render: sprite-batch: Unbind VAO *before* mapping buffers.

* sly/render/sprite-batch.scm (sprite-batch-flush): Don't worry about
VAOs here.
(with-sprite-batch): Unbind VAO before mapping vertex buffers.

1 files changed, 29 insertions, 27 deletions

diff --git a/sly/render/sprite-batch.scm b/sly/render/sprite-batch.scm
index bd008cc..7caef67 100644
--- a/sly/render/sprite-batch.scm
+++ b/sly/render/sprite-batch.scm
@@ -223,37 +223,39 @@
 (define (sprite-batch-flush! batch context)
   "Render the contents of BATCH and clear the cache."
   (unless (zero? (sprite-batch-size batch))
-    (graphics-mesh-excursion context
+    (graphics-texture-excursion context
       (lambda (context)
-        (set-graphics-mesh! context null-mesh)
-        (graphics-texture-excursion context
+        (set-graphics-texture! context (sprite-batch-texture batch))
+        (graphics-model-view-excursion context
           (lambda (context)
-            (set-graphics-texture! context (sprite-batch-texture batch))
-            (graphics-model-view-excursion context
+            (graphics-model-view-mul! context
+                                      (graphics-projection-transform context))
+            (graphics-uniform-excursion context
+                `((mvp ,(graphics-model-view-transform context))
+                  (texture? ,(not (texture-null? (graphics-texture context)))))
               (lambda (context)
-                (graphics-model-view-mul! context
-                                          (graphics-projection-transform context))
-                (graphics-uniform-excursion context
-                    `((mvp ,(graphics-model-view-transform context))
-                      (texture? ,(not (texture-null? (graphics-texture context)))))
-                  (lambda (context)
-                    (unmap-vertex-buffer! (sprite-batch-index-buffer batch))
-                    (unmap-vertex-buffer! (sprite-batch-position-buffer batch))
-                    (unmap-vertex-buffer! (sprite-batch-texture-buffer batch))
+                (unmap-vertex-buffer! (sprite-batch-index-buffer batch))
+                (unmap-vertex-buffer! (sprite-batch-position-buffer batch))
+                (unmap-vertex-buffer! (sprite-batch-texture-buffer batch))
 
-                    (glBindVertexArray (sprite-batch-vao batch))
-                    (glDrawElements (begin-mode triangles)
-                                    ;; 6 indices per sprite.
-                                    (* (sprite-batch-size batch) 6)
-                                    (data-type unsigned-int)
-                                    %null-pointer)
-                    (glBindVertexArray 0)
+                (glBindVertexArray (sprite-batch-vao batch))
+                (glDrawElements (begin-mode triangles)
+                                ;; 6 indices per sprite.
+                                (* (sprite-batch-size batch) 6)
+                                (data-type unsigned-int)
+                                %null-pointer)
+                (glBindVertexArray 0)
 
-                    (sprite-batch-reset! batch)))))))))))
+                (sprite-batch-reset! batch)))))))))
 
 (define-syntax-rule (with-sprite-batch batch context body ...)
-  (begin
-    (sprite-batch-reset! batch)
-    (sprite-batch-begin! batch)
-    body ...
-    (sprite-batch-flush! batch context)))
+  ;; IMPORTANT! We need to make sure that the current VAO is unbound
+  ;; before we start mapping/unmapping vertex buffers.  Not doing this
+  ;; created a nasty bug that took me a long time to find.
+  (graphics-mesh-excursion context
+    (lambda (context)
+      (set-graphics-mesh! context null-mesh)
+      (sprite-batch-reset! batch)
+      (sprite-batch-begin! batch)
+      body ...
+      (sprite-batch-flush! batch context))))