From 130c8015a36d1dc07b9127729d94e96c49328326 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Mon, 28 Oct 2019 08:29:33 -0400
Subject: render: phong: Add support for diffuse and specular maps.

And boilerplate for bump maps to be supported later.
---
 chickadee/render/phong.scm | 80 +++++++++++++++++++++++++++++++++-------------
 1 file changed, 58 insertions(+), 22 deletions(-)

diff --git a/chickadee/render/phong.scm b/chickadee/render/phong.scm
index 07c0eeb..2341e7a 100644
--- a/chickadee/render/phong.scm
+++ b/chickadee/render/phong.scm
@@ -26,14 +26,21 @@
   #:use-module (chickadee render)
   #:use-module (chickadee render color)
   #:use-module (chickadee render shader)
+  #:use-module (chickadee render texture)
   #:use-module (srfi srfi-9)
   #:export (make-phong-material
             phong-material?
             phong-material-name
             phong-material-ambient
             phong-material-diffuse
+            phong-material-diffuse-map
+            phong-material-use-diffuse-map?
             phong-material-specular
+            phong-material-specular-map?
+            phong-material-use-specular-map?
             phong-material-specular-exponent
+            phong-material-bump-map
+            phong-material-use-bump-map?
             default-phong-material
             load-phong-shader
             gpu-apply/phong))
@@ -49,15 +56,27 @@
   (local-field name phong-material-name)
   (float-vec3 ambient phong-material-ambient)
   (float-vec3 diffuse phong-material-diffuse)
+  (local-field diffuse-map phong-material-diffuse-map)
+  (bool use-diffuse-map phong-material-use-diffuse-map?)
   (float-vec3 specular phong-material-specular)
-  (float shininess phong-material-shininess))
+  (local-field specular-map phong-material-specular-map)
+  (bool use-specular-map phong-material-use-specular-map?)
+  (float shininess phong-material-shininess)
+  (local-field bump-map phong-material-bump-map)
+  (bool use-bump-map phong-material-use-bump-map?))
 
 (define default-phong-material
   (make-phong-material #:name "default"
                        #:ambient (vec3 0.5 0.5 0.5)
-                       #:diffuse (vec3 0.5 0.5 0.5)
-                       #:specular (vec3 0.5 0.5 0.5)
-                       #:shininess 32.0))
+                       #:diffuse (vec3 0.8 0.8 0.8)
+                       #:diffuse-map null-texture
+                       #:use-diffuse-map #f
+                       #:specular (vec3 0.3 0.3 0.3)
+                       #:specular-map null-texture
+                       #:use-specular-map #f
+                       #:shininess 32.0
+                       #:bump-map null-texture
+                       #:use-bump-map #f))
 
 
 ;;;
@@ -67,7 +86,6 @@
 (define-shader-type <directional-light>
   make-directional-light
   directional-light?
-  (float-vec4 color directional-light-color)
   (float-vec3 direction directional-light-direction)
   (float-vec3 ambient directional-light-ambient)
   (float-vec3 diffuse directional-light-diffuse)
@@ -75,12 +93,11 @@
   (float shininess directional-light-shininess))
 
 (define default-directional-light
-  (make-directional-light #:color white
-                          #:direction (vec3 -1.0 0.0 -1.0)
-                          #:ambient (vec3 0.5 0.5 0.5)
-                          #:diffuse (vec3 0.5 0.5 0.5)
-                          #:specular (vec3 0.5 0.5 0.5)
-                          #:shininess 32.0))
+  (make-directional-light #:direction (vec3 0.0 0.0 -1.0)
+                          #:ambient (vec3 -1.0 0.0 0.0)
+                          #:diffuse (vec3 0.0 0.0 0.0)
+                          #:specular (vec3 0.0 0.0 0.0)
+                          #:shininess 0.0))
 
 
 ;;;
@@ -117,12 +134,17 @@ void main() {
 struct Material {
   vec3 ambient;
   vec3 diffuse;
+  sampler2D diffuseMap;
+  bool useDiffuseMap;
   vec3 specular;
+  sampler2D specularMap;
+  bool useSpecularMap;
   float shininess;
+  sampler2D bumpMap;
+  bool useBumpMap;
 };
 
 struct DirectionalLight {
-    vec4 color;
     vec3 direction;
     vec3 ambient;
     vec3 diffuse;
@@ -136,14 +158,25 @@ uniform Material material;
 uniform DirectionalLight directionalLight;
 
 void main() {
-    vec3 lightColor = directionalLight.color.xyz;
-    vec3 ambientColor = material.ambient * lightColor;
+    vec3 baseDiffuseColor;
+    vec3 baseSpecularColor;
+    if(material.useDiffuseMap) {
+         baseDiffuseColor = texture2D(material.diffuseMap, fragTex).xyz;
+    } else {
+         baseDiffuseColor = vec3(1.0, 1.0, 1.0);
+    }
+    if(material.useDiffuseMap) {
+         baseSpecularColor = texture2D(material.specularMap, fragTex).xyz;
+    } else {
+         baseSpecularColor = vec3(1.0, 1.0, 1.0);
+    }
+    vec3 ambientColor = material.ambient * baseDiffuseColor;
     vec3 lightDir = normalize(-directionalLight.direction);
     float diffuseFactor = max(dot(lightDir, fragNorm), 0.0);
-    vec3 diffuseColor = diffuseFactor * material.diffuse * lightColor;
+    vec3 diffuseColor = diffuseFactor * baseDiffuseColor * material.diffuse;
     vec3 reflectDir = reflect(-lightDir, fragNorm);
     float specularFactor = pow(max(dot(lightDir, reflectDir), 0.0), material.shininess);
-    vec3 specularColor = specularFactor * material.specular * lightColor;
+    vec3 specularColor = specularFactor * baseSpecularColor * material.specular;
     gl_FragColor = vec4(ambientColor + diffuseColor + specularColor, 1.0);
 }
 ")))
@@ -152,9 +185,12 @@ void main() {
   (force phong-shader))
 
 (define (gpu-apply/phong shader vertex-array material model-matrix view-matrix)
-  (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-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)))))
-- 
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