summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--chickadee/render/buffer.scm26
1 files changed, 18 insertions, 8 deletions
diff --git a/chickadee/render/buffer.scm b/chickadee/render/buffer.scm
index 686197c..83a2925 100644
--- a/chickadee/render/buffer.scm
+++ b/chickadee/render/buffer.scm
@@ -66,6 +66,7 @@
typed-buffer-min
typed-buffer-sparse
typed-buffer-data
+ typed-buffer-divisor
map-typed-buffer!
unmap-typed-buffer!
with-mapped-typed-buffer
@@ -221,7 +222,7 @@ vertex buffer data back to the GPU."
(define-record-type <typed-buffer>
(%make-typed-buffer name buffer offset component-type
- normalized? length type max min sparse)
+ normalized? length type max min sparse divisor)
typed-buffer?
(name typed-buffer-name)
(buffer typed-buffer->buffer)
@@ -232,7 +233,8 @@ vertex buffer data back to the GPU."
(type typed-buffer-type)
(max typed-buffer-max)
(min typed-buffer-min)
- (sparse typed-buffer-sparse))
+ (sparse typed-buffer-sparse)
+ (divisor typed-buffer-divisor)) ; for instanced rendering
(define (typed-buffer-stride typed-buffer)
(or (buffer-stride (typed-buffer->buffer typed-buffer))
@@ -260,9 +262,10 @@ vertex buffer data back to the GPU."
component-type))
max
min
- sparse)
+ sparse
+ divisor)
(%make-typed-buffer name buffer offset component-type
- normalized? length type max min sparse))
+ normalized? length type max min sparse divisor))
(define (type-size type)
(match type
@@ -285,11 +288,14 @@ vertex buffer data back to the GPU."
(define* (make-streaming-typed-buffer type component-type length #:key
(name "anonymous")
(target 'vertex)
- data)
+ data
+ divisor)
"Return a new typed buffer to hold LENGTH elements of TYPE whose
components are comprised of COMPONENT-TYPE values. The underlying
untyped buffer is configured for GPU streaming. Optonally, a NAME can
-be specified for the buffer."
+be specified for the buffer. If the buffer will be used for instanced
+rendering, the DIVISOR argument must be used to specify the rate at
+which attributes advance when rendering multiple instances."
(let* ((buffer-length
(* length (type-size type) (component-type-size component-type)))
(buffer (if data
@@ -305,7 +311,8 @@ be specified for the buffer."
#:buffer buffer
#:type type
#:component-type component-type
- #:length length)))
+ #:length length
+ #:divisor divisor)))
(define (display-typed-buffer typed-buffer port)
(format port "#<typed-buffer name: ~s buffer: ~a type: ~s component-type: ~s length: ~d offset: ~d>"
@@ -353,7 +360,10 @@ be specified for the buffer."
(typed-buffer-type-gl typed-buffer)
(typed-buffer-normalized? typed-buffer)
(typed-buffer-stride typed-buffer)
- (make-pointer (typed-buffer-offset typed-buffer)))))
+ (make-pointer (typed-buffer-offset typed-buffer)))
+ (let ((divisor (typed-buffer-divisor typed-buffer)))
+ (when divisor
+ (gl-vertex-attrib-divisor attribute-index divisor)))))
;; TODO: Handle 4-byte alignment rule for the types that need it.
(define (typed-buffer->vector typed-buffer)