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mynameisnafe

OpenGL
[noob]How to Draw from .OBJ in memory?

6 posts in this topic

Hi There

I read this a while ago and implemented my own version, as part of a model class. It's a really useful thread!

[url="http://www.gamedev.net/topic/312335-obj-model-loading-in-detail/"]http://www.gamedev.n...ding-in-detail/[/url]

However, as someone in the thread points out: 'How do I go about drawing all this sh*t in OpenGL?'

I have learned that .obj indices start at 1, not 0. Can anybody help me apply this nugget of information to the following render method, which draws triangles from memory (stored in memory as in the thread linked above).

Many thanks in advance, I've been stuck on this forever and can't seem to find anything online about it.

Once I/we figure this out, I can get on with my project. [img]http://public.gamedev.net//public/style_emoticons/default/smile.png[/img]

As Turvold said, 'talk is cheap, show me the code'.

[CODE]
void GLModel::RenderMesh( Colour3 c ) {
glPushMatrix();

glTranslatef(pos.x, pos.y, pos.z);
glColor3f( c.r, c.g, c.b );
glLineWidth(1.0);

glBegin(GL_TRIANGLES);
for ( int i = 0; i < mesh.noTriangles; i++ ) { //for each triangle in the list
Vector3D vpos; Normal3D npos;
// this vertex is the said triangle, verts attached
vpos.x = mesh.vertices[ mesh.triangleList[i].Vertex[0] ].x;
vpos.y = mesh.vertices[ mesh.triangleList[i].Vertex[1] ].y;
vpos.z = mesh.vertices[ mesh.triangleList[i].Vertex[2] ].z;
// this vertex is the said triangle, normals attached
npos.x = mesh.normals[ mesh.triangleList[i].Normal[0] ].x;
npos.y = mesh.normals[ mesh.triangleList[i].Normal[1] ].y;
npos.z = mesh.normals[ mesh.triangleList[i].Normal[2] ].z;

glVertex3f(vpos.x, vpos.y, vpos.z);
//glNormal3f(npos.x, npos.y, npos.z);
} // i++
glEnd();
glPopMatrix();
}
[/CODE]

Please help me! - Apparently I can't upload .cpp files, if anyone wants to see the whole class, leave a comment and I'll post it [img]http://public.gamedev.net//public/style_emoticons/default/smile.png[/img]
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[quote name='DracoLacertae' timestamp='1346789401' post='4976559']
Also, BTW, as soon as you get this rendering correctly, the 1st thing you should do is render with a VBO, or, at a minimum, a vertex array.
The format you have already is kind of similar to a vertex array, you just need to rearrange the data a little bit.
[/quote]
I agree. Notice that you are using deprecated legacy OpenGL: [url="http://www.opengl.org/wiki/Legacy_OpenGL"]http://www.opengl.org/wiki/Legacy_OpenGL[/url]. Better get it right now, until it is too late.
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Thank you guys! You are heros! Sorry it's taken me so long to get back to you.

Omg I see my error now. I'm just going to try it as you suggest before I post this..

Here's the code I'm trying:
[CODE]
void GLModel::RenderMesh( Colour3 c ) {
glPushMatrix();

glTranslatef(pos.x, pos.y, pos.z);
glColor3f( c.r, c.g, c.b );
glLineWidth(1.0);

glBegin(GL_TRIANGLES);
for ( int i = 0; i < mesh.noTriangles; i++ ) { //for each triangle in the list
Vector3D vpos; Normal3D npos;
for( int j = 0; j < 3; j++ ) {
// this vertex is the said triangle, verts attached
vpos.x = mesh.vertices[ mesh.triangleList[i].Vertex[j] ].x;
vpos.y = mesh.vertices[ mesh.triangleList[i].Vertex[j] ].y;
vpos.z = mesh.vertices[ mesh.triangleList[i].Vertex[j] ].z;
// this vertex is the said triangle, normals attached
npos.x = mesh.normals[ mesh.triangleList[i].Normal[j] ].x;
npos.y = mesh.normals[ mesh.triangleList[i].Normal[j] ].y;
npos.z = mesh.normals[ mesh.triangleList[i].Normal[j] ].z;
glNormal3f(npos.x, npos.y, npos.z);
glVertex3f(vpos.x, vpos.y, vpos.z);
} //j++
} // i++
glEnd();
glPopMatrix();
}
[/CODE]

For a model of a car i have it renders nothing? For a box I have it is a bit crazy-looking.

I'm using legacy OGL? What's the latest version these days?

Okay I'll move the normals to be processed before hand - I hadn't been using them ( :/ )

Okay[quote name='larspensjo' timestamp='1346833001' post='4976737']
as soon as you get this rendering correctly, the 1st thing you should do is render with a VBO, or, at a minimum, a vertex array.
[/quote]

I thought I was rendering from a vertex array?

Okay, if you guys are willing to delve deeper, here is the code thats responsible for this, from file load to render. I really appreciate any help as I know I need tris before I can texture, have any use for lighting, worry about mtls, etc etc. I'm stuck on the first hurdle [img]http://public.gamedev.net//public/style_emoticons/default/sad.png[/img]

In winmain, we have a call to this function, with the path to the model:

[CODE]
void GLModel::AllocateMesh( string path ){
// Step 1 - Count the Elements in the Mesh
string line; // our line to read
ifstream rfile(path); // open it up from filepath given
if( rfile.is_open() ) { //while open
while ( rfile.good() ) { //while not EOF or Error
getline (rfile, line); //get content..
// update the count held by the mesh given to us
if( line.substr(0,1) == "#" ) {/* do nothing for comments */ }
else if( line.substr(0,5) == "mtllib") {/* this is the objects material */ }
else if( line.substr(0,2) == "g ") {/* and do nowt for groups */ }
else if( line.substr(0,2) == "vn") { mesh.noNormals++; }
else if( line.substr(0,2) == "vt") { mesh.noTexCoords++; }
else if( line.substr(0,2) == "v ") { mesh.noVerts++; }
else if( line.substr(0,2) == "f ") { mesh.noTriangles++; }
}
}

rfile.close(); //housekeeping
// Step 2 - Allocate the memory according to the count
mesh.vertices = (Vertex3D*) malloc(sizeof(Vertex3D)* mesh.noVerts);
mesh.normals = (Normal3D*) malloc(sizeof(Normal3D)* mesh.noNormals);
mesh.texcoords = (UV*) malloc(sizeof(UV) * mesh.noTexCoords);
mesh.triangleList = (Triangle*) malloc(sizeof(Triangle)* mesh.noTriangles);
}
[/CODE]

This is followed directly by a call to this function which reads the file:

[CODE]
void GLModel::LoadMeshData( string path ) {
string line;
ifstream rfile(path);
int ni, vi, ti, fi; //counters: normals, verts, texcoords, faces
ni = 0; vi = 0; ti = 0; fi = 0;
if ( rfile.is_open() ) { //if file is open
while ( !rfile.eof() ) { //til end of file:
getline(rfile, line);
istringstream currentline(line);
string temp, f1, f2, f3;
/* Vertex Normals */
if(line.substr(0,2) == "vn") {
currentline >> temp >>f1 >> f2 >> f3;
mesh.normals[ni].x = atof( f1.c_str() );
mesh.normals[ni].y = atof( f2.c_str() );
mesh.normals[ni].z = atof( f3.c_str() );
ni++; //next normal
}
/* Vertex texture coordinates */
else if(line.substr(0,2) == "vt") {
currentline >> temp >>f1 >> f2;
mesh.texcoords[ti].s = atof( f1.c_str() );
mesh.texcoords[ti].t = atof( f2.c_str() );
ti++; //next texcoords
}
/* Vertex */
else if(line.substr(0,1) == "v") {
currentline >> temp >>f1 >> f2 >> f3;
mesh.vertices[vi].x = atof( f1.c_str() );
mesh.vertices[vi].y = atof( f2.c_str() );
mesh.vertices[vi].z = atof( f3.c_str() );
vi++; //next vertex
}
/* Triangle/Face*/
else if(line.substr(0,1) == "f") {
string temp;
currentline >> temp >>f1 >> f2 >> f3;

int sPos = 0;
int ePos = 0;

ePos = f1.find_first_of("/");
//we have a line with the format of "f %d/%d/%d %d/%d/%d %d/%d/%d"
if(ePos != string::npos) {
temp = f1.substr(sPos, ePos - sPos);
mesh.triangleList[fi].Vertex[0] = atoi( temp.c_str() ) - 1;
sPos = ePos + 1;
ePos = f1.find( "/", sPos );
temp = f1.substr(sPos, ePos - sPos);
mesh.triangleList[fi].Vertex[1] = atoi( temp.c_str() ) - 1;
sPos = ePos + 1;
ePos = f1.length();
temp = f1.substr(sPos, ePos - sPos);
mesh.triangleList[fi].Vertex[2] = atoi( temp.c_str() )- 1;
} //end triangle vertex data
sPos = 0;
ePos = f2.find_first_of("/");
if(ePos != string::npos) {
temp = f2.substr(sPos, ePos - sPos);
mesh.triangleList[fi].TexCoord[0] = atoi( temp.c_str() ) - 1;
sPos = ePos + 1;
ePos = f2.find("/", sPos + 1);
temp = f2.substr(sPos, ePos - sPos);
mesh.triangleList[fi].TexCoord[1] = atoi( temp.c_str() ) - 1;
sPos = ePos + 1;
ePos = f2.length();
temp = f2.substr(sPos, ePos - sPos);
mesh.triangleList[fi].TexCoord[2] = atoi( temp.c_str() ) - 1;
} //end triangle texcoord data
sPos = 0;
ePos = f3.find_first_of("/");
if(ePos != string::npos) {
temp = f3.substr(sPos, ePos - sPos);
mesh.triangleList[fi].Normal[0] = atoi ( temp.c_str() ) - 1;
sPos = ePos + 1;
ePos = f3.find("/", sPos + 1);
temp = f3.substr(sPos, ePos - sPos);
mesh.triangleList[fi].Normal[1] = atoi( temp.c_str() ) - 1;
sPos = ePos + 1;
ePos = f3.length();
temp = f3.substr(sPos, ePos - sPos);
mesh.triangleList[fi].Normal[2] = atoi( temp.c_str() ) - 1;
} //end triangle normal data
fi++; //next face
} //end triangle data
} //end while not end of file
} //end if file is open
rfile.close(); //housekeeping
}//end LoadMeshData
[/CODE]

Then the model is ready to draw in Render() with this code:

[CODE]
//draw
//theScene.theModel->RenderVerts( c ); //and render the model mesh vert by vert
theScene.theModel->RenderMesh( b ); //and render the model mesh tri by tri
[/CODE]

Which calls (and which you've seen):

[CODE]
void GLModel::RenderMesh( Colour3 c ) {
glPushMatrix();

glTranslatef(pos.x, pos.y, pos.z);
glColor3f( c.r, c.g, c.b );
glLineWidth(1.0);

glBegin(GL_TRIANGLES);
for ( int i = 0; i < mesh.noTriangles; i++ ) { //for each triangle in the list
Vector3D vpos; Normal3D npos;
for( int j = 0; j < 3; j++ ) {
// this vertex is the said triangle, verts attached
vpos.x = mesh.vertices[ mesh.triangleList[i].Vertex[j] ].x;
vpos.y = mesh.vertices[ mesh.triangleList[i].Vertex[j] ].y;
vpos.z = mesh.vertices[ mesh.triangleList[i].Vertex[j] ].z;
// this vertex is the said triangle, normals attached
npos.x = mesh.normals[ mesh.triangleList[i].Normal[j] ].x;
npos.y = mesh.normals[ mesh.triangleList[i].Normal[j] ].y;
npos.z = mesh.normals[ mesh.triangleList[i].Normal[j] ].z;
glNormal3f(npos.x, npos.y, npos.z);
glVertex3f(vpos.x, vpos.y, vpos.z);
} //j++
} // i++
glEnd();
glPopMatrix();
}
[/CODE]

Edit: This is what the box looks like: Grey is the clear-colour, white is the triangles:


[attachment=11157:Capture1.PNG]
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[quote]I thought I was rendering from a vertex array?[/quote]

You are rendering from an array of vertices, but that's not an OpenGL Vertex Array. If you arrange the data just right, you can call glVertexPointer, glNormalPointer, and glTexCoordPointer, and just hand it a pointer to your data. Then you just call glDrawElements or glDrawArrays, depending on what you really want to do. This is will speed things up just because instead of individual calls to glVertex3f, you it's all done internally. Later, the next step you can take is allocate a VBO and copy it to the graphics card. You will actually keep the calls to glVertexPointer, etc, except they will be offsets to inside the VBO.

I was going to say make sure you ' - 1' from all the indices, because OBJ files start with '1' and C starts with '0'. But it looks like you already did that.

Try rendering an OBJ file with just a single face in it. If that works, the rest should :)

And instead of rendering, just printf what 'it' thinks the data is. You will probably find that you did something slightly wrong when you cut up the strings you read from the file. Can you put up one of your obj files?
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Looking back at the thread where the justinrwalsh dude says he saw a massive error in his code, looking at the DX11 rastertek tutorials (specifically his obj loading), and thinking about it,
I think I'm cutting the string up as v/v/v vt/vt/vt vn/vn/vn
and I think it should be v/vt/vn v/vt/vn v/vt/vn?

Thanks again for your help and advice I really appreciate it. :)

Heres the Obj file for the cube (can't upload so I'll copy paste it below) it should be fine because it's from a tutorial

# -----------------
# Start of obj file
g Box01
mtllib box.mat
usemtl box
v -62.0579 -41.4791 0.0
v 58.8424 -41.4791 0.0
v -62.0579 22.1865 0.0
v 58.8424 22.1865 0.0
v -62.0579 -41.4791 39.8714
v 58.8424 -41.4791 39.8714
v -62.0579 22.1865 39.8714
v 58.8424 22.1865 39.8714
vt 0.843206 0.405444 0.000499517
vt 0.482802 0.71377 0.9995
vt 0.478066 0.404023 0.000499636
vt 0.482802 0.716612 0.9995
vt 0.841627 0.688332 0.000499517
vt 0.482013 0.981029 0.9995
vt 0.480434 0.688332 0.000499636
vt 0.485959 0.978188 0.9995
vt 0.450102 0.00618343 0.000499547
vt 0.45247 0.509304 0.000499547
vt 0.000499517 0.512146 0.000499547
vt 0.000499517 0.512146 0.000499547
vt -0.0010791 0.00618302 0.000499547
vt 0.450102 0.00618343 0.000499547
vt 0.000499517 0.512009 0.9995
vt 0.450891 0.510588 0.9995
vt 0.45247 0.995237 0.9995
vt 0.45247 0.996658 0.9995
vt 0.000499636 0.9995 0.9995
vt 0.000499517 0.51343 0.9995
vt 0.478855 0.405444 0.000500023
vt 0.841627 0.408286 0.000499576
vt 0.83847 0.688332 0.000499576
vt 0.83847 0.688332 0.000499576
vt 0.477276 0.694016 0.000500023
vt 0.478855 0.405444 0.000500023
vt 0.482802 0.71377 0.9995
vt 0.845574 0.71377 0.999501
vt 0.844784 0.976767 0.999501
vt 0.844784 0.976767 0.999501
vt 0.482802 0.716612 0.9995
vt 0.842417 0.710929 0.9995
vt 0.843995 0.975346 0.9995
vt 0.843995 0.975346 0.9995
vt 0.478066 0.404023 0.000499636
vt 0.841627 0.688332 0.000499517
vn 0.0 0.0 -1.0
vn 0.0 0.0 -1.0
vn 0.0 0.0 1.0
vn 0.0 0.0 1.0
vn 0.0 -1.0 0.0
vn 0.0 -1.0 0.0
vn 1.0 0.0 0.0
vn 1.0 0.0 0.0
vn 0.0 1.0 0.0
vn 0.0 1.0 0.0
vn -1.0 0.0 0.0
vn -1.0 0.0 0.0
f 1/9/1 3/10/1 4/11/1
f 4/12/2 2/13/2 1/14/2
f 5/15/3 6/16/3 8/17/3
f 8/18/4 7/19/4 5/20/4
f 1/21/5 2/22/5 6/23/5
f 6/24/6 5/25/6 1/26/6
f 2/27/7 4/28/7 8/29/7
f 8/30/8 6/6/8 2/2/8
f 4/31/9 3/32/9 7/33/9
f 7/34/10 8/8/10 4/4/10
f 3/35/11 1/1/11 5/36/11
f 5/5/12 7/7/12 3/3/12
# end of obj file
# ---------------
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Dude!

I totally got it working!

Sorry I didn't get back to you, or keep trying earlier, uni has just started - guess what my project is.. load a .3ds model and animate it in OpenGL.

I just opened the project, looked at the loader code, saw what it was that was wrong, ran it, et viola!

I wish I could screenshot it to here for you dude, thank you anyways!

If anybody wants obj laoding code let me know!
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      #pragma once #include <cstdio> #include <cstdlib> class MyFileHandler { private: const char * fileName; unsigned long fileSize; void setFileSize(); public: MyFileHandler(const char * fileName); ~MyFileHandler(); unsigned long getFileSize(); const char * readFile(); }; MyFileHandler.cpp
      #include "MyFileHandler.h" MyFileHandler::MyFileHandler(const char * fileName) { this->fileName = fileName; this->setFileSize(); } MyFileHandler::~MyFileHandler() { } void MyFileHandler::setFileSize() { FILE * fileHandle = NULL; fopen_s(&fileHandle, this->fileName, "rb"); fseek(fileHandle, 0L, SEEK_END); this->fileSize = ftell(fileHandle); rewind(fileHandle); fclose(fileHandle); return; } unsigned long MyFileHandler::getFileSize() { return (this->fileSize); } const char * MyFileHandler::readFile() { char * buffer = (char *)malloc((this->fileSize)+1); FILE * fileHandle = NULL; fopen_s(&fileHandle, this->fileName, "rb"); fread(buffer, this->fileSize, sizeof(char), fileHandle); fclose(fileHandle); buffer[this->fileSize] = '\0'; return buffer; } VertexShader.glsl
      #version 330 core layout (location = 0) vec3 VertexPositions; void main() { gl_Position = vec4(VertexPositions, 1.0f); } FragmentShader.glsl
      #version 330 core out vec4 FragmentColor; void main() { FragmentColor = vec4(1.0f, 0.0f, 0.0f, 1.0f); } I am attempting to create a simple engine/graphics utility using some object-oriented paradigms. My first goal is to get some output from my engine, namely, a simple red triangle.
      For this goal, the MyShapes class will be responsible for defining shapes such as triangles, polygons etc. Currently, there is only a drawTriangle() method implemented, because I first wanted to see whether it works or not before attempting to code other shape drawing methods.
      The constructor of the MyEngine class creates a GLFW window (GLAD is also initialized here to load all OpenGL functionality), and the myEngine.run() method in Main.cpp is responsible for firing up the engine. In this run() method, the shaders get loaded from files via the help of my FileHandler class. The vertices for the triangle are processed by the myShapes.drawTriangle() method where a vertex array object, a vertex buffer object and vertrex attributes are set for this purpose.
      The while loop in the run() method should be outputting me the desired red triangle, but all I get is a grey window area. Why?
      Note: The shaders are compiling and linking without any errors.
      (Note: I am aware that this code is not using any good software engineering practices (e.g. exceptions, error handling). I am planning to implement them later, once I get the hang of OpenGL.)

       
    • By KarimIO
      EDIT: I thought this was restricted to Attribute-Created GL contexts, but it isn't, so I rewrote the post.
      Hey guys, whenever I call SwapBuffers(hDC), I get a crash, and I get a "Too many posts were made to a semaphore." from Windows as I call SwapBuffers. What could be the cause of this?
      Update: No crash occurs if I don't draw, just clear and swap.
      static PIXELFORMATDESCRIPTOR pfd = // pfd Tells Windows How We Want Things To Be { sizeof(PIXELFORMATDESCRIPTOR), // Size Of This Pixel Format Descriptor 1, // Version Number PFD_DRAW_TO_WINDOW | // Format Must Support Window PFD_SUPPORT_OPENGL | // Format Must Support OpenGL PFD_DOUBLEBUFFER, // Must Support Double Buffering PFD_TYPE_RGBA, // Request An RGBA Format 32, // Select Our Color Depth 0, 0, 0, 0, 0, 0, // Color Bits Ignored 0, // No Alpha Buffer 0, // Shift Bit Ignored 0, // No Accumulation Buffer 0, 0, 0, 0, // Accumulation Bits Ignored 24, // 24Bit Z-Buffer (Depth Buffer) 0, // No Stencil Buffer 0, // No Auxiliary Buffer PFD_MAIN_PLANE, // Main Drawing Layer 0, // Reserved 0, 0, 0 // Layer Masks Ignored }; if (!(hDC = GetDC(windowHandle))) return false; unsigned int PixelFormat; if (!(PixelFormat = ChoosePixelFormat(hDC, &pfd))) return false; if (!SetPixelFormat(hDC, PixelFormat, &pfd)) return false; hRC = wglCreateContext(hDC); if (!hRC) { std::cout << "wglCreateContext Failed!\n"; return false; } if (wglMakeCurrent(hDC, hRC) == NULL) { std::cout << "Make Context Current Second Failed!\n"; return false; } ... // OGL Buffer Initialization glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT); glBindVertexArray(vao); glUseProgram(myprogram); glDrawElements(GL_TRIANGLES, indexCount, GL_UNSIGNED_SHORT, (void *)indexStart); SwapBuffers(GetDC(window_handle));  
    • By Tchom
      Hey devs!
       
      I've been working on a OpenGL ES 2.0 android engine and I have begun implementing some simple (point) lighting. I had something fairly simple working, so I tried to get fancy and added color-tinting light. And it works great... with only one or two lights. Any more than that, the application drops about 15 frames per light added (my ideal is at least 4 or 5). I know implementing lighting is expensive, I just didn't think it was that expensive. I'm fairly new to the world of OpenGL and GLSL, so there is a good chance I've written some crappy shader code. If anyone had any feedback or tips on how I can optimize this code, please let me know.
       
      Vertex Shader
      uniform mat4 u_MVPMatrix; uniform mat4 u_MVMatrix; attribute vec4 a_Position; attribute vec3 a_Normal; attribute vec2 a_TexCoordinate; varying vec3 v_Position; varying vec3 v_Normal; varying vec2 v_TexCoordinate; void main() { v_Position = vec3(u_MVMatrix * a_Position); v_TexCoordinate = a_TexCoordinate; v_Normal = vec3(u_MVMatrix * vec4(a_Normal, 0.0)); gl_Position = u_MVPMatrix * a_Position; } Fragment Shader
      precision mediump float; uniform vec4 u_LightPos["+numLights+"]; uniform vec4 u_LightColours["+numLights+"]; uniform float u_LightPower["+numLights+"]; uniform sampler2D u_Texture; varying vec3 v_Position; varying vec3 v_Normal; varying vec2 v_TexCoordinate; void main() { gl_FragColor = (texture2D(u_Texture, v_TexCoordinate)); float diffuse = 0.0; vec4 colourSum = vec4(1.0); for (int i = 0; i < "+numLights+"; i++) { vec3 toPointLight = vec3(u_LightPos[i]); float distance = length(toPointLight - v_Position); vec3 lightVector = normalize(toPointLight - v_Position); float diffuseDiff = 0.0; // The diffuse difference contributed from current light diffuseDiff = max(dot(v_Normal, lightVector), 0.0); diffuseDiff = diffuseDiff * (1.0 / (1.0 + ((1.0-u_LightPower[i])* distance * distance))); //Determine attenuatio diffuse += diffuseDiff; gl_FragColor.rgb *= vec3(1.0) / ((vec3(1.0) + ((vec3(1.0) - vec3(u_LightColours[i]))*diffuseDiff))); //The expensive part } diffuse += 0.1; //Add ambient light gl_FragColor.rgb *= diffuse; } Am I making any rookie mistakes? Or am I just being unrealistic about what I can do? Thanks in advance
    • By yahiko00
      Hi,
      Not sure to post at the right place, if not, please forgive me...
      For a game project I am working on, I would like to implement a 2D starfield as a background.
      I do not want to deal with static tiles, since I plan to slowly animate the starfield. So, I am trying to figure out how to generate a random starfield for the entire map.
      I feel that using a uniform distribution for the stars will not do the trick. Instead I would like something similar to the screenshot below, taken from the game Star Wars: Empire At War (all credits to Lucasfilm, Disney, and so on...).

      Is there someone who could have an idea of a distribution which could result in such a starfield?
      Any insight would be appreciated
    • By afraidofdark
      I have just noticed that, in quake 3 and half - life, dynamic models are effected from light map. For example in dark areas, gun that player holds seems darker. How did they achieve this effect ? I can use image based lighting techniques however (Like placing an environment probe and using it for reflections and ambient lighting), this tech wasn't used in games back then, so there must be a simpler method to do this.
      Here is a link that shows how modern engines does it. Indirect Lighting Cache It would be nice if you know a paper that explains this technique. Can I apply this to quake 3' s light map generator and bsp format ?
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