model: Improve PBR material handling for glTF models.

1 files changed, 34 insertions, 19 deletions

diff --git a/chickadee/graphics/pbr.scm b/chickadee/graphics/pbr.scm
index 1ed3777..4b5b192 100644
--- a/chickadee/graphics/pbr.scm
+++ b/chickadee/graphics/pbr.scm
@@ -27,6 +27,7 @@
   #:use-module (chickadee graphics buffer)
   #:use-module (chickadee graphics color)
   #: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)
@@ -35,15 +36,18 @@
             pbr-material-name
             pbr-material-base-color-factor
             pbr-material-base-color-texture
+            pbr-material-base-color-texcoord
             pbr-material-metallic-factor
             pbr-material-roughness-factor
-            pbr-material-metallic-roughness-texture
             pbr-material-normal-factor
             pbr-material-normal-texture
+            pbr-material-normal-texcoord
             pbr-material-occlusion-facgor
             pbr-material-occlusion-texture
+            pbr-material-occlusion-texcoord
             pbr-material-emissive-factor
             pbr-material-emissive-texture
+            pbr-material-emissive-texcoord
             pbr-material-alpha-mode
             pbr-material-alpha-cutoff
             pbr-material-double-sided?
@@ -57,34 +61,48 @@
   (local-field name pbr-material-name)
   (float-vec3 base-color-factor pbr-material-base-color-factor)
   (local-field base-color-texture pbr-material-base-color-texture)
+  (bool base-color-texture-enabled pbr-material-base-color-texture-enabled?)
+  (int base-color-texcoord pbr-material-base-color-texcoord)
   (float metallic-factor pbr-material-metallic-factor)
   (float roughness-factor pbr-material-roughness-factor)
-  (local-field metallic-roughness-texture pbr-material-metallic-roughness-texture)
   (float-vec3 normal-factor pbr-material-normal-factor)
   (local-field normal-texture pbr-material-normal-texture)
+  (bool normal-texture-enabled pbr-material-normal-texture-enabled)
+  (int normal-texcoord pbr-material-normal-texcoord)
   (float-vec3 occlusion-factor pbr-material-occlusion-factor)
   (local-field occlusion-texture pbr-material-occlusion-texture)
+  (bool occlusion-texture-enabled pbr-material-occlusion-texture-enabled)
+  (int occlusion-texcoord pbr-material-occlusion-texcoord)
   (float-vec3 emissive-factor pbr-material-emissive-factor)
   (local-field emissive-texture pbr-material-emissive-texture)
+  (bool emissive-texture-enabled pbr-material-emissive-texture-enabled)
+  (int emissive-texcoord pbr-material-emissive-texcoord)
   (local-field alpha-mode pbr-material-alpha-mode)
   (float alpha-cutoff pbr-material-alpha-cutoff)
-  (bool double-sided? pbr-material-double-sided?))
+  (local-field double-sided? pbr-material-double-sided?))
 
 (define default-pbr-material
   (make-pbr-material #:name "default"
                      #:base-color-factor #v(1.0 1.0 1.0)
                      #:base-color-texture null-texture
+                     #:base-color-texture-enabled #f
+                     #:base-color-texcoord 0
                      #:metallic-factor 1.0
                      #:roughness-factor 1.0
-                     #:metallic-roughness-texture #f
                      #:normal-factor #v(1.0 1.0 1.0)
-                     #:normal-texture #f
+                     #:normal-texture null-texture
+                     #:normal-texture-enabled #f
+                     #:normal-texcoord 0
                      #:occlusion-factor #v(1.0 1.0 1.0)
-                     #:occlusion-texture #f
+                     #:occlusion-texture null-texture
+                     #:occlusion-texture-enabled #f
+                     #:occlusion-texcoord 0
                      #:emissive-factor #v(1.0 1.0 1.0)
-                     #:emissive-texture #f
+                     #:emissive-texture null-texture
+                     #:emissive-texture-enabled #f
+                     #:emissive-texcoord 0
                      #:alpha-mode 'opaque
-                     #:alpha-cutoff 0.5
+                     #:alpha-cutoff 1.0
                      #:double-sided? #f))
 
 (define-graphics-variable pbr-shader
@@ -93,24 +111,21 @@
 
 (define (shader-apply/pbr vertex-array material model-matrix view-matrix)
   (let* ((shader (graphics-variable-ref pbr-shader))
-         (base-color-texture (pbr-material-base-color-texture material))
-         (secondary-texture (or (pbr-material-metallic-roughness-texture material)
-                                (pbr-material-normal-texture material)
-                                (pbr-material-occlusion-texture material)
-                                (pbr-material-emissive-texture material)
-                                null-texture))
          (vattrs (vertex-array-attributes vertex-array))
          (sattrs (shader-attributes shader)))
-    (with-graphics-state ((g:texture-0 base-color-texture)
-                          (g:texture-1 secondary-texture))
+    (with-graphics-state ((g:cull-face-mode (if (pbr-material-double-sided? material)
+                                                no-cull-face-mode
+                                                back-cull-face-mode))
+                          (g:texture-0 (pbr-material-base-color-texture material))
+                          (g:texture-1 (pbr-material-normal-texture material))
+                          (g:texture-2 (pbr-material-occlusion-texture material))
+                          (g:texture-3 (pbr-material-emissive-texture material)))
       (shader-apply shader vertex-array
                     #:model model-matrix
                     #:view view-matrix
                     #:projection (current-projection)
-                    #:textured0 (not (eq? base-color-texture null-texture))
-                    #:textured1 (not (eq? secondary-texture null-texture))
                     #:vertex-colored (buffer-view?
                                       (assv-ref vattrs
                                                 (attribute-location
                                                  (hash-ref sattrs "color0"))))
-                    #:base-color-factor (pbr-material-base-color-factor material)))))
+                    #:material material))))