791 reputation
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location Chemnitz, Germany
age 27
visits member for 2 years, 10 months
seen Apr 15 at 16:15

Mar
17
comment Why do we use 4x4 matrices to transform things in 3D?
@concept3d Yeah, I know, the answer is good. Yet the even bigger advantage gained from the uniform way of using a matrix is not only uniformity, but representation of an entire chain of transformations in a single operation. While that might have been implied, I found it unclear and important enough to mention it explicitly. But the answer was still good anyway, it wasn't a critique.
Mar
17
comment Why do we use 4x4 matrices to transform things in 3D?
And even more than that, once you have rotation and translation both as 4x4 matrices, you can just multiply them and have the combined transformation in one single matrix without the need to transform every vertex by a thousands of different transformations using different constructs. The fact that a 4x4 matrix is overkill for a single translation or a single rotation is outweight by the fact that you usually don't just transform a vertex by single translation or a single rotation.
May
2
comment glBufferSubData and offset alignment?
@KaiserJohaan That is a completely different problem and doesn't have anything to do with glBindBufferRange itself, but with uniform buffer objects specifically and how the implementation aligns multiple uniform blocks inside a uniform buffer object. So in this case using the buffer as a uniform buffer requires offsets to be properly aligned for uniform blocks, while in your case it requires the offsets (in glVertexAttribPointer) to be properly aligned for attribute data (float[3] in your particular case).
May
2
comment How would one render dynamic vertices in OpenGL ES 2.0 like in a 3D modeling program?
"I've only seen examples where you have to re-compile a shader each time you make an array." - Those examples were either (1) complete rubbish, (2) completely ingenius complex stuff doing something totally different, or (3) you don't have the same notion of "shaders" and "vertex arrays" that OpenGL has. "does this update the data without having to recompile the shader?" - Huh? How much and what data your buffer objects contain has absolutely nothing to do with your shaders.
Oct
1
comment How to create OpenGL (ES 1.0) texture programmatically?
@labotsirc Though, the OP cannot use any fragment shaders, since he uses ES 1.0.
Jan
25
comment How to decide to use OpenGL ES 1.0 or 2.0 for Android?
@stephelton Like said, I don't have any overview of the current ES devices, so you may be on the right side regarding compatibility. It is also true that ES 1 has a shallower learning curve and may be easier to start for a beginner and get into the general ideas of transformation, lighting and texturing (which are also useful for ES 2, of course), but I think it's just not neccessary to make the detour over ES 1.
Jan
25
comment How to decide to use OpenGL ES 1.0 or 2.0 for Android?
First it was a 0, but -1 for the edit, especially the "scare away"-part which is just contraproductive.
Jan
25
comment How to decide to use OpenGL ES 1.0 or 2.0 for Android?
@stephelton And well, graphics is not easy and using an old fixed-function approach to do transformation, lighting and texturing for you, only so that you don't need to understand what it really does, is no real alternative (and doesn't make it that much easier anyway). Once you do something more involved than a rotating cube (although that's what a beginner will surely do first), the additional overhead will vanish, moreover it will result in less overhead by enabling you to implement your ideas more straight-forward than somehow crunshing them into the fixed-function features.
Jan
25
comment How to decide to use OpenGL ES 1.0 or 2.0 for Android?
@stephelton But you need to understand those things (matrix stuff) anyway. And removing it from OpenGL doesn't mislead you to think they are implemented in hardware anymore. Somebody has to implement the matrix stuff, and it's actually not really OpenGL's job to do this as it doesn't have anything to do with the graphics hardware. Get a library for it if you don't want to mess with it yet. Just use good learning resources and don't try to take on the world right from the start. Then starting with shader-only ES 2 should be no problem.
Jan
18
comment Vertex Array Object (OpenGL)
There is not much difference. The VAO just encapsulates all state regarding the vertex arrays and their usages and formats, except for the array data itself, which is stored in VBOs. But you're right in that this answer (or the link) doesn't really talk about VAOs.
Dec
17
comment GLM: Euler Angles to Quaternion
Was this a joke? Or did you you just not read the other answers (especially Daniel's)?
Dec
12
comment How do I extract a translation vector from a dual quaternion?
Ok, updated my answer.
Dec
12
comment How do I extract a translation vector from a dual quaternion?
Welcome to StackExchange, I hope you read the FAQ.
Nov
18
comment How can I write only to the stencil buffer in OpenGL ES 2.0?
@stephelton using glColorMask is enough to get sure that nothing is written to the color buffer. No need to output some artificially small color or such rubbish. Just make sure the fragment shader doesn't do unneccessary work and write out a vec4(1.0).
Nov
11
comment how can I specify interleaved vertex attributes and vertex indices
What on earth got you to insert a padding of 20 floats (80 bytes)? Such a large memory-overconsumption surely kills any possible alignment benefits. 4 floats (16 bytes) would have sufficed for a 64 byte alignment, which should be enough (if even neccessary).
Nov
11
comment Renderbuffer to GLSL shader?
Even if Nathan's answer wouldn't work, what got you to subsitute glReadPixels and glTexImage2D for glCopyTexImage2D?
Sep
26
comment Entity/Component Systems in C++, How do I discover types and construct components?
Quite unrelated comment: If you want to get proficient in C++, then use C++ and not C, regarding strings. Sorry for that, but it had to be said.
Sep
19
comment Quaternion understanding
@Daniel obviously!
Sep
19
comment Quaternion understanding
@Nathan I was educated with column-vectors. I have never seen vectors treated as 1-row matrices in any mathematical context. The fact that some frameworks use row-vectors and that there isn't that much difference in practice, doesn't give them a mathematical justification. But maybe the latter is not that important for you.
Sep
19
comment Quaternion understanding
We sure need to know more of you transformation framework. Do you use matrix * column-vector convention or some strange row-vector * matrix convention? Maybe your Lookat function is intended for cameras and therefore does the inverse transformation to what you actually want. Also in a matrix*vector convention your combined transformation first translates the object and then rotates it. Is this even intended?