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• ### Similar Content

• By lxjk
Hi guys,
There are many ways to do light culling in tile-based shading. I've been playing with this idea for a while, and just want to throw it out there.
Because tile frustums are general small compared to light radius, I tried using cone test to reduce false positives introduced by commonly used sphere-frustum test.
On top of that, I use distance to camera rather than depth for near/far test (aka. sliced by spheres).
This method can be naturally extended to clustered light culling as well.
The following image shows the general ideas

Performance-wise I get around 15% improvement over sphere-frustum test. You can also see how a single light performs as the following: from left to right (1) standard rendering of a point light; then tiles passed the test of (2) sphere-frustum test; (3) cone test; (4) spherical-sliced cone test

I put the details in my blog post (https://lxjk.github.io/2018/03/25/Improve-Tile-based-Light-Culling-with-Spherical-sliced-Cone.html), GLSL source code included!

Eric

• Good evening everyone!

I was wondering if there is something equivalent of  GL_NV_blend_equation_advanced for AMD?
Basically I'm trying to find more compatible version of it.

Thank you!

• Hello guys,

How do I know? Why does wavefront not show for me?
I already checked I have non errors yet.

And my download (mega.nz) should it is original but I tried no success...
- Add blend source and png file here I have tried tried,.....

PS: Why is our community not active? I wait very longer. Stop to lie me!
Thanks !

• 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

# OpenGL 3D Programming Bug

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I'm working on a project for one of my classes, and I'm running into an issue, and am just really unsure where to ask this. For my project, I need to create a program that reads in a .ssd file to create a 3d scene. For this project in particular, it's all about matrices, and so we are not allowed to use any matrix related functions in openGL. As it is, I've written a fair bit, and I'll try to post the segments I think are probably most relevant, but I'll upload the entire folder I'm working with as well, in case the problem lies elsewhere.

The program takes in a command line argument for a .ssd file. The .ssd files that begin with lab2_ in particular are used for this project. Some of the other files are from the first project in the course.

The main problem I'm having is that the output images I am getting are not the same as the examples, and they appear as if the camera were in the wrong position ( although I've checked, and it is reading it in from the files correctly ). From what I can see, the parsing of the file seems to be going just fine, but the problem seems to lie in the matrices themselves, or one of the functions I use to manipulate them. At this point, I am simply talking about the world -> screen transformations, and not model transformations.

Any pointers on where I am going wrong, hopefully with a hint on how to fix it, would be greatly appreciated!

Matrices are stored as [4][4] arrays, and vectors are basically just a single array of [4].

Matrix * Matrix function:
Matrix Matrix::operator*( const Matrix& rhs ){	Matrix temp;	for( int i = 0; i < 4; i++ )	{		for( int j = 0; j < 4; j++ )		{			temp.m[j] = ( m[0] * rhs.m[j][0] ) + ( m[1] * rhs.m[j][1] ) + ( m[2] * rhs.m[j][2] )				+ ( m[3] * rhs.m[j][3] );		}	}	return temp;}

Matrix * Vector function:
Vertex Matrix::operator*( Vertex& rhs ){	Vertex temp;	temp.SetX( ( m[0][0] * rhs.GetX() ) + ( m[1][0] * rhs.GetY() ) + ( m[2][0] * rhs.GetZ() ) +		( m[3][0] * rhs.GetW() ) );	temp.SetY( ( m[0][1] * rhs.GetX() ) + ( m[1][1] * rhs.GetY() ) + ( m[2][1] * rhs.GetZ() ) +		( m[3][1] * rhs.GetW() ) );	temp.SetZ( ( m[0][2] * rhs.GetX() ) + ( m[1][2] * rhs.GetY() ) + ( m[2][2] * rhs.GetZ() ) +		( m[3][2] * rhs.GetW() ) );	temp.SetW( ( m[0][3] * rhs.GetX() ) + ( m[1][3] * rhs.GetY() ) + ( m[2][3] * rhs.GetZ() ) +		( m[3][3] * rhs.GetW() ) );	temp.SetColor( rhs.GetColor() );	return temp;}

Vector cross product, division with abs value, and unary - functions:
Vertex Vertex::operator*( Vertex& rhs ){	Vertex temp;	temp.SetX( ( y * rhs.GetZ() ) - ( z * rhs.GetY() ) );	temp.SetY( ( z * rhs.GetX() ) - ( x * rhs.GetZ() ) );	temp.SetZ( ( x * rhs.GetY() ) - ( y * rhs.GetX() ) );	temp.SetW( 1 );	return temp;}Vertex Vertex::operator/(  Vertex& rhs ){	Vertex temp;	if( rhs.GetX() != 0 )		temp.SetX( x / abs( rhs.GetX() ) );	else		temp.SetX( 0 );	if( rhs.GetY() != 0 )		temp.SetY( y / abs( rhs.GetY() ) );	else		temp.SetY( 0 );	if( rhs.GetZ() != 0 )		temp.SetZ( z / abs( rhs.GetZ() ) );	else		temp.SetZ( 0 );	temp.SetW( 1 );	return temp;}Vertex Vertex::operator-(){	Vertex temp;	temp.SetX( -x );	temp.SetY( -y );	temp.SetZ( -z );	temp.SetW( -w );	return temp;}

Projection matrices are partially read from file, and then constructed:
else if( keyword == "perspective" )			{				file >> angle >> near >> far;				angle = angle * ( pi / 180 );				top = abs( near ) * tan( angle / 2 );				bottom = -top;				right = top * ( screenWidth / screenHeight );				left = -right;				Matrix tempMatrix;				tempMatrix.SetMatrix( 					2 / ( right - left ), 0, 0, -( ( right + left ) / ( right - left ) ),					0, 2 / ( top - bottom ), 0, -( ( top + bottom ) / ( top - bottom ) ),					0, 0, 2 / ( near - far ), -( ( near + far ) / ( near - far ) ),					0, 0, 0, 1 );				Matrix p;				p.SetMatrix(					1, 0, 0, 0,					0, 1, 0, 0,					0, 0, ( near + far ) / near, -far,					0, 0, 1 / near, 0 );				projectionMatrix = tempMatrix * p;			}			else if( keyword == "ortho" )			{				file >> right >> top >> near >> far;				left = -right;				bottom = -top;				Matrix tempMatrix;				tempMatrix.SetMatrix( 					2 / ( right - left ), 0, 0, -( ( right + left ) / ( right - left ) ),					0, 2 / ( top - bottom ), 0, -( ( top + bottom ) / ( top - bottom ) ),					0, 0, 2 / ( near - far ), -( ( near + far ) / ( near - far ) ),					0, 0, 0, 1 );				projectionMatrix = tempMatrix;			}

Constructing and composing final matrix:
Matrix vp, m, cam, temp;	Vertex w, u, v;	w = -( camera.GetGazeVector() / camera.GetGazeVector() );	u = ( camera.GetUpVector() * w ) / ( camera.GetUpVector() * w );	v = w * u;	cout << w.GetX() << " " << w.GetY() << " " << w.GetZ() << endl;	cout << u.GetX() << " " << u.GetY() << " " << u.GetZ() << endl;	cout << v.GetX() << " " << v.GetY() << " " << v.GetZ() << endl;	cam.SetMatrix( 		u.GetX(), u.GetY(), u.GetZ(), 0,		v.GetX(), v.GetY(), v.GetZ(), 0,		w.GetX(), w.GetY(), w.GetZ(), 0,		0, 0, 0, 1 );	temp.SetMatrix(		1, 0, 0, -camera.GetEyeX(),		0, 1, 0, -camera.GetEyeY(),		0, 0, 1, -camera.GetEyeZ(),		0, 0, 0, 1 );	cam = cam * temp;	vp.SetMatrix( 		screenWidth / 2, 0, 0, ( screenWidth - 1 ) / 2,		0, screenHeight / 2, 0, ( screenHeight - 1 ) / 2,		0, 0, 1, 0,		0, 0, 0, 1 );	m = vp * projectionMatrix * cam;

Drawing the lines:
for ( int i = 0; i < (int)polyLines.size(); i++ ) 	{		glLineWidth( polyLines->GetWidth() );		glBegin( GL_LINE_STRIP );		for ( int j = 0; j < polyLines->GetNumberOfLines(); j++ ) 		{			Vertex temp = m * polyLines->GetVertex( j );			glColor3f( polyLines->GetVertex( j ).GetColor().GetRed(), 				polyLines->GetVertex( j ).GetColor().GetGreen(),				polyLines->GetVertex( j ).GetColor().GetBlue() );			glVertex2d( temp.GetX() / temp.GetW(), temp.GetY() / temp.GetW() );		}		glEnd();	}	glFlush ();

For the full code, in case the problem doesn't actually lie in one of these bits, it can be downloaded from
http://www.dreamincode.net/forums/topic/196461-3d-programming-bug/
at the bottom of the first post as an attachment.

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My suggestion would be to compare your matrices to OpenGL generated ones for debugging. There's too much there to quickly spot a missed negative sign or incorrect variable.

Maybe along side your matrix calculations, use opengl equivalent functions and then use glGetFloatv() to retrieve the opengl computed matrices, and compare them element by element vs your own matrices. You should be able to spot where you make a mistake pretty quickly.

Since you're not allowed to use opengl functions, just strip them all out once your own code is working.