Databases
StackOverflow2013
Postsdbo
POAndroid OpenGL - difficulties with simple 2D transformations
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POAndroid OpenGL - difficulties with simple 2D transformations
    primarykey
    data
    text
    <p>I'm trying to migrate graphics in my game to OpenGL for performance reasons. </p> <ol> <li>I need to draw an object using exact screen coordinates. Say a box 100x100 pixels in the center of 240x320 screen.</li> <li>I need to rotate it around Z axis, preserving its size.</li> <li>I need to rotate it around X axis, with perspective effect, preserving (or close to) its size.</li> <li>I need to rotate it around Y axis, with perspective effect, preserving (or close to) its size.</li> </ol> <p><a href="http://img265.imageshack.us/img265/5448/1234ua.jpg" rel="nofollow">Here's a picture.</a></p> <p>So far I managed to achieve first 2 tasks:</p> <pre><code>public void onDrawFrame(GL10 gl) { gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT); gl.glLoadIdentity(); gl.glTranslatef(120, 160, 0); // move rotation point gl.glRotatef(angle, 0.0f, 0.0f, 1.0f); // rotate gl.glTranslatef(-120, -160, 0); // restore rotation point mesh.draw(gl); // draws 100x100 px rectangle with the following coordinates: (70, 110, 170, 210) } public void onSurfaceChanged(GL10 gl, int width, int height) { gl.glViewport(0, 0, width, height); gl.glMatrixMode(GL10.GL_PROJECTION); gl.glLoadIdentity(); gl.glOrthof(0f, (float)width, (float)height, 0f, -1f, 1f); gl.glMatrixMode(GL10.GL_MODELVIEW); gl.glLoadIdentity(); } </code></pre> <p>But when I'm trying to rotate my box around x or y, nasty thing are happening with my box and there is no perspective effect. I tried to use some other function instead of glRotate (glFrustum, glPerspective, gluLookAt, applying "skewing" matrix), but I couldn't make them work properly.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USgenpfault
    1. USdop2000
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POAndroid OpenGL - difficulties with simple 2D transformations
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POAndroid OpenGL - difficulties with simple 2D transformations
      1. USStuart Golodetz
      1. VTFavorite
    3. VO
      singulars
      1. POAndroid OpenGL - difficulties with simple 2D transformations
      1. This table or related slice is empty.
      1. VTUpMod
    1. COIt seems that you will need an introduction to graphics with OpenGL in general. Go to http://fly.cc.fer.hr/~unreal/theredbook/ and read at least chapters 1 through 6. Good luck.
      singulars
      1. POAndroid OpenGL - difficulties with simple 2D transformations
      1. UScli_hlt
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload