LWJGL Forum

Hi, I was working through some tutorials around to learn other techniques than immediate mode. Basically translating this C example into LWJGL: http://www.mbsoftworks.sk/index.php?page=tutorials&series=1&tutorial=5 (http://www.mbsoftworks.sk/index.php?page=tutorials&series=1&tutorial=5)

So I create a float[] of for the triangle data, push it into a buffer in my initArrays() method.

Then in my render() method I bind to that buffer and set up the vertex array pointer to start at zero and move in steps of 3 over the buffer (to get the 3 values to form the vertex locations I'm assuming). However, when it executes the call to glVertexAttribPointer() I get the following exception:

Exception in thread "main" org.lwjgl.opengl.OpenGLException: Cannot use Buffers when Array Buffer Object is enabled
at org.lwjgl.opengl.GLChecks.ensureArrayVBOdisabled(GLChecks.java:87)
at org.lwjgl.opengl.GL20.glVertexAttribPointer(GL20.java:835)
at com.gordonmcmahon.lwjgl.temp.OpenGL3App.render(OpenGL3App.java:79)
at com.gordonmcmahon.lwjgl.temp.OpenGL3App.<init>(OpenGL3App.java:39)
at com.gordonmcmahon.lwjgl.temp.OpenGL3App.main(OpenGL3App.java:85)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)



I've googled and gone through the source to try and find out why arrayBuffer is set to 1 on the Capabilities (and therefore failing the GLCheck) but I've not come up with much. Source for the two key methods below, but I can post the whole source if you think that will help.

Thanks in advance.



[tt]private void initArrays(){
        fTriangle[0] = -0.2f;   fTriangle[1] = 0.1f;    fTriangle[2] = 0.0f;
        fTriangle[3] = 0.4f;    fTriangle[4] = 0.1f;    fTriangle[5] = 0.0f;
        fTriangle[6] = 0.0f;    fTriangle[7] = 0.7f;    fTriangle[8] = 0.0f;

        triangleBuffer = BufferUtils.createFloatBuffer(fTriangle.length);
        triangleBuffer.put(fTriangle);

        uiVBO = BufferUtils.createIntBuffer(1);
        glGenBuffers(uiVBO);

        glBindBuffer(GL_ARRAY_BUFFER, uiVBO.get(0));
        glBufferData(GL_ARRAY_BUFFER, triangleBuffer, GL_STATIC_DRAW );
    }



   
private void render() {
        glClear(GL_COLOR_BUFFER_BIT);

        glEnableVertexAttribArray(0);

        // Triangle render
        glBindBuffer(GL_ARRAY_BUFFER, uiVBO.get(0));
        glVertexAttribPointer(0, 3, false, 0, triangleBuffer);    // THIS IS WHERE THE EXCEPTION IS THROWN
        glDrawArrays(GL_TRIANGLES, 0, 3);
    }


Ahh...you've all played a cunning game of "leave him alone and he'll fix it himself". Well done. I've since got my code working and have a much better understanding of what I was doing wrong.

Quote from: ReddZed on June 19, 2012, 07:48:46
Ahh...you've all played a cunning game of "leave him alone and he'll fix it himself". Well done. I've since got my code working and have a much better understanding of what I was doing wrong.

Lol... :D