render: framebuffer: Create and use a default viewport.

2 files changed, 19 insertions, 5 deletions

diff --git a/chickadee/render.scm b/chickadee/render.scm
index 9588a95..cf8a672 100644
--- a/chickadee/render.scm
+++ b/chickadee/render.scm
@@ -82,7 +82,12 @@
   (with (*current-viewport* viewport) body ...))
 
 (define-syntax-rule (with-framebuffer framebuffer body ...)
-  (with (*current-framebuffer* framebuffer) body ...))
+  (with (*current-framebuffer* framebuffer)
+        ;; As a convenience, initialize the viewport as well so that
+        ;; the user doesn't have to explicitly make a viewport unless
+        ;; they actually want to do fancy viewport manipulations.
+        (with-viewport (framebuffer-viewport framebuffer)
+          body ...)))
 
 (define-syntax-rule (with-blend-mode blend-mode body ...)
   (with (*current-blend-mode* blend-mode) body ...))
diff --git a/chickadee/render/framebuffer.scm b/chickadee/render/framebuffer.scm
index 39e4bfa..f96d6ba 100644
--- a/chickadee/render/framebuffer.scm
+++ b/chickadee/render/framebuffer.scm
@@ -31,9 +31,11 @@
   #:use-module (chickadee render gl)
   #:use-module (chickadee render gpu)
   #:use-module ((chickadee render texture) #:select (make-texture null-texture))
+  #:use-module (chickadee render viewport)
   #:export (make-framebuffer
             framebuffer?
             framebuffer-texture
+            framebuffer-viewport
             null-framebuffer
             apply-framebuffer
             *framebuffer-state*))
@@ -51,14 +53,15 @@
     (u32vector-ref bv 0)))
 
 (define-record-type <framebuffer>
-  (%make-framebuffer id renderbuffer-id texture)
+  (%make-framebuffer id renderbuffer-id texture viewport)
   framebuffer?
   (id framebuffer-id)
   (renderbuffer-id framebuffer-renderbuffer-id)
-  (texture framebuffer-texture))
+  (texture framebuffer-texture)
+  (viewport framebuffer-viewport))
 
 (define null-framebuffer
-  (%make-framebuffer 0 0 null-texture))
+  (%make-framebuffer 0 0 null-texture null-viewport))
 
 (define <<framebuffer>> (class-of null-framebuffer))
 
@@ -95,9 +98,15 @@ dimensions WIDTH x HEIGHT."
                                     #:mag-filter mag-filter
                                     #:wrap-s wrap-s
                                     #:wrap-t wrap-t))
+             ;; It is convenient to make a default viewport for the
+             ;; framebuffer so that the rendering engine can set it
+             ;; whenever it changes to this framebuffer, saving users
+             ;; the trouble of having to this tedious task themselves.
+             (viewport (make-viewport 0 0 width height))
              (framebuffer (%make-framebuffer framebuffer-id
                                              renderbuffer-id
-                                             texture)))
+                                             texture
+                                             viewport)))
         (gpu-state-set! *framebuffer-state* framebuffer)
         ;; Setup depth buffer.
         (gl-bind-renderbuffer (version-3-0 renderbuffer)