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• ### Similar Content

• I wasn't sure if this would be the right place for a topic like this so sorry if it isn't.
I'm currently working on a project for Uni using FreeGLUT to make a simple solar system simulation. I've got to the point where I've implemented all the planets and have used a Scene Graph to link them all together. The issue I'm having with now though is basically the planets and moons orbit correctly at their own orbit speeds.
I'm not really experienced with using matrices for stuff like this so It's likely why I can't figure out how exactly to get it working. This is where I'm applying the transformation matrices, as well as pushing and popping them. This is within the Render function that every planet including the sun and moons will have and run.
if (tag != "Sun") { glRotatef(orbitAngle, orbitRotation.X, orbitRotation.Y, orbitRotation.Z); } glPushMatrix(); glTranslatef(position.X, position.Y, position.Z); glRotatef(rotationAngle, rotation.X, rotation.Y, rotation.Z); glScalef(scale.X, scale.Y, scale.Z); glDrawElements(GL_TRIANGLES, mesh->indiceCount, GL_UNSIGNED_SHORT, mesh->indices); if (tag != "Sun") { glPopMatrix(); } The "If(tag != "Sun")" parts are my attempts are getting the planets to orbit correctly though it likely isn't the way I'm meant to be doing it. So I was wondering if someone would be able to help me? As I really don't have an idea on what I would do to get it working. Using the if statement is truthfully the closest I've got to it working but there are still weird effects like the planets orbiting faster then they should depending on the number of planets actually be updated/rendered.

• Hello everyone,
I have problem with texture

• Hello everyone
For @80bserver8 nice job - I have found Google search. How did you port from Javascript WebGL to C# OpenTK.?
I have been searched Google but it shows f***ing Unity 3D. I really want know how do I understand I want start with OpenTK But I want know where is porting of Javascript and C#?

Thanks!
• By mike44
Hi
I draw in a OpenGL framebuffer. All is fine but it eats FPS (frames per second), hence I wonder if I could execute the framebuffer drawing only every 5-10th loop or so?
Many thanks

• By cebugdev
hi all,
how to implement this type of effect ?
Also what is this effect called? this is considered volumetric lighting?
what are the options of doing this?
a. billboard? but i want this to have the 3D effect that when we rotate the camera we can still have that 3d feel.
b. a transparent 3d mesh? and we can animate it as well?

2. how to implement things like fireball projectile (shot from a monster) (billboard texture or a 3d mesh)?

Note: im using OpenGL ES 2.0 on mobile.

thanks!

# OpenGL issues with binary files to VBO

This topic is 971 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

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so I have been struggling with this problem for a while and have tried many different ways of doing it. Currently I am loading in a binary file that is in bytes and sending it to openGL however nothing is rendering.

this is how I have been creating the binary file

			binaryFloat x,y,z,w,u,v,normx,normy,normz;
x.f = PD[i].x;
y.f = PD[i].y;
z.f = PD[i].z;
w.f = PD[i].w;
u.f = PD[i]._U;
v.f = PD[i]._V;
normx.f = PD[i].norm.X;
normy.f = PD[i].norm.Y;
normz.f = PD[i].norm.Z;

fout << x.container[0] << x.container[1] << x.container[2] << x.container[3]
<< y.container[0] << y.container[1] << y.container[2] << y.container[3]
<< z.container[0] << z.container[1] << z.container[2] << z.container[3]
<< w.container[0] << w.container[1] << w.container[2] << w.container[3]
<< u.container[0] << u.container[1] << u.container[2] << u.container[3]
<< v.container[0] << v.container[1] << v.container[2] << v.container[3]
<< normx.container[0] << normx.container[1] << normx.container[2] << normx.container[3]
<< normy.container[0] << normy.container[1] << normy.container[2] << normy.container[3]
<< normz.container[0] << normz.container[1] << normz.container[2] << normz.container[3];


binaryFloat is a union containing a float and a char[sizeof(float)]. PD is a packedData vector that contains preparsed data.

Here is where I load it up in my engine:

	std::ifstream objFile(filename, std::ios::binary);

if (objFile.is_open())
{
unsigned int length;
char  *data;
objFile.seekg(0, std::ios::end);
length = objFile.tellg();
data = new char[length];
objFile.seekg(0, std::ios::beg);
objFile.close();
e->m_BufferSize = (length / (sizeof(float) * 9));
glGenVertexArrays(1, &e->m_VAO);
glBindVertexArray(e->m_VAO);
glGenBuffers(1, &e->m_Buffer);
glBindBuffer(GL_ARRAY_BUFFER,  e->m_Buffer);
glBufferData(GL_ARRAY_BUFFER, length, data, GL_STATIC_DRAW);
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
glEnableVertexAttribArray(2);
glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(float) * 9, BUFFER_OFFSET(0));
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 9, BUFFER_OFFSET(sizeof(float) * 4));
glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, sizeof(float) * 9, BUFFER_OFFSET(sizeof(float) * 6));
glBindVertexArray(NULL);
}


in this snippet I am loading in the file and sending it to openGL and setting the vbo settings in the VAO. When I run this code data does contain the file so I am not sure why its not rendering.

Thanks for your help and insight in advance:).

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When you examine in a hex editor the file you created on disk, is the data correct?

Did the vertex data get loaded correctly upon examination after the ifstream::read() function returns?

Does glGetError() give any errors?

Do you correctly render geometry that did not come from a file? (I assume so, since you specifically point out an issue with rendering from content from a file)

What does your rendering code look like?

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When you examine in a hex editor the file you created on disk, is the data correct?

Did the vertex data get loaded correctly upon examination after the ifstream::read() function returns?

Does glGetError() give any errors?

Do you correctly render geometry that did not come from a file? (I assume so, since you specifically point out an issue with rendering from content from a file)

What does your rendering code look like?

I took the char * data and wrote it to a file and compared the 2 files and they are identical, so I believe that its reading in correctly.

glGetError() returns 0 after every vbo and vao GL call.

I have rendered stuff to the screen so I know my pipeline is somewhat correct.

my render code is :

void renderManager::render()
{
for (unsigned int i = 0; i < renderingBuffer.size(); i++)
{
glBindVertexArray(renderingBuffer[i]->m_VAO);
glDrawArrays(GL_TRIANGLES, 0, renderingBuffer[i]->m_BufferSize);
}

glBindVertexArray(NULL);
}



my shaders and program are linked and binded already. In this snippet I am passing my view, projection and model matrix to the shader.

After that I am binding the objects VAO then calling draw.

then unbinding all VAOs.

as for the hex editor would you be able to recommend one I have notePad++ but im not sure if it has a hex editor plugin

thanks for your time

**so I found the hex editor plugin for notePad++ however I selected the file and ran it and it outputted bad allocation..

originally the data was in floats and I put them into a union with a float and a char[4] its a little odd that its corrupted:/

here is a file that im trying to render it is just a small cube that is triangulated

ÉÞMÁÉÞMÁÉÞMA  €?  À>              €?ÉÞMAÉÞMÁÉÞMA  €?   ?              €?ÉÞMÁÉÞMAÉÞMA  €?  À>  €>          €?ÉÞMÁÉÞMAÉÞMA  €?  À>  €>          €?ÉÞMAÉÞMÁÉÞMA  €?   ?              €?ÉÞMAÉÞMAÉÞMA  €?   ?  €>          €?ÉÞMÁÉÞMAÉÞMA  €?  À>  €>      €?    ÉÞMAÉÞMAÉÞMA  €?   ?  €>      €?    ÉÞMÁÉÞMAÉÞMÁ  €?  À>   ?      €?    ÉÞMÁÉÞMAÉÞMÁ  €?  À>   ?      €?    ÉÞMAÉÞMAÉÞMA  €?   ?  €>      €?    ÉÞMAÉÞMAÉÞMÁ  €?   ?   ?      €?    ÉÞMÁÉÞMAÉÞMÁ  €?  À>   ?          €¿ÉÞMAÉÞMAÉÞMÁ  €?   ?   ?          €¿ÉÞMÁÉÞMÁÉÞMÁ  €?  À>  @?          €¿ÉÞMÁÉÞMÁÉÞMÁ  €?  À>  @?          €¿ÉÞMAÉÞMAÉÞMÁ  €?   ?   ?          €¿ÉÞMAÉÞMÁÉÞMÁ  €?   ?  @?          €¿ÉÞMÁÉÞMÁÉÞMÁ  €?  À>  @?      €¿    ÉÞMAÉÞMÁÉÞMÁ  €?   ?  @?      €¿    ÉÞMÁÉÞMÁÉÞMA  €?  À>  €?      €¿    ÉÞMÁÉÞMÁÉÞMA  €?  À>  €?      €¿    ÉÞMAÉÞMÁÉÞMÁ  €?   ?  @?      €¿    ÉÞMAÉÞMÁÉÞMA  €?   ?  €?      €¿    ÉÞMAÉÞMÁÉÞMA  €?   ?      €?        ÉÞMAÉÞMÁÉÞMÁ  €?  ?      €?        ÉÞMAÉÞMAÉÞMA  €?   ?  €>  €?        ÉÞMAÉÞMAÉÞMA  €?   ?  €>  €?        ÉÞMAÉÞMÁÉÞMÁ  €?  ?      €?        ÉÞMAÉÞMAÉÞMÁ  €?  ?  €>  €?        ÉÞMÁÉÞMÁÉÞMÁ  €?   >      €¿        ÉÞMÁÉÞMÁÉÞMA  €?  À>      €¿        ÉÞMÁÉÞMAÉÞMÁ  €?   >  €>  €¿        ÉÞMÁÉÞMAÉÞMÁ  €?   >  €>  €¿        ÉÞMÁÉÞMÁÉÞMA  €?  À>      €¿        ÉÞMÁÉÞMAÉÞMA  €?  À>  €>  €¿

Edited by og knuckles

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so I wrote a little code on the engine to cast it back to float and the data looks perfect:/

heres the code

	for (int i = 0; i < buffer.size() - 3; i += 4)
{
char tempArray[4] = { buffer[i], buffer[i + 1], buffer[i + 2], buffer[i + 3] };
float f;
memcpy(&f, &tempArray, sizeof(f));
packedData.push_back(f);
}
`

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Assuming the data and buffers are correct, have you checked the active shader is setup correct?

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Assuming the data and buffers are correct, have you checked the active shader is setup correct?

The shaders are correct they have a built in error checking system. :/maybe its my drawing I really am at a loss right now.

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guys I am such an idiot. I wrote some quick camera class and hacked the view matrix real quick to make it do what I want and I changed a scale value that when multiplied by a translation matrix makes the w or data[15] go right out of wack-.-. I am sorry for wasting peoples time. on the plus note I am not crazy lol I went through so much data and everything was working perfectly.