From 1a76ff6b213d9975921dc3ff707da549917cba3e Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Mon, 28 Oct 2019 17:17:07 -0400
Subject: render: phong: Add ambient map to material.

---
 chickadee/render/phong.scm | 40 +++++++++++++++++++++++++++++-----------
 1 file changed, 29 insertions(+), 11 deletions(-)

diff --git a/chickadee/render/phong.scm b/chickadee/render/phong.scm
index 2341e7a..cb649de 100644
--- a/chickadee/render/phong.scm
+++ b/chickadee/render/phong.scm
@@ -32,6 +32,8 @@
             phong-material?
             phong-material-name
             phong-material-ambient
+            phong-material-ambient-map
+            phong-material-use-ambient-map?
             phong-material-diffuse
             phong-material-diffuse-map
             phong-material-use-diffuse-map?
@@ -55,6 +57,8 @@
   phong-material?
   (local-field name phong-material-name)
   (float-vec3 ambient phong-material-ambient)
+  (local-field ambient-map phong-material-ambient-map)
+  (bool use-ambient-map phong-material-use-ambient-map?)
   (float-vec3 diffuse phong-material-diffuse)
   (local-field diffuse-map phong-material-diffuse-map)
   (bool use-diffuse-map phong-material-use-diffuse-map?)
@@ -68,6 +72,8 @@
 (define default-phong-material
   (make-phong-material #:name "default"
                        #:ambient (vec3 0.5 0.5 0.5)
+                       #:ambient-map null-texture
+                       #:use-ambient-map #f
                        #:diffuse (vec3 0.8 0.8 0.8)
                        #:diffuse-map null-texture
                        #:use-diffuse-map #f
@@ -133,6 +139,8 @@ void main() {
 
 struct Material {
   vec3 ambient;
+  sampler2D ambientMap;
+  bool useAmbientMap;
   vec3 diffuse;
   sampler2D diffuseMap;
   bool useDiffuseMap;
@@ -158,10 +166,19 @@ uniform Material material;
 uniform DirectionalLight directionalLight;
 
 void main() {
+    vec3 baseAmbientColor;
     vec3 baseDiffuseColor;
     vec3 baseSpecularColor;
+    if(material.useAmbientMap) {
+         baseAmbientColor = texture2D(material.ambientMap, fragTex).xyz;
+    } else {
+         baseAmbientColor = vec3(1.0, 1.0, 1.0);
+    }
     if(material.useDiffuseMap) {
-         baseDiffuseColor = texture2D(material.diffuseMap, fragTex).xyz;
+         // discard transparent fragments.
+         vec4 color = texture2D(material.diffuseMap, fragTex);
+         if(color.a == 0.0) { discard; }
+         baseDiffuseColor = color.xyz;
     } else {
          baseDiffuseColor = vec3(1.0, 1.0, 1.0);
     }
@@ -170,7 +187,7 @@ void main() {
     } else {
          baseSpecularColor = vec3(1.0, 1.0, 1.0);
     }
-    vec3 ambientColor = material.ambient * baseDiffuseColor;
+    vec3 ambientColor = material.ambient * baseAmbientColor * baseDiffuseColor;
     vec3 lightDir = normalize(-directionalLight.direction);
     float diffuseFactor = max(dot(lightDir, fragNorm), 0.0);
     vec3 diffuseColor = diffuseFactor * baseDiffuseColor * material.diffuse;
@@ -185,12 +202,13 @@ void main() {
   (force phong-shader))
 
 (define (gpu-apply/phong shader vertex-array material model-matrix view-matrix)
-  (with-texture 0 (phong-material-diffuse-map material)
-    (with-texture 1 (phong-material-specular-map material)
-      (with-texture 2 (phong-material-bump-map material)
-        (gpu-apply shader vertex-array
-                   #:model model-matrix
-                   #:view view-matrix
-                   #:projection (current-projection)
-                   #:material material
-                   #:directional-light default-directional-light)))))
+  (with-texture 0 (phong-material-ambient-map material)
+    (with-texture 1 (phong-material-diffuse-map material)
+      (with-texture 2 (phong-material-specular-map material)
+        (with-texture 3 (phong-material-bump-map material)
+          (gpu-apply shader vertex-array
+                     #:model model-matrix
+                     #:view view-matrix
+                     #:projection (current-projection)
+                     #:material material
+                     #:directional-light default-directional-light))))))
-- 
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