From dcec0300b471b424d8f466c181af6ee1fc53f8e6 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Wed, 26 Aug 2020 21:32:58 -0400
Subject: render: Add stencil test to render context.

---
 chickadee/render.scm | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/chickadee/render.scm b/chickadee/render.scm
index 195529d..23dc6d2 100644
--- a/chickadee/render.scm
+++ b/chickadee/render.scm
@@ -35,12 +35,14 @@
             current-framebuffer
             current-blend-mode
             current-depth-test
+            current-stencil-test
             current-texture
             current-projection
             with-viewport
             with-framebuffer
             with-blend-mode
             with-depth-test
+            with-stencil-test
             with-texture
             with-projection
             clear-screen
@@ -51,12 +53,13 @@
 
 (define-record-type <render-context>
   (make-render-context viewport framebuffer blend-mode depth-test
-                       projection textures)
+                       stencil-test projection textures)
   render-context?
   (viewport render-context-viewport set-render-context-viewport!)
   (framebuffer render-context-framebuffer set-render-context-framebuffer!)
   (blend-mode render-context-blend-mode set-render-context-blend-mode!)
   (depth-test render-context-depth-test set-render-context-depth-test!)
+  (stencil-test render-context-stencil-test set-render-context-stencil-test!)
   (projection render-context-projection set-render-context-projection!)
   (textures render-context-textures))
 
@@ -65,6 +68,7 @@
                        null-framebuffer
                        'replace
                        #f
+                       #f
                        (make-identity-matrix4)
                        (make-vector 32 null-texture)))
 
@@ -80,6 +84,9 @@
 (define (current-depth-test)
   (render-context-depth-test render-context))
 
+(define (current-stencil-test)
+  (render-context-stencil-test render-context))
+
 (define (current-texture i)
   (vector-ref (render-context-textures render-context) i))
 
@@ -120,6 +127,10 @@
   (with (render-context-depth-test set-render-context-depth-test! depth-test)
         body ...))
 
+(define-syntax-rule (with-stencil-test stencil-test body ...)
+  (with (render-context-stencil-test set-render-context-stencil-test! stencil-test)
+        body ...))
+
 (define-syntax-rule (with-texture n texture body ...)
   (let* ((textures (render-context-textures render-context))
          (prev (vector-ref textures n)))
@@ -155,6 +166,7 @@
     (set-gpu-viewport! gpu (current-viewport))
     (set-gpu-blend-mode! gpu (current-blend-mode))
     (set-gpu-depth-test! gpu (current-depth-test))
+    (set-gpu-stencil-test! gpu (current-stencil-test))
     (set-gpu-shader! gpu shader)
     (let loop ((i 0))
       (when (< i 32)
-- 
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