[osg-users] Generating a cube using geometry shaders
Hi, I'm trying to generate a cube using GLSL shaders. The basic idea is to pass a single vertex that represents the center of the cube, and let the geometry shader do the calculations. No luck so far, the only output I get is a single white pixel (point) in the center of the screen. C++/GLSL code below, any ideas are appreciated. Thank you! Cheers, Ahmed -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=61028#61028 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Generating a cube using geometry shaders
CPP file:
Code:
#include osgDB/ReadFile
#include osgViewer/Viewer
struct ModelViewProjectionMatrixCallback : public osg::Uniform::Callback {
ModelViewProjectionMatrixCallback(osg::Camera *fCamera) :
_camera(fCamera) {
}
virtual void operator()(osg::Uniform *uniform, osg::NodeVisitor *nv) {
osg::Matrixd viewMatrix = _camera-getViewMatrix();
osg::Matrixd modelMatrix = osg::computeLocalToWorld(nv-getNodePath());
osg::Matrixd modelViewProjectionMatrix = modelMatrix * viewMatrix *
_camera-getProjectionMatrix();
uniform-set(modelViewProjectionMatrix);
}
osg::Camera *_camera;
};
osg::ref_ptrosg::Program createProgram(std::string fProgramName, std::string
fVertexShader, std::string fGeometryShader, std::string fFragmentShader)
{
osg::ref_ptrosg::Shader vertexShader =
osgDB::readShaderFile(fVertexShader);
osg::ref_ptrosg::Shader geometryShader =
osgDB::readShaderFile(fGeometryShader);
osg::ref_ptrosg::Shader fragmentShader =
osgDB::readShaderFile(fFragmentShader);
osg::ref_ptrosg::Program program = new osg::Program;
program-setName(fProgramName);
program-addShader(vertexShader);
program-addShader(geometryShader);
program-addShader(fragmentShader);
return program.release();
}
int main(int argc, char **argv)
{
// Program
osg::ref_ptrosg::Program program = createProgram(SinglePass,
singlepass.vert, singlepass.geom, singlepass.frag);
// Vertices
osg::ref_ptrosg::Vec3Array vertices = new osg::Vec3Array;
vertices-push_back(osg::Vec3(0.5f, 0.0f, 0.5f));
// Geometry
osg::ref_ptrosg::Geometry geom = new osg::Geometry;
geom-setUseDisplayList(false);
geom-setVertexArray(vertices);
geom-setVertexAttribArray(0, vertices);
geom-addPrimitiveSet(new osg::DrawArrays(GL_POINTS, 0, vertices-size()));
// Geode
osg::ref_ptrosg::Geode screenGeode = new osg::Geode;
screenGeode-addDrawable(geom);
// State set
osg::StateSet *geomStateSet = geom-getOrCreateStateSet();
geomStateSet-setAttribute(program);
osg::ref_ptrosg::Point point = new osg::Point;
point-setSize(5.0f);
geomStateSet-setAttribute(point);
// Viewer
osgViewer::Viewer viewer;
viewer.setSceneData(screenGeode.get());
viewer.setUpViewInWindow(50, 50, 800, 600, 0);
viewer.getCamera()-setViewport(0, 0, 800, 600);
viewer.getCamera()-setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
viewer.getCamera()-setClearColor(osg::Vec4(0.2f, 0.2f, 0.2f, 1.0f));
// MVP
osg::ref_ptrosg::Uniform MVP = new osg::Uniform(osg::Uniform::FLOAT_MAT4,
ModelviewProjection);
MVP-setUpdateCallback(new
ModelViewProjectionMatrixCallback(viewer.getCamera()));
geomStateSet-addUniform(MVP);
return viewer.run();
}
Vertex shader:
Code:
#version 330
in vec4 Position;
out vec4 vPosition;
uniform mat4 ModelviewProjection;
void main()
{
gl_Position = ModelviewProjection * Position;
vPosition = Position;
}
Geometry shader:
Code:
#version 330
layout(points) in;
layout(triangle_strip, max_vertices = 24) out;
in vec4 vPosition[1];
uniform mat4 ModelviewProjection;
uniform mat4 ProjectionMatrix;
uniform mat4 ViewMatrix;
uniform mat4 Modelview;
vec4 objCube[8]; // Object space coordinate of cube corner
vec4 ndcCube[8]; // Normalized device coordinate of cube corner
ivec4 faces[6]; // Vertex indices of the cube faces
void emit_vert(int vert)
{
gl_Position = ndcCube[vert];
EmitVertex();
}
void emit_face(int face)
{
emit_vert(faces[face][1]); emit_vert(faces[face][0]);
emit_vert(faces[face][3]); emit_vert(faces[face][2]);
EndPrimitive();
}
void main()
{
faces[0] = ivec4(0,1,3,2); faces[1] = ivec4(5,4,6,7);
faces[2] = ivec4(4,5,0,1); faces[3] = ivec4(3,2,7,6);
faces[4] = ivec4(0,3,4,7); faces[5] = ivec4(2,1,6,5);
vec4 P = vPosition[0];
vec4 I = vec4(0.25,0,0,0);
vec4 J = vec4(0,0.25,0,0);
vec4 K = vec4(0,0,0.25,0);
objCube[0] = P+K+I+J; objCube[1] = P+K+I-J;
objCube[2] = P+K-I-J; objCube[3] = P+K-I+J;
objCube[4] = P-K+I+J; objCube[5] = P-K+I-J;
objCube[6] = P-K-I-J; objCube[7] = P-K-I+J;
// Transform the corners of the box:
for (int vert = 0; vert 8; vert++)
ndcCube[vert] = ModelviewProjection * objCube[vert];
// Emit the six faces:
for (int face = 0; face 6; face++)
emit_face(face);
}
Fragment shader:
Code:
#version 330
out vec4 FragColor;
void main()
{
FragColor = vec4(1.0, 0.0, 0.0, 1.0);
}
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Re: [osg-users] About HUD' projection
For a normal 2D HUD I suggest orthogonal. -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=61031#61031 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
[osg-users] order of MatrixTransform
Hi, I'm a little confused about something simple... the order in which to add MatrixTransform. For example I want to rotate something around x,y,z using 3 matrixtransforms. as I understand I can do this by: -translate(-x,-y,-z) -rotate -translate(x,y,z) when I add them, which is the correct order? -root- translate(-x,-y,-z) - rotate - translate(x,y,z) - geode or... -root- translate(x,y,z) - rotate - translate(-x,-y,-z) - geode thanks! -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=61032#61032 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] order of MatrixTransform
HI Bram, On 14 September 2014 13:23, Bram Vaessen bram.vaes...@gmail.com wrote: Hi, I'm a little confused about something simple... the order in which to add MatrixTransform. For example I want to rotate something around x,y,z using 3 matrixtransforms. as I understand I can do this by: -translate(-x,-y,-z) -rotate -translate(x,y,z) when I add them, which is the correct order? -root- translate(-x,-y,-z) - rotate - translate(x,y,z) - geode or... -root- translate(x,y,z) - rotate - translate(-x,-y,-z) - geode The second version is the correct one. You can of course do this all with a single PositionAttitudeTransform or a single Transform node, this will be neater and lead to better performance. Robert. ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
[osg-users] OpenGL error 'invalid operation' when adding 'unsigned int' Uniform
Hi,
I encountered something peculiar. Everything seems to work fine, though.
I get the following warning message:
Warning: detected OpenGL error 'invalid operation' at After Renderer::compile
Investigating the issue (and stripping it down somewhat), I found that the
error message disappears when I change 'unsigned int' in the following piece of
code to 'int':
Code:
unsigned int texUnit = 0;
ref_ptrUniform uniform = new Uniform(sampler, texUnit);
stateSet-addUniform(uniform);
I'm curious if this is a bug or something I'm forgetting?
For completeness, here's the code that replicates the 'issue' for me:
Code:
#include osgViewer/Viewer
using namespace osg;
int main(int argc, char** argv)
{
osgViewer::Viewer viewer;
viewer.setUpViewInWindow(50, 50, 640, 480);
ref_ptrGroup root = new Group;
ref_ptrGeode geode = new Geode;
ref_ptrGeometry geometry = new Geometry;
root-addChild(geode);
geode-addChild(geometry);
geometry-setUseDisplayList(false);
geometry-setUseVertexBufferObjects(true);
ref_ptrStateSet stateSet = geometry-getOrCreateStateSet();
ref_ptrProgram program = new Program();
program-setName(TestProgram);
stateSet-setAttributeAndModes( program, StateAttribute::ON );
ref_ptrShader vertShader = new Shader(osg::Shader::Type::VERTEX);
ref_ptrShader fragShader = new Shader(osg::Shader::Type::FRAGMENT);
program-addShader(vertShader);
program-addShader(fragShader);
vertShader-setShaderSource(
void main(void){\n
gl_Position = gl_ProjectionMatrix * gl_ModelViewMatrix * gl_Vertex;\n
}\n
);
fragShader-setShaderSource(
uniform sampler2D sampler;\n
void main (void){\n
gl_FragColor = vec4(1, 1, 1, 1) + texture2D(sampler, vec2(0,
0)).rgba;\n
}\n
);
osg::Vec3 quadVerts[] = {
osg::Vec3(-1, -1, 1),
osg::Vec3(1, -1, 1),
osg::Vec3(1, 1, -1),
osg::Vec3(-1, 1, -1)};
geometry-setVertexArray( new Vec3Array(4, quadVerts) );
geometry-addPrimitiveSet( new DrawArrays(PrimitiveSet::QUADS, 0, 1) );
unsigned int texUnit = 0;
ref_ptrUniform uniform = new Uniform(sampler, texUnit);
stateSet-addUniform(uniform);
viewer.setSceneData(root);
viewer.run();
}
Thanks,
Selmar[/code]
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Re: [osg-users] order of MatrixTransform
Thanks. Is there a way to make it a single node, but still being able to easily change the rotation around the point (the point on which to rotate doesn't change) ? -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=61035#61035 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] order of MatrixTransform
Hi Bram, If you use single MatrixTransform you can achieve the same effect in the way you are constructing the scenegraph above by multiplication of different matrices. Something like osg::MatrixTransform *mxt = new osg::MatrixTransform; mxt-setMatrix( osg::Matrix::translate(-myPoint) * osg::Matrix::rotate(myRotation) * osg::Matrix::translate(myPoint) ); And you keep track and change myRotation, which is osg::Quat. Nick On Sun, Sep 14, 2014 at 5:29 PM, Bram Vaessen bram.vaes...@gmail.com wrote: Thanks. Is there a way to make it a single node, but still being able to easily change the rotation around the point (the point on which to rotate doesn't change) ? -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=61035#61035 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org -- trajce nikolov nick ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] order of MatrixTransform
Ok thanks, I would have to recalculate the matrix every time the rotation changes I assume, but in the end that is probably more efficient than having 3 matrixtransforms in the scenegraph... right? -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=61037#61037 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] order of MatrixTransform
yes. This is what I think Robert had in mind when he mentioned performance efficiency Nick On Sun, Sep 14, 2014 at 10:42 PM, Bram Vaessen bram.vaes...@gmail.com wrote: Ok thanks, I would have to recalculate the matrix every time the rotation changes I assume, but in the end that is probably more efficient than having 3 matrixtransforms in the scenegraph... right? -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=61037#61037 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org -- trajce nikolov nick ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
[osg-users] OSG Android and Vuforia
Hi, Any one knows how to render an osg model in OpenGL ES 2.0? I am working on an Android project, and had been using the osgAndroid (https://gitorious.org/osgandroid) open source project, which supports OpenGL ES 1.x only, but Vuforia (QCAR) supports only ES 2.0. I have been trying to migrate the osg rendering with OpenGL ES 2.0, but there are lots of errors in the rendering calls. A quick search in this forum shows that I need to write some shader files for these osg models. Anyone knows how to write such shader files? Thank you! David -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=61039#61039 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
