lib/gamnit/depth/depth_core.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # Licensed under the Apache License, Version 2.0 (the "License");
   4 # you may not use this file except in compliance with the License.
   5 # You may obtain a copy of the License at
   6 #
   7 #     http://www.apache.org/licenses/LICENSE-2.0
   8 #
   9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 # See the License for the specific language governing permissions and
  13 # limitations under the License.
  14
  15 # Base entities of the depth 3D game framework
  16 module depth_core
  17
  18 intrude import gamnit::flat
  19
  20 # Visible entity in the game world, represented by its `model` modified by the other attributes
  21 class Actor
  22
  23         # Model used to dray this actor
  24         var model: Model
  25
  26         # Position of this sprite in world coordinates
  27         var center: Point3d[Float] is writable
  28
  29         # Rotation on the Z axis
  30         var rotation = 0.0 is writable
  31
  32         # Scale applied to this sprite
  33         var scale = 1.0 is writable
  34
  35         # Transparency applied to the texture on draw
  36         var alpha = 1.0 is writable
  37 end
  38
  39 # Entire 3D model defined by its `leaves`, an association of `Mesh` to `Material`
  40 abstract class Model
  41
  42         # Load this model in memory
  43         fun load do end
  44
  45         # All `LeafModel` composing this model
  46         #
  47         # Usually, there is one `LeafModel` per material.
  48         # At each frame, each material is asked to draw all the live `LeafModel` instaces.
  49         fun leaves: Array[LeafModel] is abstract
  50 end
  51
  52 # Model composed of one or many other `LeafModel`
  53 class CompositeModel
  54         super Model
  55
  56         redef var leaves = new Array[LeafModel]
  57 end
  58
  59 # Single model with a `mesh` and `material`
  60 #
  61 # Only leaves are actually drawn by the `material`.
  62 class LeafModel
  63         super Model
  64
  65         # Mesh forming this model
  66         var mesh: Mesh
  67
  68         # Material applied on this model
  69         var material: Material
  70
  71         redef var leaves = [self]
  72 end
  73
  74 # Material for a model or how to draw the model
  75 abstract class Material
  76
  77         # Draw `actor`
  78         #
  79         # This method should be refined by subclasses as the default implementation is a no-op.
  80         #
  81         # This method is called on many materials for many `actor` and `model` at each frame.
  82         # It is expected to use a `GLProgram` and call an equivalent to `glDrawArrays`.
  83         # However, it should not call `glClear` nor `GamnitDisplay::flip`.
  84         fun draw(actor: Actor, model: LeafModel) do end
  85 end
  86
  87 # Mesh with all geometry data
  88 class Mesh
  89
  90         # Vertices coordinates
  91         var vertices = new Array[Float] is lazy, writable
  92
  93         # Indices to draw triangles with `glDrawElements`
  94         #
  95         # If `not_empty`, use `glDrawElements`, otherwise use `glDrawArrays`.
  96         var indices = new Array[Int] is lazy, writable
  97
  98         private var indices_c = new CUInt16Array.from(indices) is lazy, writable
  99
 100         # Normals on each vertex
 101         var normals = new Array[Float] is lazy, writable
 102
 103         # Coordinates on the texture per vertex
 104         var texture_coords = new Array[Float] is lazy, writable
 105
 106         # `GLDrawMode` used to display this mesh, defaults to `gl_TRIANGLES`
 107         fun draw_mode: GLDrawMode do return gl_TRIANGLES
 108
 109         # Create an UV sphere of `radius` with `n_meridians` and `n_parallels`
 110         init uv_sphere(radius: Float, n_meridians, n_parallels: Int)
 111         do
 112                 var w = n_meridians
 113                 var h = n_parallels
 114
 115                 var vertices = new Array[Float].with_capacity(w*h*3)
 116                 self.vertices = vertices
 117
 118                 var texture_coords = new Array[Float].with_capacity(w*h*2)
 119                 self.texture_coords = texture_coords
 120
 121                 var normals = new Array[Float].with_capacity(w*h*3)
 122                 self.normals = normals
 123
 124                 # Build vertices
 125                 for m in [0..w[ do
 126                         for p in [0..h[ do
 127                                 var u = m.to_f * 2.0 * pi / (w-1).to_f
 128                                 var v = p.to_f * pi / (h-1).to_f
 129
 130                                 vertices.add radius * u.cos * v.sin
 131                                 vertices.add radius * v.cos
 132                                 vertices.add radius * u.sin * v.sin
 133
 134                                 texture_coords.add (1.0 - m.to_f/(w-1).to_f)
 135                                 texture_coords.add(p.to_f/(h-1).to_f)
 136
 137                                 normals.add u.cos * v.sin
 138                                 normals.add v.cos
 139                                 normals.add u.sin * v.sin
 140                         end
 141                 end
 142
 143                 # Build faces
 144                 var indices = new Array[Int].with_capacity((w-1)*(h-1)*6)
 145                 self.indices = indices
 146                 for m in [0..w-1[ do
 147                         for p in [0..h-1[ do
 148                                 var a = m*h + p
 149
 150                                 indices.add a
 151                                 indices.add a+h
 152                                 indices.add a+1
 153
 154                                 indices.add a+h
 155                                 indices.add a+h+1
 156                                 indices.add a+1
 157                         end
 158                 end
 159         end
 160 end
 161
 162 # Source of light
 163 #
 164 # Instances of this class define a light source position and type.
 165 class Light
 166
 167         # TODO point light, spotlight, directional light, etc.
 168
 169         # Center of this light source in world coordinates
 170         var position = new Point3d[Float](0.0, 1000.0, 0.0)
 171 end
 172
 173 redef class App
 174
 175         # Live actors to be drawn on screen
 176         var actors = new Array[Actor]
 177
 178         # Single light of the scene
 179         var light = new Light
 180
 181         # TODO move `actors & light` to a scene object
 182         # TODO support more than 1 light
 183 end