graphics: Add skybox module.

2 files changed, 102 insertions, 0 deletions

diff --git a/Makefile.am b/Makefile.am
index f7f4453..338a009 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -80,6 +80,7 @@ SOURCES = 					\
   chickadee/graphics/font.scm			\
   chickadee/graphics/tile-map.scm		\
   chickadee/graphics/particles.scm		\
+  chickadee/graphics/skybox.scm			\
   chickadee/graphics/light.scm			\
   chickadee/graphics/mesh.scm			\
   chickadee/graphics/phong.scm			\
diff --git a/chickadee/graphics/skybox.scm b/chickadee/graphics/skybox.scm
new file mode 100644
index 0000000..aecba59
--- /dev/null
+++ b/chickadee/graphics/skybox.scm
@@ -0,0 +1,101 @@
+;;; Chickadee Game Toolkit
+;;; Copyright © 2021 David Thompson <dthompson2@worcester.edu>
+;;;
+;;; Chickadee is free software: you can redistribute it and/or modify
+;;; it under the terms of the GNU General Public License as published
+;;; by the Free Software Foundation, either version 3 of the License,
+;;; or (at your option) any later version.
+;;;
+;;; Chickadee is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;;; General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with this program.  If not, see
+;;; <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; 3D Skybox
+;;
+;;; Code:
+
+(define-module (chickadee graphics skybox)
+  #:use-module (chickadee config)
+  #:use-module (chickadee graphics buffer)
+  #:use-module (chickadee graphics blend)
+  #:use-module (chickadee graphics color)
+  #:use-module (chickadee graphics depth)
+  #:use-module (chickadee graphics engine)
+  #:use-module (chickadee graphics polygon)
+  #:use-module (chickadee graphics shader)
+  #:use-module (chickadee graphics texture)
+  #:use-module (srfi srfi-9)
+  #:export (make-skybox
+            skybox?
+            skybox-cube-map
+            skybox-mesh
+            draw-skybox))
+
+(define-record-type <skybox>
+  (%make-skybox cube-map vertex-array)
+  skybox?
+  (cube-map skybox-cube-map)
+  (vertex-array skybox-vertex-array))
+
+(define (make-skybox cube-map)
+  (let* ((index (u32vector 0 3 2 0 2 1
+                           4 7 6 4 6 5
+                           8 11 10 8 10 9
+                           12 15 14 12 14 13
+                           16 19 18 16 18 17
+                           20 23 22 20 22 21))
+         (verts (f32vector -1.0 -1.0 -1.0 ; bottom
+                           1.0 -1.0 -1.0
+                           1.0 -1.0 1.0
+                           -1.0 -1.0 1.0
+                           -1.0 1.0 -1.0 ; top
+                           1.0 1.0 -1.0
+                           1.0 1.0 1.0
+                           -1.0 1.0 1.0
+                           -1.0 -1.0 -1.0 ; left
+                           -1.0 1.0 -1.0
+                           -1.0 1.0 1.0
+                           -1.0 -1.0 1.0
+                           1.0 -1.0 -1.0 ; right
+                           1.0 1.0 -1.0
+                           1.0 1.0 1.0
+                           1.0 -1.0 1.0
+                           -1.0 -1.0 1.0 ; front
+                           1.0 -1.0 1.0
+                           1.0 1.0 1.0
+                           -1.0 1.0 1.0
+                           -1.0 -1.0 -1.0 ; back
+                           1.0 -1.0 -1.0
+                           1.0 1.0 -1.0
+                           -1.0 1.0 -1.0))
+         (index-buffer (make-buffer index #:target 'index))
+         (vertex-buffer (make-buffer verts))
+         (indices (make-buffer-view #:buffer index-buffer
+                                    #:type 'scalar
+                                    #:component-type 'unsigned-int))
+         (positions (make-buffer-view #:buffer vertex-buffer
+                                      #:type 'vec3
+                                      #:component-type 'float))
+         (va (make-vertex-array #:indices indices
+                                #:attributes `((0 . ,positions)))))
+    (%make-skybox cube-map va)))
+
+(define %skybox-shader
+  (delay (load-shader (scope-datadir "shaders/skybox-vert.glsl")
+                      (scope-datadir "shaders/skybox-frag.glsl"))))
+
+(define (skybox-shader)
+  (force %skybox-shader))
+
+(define (draw-skybox skybox view)
+  (with-graphics-state ((g:texture-0 (skybox-cube-map skybox)))
+    (shader-apply (skybox-shader) (skybox-vertex-array skybox)
+                  #:view view
+                  #:projection (current-projection))))