CustomFilterMeshGenerator::CustomFilterMeshGenerator(unsigned columns, unsigned rows, const FloatRect& meshBox, CustomFilterMeshType meshType)
: m_meshType(meshType)
, m_points(columns + 1, rows + 1)
, m_tiles(columns, rows)
, m_tileSizeInPixels(meshBox.width() / m_tiles.width(), meshBox.height() / m_tiles.height())
, m_tileSizeInDeviceSpace(1.0f / m_tiles.width(), 1.0f / m_tiles.height())
, m_meshBox(meshBox)
{
// Build the two buffers needed to draw triangles:
// * m_vertices has a number of float attributes that will be passed to the vertex shader
// for each computed vertex. This number is calculated in floatsPerVertex() based on the meshType.
// * m_indices is a buffer that will have 3 indices per triangle. Each index will point inside
// the m_vertices buffer.
m_vertices.reserveCapacity(verticesCount() * floatsPerVertex());
m_indices.reserveCapacity(indicesCount());
// Based on the meshType there can be two types of meshes.
// * attached: each triangle uses vertices from the neighbor triangles. This is useful to save some GPU memory
// when there's no need to explode the tiles.
// * detached: each triangle has its own vertices. This means each triangle can be moved independently and a vec3
// attribute is passed, so that each vertex can be uniquely identified.
if (m_meshType == MeshTypeAttached)
generateAttachedMesh();
else
generateDetachedMesh();
#ifndef NDEBUG
if (s_dumpCustomFilterMeshBuffers)
dumpBuffers();
#endif
}
//===================================================================
void Mesh::computeNormal()
{
// calculates the vector components normal to the plane containing the vertices
for (int index = 0; index < verticesCount(); index += 3) {
QVector3D v1 = vertex(index + 1).pos() - vertex(index).pos();
QVector3D v2 = vertex(index + 2).pos() - vertex(index).pos();
// Caclulates the normal vector
vertex(index).setNx((v1.y() * v2.z()) - (v2.y() * v1.z()));
vertex(index).setNy((v1.x() * v2.z()) - (v2.x() * v1.z()));
vertex(index).setNz((v1.x() * v2.y()) - (v2.x() * v1.y()));
vertex(index).setNormal(vertex(index).normal().normalized());
vertex(index + 1).setNormal(vertex(index).normal().normalized());
vertex(index + 2).setNormal(vertex(index).normal().normalized());
}
}
