model: Add crude support for secondary textures in glTF models.

2 files changed, 49 insertions, 27 deletions

diff --git a/chickadee/graphics/model.scm b/chickadee/graphics/model.scm
index 58204d6..55374fe 100644
--- a/chickadee/graphics/model.scm
+++ b/chickadee/graphics/model.scm
@@ -896,7 +896,7 @@
                 1.0))
            (metallic-roughness-texture
             (match (object-ref/optional pbrmr "metallicRoughnessTexture")
-              (#f null-texture)
+              (#f #f)
               (obj
                (vector-ref textures (number-ref obj "index")))))
            (normal-factor
@@ -905,7 +905,7 @@
               (vec3 (vector-ref v 0) (vector-ref v 1) (vector-ref v 2))))
            (normal-texture
             (match (object-ref/optional obj "normalTexture")
-              (#f null-texture)
+              (#f #f)
               (obj (vector-ref textures (number-ref obj "index")))))
            (occlusion-factor
             (let ((v (or (array-ref/optional obj "occlusionFactor")
@@ -913,7 +913,7 @@
               (vec3 (vector-ref v 0) (vector-ref v 1) (vector-ref v 2))))
            (occlusion-texture
             (match (object-ref/optional obj "occlusionTexture")
-              (#f null-texture)
+              (#f #f)
               (obj (vector-ref textures (number-ref obj "index")))))
            (emissive-factor
             (let ((v (or (array-ref/optional obj "emissiveFactor")
@@ -921,7 +921,7 @@
               (vec3 (vector-ref v 0) (vector-ref v 1) (vector-ref v 2))))
            (emissive-texture
             (match (object-ref/optional obj "emissiveTexture")
-              (#f null-texture)
+              (#f #f)
               (obj (vector-ref textures (number-ref obj "index")))))
            (alpha-mode (match (or (string-ref/optional obj "alphaMode")
                                   "BLEND")
@@ -958,7 +958,9 @@
         ("TEXCOORD_0"
          (attribute-location
           (hash-ref (shader-attributes shader) "texcoord0")))
-        ("TEXCOORD_1" 11)
+        ("TEXCOORD_1"
+         (attribute-location
+          (hash-ref (shader-attributes shader) "texcoord1")))
         ("COLOR_0"
          (attribute-location
           (hash-ref (shader-attributes shader) "color0")))
diff --git a/chickadee/graphics/pbr.scm b/chickadee/graphics/pbr.scm
index 73f057b..01a330c 100644
--- a/chickadee/graphics/pbr.scm
+++ b/chickadee/graphics/pbr.scm
@@ -75,13 +75,13 @@
                      #:base-color-texture null-texture
                      #:metallic-factor 1.0
                      #:roughness-factor 1.0
-                     #:metallic-roughness-texture null-texture
+                     #:metallic-roughness-texture #f
                      #:normal-factor #v(1.0 1.0 1.0)
-                     #:normal-texture null-texture
+                     #:normal-texture #f
                      #:occlusion-factor #v(1.0 1.0 1.0)
-                     #:occlusion-texture null-texture
+                     #:occlusion-texture #f
                      #:emissive-factor #v(1.0 1.0 1.0)
-                     #:emissive-texture null-texture
+                     #:emissive-texture #f
                      #:alpha-mode 'opaque
                      #:alpha-cutoff 0.5
                      #:double-sided? #f))
@@ -94,56 +94,69 @@
 #ifdef GLSL330
 layout (location = 0) in vec3 position;
 layout (location = 1) in vec2 texcoord0;
-layout (location = 2) in vec4 color0;
+layout (location = 2) in vec2 texcoord1;
+layout (location = 3) in vec4 color0;
 #elif defined(GLSL130)
 in vec3 position;
 in vec2 texcoord0;
+in vec2 texcoord1;
 in vec4 color0;
 #elif defined(GLSL120)
 attribute vec3 position;
 attribute vec2 texcoord0;
+attribute vec2 texcoord1;
 attribute vec4 color0;
 #endif
 #ifdef GLSL120
-varying vec2 fragTex;
-varying vec4 fragVertColor;
+varying vec2 fragTexcoord0;
+varying vec2 fragTexcoord1;
+varying vec4 fragColor0;
 #else
-out vec2 fragTex;
-out vec4 fragVertColor;
+out vec2 fragTexcoord0;
+out vec2 fragTexcoord1;
+out vec4 fragColor0;
 #endif
 uniform mat4 model;
 uniform mat4 view;
 uniform mat4 projection;
 
 void main(void) {
-  fragTex = texcoord0;
-  fragVertColor = color0;
+  fragTexcoord0 = texcoord0;
+  fragTexcoord1 = texcoord1;
+  fragColor0 = color0;
   gl_Position = projection * view * model * vec4(position.xyz, 1.0);
 }
 "
    "
 #ifdef GLSL120
-attribute vec2 fragTex;
-attribute vec4 fragVertColor;
+attribute vec2 fragTexcoord0;
+attribute vec2 fragTexcoord1
+attribute vec4 fragColor0;
 #else
-in vec2 fragTex;
-in vec4 fragVertColor;
+in vec2 fragTexcoord0;
+in vec2 fragTexcoord1;
+in vec4 fragColor0;
 #endif
 #ifdef GLSL330
 out vec4 fragColor;
 #endif
-uniform bool textured;
+uniform bool textured0;
+uniform bool textured1;
 uniform bool vertexColored;
 uniform vec3 baseColorFactor;
-uniform sampler2D baseColorTexture;
+uniform sampler2D texture0;
+uniform sampler2D texture1;
 
 void main (void) {
   vec4 finalColor = vec4(baseColorFactor, 1.0);
   if(vertexColored) {
-    finalColor *= fragVertColor;
+    finalColor *= fragColor0;
   }
-  if(textured) {
-    finalColor *= texture(baseColorTexture, fragTex);
+  if(textured0) {
+    finalColor *= texture(texture0, fragTexcoord0);
+  }
+  if(textured1) {
+    finalColor += texture(texture1, fragTexcoord1);
   }
 #ifdef GLSL330
   fragColor = finalColor;
@@ -156,14 +169,21 @@ void main (void) {
 (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))
+    (with-graphics-state ((g:texture-0 base-color-texture)
+                          (g:texture-1 secondary-texture))
       (shader-apply shader vertex-array
                     #:model model-matrix
                     #:view view-matrix
                     #:projection (current-projection)
-                    #:textured (not (eq? base-color-texture null-texture))
+                    #:textured0 (not (eq? base-color-texture null-texture))
+                    #:textured1 (not (eq? secondary-texture null-texture))
                     #:vertex-colored (buffer-view?
                                       (assv-ref vattrs
                                                 (attribute-location