lwjgl 3，glUniformMatrix4导致jre崩溃 [英] lwjgl 3 , glUniformMatrix4 causes jre to crash
问题描述
我正在使用lwjgl 3并学习现代的opengl(3).我想将统一矩阵发送到顶点着色器，以便我可以应用变换.我试过了，程序因该错误而崩溃
I'm using lwjgl 3 and learning modern opengl (3). I want to send a uniform matrix to the vertex shader so i can apply transformations. I tried that and the program crashes with this error
#
# A fatal error has been detected by the Java Runtime Environment:
#
# EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x0000000073a9820d, pid=8644, tid=2760
#
# JRE version: Java(TM) SE Runtime Environment (8.0_31-b13) (build 1.8.0_31-b13)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (25.31-b07 mixed mode windows-amd64 compressed oops)
# Problematic frame:
# C [nvoglv64.DLL+0xd5820d]
#
# Failed to write core dump. Minidumps are not enabled by default on client versions of Windows
#
# An error report file with more information is saved as:
# E:\Copy\Code\Personal\atei-graphics\GraphicsProject\hs_err_pid8644.log
#
# If you would like to submit a bug report, please visit:
# http://bugreport.java.com/bugreport/crash.jsp
# The crash happened outside the Java Virtual Machine in native code.
# See problematic frame for where to report the bug.
#
很明显我做错了事.
问题似乎出在这行代码中
The problem seems to be in this line of code
glUniformMatrix4(uniformMatrixLocation, false, mvp.getBuffer());
如果我删除此行代码，程序将无错误执行.
The program executes without error if i remove this line of code.
我尝试传递对角矩阵以检查问题是否出在矩阵本身上，但我仍然得到相同的结果
I tried passing a diagonal matrix to check if the problem was with the matrix itself and still i got the same result
mvp是我传递给着色器的对角矩阵.
UniformMatrixLocation保持我在此行代码中找到的位置
mvp is the diagonal matrix i am passing to the shader.
uniformMatrixLocation hold the position i found with this line of code
glGetUniformLocation(shaderProgram.programId, "MVP");
它不会返回负数，因此这里可能没有错误.
which doesn't return a negative number, so probably there are no error here.
我正在将此库用于Mat4类
https://github.com/jroyalty/jglm
I am using this library for the Mat4 class
https://github.com/jroyalty/jglm
Bellow是我的代码的一个可行的"示例，我所能得到的很小.
Bellow is a "working" example of my code as small as i can get it.
//glfw create windows and etc
int programId = glCreateProgram();
int vertexShaderId = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShaderId, FileUtils.readFile("shaders/vertex.glsl"));
glCompileShader(vertexShaderId);
if (glGetShaderi(vertexShaderId, GL_COMPILE_STATUS) == GL_FALSE) {
throw new RuntimeException("Error creating vertex shader\n"
+ glGetShaderInfoLog(vertexShaderId, glGetShaderi(vertexShaderId, GL_INFO_LOG_LENGTH)));
}
glAttachShader(programId, vertexShaderId);
int fragmentShaderId = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShaderId, FileUtils.readFile("shaders/fragment.glsl"));
glCompileShader(fragmentShaderId);
if (glGetShaderi(fragmentShaderId, GL_COMPILE_STATUS) == GL_FALSE) {
throw new RuntimeException("Error creating vertex shader\n"
+ glGetShaderInfoLog(fragmentShaderId, glGetShaderi(fragmentShaderId, GL_INFO_LOG_LENGTH)));
}
glAttachShader(programId, fragmentShaderId);
glLinkProgram(programId);
if (glGetProgrami(programId, GL_LINK_STATUS) == GL_FALSE) {
throw new RuntimeException("Unable to link shader program:");
}
/*
Hold the location of the matrix in the shader
*/
int uniformMatrixLocation = glGetUniformLocation(programId, "MVP");
float[] vertices = {
+0.0f, +0.8f, 0,
-0.8f, -0.8f, 0,
+0.8f, -0.8f, 0
};
int vaoId = glGenVertexArrays();
glBindVertexArray(vaoId);
FloatBuffer verticesBuffer = BufferUtils.createFloatBuffer(vertices.length);
verticesBuffer.put(vertices).flip();
int vboId = glGenBuffers();
glBindBuffer(GL_ARRAY_BUFFER, vboId);
glBufferData(GL_ARRAY_BUFFER, verticesBuffer ,GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, 0);
glBindVertexArray(0);
glClearColor(0,0,0,1);
while (glfwWindowShouldClose(window) == GL_FALSE) {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // clear the framebuffer
glUseProgram(programId);
Mat4 mvp = new Mat4(1.0f);//diagonal matrix , should just show a triangle on the screen
/*
Crashes here
*/
//glUniformMatrix4(uniformMatrixLocation, false, mvp.getBuffer());
glBindVertexArray(vaoId);
glEnableVertexAttribArray(0);
glDrawArrays(GL_TRIANGLES, 0, 3);
glDisableVertexAttribArray(0);
glBindVertexArray(0);
glUseProgram(0);
glfwPollEvents();
glfwSwapBuffers(window); // swap the color buffers
}
//dispose stuff no point showing them here
顶点着色器
#version 330 core
layout(location = 0) in vec3 position;
uniform mat4 MVP;
void main(){
gl_Position = MVP*vec4(position,1);
}
片段着色器
#version 330 core
out vec4 color;
void main()
{
color = vec4(1,1,1,1);
}
打扰一下，如果以前有人问过这个问题，我在网上搜索，没有发现任何有用的信息.预先谢谢你.
Excuse me if this has been asked before, i search the web and didn't find anything useful. Thank you in advance.
推荐答案
最有可能发生崩溃，因为您正在传递LWJGL，它是从 Mat4.getBuffer()返回的堆上浮动缓冲区. JWJGL要求您将其直接传递给缓冲区:
The crash is most likely happening because you are passing LWJGL an on-heap float buffer returned from Mat4.getBuffer(). JWJGL requires that you pass it direct buffers:
LWJGL要求传递给它的所有NIO缓冲区都是直接缓冲区.直接缓冲区实际上包装了指向堆外内存的地址，即本机指针.这是LWJGL可以安全地将数据从Java代码传递到本机代码，反之亦然的唯一方法，而不会影响性能.它不支持堆上Java数组(或包装它们的普通NIO缓冲区)，因为在本机代码访问它们时，JVM的垃圾收集器可能会在内存中四处移动数组.另外，Java数组具有未指定的布局，即它们不一定在内存中是连续的.
LWJGL requires that all NIO buffers passed to it are direct buffers. Direct buffers essentially wrap an address that points to off-heap memory, i.e. a native pointer. This is the only way LWJGL can safely pass data from Java code to native code, and vice-versa, without a performance penalty. It does not support on-heap Java arrays (or plain NIO buffers, which wrap them) because arrays may be moved around in memory by the JVM's garbage collector while native code is accessing them. In addition, Java arrays have an unspecified layout, i.e. they are not necessarily contiguous in memory.
您可以像使用顶点一样使用BufferUtils类:
You can use the BufferUtils class like you are already using for your vertices:
FloatBuffer matrixBuffer = BufferUtils.createFloatBuffer(16).put(mvp.getBuffer()).flip();
...
glUniformMatrix4(uniformMatrixLocation, false, matrixBuffer);
如果这不起作用，请尝试以下方法:
If that doesn't work, try this instead:
FloatBuffer matrixBuffer = BufferUtils.createFloatBuffer(16).put(new float[] {
1.0f, 0.0f, 0.0f, 0.0f,
0.0f, 1.0f, 0.0f, 0.0f,
0.0f, 0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 0.0f, 1.0f}).flip();
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