TextRenderer speed

OpenGL Development JOGL Development
#1

I’m rendering approximately 150 different labels where each letter is rendered on a curve. My solution has been to render each letter separately but this is horribly slow (4 fps). Is there any way of speeding this up?

#2

You’re not calling beginRendering() / endRendering() between each letter, are you? If you don’t do this then you should get good performance.

#3

I do this for each label:


private void renderLabel(GL gl, TextRenderer textRenderer, String label, float[] color) {
        gl.glPushMatrix();
        textRenderer.setColor(color[0], color[1], color[2], color[3]);
        textRenderer.begin3DRendering();

        float maxW = 0.0f;
        float span = 0;
        for (int i = 0; i < label.length(); i++) {
            float w = textRenderer.getCharWidth(label.charAt(i));
            if (w > maxW) {
                maxW = w;
            }
            span += w;
        }


        float angle = span * 180.0f / 2500.0f;
        float step = angle / span;
        float rotate = 0.0f;
        gl.glRotatef(-(180.0f - angle) / 2.0f, 0, 0, 1);

        for (int i = 0; i < label.length(); i++) {

            char c = label.charAt(i);
            float w = textRenderer.getCharWidth(c);

            gl.glPushMatrix();

            gl.glRotatef(-rotate, 0, 0, 1);
            gl.glTranslatef(-0.86f, 0, 0);
            gl.glRotatef(90, 0, 0, 1);
            textRenderer.draw3D("" + c, 0, 0, 0, 0.001f);
            textRenderer.flush();
            gl.glPopMatrix();
            rotate += step * w;
        }

        textRenderer.end3DRendering();
        gl.glPopMatrix();
}

TextRenderer is made once. The code is not optimal and there are some magic numbers but this was the only way I could make it work

#4

I reworked the algorithm to only call begin3DRendering() and end3DRendering() once for all labels, but there is no improvement on speed.

I profiled the application using JProfiler and it seems more than half of the slow rendering time is spent in flush()

#5

just try not calling flush() at all. i think it is automatically called in the end3Drendering()

#6

If I don’t call flush() then the translate and rotate transformations are not applied to each letter.

#7

are you using the latest version of jogl (RC8) ?

try changing the value of:
setUseVertexArrays(true/false)

#8

I updated to the current nightly build and tried setting setUseVertexArrays(true/false) but the results are the same.

#9

Can you email me a complete test case? kenneth dot russell at sun dot com .

#10

I was in the process of making a test case when I retried setting setUseVertexArrays(false) and now it was fast. ???