Question

编辑：我只是忘了绑定着色器。现在它正在发挥作用。

我目前正试图让变换反馈运行，但事实并非如此。我正在使用OpenGL 3.3并按照this教程中的步骤将其转换为Java和LWJGL。

着色器代码：

#version 330 core

in float inValue;
out float outValue;

void main(){
    outValue = sqrt(inValue);
}

着色器类代码：

... loading shaders, uniforms, attribute locations etc. ...

public void setTransformFeedbackVaryings(String[] varyings, boolean interleaved){
    int bufferMode = interleaved ? GL_INTERLEAVED_ATTRIBS : GL_SEPERATE_ATTRIBS;
    glTransformFeedbackVaryings(programID, varyings, bufferMode);
}

public void compile(){
    glLinkProgram(programID);
    glValidateProgram(programID);
    ... //error catching
}

其他：

...
//sets the list of feedback varyings names with GL_INTERLEAVED_ATTRIBS
shader.setTransformFeedbackVaryings(new String[]{"outValue"}, true);

//linking and validating shader
shader.compile();

attribLocation = shader.getAttribLocation("inValue");

//create VAO
VAO = glGenVertexArrays();
glBindVertexArrayObject(VAO);

//create data buffer
FloatBuffer buffer = ... //contains the values to be send to the shader

//create VBO
VBO = glGenBuffers();
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, buffer, GL_STATIC_DRAW);

glEnableVertexAttribArray(attribLocation);
glVertexAttribPointer(attribLocation, 1, GL_FLOAT, false, 0, 0);

//create test buffer
FloatBuffer test = ... //some values

//create transform feedback buffer
TBO = glGenBuffers();
glBindBuffer(GL_ARRAY_BUFFER, TBO);
glBufferData(GL_ARRAY_BUFFER, test, GL_STATIC_READ);

//perform feedback
glEnable(GL_RASTERIZER_DISCARD);

glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, TBO);
glBeginTransformFeedBack(GL_POINTS);

glDrawArrays(GL_POINTS, 0, NUM_VALUES);

glEndTransformFeedback();

glDisable(GL_RASTERIZER_DISCARD);

glFlush();

//read data
FloatBuffer feedback = ... //empty buffer
glGetBufferSubData(GL_TRANSFORM_FEEDBACK_BUFFER, 0, feedback);

我从反馈缓冲区获得的值是来自测试缓冲区的值。因此，编写和读取缓冲区似乎有效。当省略测试缓冲区并将空的加载到TBO时，结果都是0.我在使用{{1}时尝试用GL_ARRAY_BUFFER替换GL_TRANSFORM_FEEDBACK_BUFFER当我阅读here但它也没有用。

我没有得到任何OpenGL错误。

转换反馈空缓冲区

0 个答案: