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by blu
Fri Mar 08, 2013 4:39 pm
Forum: OpenGLES
Topic: Explanation of vertex skinning
Replies: 6
Views: 3822

Re: Explanation of vertex skinning

I do have a patch that may improve things. Where the shader compile previously failed it will now try again with a different register allocation scheme that should handle loops better. I tried it a while back, and it didn't fix the case I was looking at (Mandelbrots). Because the new scheme only ru...
by blu
Fri Mar 08, 2013 12:09 am
Forum: OpenGLES
Topic: Explanation of vertex skinning
Replies: 6
Views: 3822

Re: Explanation of vertex skinning

Janq's really concise post on skinning deserves commendation. Just to add the traditional extra .02 to the subject: Bone transformations usually form a skeletal structure - normally a tree where each node is defined in the space of a single parent, with the sole exception of the root node which has ...
by blu
Fri Jan 25, 2013 11:16 am
Forum: OpenGLES
Topic: Announcement: GLSL live coder(yet another
Replies: 3
Views: 2644

Re: Announcement: GLSL live coder(yet another

Great job! Thank you for sharing. I've been meaning to do something similar for ages, but never got to it.
by blu
Fri Dec 21, 2012 9:03 am
Forum: Graphics programming
Topic: How to use EGL Lock Surface extension?
Replies: 3
Views: 1832

Re: How to use EGL Lock Surface extension?

From 3D guy: "I don't think we support it in any useful way, no." I have a few Why It's not supported? What is lacking for support it? Is it a hardware issue or a software one? Is it on the roadmap? There isn't any workaround? Thanks, I remember bumping into the same issue when I was trying to get ...
by blu
Mon Nov 05, 2012 2:48 pm
Forum: OpenGLES
Topic: Floating point multiplication
Replies: 2
Views: 1998

Re: Floating point multiplication

While you would not want to do that just for a few scalars (the latency cost of the op would be enormous), the normal way to do GPGPU would be through FP32 (single precision) or FP16 (half precision) textures containing the arguments, potentially on a fast client-update path if the arg data is highl...
by blu
Mon Nov 05, 2012 2:31 pm
Forum: OpenGLES
Topic: 1.1 vs 2.0 performance?
Replies: 8
Views: 2843

Re: 1.1 vs 2.0 performance?

Hi blu, do you mind if I ask you if the "codegen -> compile -> link" bit is an educated guess or you have some inside information? I would hope that 1.1 drivers could just stitch and patch some pre-written code blocks together. Hi Emanuele. Yes, stitching & patching pre-existing blocks of code is n...
by blu
Thu Nov 01, 2012 8:58 am
Forum: OpenGLES
Topic: 1.1 vs 2.0 performance?
Replies: 8
Views: 2843

Re: 1.1 vs 2.0 performance?

Normally, ES1.1 implementations sit on top of ES2 (basically as wrappers with extra state tracking), so the main difference you'd encounter in speed would come from the API assumptions about the render state which is relevant to your app's needs. For instance, ES1.1 needs to re-create shaders before...
by blu
Wed Oct 10, 2012 9:13 am
Forum: OpenGLES
Topic: OUT_OF_MEMORY in glDrawElements
Replies: 4
Views: 1956

Re: OUT_OF_MEMORY in glDrawElements

I faced the same issue some time ago - glDraw* ending in GL_OUT_OF_MEMORY, but the issue in my case was the shader compiler - the vertex shader was too complex. I suggest you dumb down your shaders for the sake of the experiment.
by blu
Fri Oct 05, 2012 9:53 am
Forum: OpenGLES
Topic: Minor question on GLES2 VBOs
Replies: 1
Views: 1310

Re: Minor question on GLES2 VBOs

The latter.
by blu
Fri Oct 05, 2012 6:18 am
Forum: OpenGLES
Topic: Embedding binary files in Opengl ES
Replies: 2
Views: 1482

Re: Embedding binary files in Opengl ES

The code you quote above is C preprocessor code - those are basically convenience macros. Let's go in details: #define is a preprocessor keyword for defining a macro. TEXTUREREF() and TEXTURE() are the names of the macros being defined. The first is an external variable declaration statement (i.e. e...
by blu
Mon Sep 24, 2012 6:35 pm
Forum: Graphics programming
Topic: I can see X through my OpenGL pixels
Replies: 3
Views: 2004

Re: I can see X through my OpenGL pixels

You need to explicitly tell dispmanx to not use the GL fb's alpha as source for the overlay blend, like this:

http://code.google.com/p/test-es/source ... cm.cpp#567
by blu
Mon Sep 17, 2012 10:03 am
Forum: OpenGLES
Topic: Taking screenshots of native window
Replies: 3
Views: 1788

Re: Taking screenshots of native window

Well, as you say such a function is fairly trivial. Here's one version:

http://code.google.com/p/test-es/source ... in.cpp#861
by blu
Sun Sep 16, 2012 11:01 pm
Forum: OpenGLES
Topic: Taking screenshots of native window
Replies: 3
Views: 1788

Re: Taking screenshots of native window

by blu
Mon Sep 10, 2012 10:08 am
Forum: Graphics programming
Topic: GLES2 -- how supported?
Replies: 11
Views: 3977

Re: GLES2 -- how supported?

But anyway: my shader test works now, but still, the part where the obviously not correct vertex shader returns an GL_TRUE on getting the compilation state is very weird, and this even happens in the hello_triangle2 demo as I demonstrated in the above post... Actually, it might not be as weird as i...
by blu
Fri Aug 31, 2012 6:56 pm
Forum: OpenGLES
Topic: EGL display not pixel precise
Replies: 4
Views: 1909

Re: EGL display not pixel precise

Well, that's not EGL picking the res - that's dispmanx, IIRC. So you're saying that 720x480 spans the entire screen, while the actual res of 320x240 - only a quarter? BTW, 720x480 is a standard NTSC res (well, with some overscan), so my guess is that there's some firmware/driver logic somewhere whic...
by blu
Fri Aug 31, 2012 12:16 pm
Forum: OpenGLES
Topic: EGL display not pixel precise
Replies: 4
Views: 1909

Re: EGL display not pixel precise

Can you post some code showing how you init the EGL context? Generally, I'm not aware how EGL could automatically pick fb resolutions, but apparently I'm missing something from the picture.
by blu
Wed Aug 29, 2012 10:38 am
Forum: Bare metal, Assembly language
Topic: ARM assembler tutorial for Raspberry Pi
Replies: 25
Views: 19972

Re: ARM assembler tutorial for Raspberry Pi

Good tutorial! Though I'm not convinced its place is under the 'bare metal' section ; ]

While on the subject of 'ARM assembly intros out there', here's something light and educational (well, lighter than ARM's official ARM anyway): http://simplemachines.it/doc/arm_inst.pdf
by blu
Tue Aug 28, 2012 2:26 pm
Forum: OpenGLES
Topic: Gimbal lock, despite using Matrices and Quaternions
Replies: 15
Views: 4279

Re: Gimbal lock, despite using Matrices and Quaternions

Davespice, I'd advise you to leave quaternions aside for now (you can always revisit them later) and focus on the Euler-based transforms. What Janq says about small, relative rotations avoiding the Gimbal Lock is true for any kind of transformation which implements rotations around the axes of a coo...
by blu
Tue Aug 28, 2012 11:21 am
Forum: OpenGLES
Topic: Gimbal lock, despite using Matrices and Quaternions
Replies: 15
Views: 4279

Re: Gimbal lock, despite using Matrices and Quaternions

Well, let's say the logical order of your transformations is: 1. flip object from its original orientation to the desired 'base' orientation - let's call this transform FLIP 2. roll/yaw/pitch transform - let's call it CARDAN 3. offset of the object away from the view plane - OFFSET then the proper o...
by blu
Tue Aug 28, 2012 10:46 am
Forum: OpenGLES
Topic: Gimbal lock, despite using Matrices and Quaternions
Replies: 15
Views: 4279

Re: Gimbal lock, despite using Matrices and Quaternions

Davespice, from the code you posted I think you've missed a small detail about the GL1x matrix stacks, namely: Each new MultMatrix(m) does current = current * m. Combined with the fact that the final vertex transformation uses operator-leftism, i.e the matrix operator is on the left of the column-ve...
by blu
Mon Aug 27, 2012 9:30 pm
Forum: Graphics programming
Topic: Drawing a 2D triangle with EGL and GLESv1
Replies: 5
Views: 3537

Re: Drawing a 2D triangle with EGL and GLESv1

Don't mention it. And a minor correction re point 2: two of your vertices wouldn't have been clipped by your matrix if argument order got corrected, not at those magnitudes anyway. Actually they'd produce a triangle in the lower-left corner of the viewport. I got carried away a bit with the quick in...
by blu
Mon Aug 27, 2012 7:34 pm
Forum: Graphics programming
Topic: Drawing a 2D triangle with EGL and GLESv1
Replies: 5
Views: 3537

Re: Drawing a 2D triangle with EGL and GLESv1

Aloshi, you really need to wind your vertices in a CCW manner (or change your glFrontFace, or turn off culling altogether). Other than that: 1. The order of parameters to glOrtho is not (x, y, w, h) like with glViewport - it's (left, right, bottom, top, near, far). Check out http://www.khronos.org/o...
by blu
Mon Aug 27, 2012 6:59 pm
Forum: OpenGLES
Topic: Seam visible when drawing textured quad
Replies: 9
Views: 2260

Re: Seam visible when drawing textured quad

So you get the same artifact in all three cases - GL_TRIANGLES, GL_TRIANGLE_STRIP and GL_TRIANGLE_FAN?

What types are your vertex attributes for that mesh, particularly the texture coordinates?
by blu
Mon Aug 27, 2012 10:54 am
Forum: OpenGLES
Topic: Seam visible when drawing textured quad
Replies: 9
Views: 2260

Re: Seam visible when drawing textured quad

Sounds peculiar. Is that a trilist you're drawing (i.e. GL_TRIANGLES)? If so, is the artifact still there if you used a tri strip/fan instead (GL_TRIANGLE_STRIP/GL_TRIANGLE_FAN)?

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