[osg-users] Texture Mapping Meeting Point Shadow

[Farshid Lashkari]

Hi Erik,

That looks like a texture wrap issue. Try setting your texture wrap mode to
CLAMP_TO_EDGE:

pTexture->setWrap(osg::Texture::WRAP_S, osg::Texture::CLAMP_TO_EDGE);
pTexture->setWrap(osg::Texture::WRAP_T, osg::Texture::CLAMP_TO_EDGE);

Cheers,
Farshid

On Mon, May 11, 2015 at 12:39 PM, Erik Hensens <ehensens at hunter.com> wrote:

> Hello all!
>
> I'm having trouble with image texture mapping a geode. Specifically, where
> the top and the bottom of the image meet, there is a dark shadow effect
> that I want to avoid.
>
> I've created the simplest example of how I'm attempting the texture
> mapping and I've taken screenshots that show the unwanted shadow (please
> see the attached screenshots and the overlay image itself).
>
> Below is the code I'm using. As you can see, it's very simple: just four
> quadrangle faces that form four sides of an open-ended box. I've attempted
> to map the overlay image around the entire box so that the top and bottom
> meet at one of the four edges.
>
> Does anyone have any idea what I'm doing wrong or how I can modify my code
> to get rid of the shadow effect? Thanks a bunch in advance!
>
>
> Code:
> // Create the new geode node
> osg::ref_ptr < osg::Geode > pGeode = new osg::Geode;
>
> // Create the single new geometry
> osg::ref_ptr < osg::Geometry > pGeometry = new osg::Geometry;
>
> // The vertex array to define the geometry shape
> osg::ref_ptr < osg::Vec3Array > pVertices = new osg::Vec3Array;
>
> // Add face 1/4 quad vertices
> pVertices->push_back(osg::Vec3(0.0f, 0.0f, 0.0f));
> pVertices->push_back(osg::Vec3(10.0f, 0.0f, 0.0f));
> pVertices->push_back(osg::Vec3(10.0f, 5.0f, 5.0f));
> pVertices->push_back(osg::Vec3(0.0f, 5.0f, 5.0f));
>
> // Add face 2/4 quad vertices
> pVertices->push_back(osg::Vec3(0.0f, 5.0f, 5.0f));
> pVertices->push_back(osg::Vec3(10.0f, 5.0f, 5.0f));
> pVertices->push_back(osg::Vec3(10.0f, 0.0f, 10.0f));
> pVertices->push_back(osg::Vec3(0.0f, 0.0f, 10.0f));
>
> // Add face 3/4 quad vertices
> pVertices->push_back(osg::Vec3(0.0f, 0.0f, 10.0f));
> pVertices->push_back(osg::Vec3(10.0f, 0.0f, 10.0f));
> pVertices->push_back(osg::Vec3(10.0f, -5.0f, 5.0f));
> pVertices->push_back(osg::Vec3(0.0f, -5.0f, 5.0f));
>
> // Add face 4/4 quad vertices
> pVertices->push_back(osg::Vec3(0.0f, -5.0f, 5.0f));
> pVertices->push_back(osg::Vec3(10.0f, -5.0f, 5.0f));
> pVertices->push_back(osg::Vec3(10.0f, 0.0f, 0.0f));
> pVertices->push_back(osg::Vec3(0.0f, 0.0f, 0.0f));
>
> // Set the vertex array on the geometry
> pGeometry->setVertexArray(pVertices);
>
> // Create the geometry's color array
> osg::ref_ptr < osg::Vec4Array > pColors = new osg::Vec4Array;
> pColors->push_back(osg::Vec4(1.0f, 1.0f, 1.0f, 1.0f));
>
> // Set the color array on the geometry
> pGeometry->setColorArray(pColors);
> pGeometry->setColorBinding(osg::Geometry::BIND_OVERALL);
>
> // Set the quad draw array on the geometry
> osg::ref_ptr < osg::DrawArrays > pDrawArrays = new
> osg::DrawArrays(osg::PrimitiveSet::QUADS, 0, static_cast < GLsizei
> >(pVertices->size()));
> pGeometry->addPrimitiveSet(pDrawArrays);
>
> // Load the overlay image
> osg::ref_ptr < osg::Image > pImage = osgDB::readImageFile("overlay.png");
>
> // Create the image texture
> osg::ref_ptr < osg::Texture2D > pTexture = new osg::Texture2D(pImage);
>
> // Create the texture coordinates array
> osg::ref_ptr < osg::Vec2Array > pTexCoords = new osg::Vec2Array;
>
> // Set face 1/4 quad texture overlay coordinates
> pTexCoords->push_back(osg::Vec2(0.0f, 0.0f));
> pTexCoords->push_back(osg::Vec2(1.0f, 0.0f));
> pTexCoords->push_back(osg::Vec2(1.0f, 0.25f));
> pTexCoords->push_back(osg::Vec2(0.0f, 0.25f));
>
> // Set face 2/4 quad texture overlay coordinates
> pTexCoords->push_back(osg::Vec2(0.0f, 0.25f));
> pTexCoords->push_back(osg::Vec2(1.0f, 0.25f));
> pTexCoords->push_back(osg::Vec2(1.0f, 0.50f));
> pTexCoords->push_back(osg::Vec2(0.0f, 0.50f));
>
> // Set 3/4 quad texture overlay coordinates
> pTexCoords->push_back(osg::Vec2(0.0f, 0.50f));
> pTexCoords->push_back(osg::Vec2(1.0f, 0.50f));
> pTexCoords->push_back(osg::Vec2(1.0f, 0.75f));
> pTexCoords->push_back(osg::Vec2(0.0f, 0.75f));
>
> // Set 4/4 quad texture overlay coordinates
> pTexCoords->push_back(osg::Vec2(0.0f, 0.75f));
> pTexCoords->push_back(osg::Vec2(1.0f, 0.75f));
> pTexCoords->push_back(osg::Vec2(1.0f, 1.0f));
> pTexCoords->push_back(osg::Vec2(0.0f, 1.0f));
>
> // Set the geometry's texture coordinates array
> pGeometry->setTexCoordArray(0, pTexCoords);
>
> // Get the geometry's stateset
> osg::ref_ptr < osg::StateSet > pStateSet =
> pGeometry->getOrCreateStateSet();
>
> // Set the texture on the stateset
> pStateSet->setTextureAttributeAndModes(0, pTexture,
> osg::StateAttribute::ON);
>
> // Set the geometry's stateset
> pGeometry->setStateSet(pStateSet);
>
> // Add the single drawable to the geode node
> pGeode->addDrawable(pGeometry);
>
> // Add this new geode to the scene
> pTopGroupNode->addChild(pGeode);
>
>
>
> Cheers,
> Erik
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=63711#63711
>
>
>
>
> _______________________________________________
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>
>
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