Jump to content
  • Advertisement

Archived

This topic is now archived and is closed to further replies.

Polymorph2000

OpenGL opengl and side scrolling

This topic is 5553 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

I''m trying to make a program that follows a character centered on the main screen using openGL. My initial idea was to use glTranslate to move the screen axis based on how much the character moves. But for some reason this doesn''t work. Also, the game is 2D, so there is only x and y axis movement. Is there an easier way to make the screen move?

Share this post


Link to post
Share on other sites
Advertisement
glTranslate should work! both in perspective or in orthogonal mode..

its the simplest and fastest(in a simple 2d tile/billboard scroller) to move stuff with opengl!

Other methods would require you to recalc every vertex you send to OGL every frame ,if CPU power dont is a problem, this should be as fast as glTranslate (if you send every vertex to OGL every frame anyway), but then you talk about simplicity, and glTranslate wins again!

If you have a advanced culling method, you might need to do some calculations even if you use glTranslate, and simplicity might fall as a argument, but why not create a method, based on that you use glTranslate!( = fast and simple)

look it up, and learn it well! its the best and simplest way! (for a simple 2d tile/billboard scroller)

Share this post


Link to post
Share on other sites
My OpenGL class at www.icarusindie.com in the DevZone includes a method for calculating 3D coordinates from 2D coordinates. I prefer doing it that way since I still want pespective. The method just gives me an easier way to specify where to start drawing.

Ben

Share this post


Link to post
Share on other sites
i don''t see where in your opengl class (http://www.icarusindie.com/devzone/mysource/OpenGLclass/Data/ ?) is that method

Share this post


Link to post
Share on other sites
Since my 3D to 2D methods are apparently not in the version I released, here it is.


  
GLvoid oglClass::SetTranslate2D(float x, float y, float z)
{
glTranslatef(x*4.0f/(float)screenW-2.0f,1.5f-y*3.0f/(float)screenH,z-3.63f);
}

GLvoid oglClass::ReSizeGLScene(GLsizei width, GLsizei height)
{
if (height==0)
height=1;

glViewport(0,0,width,height);

glMatrixMode(GL_PROJECTION);
glLoadIdentity();

// Calculate The Aspect Ratio Of The Window

gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f);

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();

screenH=(float)height;
screenW=(float)width;
xratio=1024.0f/screenW;
yratio=768.0f/screenH;
}


The equations I use must use the gluPerspective settings I use above. xration and yratio are then applied to any shapes you want to remain the same number of pixels regardless of the resolution the user sets.

With the above 1 unit is 256 pixels so you can draw your primitives accordingly.

My OpenGL class will be rereleased some time in the future with MD2 model support and a particle system and whatever else I need for my current project.

Ben


IcarusIndie.com


KalvinB - (to Jessika) do you accept Jesus as your lord and savior

Jessika - Sure I can accept all forms of payment.

Share this post


Link to post
Share on other sites

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!