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• ### Similar Content

• 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

• 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!

# OpenGL Why are my mouse coords using gluUnProject so small

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I want to draw my current mouse cursor on the screen using opengl - so i convert the mouse window coordinates to world coordinates using gluUnProject.

But the resulting world coordinates are very small and does fit into the world space coordinates at all.

What am i doing wrong?

#include <string.h>
#include <stdio.h>
#include <iostream>
#include <GL/freeglut.h>

using std::cout;

float mouseX, mouseY;

void Draw()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

glMatrixMode(GL_MODELVIEW);
glTranslatef(0.0f, 0.0f, -25.0f);

glPointSize(40.0f);
glColor3f(1.0f, 1.0f, 1.0f);
glBegin(GL_POINTS);
glVertex2f(mouseX, mouseY);
glEnd();
glPointSize(1.0f);

glutSwapBuffers();
}

void Keyboard(unsigned char key, int x, int y)
{
switch (key)
{
case 27:
exit(0);
break;
}
}

void Mouse(int button, int state, int x, int y) {

}

void MouseMove(int x, int y) {
double modelview[16], projection[16];
int viewport[4];
//get the projection matrix
glGetDoublev( GL_PROJECTION_MATRIX, projection );
//get the modelview matrix
glGetDoublev( GL_MODELVIEW_MATRIX, modelview );
//get the viewport
glGetIntegerv( GL_VIEWPORT, viewport );

float z;
double posX, posY, posZ;

glReadPixels( x, viewport[3] - y - 1, 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, &z );

gluUnProject( x, viewport[3] - y - 1, z, modelview, projection, viewport, &posX, &posY, &posZ );

cout << x << ", " << y << ", " << z << " to " << posX << ", " << posY << ", " << posZ << "\n";

mouseX = posX;
mouseY = posY;
}

void Reshape(int width, int height)
{
if (height == 0) {
height = 1;
}
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
gluPerspective(45.0, (float)width/(float)height, 0.1, 100.0);
glMatrixMode( GL_MODELVIEW );
}

int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
glutInitWindowSize(800, 800);
glutCreateWindow("GLUT Mouse!");

glutReshapeFunc(Reshape);
glutDisplayFunc(Draw);
glutKeyboardFunc(Keyboard);
glutMouseFunc(Mouse);
glutMotionFunc(MouseMove);
glutPassiveMotionFunc(MouseMove);
glutIdleFunc(SimulationLoop);

glClearColor( 0.0f, 0.0f, 0.0f, 1.0f );

glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);

glutMainLoop();

return 0;
}


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first of all explain what do you expect, and what results you get.

secondly i see many errors here:

first you do not draw anything on the screen and yet you take the value from Depth buffer which is situated in your far plane (1.0 depth) (100.0 - in your case)

second thing you are not using ortographic projection but perspective projection, so you cant actually see the pixel (gl_point you try to draw) at the exact part of the screen you i think desire

so

cout << x << ", " << y << ", " << z << " to " << posX << ", " << posY << ", " << posZ << "\n";

should always show a point that is 100.0 units away from actual camera

heres a code that sets ortho projection (so you can draw things, with defining pixel position)


void __fastcall glPush2DDrawing()
{

glPushAttrib(GL_DEPTH_TEST);
glDisable(GL_DEPTH_TEST);

glMatrixMode(GL_PROJECTION);
glPushMatrix();

glOrtho(0, WINDOW_WIDTH, 0, WINDOW_HEIGHT, -1000.0f, 1000.0f);  // Change the projection matrix using an orthgraphic projection
glMatrixMode(GL_MODELVIEW);
glPushMatrix();

}

void __fastcall glPop2DDrawing()
{
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
glPopAttrib();
}


usage is simple

glPush2DDrawing();

glVertex2f(0.0, 0.0);

glVertex2f(640.0, 0.0);

glVertex2f(640.0, 480.0);

glVertex2f(0.0, 480.0);

glEnd();

glPop2DDrawing();

this should draw a quad that is 640x480 pixels

Edited by WiredCat

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first of all explain what do you expect, and what results you get.

secondly i see many errors here:

first you do not draw anything on the screen and yet you take the value from Depth buffer which is situated in your far plane (1.0 depth) (100.0 - in your case)

second thing you are not using ortographic projection but perspective projection, so you cant actually see the pixel (gl_point you try to draw) at the exact part of the screen you i think desire

...

Thats not true, i draw the mouseX and mouseY which are set in the MouseMove method. Also my goal was to draw a point in the actual world coordinate system for the current mouse position. So that the point is always on that mouse position for that given depth (view z translation).

But never mind, i fixed it already by projecting the world origin (0, 0, 0) to the screen coordinates (gluProject) and use the resulting z-value in (gluUnProject). Now it works fine ;-)

The problem was that glReadPixels was not returning a proper z-value, so that the resulting world coordinate was too small.

Edited by Finalspace

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apparently you didint show all the code because your was drawing exactly nothing.

yeah that ortho thing was not the best answer.