[osg-users] getting eye position / direction
Hi,
i am trying to get eyePosition and direction, more precisely, the direction of
a ray for the purpose of ray tracing.
this is what i am doing:
Code:
const osg::Vec3d collisionPoint = intersection.getWorldIntersectPoint();
...
osg::Vec3d eyeDirection = collisionPoint - _tracer-getEye();
eyeDirection.normalize();
where the _tracer-getEye() method returns the position of the eye (computed
once for a frame):
Code:
if (!_eye_set) {
osg::Vec3d center, up;
getCamera()-getViewMatrixAsLookAt(_eye, center, up);
_eye_set = true;
}
i am not sure whether this is the correct way to get the eye
position/direction. i was thinking there has to be a way to get the direction
from an intersection itself, but i am not confident using the start/end points
(transforming them into appropriate coordinates) considering i create the rays
(line segment intersectors) in WINDOW and also MODEL coordinate frames.
can anyone tell me whether my method is correct or i should rather try getting
the start/end points from the intersector, transforming them and this way
getting the ray (==eye) direction ?
Thank you!
Cheers,
Andrey[/code]
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Re: [osg-users] [build] OpenGLES2.0 build error
Hi Mike,
Attached is a cmake toolchain to build osg against GLES2. You need to
comment lines from 204 - 207 in the CMakeLists.txt:
#the below is taken from ogre, it states the gcc stuff needs to happen
before PROJECT() is called. I've no clue if we even need it
# Force gcc = 4.2 on iPhone
#include(CMakeForceCompiler)
#CMAKE_FORCE_C_COMPILER(gcc-4.2 GNU)
#CMAKE_FORCE_CXX_COMPILER(gcc-4.2 GNU)
#SET(GCC_THUMB_SUPPORT NO)
And then simply do:
$cmake -DCMAKE_TOOLCHAIN_FILE=iOS5_GLES2.cmake and make install
or if you prefer to compile in XCode:
$cmake -GXCode -DCMAKE_TOOLCHAIN_FILE=iOS5_GLES2.cmake
If it solves your problem please report here and I will try to submit this
with a simple GLES2 example.
Cheers.
2012/3/8 Mike Wozniewski m...@mikewoz.com
Hi Tobias,
Is there any chance you can post your cmake command that builds for OpenGL
ES2? I tried yours (had to change the SDK to 5.0) but I get a ton of
compile errors, starting with:
'glLoadMatrixf' was not declared in this scope
Thanks,
Mike
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gvSIG 3D blog
http://gvsig3d.blogspot.com
Instituto de Automática e Informática Industrial
http://www.ai2.upv.es
# force CMake to assume crosscompiling
set(CMAKE_CROSSCOMPILING 1)
# assume we are somewhat on a Darwin system
set(CMAKE_SYSTEM_NAME Darwin)
set(CMAKE_SYSTEM_PROCESSOR arm )
# set the platform flags manually
set(APPLE 1)
set(IOS 1)
# hard set values
set(IOS_SDK_VERSION 5.0)
set(IOS_TARGET iPhoneOS)
set(IOS_ARCH armv7)
# some internal values
set(IOS_DEVELOPER_ROOT /Developer/Platforms/${IOS_TARGET}.platform/Developer)
set(IOS_SDK_ROOT ${IOS_DEVELOPER_ROOT}/SDKs/${IOS_TARGET}${IOS_SDK_VERSION}.sdk)
# for Xcode 4.x we need to set the sysroot to the internal string
if(XCODE)
set(CMAKE_OSX_SYSROOT ${IOS_SDK_ROOT} CACHE STRING SDK version FORCE)
else()
set(CMAKE_OSX_SYSROOT ${IOS_SDK_ROOT} CACHE STRING SDK version FORCE)
endif()
#
set(CMAKE_OSX_ARCHITECTURES ${IOS_ARCH} CACHE STRING SDK Architecture FORCE)
# default to searching for frameworks first
set (CMAKE_FIND_FRAMEWORK FIRST)
# set up the default search directories for frameworks
set (CMAKE_SYSTEM_FRAMEWORK_PATH
${IOS_SDK_ROOT}/System/Library/Frameworks
${IOS_SDK_ROOT}/System/Library/PrivateFrameworks
${IOS_SDK_ROOT}/Developer/Library/Frameworks
)
# set appropriate flags
set(CMAKE_C_FLAGS --sysroot=${IOS_SDK_ROOT} -miphoneos-version-min=${IOS_SDK_VERSION} -arch ${IOS_ARCH} -v CACHE STRING C flags FORCE)
set(CMAKE_CXX_FLAGS ${CMAKE_C_FLAGS} CACHE STRING C++ flags FORCE)
# specify compiler
set(CMAKE_C_COMPILER ${IOS_DEVELOPER_ROOT}/usr/bin/clang CACHE PATH C compiler FORCE)
set(CMAKE_CXX_COMPILER ${IOS_DEVELOPER_ROOT}/usr/bin/clang++ CACHE PATH C++ compiler FORCE)
# for Xcode we need to skip the compiler introspection
if(XCODE)
set(CMAKE_CXX_COMPILER_WORKS TRUE)
set(CMAKE_C_COMPILER_WORKS TRUE)
endif()
# root path settings
set(CMAKE_FIND_ROOT_PATH
${IOS_DEVELOPER_ROOT}
${IOS_SDK_ROOT}/usr
${IOS_SDK_ROOT}/System
)
FIND_LIBRARY(OPENGLES_LIBRARY OpenGLES)
# search paths (for makefiles the first one might be switched to NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
SET(OSG_WINDOWING_SYSTEM IOS CACHE STRING Forced IPhone windowing system on iOS FORCE)
SET(OSG_DEFAULT_IMAGE_PLUGIN_FOR_OSX imageio CACHE STRING Forced imageio default image plugin for iOS FORCE)
#set OpenGL_ES2 Flags
SET(OSG_BUILD_PLATFORM_IPHONE ON CACHE STRING Forced iOS Platform FORCE)
SET(OSG_GL1_AVAILABLE OFF CACHE STRING Forced for GLES2 compilation FORCE )
SET(OSG_GL2_AVAILABLE OFF CACHE STRING Forced for GLES2 compilation FORCE)
SET(OSG_GLES1_AVAILABLE OFF CACHE STRING Forced for GLES2 compilation FORCE)
SET(OSG_GLES2_AVAILABLE ON CACHE STRING Forced for GLES2 compilation FORCE)
SET(OSG_GL_DISPLAYLISTS_AVAILABLE OFF CACHE STRING Forced iOS Platform FORCE)
SET(OSG_GL_LIBRARY_STATIC OFF CACHE STRING Forced iOS Platform FORCE)
SET(OSG_GL_MATRICES_AVAILABLE OFF CACHE STRING Forced for GLES2 compilation FORCE)
SET(OSG_GL_VERTEX_ARRAY_FUNCS_AVAILABLE OFF CACHE STRING Forced for GLES2 compilation FORCE)
SET(OSG_GL_VERTEX_FUNCS_AVAILABLE OFF CACHE STRING Forced for GLES2 compilation FORCE)
SET(DYNAMIC_OPENSCENEGRAPH OFF CACHE STRING Forced iOS Platform FORCE)
SET(DYNAMIC_OPENTHREADS OFF CACHE STRING Forced iOS Platform FORCE)
SET(_OPENTHREADS_ATOMIC_USE_GCC_BUILTINS_EXITCODE 0 CACHE STRING Forced iOS Platform FORCE)
SET (BUILD_OSG_APPLICATIONS OFF CACHE STRING Forced iOS Platform FORCE)
SET(_OPENTHREADS_ATOMIC_USE_BSD_ATOMIC_EXITCODE 0 CACHE STRING Forced IPhone Platform FORCE)
SET (BUILD_OSG_EXAMPLES
Re: [osg-users] [build] OpenGLES2.0 build error
I guess you are trying to compile for iOS5, if you are not sorry for the noise. Cheers. 2012/3/9 Jordi Torres jtorresfa...@gmail.com Hi Mike, Attached is a cmake toolchain to build osg against GLES2. You need to comment lines from 204 - 207 in the CMakeLists.txt: #the below is taken from ogre, it states the gcc stuff needs to happen before PROJECT() is called. I've no clue if we even need it # Force gcc = 4.2 on iPhone #include(CMakeForceCompiler) #CMAKE_FORCE_C_COMPILER(gcc-4.2 GNU) #CMAKE_FORCE_CXX_COMPILER(gcc-4.2 GNU) #SET(GCC_THUMB_SUPPORT NO) And then simply do: $cmake -DCMAKE_TOOLCHAIN_FILE=iOS5_GLES2.cmake and make install or if you prefer to compile in XCode: $cmake -GXCode -DCMAKE_TOOLCHAIN_FILE=iOS5_GLES2.cmake If it solves your problem please report here and I will try to submit this with a simple GLES2 example. Cheers. 2012/3/8 Mike Wozniewski m...@mikewoz.com Hi Tobias, Is there any chance you can post your cmake command that builds for OpenGL ES2? I tried yours (had to change the SDK to 5.0) but I get a ton of compile errors, starting with: 'glLoadMatrixf' was not declared in this scope Thanks, Mike -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=46116#46116 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org -- Jordi Torres Fabra gvSIG 3D blog http://gvsig3d.blogspot.com Instituto de Automática e Informática Industrial http://www.ai2.upv.es -- Jordi Torres Fabra gvSIG 3D blog http://gvsig3d.blogspot.com Instituto de Automática e Informática Industrial http://www.ai2.upv.es ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] osg::text Question on character size when set to SCREEN_COORDS mode
HI David, On 9 March 2012 02:09, David Glenn david.e.glenn@navy.mil wrote: Just wondering: We had always assumed that if you set your setCharacterSize in the SCREEN_COORDS mode that you set it the size of pixels (as told to me originally by a friend) and the height in meters if you are in OBJECT_COORDS mode. I assume Right? This is mostly correctly, the only thing I'd add is the OBJECT_COORDS mean local objects coords so will be in the coordinate system and units that the text drawable sits below, this could be Meters, it could be feet, it could be miles, it could be anything - it all depends upon your the parental chain in the scene graph above the text. Robert. ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] getting eye position / direction
HI Andrey,
I'm rather confused about what you are trying to do, you question
seems rather mixed up. Could you take a step back and explain at a
higher level what you are trying to achieve and we can then point you
in the right direction of how to achieve.
Robert.
On 9 March 2012 08:29, Andrey Ibe xry...@gmail.com wrote:
Hi,
i am trying to get eyePosition and direction, more precisely, the direction
of a ray for the purpose of ray tracing.
this is what i am doing:
Code:
const osg::Vec3d collisionPoint = intersection.getWorldIntersectPoint();
...
osg::Vec3d eyeDirection = collisionPoint - _tracer-getEye();
eyeDirection.normalize();
where the _tracer-getEye() method returns the position of the eye (computed
once for a frame):
Code:
if (!_eye_set) {
osg::Vec3d center, up;
getCamera()-getViewMatrixAsLookAt(_eye, center, up);
_eye_set = true;
}
i am not sure whether this is the correct way to get the eye
position/direction. i was thinking there has to be a way to get the direction
from an intersection itself, but i am not confident using the start/end
points (transforming them into appropriate coordinates) considering i create
the rays (line segment intersectors) in WINDOW and also MODEL coordinate
frames.
can anyone tell me whether my method is correct or i should rather try
getting the start/end points from the intersector, transforming them and this
way getting the ray (==eye) direction ?
Thank you!
Cheers,
Andrey[/code]
--
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http://forum.openscenegraph.org/viewtopic.php?p=46123#46123
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Re: [osg-users] getting eye position / direction
i am trying to compute the direction of an osg::LineSegmentIntersector object. i can get the collision point and i am trying to get the starting point - i need the vector of the intersector's direction. i do this for the purpose of ray tracing (or ray casting). i create the intersectors this way Code: new osgUtil::LineSegmentIntersector(cf, x, y); where cf is 'WINDOW' (this is for the primary rays). i am not sure how to transform the starting/end point of the intersector into model (world) space. that's why i am trying to get the position of the camera as the starting point. i looked at the code of the linesegmentintersector thoroughly, but still am confused about the matrices, so i decided it could be less difficult to use the camera. i need the vector to calculate the specular color. robert, thank you very much for your help. andrey -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=46129#46129 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] getting eye position / direction
Hi Andrey, Thanks for the explanation, make more sense now. If you have a perspective camera then you'll be able to assume that the all the line segments will start at the cameras eye point and end at the intersection point that is returned. To compute the camera's eye position in world coordinates what you need to do is multiple the (0,0,0) eye position in eye coorindates into the world coordinates by multiply it by the the inverse of the camera's view matrix. i.e. osg::Vec3d eyeInWorld = osg::Vec3d(0.0,0.0,0.0) * osg::Matrixd::inverse(camera-getViewMatrix()); Robert. On 9 March 2012 10:41, Andrey Ibe xry...@gmail.com wrote: i am trying to compute the direction of an osg::LineSegmentIntersector object. i can get the collision point and i am trying to get the starting point - i need the vector of the intersector's direction. i do this for the purpose of ray tracing (or ray casting). i create the intersectors this way Code: new osgUtil::LineSegmentIntersector(cf, x, y); where cf is 'WINDOW' (this is for the primary rays). i am not sure how to transform the starting/end point of the intersector into model (world) space. that's why i am trying to get the position of the camera as the starting point. i looked at the code of the linesegmentintersector thoroughly, but still am confused about the matrices, so i decided it could be less difficult to use the camera. i need the vector to calculate the specular color. robert, thank you very much for your help. andrey -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=46129#46129 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] [osgPlugins] Write animation to mpeg or other video format
on linux you can use glc (google for glc capture) for this task. on output you'll get either *.png's per frame, or uncompressed video. on encoding to more usable format you can check this page https://wiki.archlinux.org/index.php/GLC 08.03.2012, 20:33, Zachary Hilbun osgfo...@tevs.eu: Hi, I want to be able to animate a scene and then write the images to an image format such as mpeg or other format. Is this possible using OSG? If so, is there any documentation on how to do it or is this just one of those read the source code things? Thank you! Cheers, Zachary -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=46108#46108 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
[osg-users] OpenSceneGraph 3.1.1 dev release tagged
Hi All, I have just tagged the OpenSceneGraph-3.1.1 developer release. Merged pending submissions that fixed a range of bugs, full ChangeLog below. source package : OpenSceneGraph-3.1.1.zip svn tag: svn co http://www.openscenegraph.org/svn/osg/OpenSceneGraph/tags/OpenSceneGraph-3.1.1 OpenSceneGraph My plan is to keep pushing out the dev releases and then go for a 3.2 stable release before the end of April. Cheers, Robert. -- ChangeLog since 3.1.0: 2012-03-09 10:20 robert * ChangeLog, include/osgManipulator/Projector, include/osgManipulator/RotateCylinderDragger, src/osgManipulator/Projector.cpp, src/osgManipulator/RotateCylinderDragger.cpp: From Chuck Seberino, Attached are modified versions of RotateCylinderDragger and Projector files that clean up the use of _onCylinder / isProjectionOnCylinder(). I have also made changes to the RotateCylinderDragger to provide a cylinder ring with a thickness. It is totally optional, but IMHO makes the default behavior work better than a solid cylinder (which typically obscures the geometry you are trying to drag). Gives it a bit more to grab, especially in the case where eyepoint and cylinder axis are near parallel. 2012-03-08 16:33 robert * CMakeLists.txt, ChangeLog, include/osg/Version: Updated version number for 3.1.1 dev release 2012-03-08 16:05 robert * include/osg/Image, src/osg/Image.cpp: From Farshid Lashkari, I've added support for reading contents of cubemap textures to the osg::Image::readImageFromCurrentTexture method. I added a new parameter to the method for specifying which face of the cubemap to read. 2012-03-07 09:32 robert * src/osgViewer/GraphicsWindowWin32.cpp: From Olaf Flebbe, Appended now a bugfixed proposition for the Win7 Multitouch Support. Now examples/osgmultitouch really works ;-) Based on yesterdays trunk. * It should now work with all Visual Studio Versions. * WIN_VER is left as-is * I added the missing declarations from a recent SDK, if not supplied by the SDK * If someone chooses to update WIN_VER, the declarations should not break. * All API Calls are runtime detected. * No CMake Variable, Support is enabled automatically . 2012-03-06 10:35 robert * src/osgUtil/Optimizer.cpp: From Guillaume Millet, Please find a small fix to avoid crash of texture Atlas builder in case of textures with NULL image. If an object is comming with texture and NULL image, the texture atlas builder crash when sorting textures according to texture height. The fix is to skip textures with NULL image when inserting textures in the builder texture list. 2012-03-06 10:33 robert * src/osgParticle/PrecipitationEffect.cpp: From Farshild Laskari, The vertex shader for the point stateset of PrecipitationEffect was not properly computing the clip vertex. It needed to apply a modelview transformation to the clip vertex. Attached is the fix. 2012-03-06 10:29 robert * examples/CMakeLists.txt, examples/osgsimpleshaders, examples/osgsimpleshaders/CMakeLists.txt, examples/osgsimpleshaders/osgsimpleshaders.cpp: From Christian Buchner, The attached openscenegraph example is much simpler than osgshaders.cpp and demonstrates the use of GLSL vertex and fragment shaders with a simple animation callback. I found the osgshaders.cpp too complex to serve as a starting point for GLSL programming 2012-03-06 10:08 robert * include/osgManipulator/Projector, src/osgManipulator/Projector.cpp: From Chuck Seberino, Here is a fix for the RotateCylinderDragger. This patch fixes the case where the picking direction is close to the cylinder axis. The current behavior is this: * If the eyepoint and cylinder axis are close to parallel (given some tolerance), then it uses a plane perpendicular to the cylinder axis. * Otherwise it uses a plane parallel to the cylinder axis oriented towards the eyepoint (previous behavior). This gives decent behavior and is the only path that was taken in the previous code. I kept with previous behavior and that allowed a good bit of code to be removed, simplifying things. There is now no need for the _onCylinder flag, but since there is a public accessor, I wasn't sure how to handle it for backwards compatibility, so I left it in. NOTE - there is no default
Re: [osg-users] Screen Shot question
Is there also a high res example code? Am 09.03.2012 01:45, schrieb Sergey Kurdakov: Hi Thomas Is there a way to capture this programatically? here is example from osgWorks where you have full control: http://code.google.com/p/osgworks/source/browse/trunk/src/osgwTools/ScreenCapture.cpp Regards Sergey On Fri, Mar 9, 2012 at 4:27 AM, Thomas Lerman osgfo...@tevs.eu mailto:osgfo...@tevs.eu wrote: I know I can capture a single screen capture with _keyEventTakeScreenShot in the ScreenCaptureHandler. As long as I remember correctly, this writes it out to some file. Is there a way to capture this programatically? How about capture it to the clipboard or at least query what the file path is? ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Performance question: Switch / NodeMask / WriteToFile
Here is my repro case for the 1 children of a switch node causing massive cull times. Tried this piece of code on Linux with osg 3.1.1 developer release. I do not observe any high cull times here, even when drastically increasing the number of children of the switch node. Too bad, my intention was to do code profiling to get to the bottom of this. So either osg 3.1 fixes this, or some implementation detail is more efficient on Linux than it is on Windows. I would have profiled on Windows, except the Visual Studio versions with this feature cost a fortune (you can purchase a car for that price). Christian ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
[osg-users] Screen Shot question
Hi Is there also a high res example code? http://forum.openscenegraph.org/viewtopic.php?t=3482 regards Sergey On Fri, Mar 9, 2012 at 7:33 PM, Werner Modenbach werner.modenb...@texion.eu wrote: Is there also a high res example code? ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
[osg-users] Simuating realistic large crowds with RVO2 C++ library
Hello, I am currently working on a demo that shows the use of the RVO2 C++ library with OpenSceneGraph. Check out these videos to get an idea of what RVO2 is capable of: http://www.youtube.com/playlist?list=PLD56A0C7765234DCDfeature=plcp This amazing library can be used for simulating large crowd of agents. It implements an algorithm called optimal reciprocal collision avoidance. My demo will be using an efficient billboarded renderer for animated persons with approximation of camera perspective (this can display thousands of people and is loosely based on the billboard shaders found in the osgforest sample). When done, I will be submitting the demo to osg-submissions. However the textures required for the animated walking persons would be a few hundred kilobytes in size. Unfortunately there are dependencies on OpenMP (for which a CMake Module exists) and on the RVO2 library however (for which I crafted my own CMake module that hasn't been tested much so far). Christian ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] If I set a vertex color using floats and access the vertex color in a shader, is there a loss of precision?
So I decided to go again and try to use a generic vertex attribute to store my
index numbers. I noticed from another osg forum thread that there is currently
a problem using int values for vertex attributes but that floats are working
and can be converted to ints in the shader. With that in mind, I implemented
Christian's code snippet up to the part where I've already added a vec2 float
vertex attribute to the 6th position. I have a couple of questions though:
1. in osg there is no Vec1Array (which makes sense), but then if I only wanted
to store 1 float value for each vertex, what would I use? osg::array ?
2. I need to access the vertex values from a frag shader instead of the vertex
shader as seen in Christian's code snippet. If I have a generic vertex shader
like this:
Code:
void main(void)
{
gl_FrontColor = gl_Color;
gl_Position = ftransform();
}
then can I access the vertex attribute in the frag shader like this?
Code:
in vec2 indices;
void main(void)
{
//get index from vertex attribute 6
vec2 index = indices;
}
[/code]
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Re: [osg-users] If I set a vertex color using floats and access the vertex color in a shader, is there a loss of precision?
On 03/09/2012 02:08 PM, Ethan Fahy wrote:
So I decided to go again and try to use a generic vertex attribute to store my
index numbers. I noticed from another osg forum thread that there is currently
a problem using int values for vertex attributes but that floats are working
and can be converted to ints in the shader. With that in mind, I implemented
Christian's code snippet up to the part where I've already added a vec2 float
vertex attribute to the 6th position. I have a couple of questions though:
1. in osg there is no Vec1Array (which makes sense), but then if I only wanted
to store 1 float value for each vertex, what would I use? osg::array ?
Close, osg::FloatArray :-)
2. I need to access the vertex values from a frag shader instead of the vertex
shader as seen in Christian's code snippet. If I have a generic vertex shader
like this:
Code:
void main(void)
{
gl_FrontColor = gl_Color;
gl_Position = ftransform();
}
then can I access the vertex attribute in the frag shader like this?
Code:
in vec2 indices;
void main(void)
{
//get index from vertex attribute 6
vec2 index = indices;
}
Depends on what you're after, but I'm guessing not. The fragment values
will be interpolated between the vertices, so if you have a value of 6.0
on one vertex and 8.0 on another, the value for the fragment halfway
between those vertices will be 7.0. If you're drawing triangles, and
you want all of the fragments on a particular triangle to have the same
value, you can specify flat shading in the fragment shader:
flat in vec2 indices;
which might give you what you're looking for (without knowing how your
geometry is laid out and how you're using the indices, I can only guess).
--J
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