Thanks for your answer. my matrix is GL_MODELVIEW. I have noticed that once I have traslated and rotated the quad, also the aces x,y,z seem to be rotated of 45 degree. If it is right, it's normal that when i applied the second traslalte the quad goes in another position.
is it normal? is there something wrong? On 18 Giu, 18:21, Leigh McRae <[email protected]> wrote: > OpenGL applies it's transforms in reverse so maybe swap the two > translates. Sounds lame but this is the sort of thing you get right > once and don't look at again for sometime. Also make sure your matrix > mode is GL_MODELVIEW. > > Leigh > > On 6/18/2010 11:58 AM, Paolo wrote: > > > > > > > Hi leigh! > > I've tried, but it doesn't work... the quad goes in a wrong position : > > ( > > > My quad has these coordinates > > > //vertex bottom left > > vertex[0] = 9.5f; > > vertex[1] = 10f; > > vertex[2] = 0.0f; > > //top left > > vertex[3] = 9.5f; > > vertex[4] = 11.0f; > > vertex[5] = 0.0f; > > //bottom right > > vertex[6] = 10.5f; > > vertex[7] = 10f; > > vertex[8] = 0.0f; > > //top right > > vertex[9] = 10.5; > > vertex[10] = 11f; > > vertex[11] = 0.0f; > > > and this is my draw function... > > > public void draw(GL10 gl){ > > gl.glPushMatrix(); > > gl.glTranslatef(-10, -10.5f, 0); //to the origin > > > gl.glRotatef(45, 0, 0, -1); //rotate > > > gl.glTranslatef(10, 10.5f, -2.0f); //back to previous position > > > // Enabled the vertices buffer for writing and to be used during > > // rendering. > > gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); > > // Specifies the location and data format of an array of vertex > > // coordinates to use when rendering. > > gl.glVertexPointer(3, GL10.GL_FLOAT, 0, markerBuffer); > > gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, NUMERO_VERTICI); > > // Disable the vertices buffer. > > gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); > > gl.glPopMatrix(); > > > } > > > On 18 Giu, 17:31, Leigh McRae<[email protected]> wrote: > > >> Translate the quad to the origin, rotate, translate back. > > >> Leigh > > >> On 6/18/2010 11:12 AM, Paolo wrote: > > >>> Hi guys! > >>> I'm a newbie in OpenGL. :D > >>> I'm trying to rotate a quad around its center. > > >>> This is my scenario: I've a quad, drawn with TRIANGLE_STRIP, at > >>> specified coordinates. Now I want to rotate of 45 degrees around its > >>> center, without move it from its position, not around the origin of > >>> the aces. > >>> I hope you are able to understand my english... :) > > >>> How can I do that? > > >>> Thanks > > >>> Paolo > > >> -- > >> Leigh McRaewww.lonedwarfgames.com > > -- > Leigh McRaewww.lonedwarfgames.com -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
