[PO] 2007/03/01 Inspired by [RS] famous weekend fun projects I'm trying to release a new [Tcl3D] demo every month. Note: These demos are not contained in the current Tcl3D distribution. Visit the Tcl3D demo page [http://www.tcl3d.org/html/demos.html] for more demos. ---- **December 2008 Demo** This demo is a tool to visualize certain aspects of ray-tracing algorithms. A description and more screenshots can be found on the Tcl3D homepage [http://www.tcl3d.org/html/docRtVis.html]. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/08-12-rtVis.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/08-12-rtVis.jpg] ---- **November 2008 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/usersrc/usersrc_6.htm#oglu_projtexture] demonstrates the use of projective textures. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/08-11-oglu_projtexture.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/08-11-oglu_projtexture.jpg] ---- **October 2008 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/oglsrc/oglsrc_5.htm#ogl_lighting] demonstrates the three basic types of lights available in OpenGL: directional, spot, and point lights. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/08-10-ogl_lighting.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/08-10-ogl_lighting.jpg] ---- **September 2008 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/oglsrc/oglsrc_5.htm#ogl_color_tracking] demonstrates color-tracking and two-sided lighting in OpenGL. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/08-09-ogl_color_tracking.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/08-09-ogl_color_tracking.jpg] ---- **August 2008 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/oglsrc/oglsrc_7.htm#ogl_planar_shadow] demonstrates how to create a planar shadow under OpenGL. Planar shadows are created by building a special matrix transform which flattens an object's geometry into a plane when rendered and is definitely one of the simplest ways of creating real-time shadows. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/08-08-ogl_planar_shadow.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/08-08-ogl_planar_shadow.jpg] ---- **July 2008 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/oglsrc/oglsrc_4.htm#ogl_alpha_blending_framebuffer] demonstrates how to perform alpha blending using the framebuffer. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/08-07-ogl_alpha_blending_framebuffer.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/08-07-ogl_alpha_blending_framebuffer.jpg] ---- **June 2008 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/oglsrc/oglsrc_3.htm#ogl_alpha_blending_texture] demonstrates how to perform alpha blending using the alpha channel of a standard texture. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/08-06-ogl_alpha_blending_texture.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/08-06-ogl_alpha_blending_texture.jpg] ---- **May 2008 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/oglsrc/oglsrc_5.htm#ogl_material] demonstrates how to use materials with lighting to produce different surface effects. It also shows the usage of GL_COLOR_MATERIAL to override material values. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/08-05-ogl_material.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/08-05-ogl_material.jpg] ---- **April 2008 Demo** This demo originating from discussions on Wiki page [Simple Chaos Theory with Tcl] has been on the Wiki for some time. It is now part of the official Tcl3D demos. OpenGL stuff demonstrated in the script are GL_POINTS. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/08-04-tcl3dChaos.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/08-04-tcl3dChaos.jpg] ---- **March 2008 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/oglsrc/oglsrc_8.htm#ogl_point_rotated_billboard] demonstrates how to orient a billboard perpendicular to the viewer's direction as defined by the model-view matrix. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/08-03-ogl_point_rotated_billboard.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/08-03-ogl_point_rotated_billboard.jpg] ---- **February 2008 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/oglsrc/oglsrc_8.htm#ogl_axis_aligned_billboard] demonstrates how to rotate and orient a textured quad along a particular axis for the purposes of billboarding. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/08-02-ogl_axis_aligned_billboard.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/08-02-ogl_axis_aligned_billboard.jpg] ---- '''Happy new year''' **January 2008 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/oglsrc/oglsrc_7.htm#ogl_occlusion_query] demonstrates how to use OpenGL's new extension, ARB_occlusion_query, and nVIDIA's older extension, NV_occlusion_query to perform occlusion queries. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/08-01-ogl_occlusion_query.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/08-01-ogl_occlusion_query.jpg] ---- **December 2007 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/oglsrc/oglsrc_5.htm#ogl_polygon_offset] demonstrates how to eliminate z-fighting when rendering polygons directly on top of other polygons. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/07-12-ogl_polygon_offset.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/07-12-ogl_polygon_offset.jpg] ---- **November 2007 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/oglsrc/oglsrc_2.htm#ogl_near_far_clip] demonstrates how adjustments to OpenGL's near and far clip planes effect the view. Look at the source to see how to use the Tcl3D supplied math functions to update the view matrix. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/07-11-ogl_near_far_clip.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/07-11-ogl_near_far_clip.jpg] ---- **October 2007 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/oglsrc/oglsrc_10.htm#ogl_cg_multitexture] demonstrates how to blend two textures together with Cg using either OpenGL's native multi-texture support (using semantics) or by using Cg's special texture functions. The original demo has been extended with a little GUI to allow switching between the two call semantics at runtime. See also the July 2007 demo for multi-texturing with OpenGL extensions. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/07-10-ogl_cg_multitexture.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/07-10-ogl_cg_multitexture.jpg] ---- **September 2007 Demo** This demo from the SIGGRAPH 1996 course "Advanded Rendering" [http://www.opengl.org/resources/code/samples/glut_examples/advanced/advanced.html] shows examples of various image processing operations coded as OpenGL accumulation buffer operations. The course notes are still available [http://www.cse.ucsc.edu/~pang/160/f96/sig96/COURSE23/COURSE23.PDF] and interesting to read. The file header says: This allows extremely fast image processing on machines with hardware accumulation buffers like RealityEngine or InfiniteReality. The Times They Are A-Changin' Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/07-09-imgproc.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/07-09-imgproc.jpg] ---- **August 2007 Demo** Here is another demo from NeHe's OpenGL tutorials. Lesson 27 [http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=27] shows how to calculate shadows with the help of the stencil buffer. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/07-08-NeHe-Lesson27.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/07-08-NeHe-Lesson27.jpg] ---- **July 2007 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/oglsrc/oglsrc_4.htm#ogl_multitexture_blending] demonstrates how to use the OpenGL extensions GL_ARB_multitexture and GL_ARB_texture_env_combine in conjunction with specially encoded vertex colors to blend three textures together. This technique is very popular in terrain rendering engines which use it to blend dramatically different textures such as rock and grass together with out creating a noticeable edge. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/07-07-ogl_multitexture_blending.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/07-07-ogl_multitexture_blending.jpg] ---- **June 2007 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/oglsrc/oglsrc_3.htm#ogl_texture_addressing] demonstrates the different texture addressing modes of OpenGL: * GL_REPEAT * GL_CLAMP * GL_MIRRORED_REPEAT_ARB * GL_CLAMP_TO_BORDER_ARB * GL_CLAMP_TO_EDGE Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/07-06-ogl_texture_addressing.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/07-06-ogl_texture_addressing.jpg] ---- **May 2007 Demo** This month is a [GLSL] demo with Photo Booth (see [http://en.wikipedia.org/wiki/Photo_Booth]) image warping effects. The original demo was written in C by Libero Spagnolini. A description of the effect shaders and the original sources are available at [http://dem.ocracy.org/libero/photobooth/] The Tcl3D demo has been modified to allow up to 2 shader parameters to be changed interactively via a slider. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/07-05-PhotoBooth.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/07-05-PhotoBooth.jpg] ---- **April 2007 Demo** The April demo is NeHe's Lesson 25 [http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=25], a nice example of morphing. Although lots of code is done on the CPU with Tcl, it runs quite smooth. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/07-04-NeHe-Lesson25.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/07-04-NeHe-Lesson25.jpg] ---- **March 2007 Demo** This sample from Kevin Harris CodeSampler page [http://www.codesampler.com/oglsrc/oglsrc_14.htm#ogl_frame_buffer_object] demonstrates how to create dynamic textures through off-screen rendering with framebuffer objects. Demo sources are available here: [http://www.tcl3d.org/download/DemoOfTheMonth/07-03-ogl_frame_buffer_object.zip] [http://www.tcl3d.org/demos/DemoOfTheMonth/07-03-ogl_frame_buffer_object.jpg] ---- !!!!!! %| [Category Graphics] | [Category 3D Graphics] | [Category Tcl3D] |% !!!!!!