我正在尝试对对象纹理执行实时绘画。现在使用Irrlicht,但这并不重要。实时对象绘画
到目前为止,我已经得到了使用该算法正确的UV坐标:
找出哪些对象的三角用户选择(光线投射,什么 真的很难)
找出UV (baricentric)坐标上的交点 即三角形
找出每个三角形顶点的UV(纹理)坐标
找出UV(纹理)交点坐标
计算纹理图像坐标交叉点
但不知何故,当我在我的得到了点我画第五步纹理图像,我得到完全错误的结果。因此,绘制在光标处长方形的情况下,X(或Z)其反转坐标:
下面是我使用来获取纹理的代码坐标:
core::vector2df getPointUV(core::triangle3df tri, core::vector3df p)
{
core::vector3df
v0 = tri.pointC - tri.pointA,
v1 = tri.pointB - tri.pointA,
v2 = p - tri.pointA;
float dot00 = v0.dotProduct(v0),
dot01 = v0.dotProduct(v1),
dot02 = v0.dotProduct(v2),
dot11 = v1.dotProduct(v1),
dot12 = v1.dotProduct(v2);
float invDenom = 1.f/((dot00 * dot11) - (dot01 * dot01)),
u = (dot11 * dot02 - dot01 * dot12) * invDenom,
v = (dot00 * dot12 - dot01 * dot02) * invDenom;
scene::IMesh* m = Mesh->getMesh(((scene::IAnimatedMeshSceneNode*)Model)->getFrameNr());
core::array<video::S3DVertex> VA, VB, VC;
video::SMaterial Material;
for (unsigned int i = 0; i < m->getMeshBufferCount(); i++)
{
scene::IMeshBuffer* mb = m->getMeshBuffer(i);
video::S3DVertex* vertices = (video::S3DVertex*) mb->getVertices();
for (unsigned long long v = 0; v < mb->getVertexCount(); v++)
{
if (vertices[v].Pos == tri.pointA)
VA.push_back(vertices[v]); else
if (vertices[v].Pos == tri.pointB)
VB.push_back(vertices[v]); else
if (vertices[v].Pos == tri.pointC)
VC.push_back(vertices[v]);
if (vertices[v].Pos == tri.pointA || vertices[v].Pos == tri.pointB || vertices[v].Pos == tri.pointC)
Material = mb->getMaterial();
if (VA.size() > 0 && VB.size() > 0 && VC.size() > 0)
break;
}
if (VA.size() > 0 && VB.size() > 0 && VC.size() > 0)
break;
}
core::vector2df
A = VA[0].TCoords,
B = VB[0].TCoords,
C = VC[0].TCoords;
core::vector2df P(A + (u * (C - A)) + (v * (B - A)));
core::dimension2du Size = Material.getTexture(0)->getSize();
CursorOnModel = core::vector2di(Size.Width * P.X, Size.Height * P.Y);
int X = Size.Width * P.X, Y = Size.Height * P.Y;
// DRAWING SOME RECTANGLE
Material.getTexture(0)->lock(true);
Device->getVideoDriver()->setRenderTarget(Material.getTexture(0), true, true, 0);
Device->getVideoDriver()->draw2DRectangle(video::SColor(255, 0, 100, 75), core::rect<s32>((X - 10), (Y - 10),
(X + 10), (Y + 10)));
Device->getVideoDriver()->setRenderTarget(0, true, true, 0);
Material.getTexture(0)->unlock();
return core::vector2df(X, Y);
}
我只是想让我的对象实时绘制。我目前的问题是:错误的纹理坐标计算和非唯一的顶点UV坐标(所以,在矮人的斧头的一侧绘制东西会在该斧头的另一侧绘制相同的东西)。
我应该怎么做?
嗯...要具有独特的顶点的UV坐标你需要改变纹理,复制修改并应用到右三新UV的区域,不要你呢? – LBarret 2012-01-11 17:52:57
我认为不是。因为首先,我需要确定绘画区域。它需要独特的UV;) – shybovycha 2012-01-11 19:58:12