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local mesh = {}
local gl = honey.gl
setmetatable(mesh, {__index=_G})
setfenv(1, mesh)
local function insertVertex(vertices, attrib, vertex)
local pos = 3*vertex.v_idx
for i=1,3 do
table.insert(vertices, attrib.vertices[pos+i])
end
local normal = 3*vertex.vn_idx
for i=1,3 do
table.insert(vertices, attrib.normals[normal+i])
end
local tex = 3*vertex.vt_idx
for i=1,2 do
table.insert(vertices, attrib.texcoords[tex+i])
end
end
function loadShape(shape, attrib)
local vertices = {}
local indices = {}
local start = shape.face_offset
local finish = start + shape.length
for i=start,finish-1 do
assert(attrib.face_num_verts[i+1] == 3, "non-triangular face!")
for j=0,2 do
local vertex = attrib.faces[(3*i) + j + 1]
insertVertex(vertices, attrib, vertex)
table.insert(indices, #indices)
end
end
return vertices, indices
end
function loadFile(filename)
local flags = honey.tinyobj.FLAG_TRIANGULATE
local attrib, shapes, materials = honey.tinyobj.parse_obj(filename, flags)
local meshes = {}
for _, shape in ipairs(shapes) do
local vertices, indices = loadShape(shape, attrib)
table.insert(meshes, Mesh(vertices, indices))
end
return meshes
end
Mesh = {}
Mesh.__index = Mesh
function Mesh.new(_, vertices, indices)
local self = {}
setmetatable(self, Mesh)
self.vertexArray = gl.GenVertexArrays()
self.vertexBuffer = gl.GenBuffers()
self.elementBuffer = gl.GenBuffers()
self.vertexCount = #indices
gl.BindVertexArray(self.vertexArray)
gl.BindBuffer(gl.ARRAY_BUFFER, self.vertexBuffer)
gl.BufferData(gl.ARRAY_BUFFER, gl.FLOAT, vertices, gl.STATIC_DRAW)
gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, self.elementBuffer)
gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, gl.UNSIGNED_INT, indices, gl.STATIC_DRAW)
gl.VertexAttribPointer(0, 3, false, 8, 0)
gl.EnableVertexAttribArray(0)
gl.VertexAttribPointer(1, 3, false, 8, 3)
gl.EnableVertexAttribArray(1)
gl.VertexAttribPointer(2, 2, false, 8, 6)
gl.EnableVertexAttribArray(2)
return self
end
setmetatable(Mesh, {__call=Mesh.new})
function Mesh.drawElements(self)
gl.BindVertexArray(self.vertexArray)
gl.DrawElements(gl.TRIANGLES, self.vertexCount, gl.UNSIGNED_INT, 0)
end
return mesh
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