Runs at 6fps =( about cubecloud

[quinkennedy]

I migrated to VBOs, but didn't see a big improvement on my computer. Still want to figure out how to push a lot of the logic to the graphics card instead of using a nested for loop.

[obviousjim]

we gotta try vbo instancing example!

On Tue, Jul 30, 2013 at 10:51 AM, quinkennedy [email protected]:

I migrated to VBOs, but didn't see a big improvement on my computer. Still
want to figure out how to push a lot of the logic to the graphics card
instead of using a nested for loop.

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/1#issuecomment-21796245
.

• James

[larsberg]

It seems like we could do all of the rendering / randomness in the shader.
Using a big VBO with all the vertices for each box we could get the
randomness and color in the shader with no CPU computation;

I'm happy to help out, maybe I'll branch it and make a little test

On Tue, Jul 30, 2013 at 12:06 PM, James George [email protected]:

we gotta try vbo instancing example!

On Tue, Jul 30, 2013 at 10:51 AM, quinkennedy [email protected]:

I migrated to VBOs, but didn't see a big improvement on my computer.
Still
want to figure out how to push a lot of the logic to the graphics card
instead of using a nested for loop.

—
Reply to this email directly or view it on GitHub<
https://github.com/CLOUDS-Interactive-Documentary/CubeCloud/issues/1#issuecomment-21796245>

.

• James

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/1#issuecomment-21802075
.

[quinkennedy]

I'd love to work through it with you Lars, but I am a little worried that if you create a branch, all the work will be done and I'll learn nothing!

[quinkennedy]

it looks like ofVboMesh.drawInstanced does not exist in our version of oF. Also, I can't seem to find ofBoxPrimitive either (which he uses in his example to construct the ofVboMesh). There is an instanced arrays extension in OpenGL (http://sol.gfxile.net/instancing.html) but I'm not familiar enough with the OpenGL pipeline and oF to understand how I would go about experimenting with it.

Would it make sense to create a VBO that is the 10,000 cubes, so in draw all I do is "vboLotsBox.drawElements(...) and the shader handles the rest? Or how else can you efficiently push 10,000 cubes into the pipeline every frame? Anything better than for(1->10000){vboBox.drawElements(...);}?

[quinkennedy]

so I'm trying this:

vboBox.bind();
glDrawElementsInstanced(GL_TRIANGLES, 36, GL_UNSIGNED_INT, NULL, 10000);

where vboBox is a vbo representing a cube (ripped from ofBox) with 36 indices.

but getting Bad Access errors. :(

[jonathanminard]

Any progress on this? Would be great to include it!

[quinkennedy]

so I think I got instancing working on the cpp side with the following code:

vboBox.bind();
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vboBox.getIndexId());
glDrawElementsInstanced(GL_TRIANGLES, 36, GL_UNSIGNED_INT, NULL, 10000);
vboBox.unbind();

but in the example they are using version 150 for the fragment shader, and xcode complains if I set the version above 120. And as it sits now, I don't have access to the ever-important gl_InstanceID variable to know which instance I am rendering.

I tried creating a huge vbo of 10000 cubes up-front so I only have to draw one vbo once each frame, but my framerate is horrible.

[quinkennedy]

maybe I was mistaken, just tried the 10000 cubes in one vbo and was at 60fps, now I have to update my shader to accommodate.

[obviousjim]

Any updates we can try to pull in Quin? would love to see the optimized VBO version

[quinkennedy]

Not yet, I started but might not have time until October to finish up the optimization. I'll lift my "Lars Ban" in case you really want to jam it out, y'know, or anyone else.

[larsberg]

I could take a pass at it later tonight. Quin, what's the setup here? Are the boxes randomly scaling in one direction? Or is it more complicated then that. I know you were talking about filling buckets… does that mean that the randomness accumulates and dissipates gradually?

[quinkennedy]

the original code the buckets fill up to 200 and then roll-over to 0, each
bucket corresponds to the height of one cube. from 0-100 the cube bottom is
at 0 and the height increases. from 100-200 the cube top is at full height
and the cube bottom goes up to meet it.

so I was thinking 2 textures to ping-pong the buckets, and then rendering
the cubes based on the bucket texture data.

On Mon, Sep 9, 2013 at 12:01 PM, Lars Berg [email protected] wrote:

I could take a pass at it later tonight. Quin, what's the setup here? Are
the boxes randomly scaling in one direction? Or is it more complicated then
that. I know you were talking about filling buckets… does that mean that
the randomness accumulates and dissipates gradually?

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/1#issuecomment-24089547
.

Quin Kennedy
[email protected]
cell: [phone]

[quinkennedy]

I have updated the code to use a shader and set of FBOs to control the cube extrusion. It is in an interim state right now as I test out different approaches for getting the pseudo-randomness to appear truly random.