render: Add framebuffers.

1 files changed, 14 insertions, 0 deletions

diff --git a/chickadee/render.scm b/chickadee/render.scm
index efb5004..9588a95 100644
--- a/chickadee/render.scm
+++ b/chickadee/render.scm
@@ -26,16 +26,19 @@
   #:use-module (chickadee math matrix)
   #:use-module (chickadee render gpu)
   #:use-module (chickadee render blend)
+  #:use-module (chickadee render framebuffer)
   #:use-module (chickadee render shader)
   #:use-module (chickadee render texture)
   #:use-module (chickadee render vertex-buffer)
   #:use-module (chickadee render viewport)
   #:export (current-viewport
+            current-framebuffer
             current-blend-mode
             current-depth-test
             current-texture
             current-projection
             with-viewport
+            with-framebuffer
             with-blend-mode
             with-depth-test
             with-texture
@@ -44,6 +47,7 @@
             gpu-apply*))
 
 (define *current-viewport* null-viewport)
+(define *current-framebuffer* null-framebuffer)
 (define *current-blend-mode* 'replace)
 (define *current-depth-test* #f)
 (define *current-texture* null-texture)
@@ -52,6 +56,9 @@
 (define (current-viewport)
   *current-viewport*)
 
+(define (current-framebuffer)
+  *current-framebuffer*)
+
 (define (current-blend-mode)
   *current-blend-mode*)
 
@@ -74,6 +81,9 @@
 (define-syntax-rule (with-viewport viewport body ...)
   (with (*current-viewport* viewport) body ...))
 
+(define-syntax-rule (with-framebuffer framebuffer body ...)
+  (with (*current-framebuffer* framebuffer) body ...))
+
 (define-syntax-rule (with-blend-mode blend-mode body ...)
   (with (*current-blend-mode* blend-mode) body ...))
 
@@ -133,6 +143,10 @@
 
 (define-syntax-rule (gpu-apply* shader vertex-array count . uniforms)
   (begin
+    ;; It's important that the framebuffer is set before setting the
+    ;; viewport because applying a new viewport will clear the current
+    ;; framebuffer.
+    (gpu-state-set! *framebuffer-state* (current-framebuffer))
     (gpu-state-set! *viewport-state* (current-viewport))
     (gpu-state-set! *blend-mode-state* (current-blend-mode))
     (gpu-state-set! *depth-test-state* (current-depth-test))