diff options
Diffstat (limited to 'src/jogl/classes')
| -rw-r--r-- | src/jogl/classes/com/jogamp/opengl/util/texture/Texture.java | 39 |
1 files changed, 27 insertions, 12 deletions
diff --git a/src/jogl/classes/com/jogamp/opengl/util/texture/Texture.java b/src/jogl/classes/com/jogamp/opengl/util/texture/Texture.java index bf85bea87..d6a8090fb 100644 --- a/src/jogl/classes/com/jogamp/opengl/util/texture/Texture.java +++ b/src/jogl/classes/com/jogamp/opengl/util/texture/Texture.java @@ -52,18 +52,32 @@ import com.jogamp.opengl.util.texture.spi.*; * Represents an OpenGL texture object. Contains convenience routines * for enabling/disabling OpenGL texture state, binding this texture, * and computing texture coordinates for both the entire image as well - * as a sub-image. + * as a sub-image. + * + * <a name="textureCallOrder"><h5>Order of Texture Commands</h5></a> + * <p> + * Due to many confusions w/ texture usage, following list described the order + * and semantics of texture unit selection, binding and enabling. + * <ul> + * <li><i>Optional:</i> Set active textureUnit via <code>gl.glActiveTexture(GL.GL_TEXTURE0 + textureUnit)</code>, <code>0</code> is default.</li> + * <li>Bind <code>textureId</code> -> active <code>textureUnit</code>'s <code>textureTarget</code> via <code>gl.glBindTexture(textureTarget, textureId)</code></li> + * <li><i>Compatible Context Only:</i> Enable active <code>textureUnit</code>'s <code>textureTarget</code> via <code>glEnable(textureTarget)</code>. + * <li><i>Optional:</i> Fiddle with the texture parameters and/or environment settings.</li> + * <li>GLSL: Use <code>textureUnit</code> in your shader program, enable shader program.</li> + * <li>Issue draw commands</li> + * </ul> + * </p> * * <p><a name="nonpow2"><b>Non-power-of-two restrictions</b></a> * <br> When creating an OpenGL texture object, the Texture class will - * attempt to leverage the <a - * href="http://www.opengl.org/registry/specs/ARB/texture_non_power_of_two.txt">GL_ARB_texture_non_power_of_two</a> - * and <a - * href="http://www.opengl.org/registry/specs/ARB/texture_rectangle.txt">GL_ARB_texture_rectangle</a> - * extensions (in that order) whenever possible. If neither extension - * is available, the Texture class will simply upload a non-pow2-sized + * attempt to use <i>non-power-of-two textures</i> (NPOT) if available, see {@link GL#isNPOTTextureAvailable()}. + * Further more, + * <a href="http://www.opengl.org/registry/specs/ARB/texture_rectangle.txt">GL_ARB_texture_rectangle</a> + * (RECT) will be attempted on OSX w/ ATI drivers. + * If NPOT is not available or RECT not chosen, the Texture class will simply upload a non-pow2-sized * image into a standard pow2-sized texture (without any special - * scaling). Since the choice of extension (or whether one is used at + * scaling). + * Since the choice of extension (or whether one is used at * all) depends on the user's machine configuration, developers are * recommended to use {@link #getImageTexCoords} and {@link * #getSubImageTexCoords}, as those methods will calculate the @@ -91,9 +105,12 @@ import com.jogamp.opengl.util.texture.spi.*; * when switching between textures it is necessary to call {@link * #bind}, but when drawing many triangles all using the same texture, * for best performance only one call to {@link #bind} should be made. + * User may also utilize multiple texture units, + * see <a href="#textureCallOrder"> order of texture commands above</a>. * * <p><a name="premult"><b>Alpha premultiplication and blending</b></a> - * <br> The mathematically correct way to perform blending in OpenGL + * <br/><i>Disclaimer: Consider performing alpha premultiplication in shader code, if really desired! Otherwise use RGBA.</i> + * <br/> The mathematically correct way to perform blending in OpenGL * (with the SrcOver "source over destination" mode, or any other * Porter-Duff rule) is to use "premultiplied color components", which * means the R/G/ B color components have already been multiplied by @@ -138,9 +155,7 @@ import com.jogamp.opengl.util.texture.spi.*; <TR> <TD> AlphaXor <TD> GL_ONE_MINUS_DST_ALPHA <TD> GL_ONE_MINUS_SRC_ALPHA </TABLE> </CENTER> - * - * @author Chris Campbell - * @author Kenneth Russell + * @author Chris Campbell, Kenneth Russell, et.al. */ public class Texture { /** The GL target type. */ |