render: sprite: batch: Combine vertices and texcoords into one buffer.

Not sure how much of a gain this is, but it's one less buffer to map
each frame.

* chickadee/render/sprite.scm (init-sprite-batch): Create combined
vertex/texcoord buffer.
(double-sprite-batch-size!): Map and copy only a single buffer.
(sprite-batch-begin!): Map just one buffer.
(sprite-batch-add!): Use new packed buffer layout.

1 files changed, 36 insertions, 31 deletions

diff --git a/chickadee/render/sprite.scm b/chickadee/render/sprite.scm
index ccb731c..8ccd32b 100644
--- a/chickadee/render/sprite.scm
+++ b/chickadee/render/sprite.scm
@@ -148,10 +148,23 @@ void main (void) {
                                              'unsigned-int
                                              (* capacity 6)
                                              #:target 'index))
-         (pos (make-streaming-typed-buffer 'vec2 'float (* capacity 4)
-                                           #:name "batched-sprite-vertices"))
-         (tex (make-streaming-typed-buffer 'vec2 'float (* capacity 4)
-                                           #:name "batched-sprite-vertices"))
+         (stride 16) ; 4 f32s, 2 for vertex, 2 for texcoord
+         (buffer (make-buffer #f
+                              #:name "sprite batch buffer"
+                              #:length (* capacity stride 4)
+                              #:stride stride
+                              #:usage 'stream))
+         (pos (make-typed-buffer #:name "sprite batches vertices"
+                                 #:buffer buffer
+                                 #:type 'vec2
+                                 #:component-type 'float
+                                 #:length (* capacity 4)))
+         (tex (make-typed-buffer #:name "batched-sprite-vertices"
+                                 #:buffer buffer
+                                 #:type 'vec2
+                                 #:component-type 'float
+                                 #:length (* capacity 4)
+                                 #:offset (/ stride 2)))
          (va (make-vertex-array #:indices index
                                 #:attributes `((0 . ,pos) (1 . ,tex)))))
     (set-sprite-batch-capacity! batch capacity)
@@ -172,25 +185,20 @@ void main (void) {
 (define (double-sprite-batch-size! batch)
   (let* ((old-index (sprite-batch-index-buffer batch))
          (old-verts (sprite-batch-position-buffer batch))
-         (old-tex (sprite-batch-texture-buffer batch))
          (old-index-data (typed-buffer-data old-index))
-         (old-verts-data (typed-buffer-data old-verts))
-         (old-tex-data (typed-buffer-data old-tex)))
+         (old-vertex-data (typed-buffer-data old-verts)))
     (unmap-typed-buffer! old-index)
     (unmap-typed-buffer! old-verts)
-    (unmap-typed-buffer! old-tex)
     (init-sprite-batch batch (* (sprite-batch-capacity batch) 2))
     (sprite-batch-begin! batch)
     (let ((new-index (sprite-batch-index-buffer batch))
-          (new-verts (sprite-batch-position-buffer batch))
-          (new-tex (sprite-batch-texture-buffer batch)))
+          (new-verts (sprite-batch-position-buffer batch)))
       (define (copy from to)
         (bytevector-copy! from 0
                           (typed-buffer-data to) 0
                           (bytevector-length from)))
       (copy old-index-data new-index)
-      (copy old-verts-data new-verts)
-      (copy old-tex-data new-tex))))
+      (copy old-vertex-data new-verts))))
 
 (define (sprite-batch-reset! batch)
   "Reset BATCH to size 0."
@@ -201,8 +209,7 @@ void main (void) {
 
 (define (sprite-batch-begin! batch)
   (map-typed-buffer! (sprite-batch-index-buffer batch))
-  (map-typed-buffer! (sprite-batch-position-buffer batch))
-  (map-typed-buffer! (sprite-batch-texture-buffer batch)))
+  (map-typed-buffer! (sprite-batch-position-buffer batch)))
 
 (define (sprite-batch-flush! batch)
   "Render the contents of BATCH and clear the cache."
@@ -211,7 +218,6 @@ void main (void) {
       (with-texture 0 (sprite-batch-texture batch)
         (unmap-typed-buffer! (sprite-batch-index-buffer batch))
         (unmap-typed-buffer! (sprite-batch-position-buffer batch))
-        (unmap-typed-buffer! (sprite-batch-texture-buffer batch))
         (gpu-apply* (sprite-batch-shader batch)
                     (sprite-batch-vertex-array batch)
                     (* (sprite-batch-size batch) 6)
@@ -274,33 +280,32 @@ void main (void) {
             (u32vector-set! indices (+ (offset) 4) (+ index-vertex-offset 2))
             (u32vector-set! indices (+ (offset) 5) (+ index-vertex-offset 1)))
           ;; Add vertices.
-          (set-offset (* size 8)) ;; 4 vertices, 2 floats per vertex
+          (set-offset (* size 16))
           ;; Bottom-left
           (f32vector-set! vertices (offset) (vec2-x world1))
           (f32vector-set! vertices (+ (offset) 1) (vec2-y world1))
           ;; Bottom-right
-          (f32vector-set! vertices (+ (offset) 2) (vec2-x world2))
-          (f32vector-set! vertices (+ (offset) 3) (vec2-y world2))
+          (f32vector-set! vertices (+ (offset) 4) (vec2-x world2))
+          (f32vector-set! vertices (+ (offset) 5) (vec2-y world2))
           ;; Top-right
-          (f32vector-set! vertices (+ (offset) 4) (vec2-x world3))
-          (f32vector-set! vertices (+ (offset) 5) (vec2-y world3))
+          (f32vector-set! vertices (+ (offset) 8) (vec2-x world3))
+          (f32vector-set! vertices (+ (offset) 9) (vec2-y world3))
           ;; Top-left
-          (f32vector-set! vertices (+ (offset) 6) (vec2-x world4))
-          (f32vector-set! vertices (+ (offset) 7) (vec2-y world4))
+          (f32vector-set! vertices (+ (offset) 12) (vec2-x world4))
+          (f32vector-set! vertices (+ (offset) 13) (vec2-y world4))
           ;; Add texture coordinates.
-          (set-offset (* size 8))
           ;; Bottom-left
-          (f32vector-set! texcoords (offset) s1)
-          (f32vector-set! texcoords (+ (offset) 1) t2)
-          ;; Bottom-right
-          (f32vector-set! texcoords (+ (offset) 2) s2)
+          (f32vector-set! texcoords (+ (offset) 2) s1)
           (f32vector-set! texcoords (+ (offset) 3) t2)
+          ;; Bottom-right
+          (f32vector-set! texcoords (+ (offset) 6) s2)
+          (f32vector-set! texcoords (+ (offset) 7) t2)
           ;; Top-right
-          (f32vector-set! texcoords (+ (offset) 4) s2)
-          (f32vector-set! texcoords (+ (offset) 5) t1)
+          (f32vector-set! texcoords (+ (offset) 10) s2)
+          (f32vector-set! texcoords (+ (offset) 11) t1)
           ;; Top-left
-          (f32vector-set! texcoords (+ (offset) 6) s1)
-          (f32vector-set! texcoords (+ (offset) 7) t1)
+          (f32vector-set! texcoords (+ (offset) 14) s1)
+          (f32vector-set! texcoords (+ (offset) 15) t1)
           (set-sprite-batch-size! batch (1+ size)))))))
 
 (define *batch?* #f)