolkit.cardboard.samples.treasurehunt E/MainActivity: Screen program params: glError 1281
01-16 20:17:40.535 9167-9305/com.google.vrtoolkit.cardboard.samples.treasurehunt V/RenderScript: 0xa126c400 Launching thread(s), CPUs 4
01-16 20:17:40.545 9167-9302/com.google.vrtoolkit.cardboard.samples.treasurehunt E/AndroidRuntime: FATAL EXCEPTION: GLThread 231450
                                                                                               Process: com.google.vrtoolkit.cardboard.samples.treasurehunt, PID: 9167
                                                                                               java.lang.RuntimeException: Screen program params: glError 1281
                                                                                                   at com.google.vrtoolkit.cardboard.samples.treasurehunt.MainActivity.checkGLError(MainActivity.java:177)
                                                                                                   at com.google.vrtoolkit.cardboard.samples.treasurehunt.MainActivity.onSurfaceCreated(MainActivity.java:292)
                                                                                                   at com.google.vrtoolkit.cardboard.CardboardViewNativeImpl$RendererHelper.callOnSurfaceCreated(CardboardViewNativeImpl.java:811)
                                                                                                   at com.google.vrtoolkit.cardboard.CardboardViewNativeImpl$RendererHelper.onSurfaceCreated(CardboardViewNativeImpl.java:832)
                                                                                                   at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1509)
                                                                                                   at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1248)

我的主要问题是我并没有真正得到任何关于错误的更详细信息，glError 1281 非常广泛。通过反复试验，我发现在评论第 289 行（上面提到的）之后，应用程序开始运行并且看起来像在运行，但它充斥着 LogCat 这个（不好）：

01-16 16:38:57.984 30664-30723/com.google.vrtoolkit.cardboard.samples.treasurehunt W/Adreno-ES20: <core_glVertexAttribPointer:533>: GL_INVALID_VALUE
01-16 16:38:57.984 30664-30723/com.google.vrtoolkit.cardboard.samples.treasurehunt E/MainActivity: drawing screen: glError 1281
01-16 16:38:57.984 30664-30723/com.google.vrtoolkit.cardboard.samples.treasurehunt W/System.err: java.lang.RuntimeException: drawing screen: glError 1281
01-16 16:38:57.984 30664-30723/com.google.vrtoolkit.cardboard.samples.treasurehunt W/System.err:     at com.google.vrtoolkit.cardboard.samples.treasurehunt.MainActivity.checkGLError(MainActivity.java:177)
01-16 16:38:57.984 30664-30723/com.google.vrtoolkit.cardboard.samples.treasurehunt W/System.err:     at com.google.vrtoolkit.cardboard.samples.treasurehunt.MainActivity.drawScreen(MainActivity.java:406)
01-16 16:38:57.984 30664-30723/com.google.vrtoolkit.cardboard.samples.treasurehunt W/System.err:     at com.google.vrtoolkit.cardboard.samples.treasurehunt.MainActivity.onDrawEye(MainActivity.java:368)
01-16 16:38:57.984 30664-30723/com.google.vrtoolkit.cardboard.samples.treasurehunt W/System.err:     at com.google.vrtoolkit.cardboard.CardboardViewNativeImpl.nativeOnDrawFrame(Native Method)
01-16 16:38:57.984 30664-30723/com.google.vrtoolkit.cardboard.samples.treasurehunt W/System.err:     at com.google.vrtoolkit.cardboard.CardboardViewNativeImpl.access00(CardboardViewNativeImpl.java:52)
01-16 16:38:57.984 30664-30723/com.google.vrtoolkit.cardboard.samples.treasurehunt W/System.err:     at com.google.vrtoolkit.cardboard.CardboardViewNativeImpl$RendererHelper.onDrawFrame(CardboardViewNativeImpl.java:741)
01-16 16:38:57.984 30664-30723/com.google.vrtoolkit.cardboard.samples.treasurehunt W/System.err:     at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1531)
01-16 16:38:57.984 30664-30723/com.google.vrtoolkit.cardboard.samples.treasurehunt W/System.err:     at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1248)

调用堆栈将我引向 checkGLError，这将我引向通用 glError 1281。我是 OpenGL 调试的新手，感谢任何帮助。

Answer 1

在我的简单着色器中，我实际上并没有使用法线进行计算。我注意到 screenNormalParam 整数的值为 -1。我修改了顶点着色器并添加了一个 varying vec3 v_Normal 变量。我仍然没有将这个变量用于任何计算，因为闪电对我的应用程序无关紧要，但我只是做了一个虚拟赋值 v_Normal = a_Normal:

uniform mat4 u_Model;
uniform mat4 u_MVMatrix;
uniform mat4 u_MVP;

attribute vec4 a_Position;
attribute vec3 a_Normal;
attribute vec2 a_TexCoordinate;

varying vec2 v_TexCoordinate;
varying vec3 v_Normal;

void main() {
   v_TexCoordinate = a_TexCoordinate;
   v_Normal = a_Normal;

   gl_Position = u_MVP * a_Position;
}

screenModelParam（u_Model）和screenModelViewParam（u_MVMatrix）仍然是-1，但它们不像u_MVP那样使用，我不'对他们打电话 GLES20.glEnableVertexAttribArray。到目前为止，我现在没有看到错误消息，但我不明白为什么需要虚拟变量，我想我需要了解更多有关着色器的知识。

模型法线（或其他东西）的 GLES 2.0 错误

GLES 2.0 error with model normals (or something else)

java

android

opengl-es

opengl-es-2.0

google-cardboard