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Re: [gl4java-usergroup] Follow-up texture-mapping questions
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From: <lec...@ya...> - 2003-03-23 10:38:44
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I think the error occurs because your 2048*1024
texture is not a square. I think OpenGL can only
handle square textures !
You'll need to add black rectangles on both parts of
your image, in order to have a 2048*2048 one, and then
play with the texture coordinates of your polygon...
Hope this helps...
--- Mark Montana <pat...@lm...> a
écrit : > All,
>
> Follow up texture-mapping questions...
>
> First, I fixed my original problem that was causing
> textures in my application to
> be all white. I had a special initialization method
> to set all the texture mapping
> parameters. I forgot to surround those GL calls
> with:
> glc.getGLContext().gljMakeCurrent(); AND
> glc.getGLContext().gljFree();
> A rather newbie-sounding mistake, but it's been a
> while since I wrote rendering
> code in GL4Java. I hate that you have to perform
> those steps in the non-draw
> methods, but I realize it is a necessary evil
> (Magician had the same thing).
>
> On to my 2 new questions (somewhat more advanced):
>
> (Q1) I am loading fairly large textures of satellite
> imagery of the Earth. Two of
> them are 1024x1024 (powers of two) in RGB format.
> These two images load and render
> just fine. The third texture is 2048x1024 (also
> powers of two) in RGB format. This
> one gets a GL error during my call to
> glTexImage2d(), and the error is "invalid
> value." I determined that value that makes it
> unhappy is the image width (2048).
> If I lie to OpenGL and tell it that the width is
> only1024, the image loads and
> renders without an error (of course it looks screwed
> up, but I expect that since I
> lied about the true width). Any insight on why it
> cannot handle the 2048 width?
>
> I know that it is not related to the hardware,
> graphics card, graphics card
> driver, or machine configuration. I know this
> because our application is half
> GL4Java and half Java3D. The Java3D display loads
> the same exact textures and
> renders them with no problem. I also do not think it
> is related to the total
> amount of texture memory available; again because
> Java3D has no problem, and I can
> disable the Java3D display and disable to two
> 1024x1024 textures in the GL4Java
> display...and the GL4Java display still gets the
> same error on the 2048x1024
> texture.
>
> Could it have something to do with the OpenGL
> context or configuration that I am
> requesting???
> Could it be related to the fact that I am using
> display-lists???
>
> [[ I inserted my texture mapping method at the
> bottom of this message. ]]
>
> (Q2) My textures are rendered in a 2D display, no
> lighting, no normals, no
> materials. The polygons underneath the texture are
> white. The texture comes out
> way to dark with GL_DECAL or GL_REPLACE. When I try
> GL_MODULATE or GL_BLEND, it
> gets really washed-out. We had this same exact
> problem in the Java3D display with
> these textures. We fixed it there by using some
> texture-environment settings that
> are unique to Java3D. (In other words, the Java3D
> people used some of the more
> advanced features of blending functions and/or
> filters to create a new blending
> equation that works well.) I was considering a
> decompile of the Java3D code to see
> how they did it, but I thought I would as for some
> advice on this problem first.
>
>
----------------------------------------------------------------------------------------
>
> My texture map initialization code (sorry for the
> formatting if your mail tool
> doesn't support fixed-width fonts):
>
>
> private void initialize()
> {
> // Must make the GLComponent's OpenGL context
> current when outside a
> // GLEventListener callback method. Then don't
> forget to unlock() it.
>
> glc.getGLContext().gljMakeCurrent(); //
> Make current to call OpenGL
>
>
> GeoTiffImage image =
> geoTiffDef.getGeoTiffImage();
> Raster raster = image.getAsRaster();
> Object data = raster.getDataElements(
> 0, 0,
>
> raster.getWidth(),
>
> raster.getHeight(),
>
> null );
>
> if( ToolkitConstants.TK_DEBUG_PATCH2D == true
> )
> {
> if( raster.getTransferType() ==
> DataBuffer.TYPE_BYTE )
> System.out.println( "Texture storage
> type = TYPE_BYTE");
> else
> {
> System.err.println(
> "TexturedPatch2d.initialize() - " +
> "What is the texture
> storage type?");
> System.err.flush();
> }
>
> System.out.println( "Num data elements = "
> +
>
> raster.getNumDataElements() );
> System.out.println( "Geotiff size = (" +
> raster.getWidth() + ", "
> +
> raster.getHeight() + ")" );
> }
>
>
> // Set unpacking to use 1 byte allignment
> gl_.glPixelStorei( GLEnum.GL_UNPACK_ALIGNMENT,
> 1 );
>
> // Ask for valid, unused texture name
> gl_.glGenTextures( 1, textureName );
>
> // Bind a texture object to the name
> gl_.glBindTexture( GLEnum.GL_TEXTURE_2D,
> textureName[0] );
>
> // Set clamping preferences
> gl_.glTexParameteri( GLEnum.GL_TEXTURE_2D,
> GLEnum.GL_TEXTURE_WRAP_S,
> GLEnum.GL_CLAMP );
> gl_.glTexParameteri( GLEnum.GL_TEXTURE_2D,
> GLEnum.GL_TEXTURE_WRAP_T,
> GLEnum.GL_CLAMP );
>
> // Set mag and min filter preferences
> gl_.glTexParameteri( GLEnum.GL_TEXTURE_2D,
> GLEnum.GL_TEXTURE_MAG_FILTER,
> GLEnum.GL_NEAREST );
> gl_.glTexParameteri( GLEnum.GL_TEXTURE_2D,
> GLEnum.GL_TEXTURE_MIN_FILTER,
> GLEnum.GL_NEAREST );
>
> gl_.glTexEnvi( GLEnum.GL_TEXTURE_ENV,
> GLEnum.GL_TEXTURE_ENV_MODE,
> GLEnum.GL_MODULATE ); //
> GL_REPLACE, GL_BLEND, GL_DECAL
>
> gl_.glHint(
> GLEnum.GL_PERSPECTIVE_CORRECTION_HINT,
> GLEnum.GL_FASTEST );
>
> // Define the 2D texture
> gl_.glTexImage2D( GLEnum.GL_TEXTURE_2D, 0,
> GLEnum.GL_RGB,
> raster.getWidth()/2,
> raster.getHeight(),
> 0, GLEnum.GL_RGB,
> GLEnum.GL_UNSIGNED_BYTE,
> (byte[]) data );
>
>
> if( ToolkitConstants.TK_DEBUG_PATCH2D == true
> )
> {
> int errorCode = GLEnum.GL_NO_ERROR;
>
> if( (errorCode = gl_.glGetError()) !=
> GLEnum.GL_NO_ERROR )
> {
> System.err.println(
> "TexturedPatch2d.initialize() - " +
> "GL Error: " +
> glu_.gluErrorString(errorCode) );
> System.err.flush();
> }
> }
>
>
=== message truncated ===
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