diff options
| -rw-r--r-- | sly/render/mesh.scm | 69 |
1 files changed, 56 insertions, 13 deletions
diff --git a/sly/render/mesh.scm b/sly/render/mesh.scm index 04a8ab2..acf9a0f 100644 --- a/sly/render/mesh.scm +++ b/sly/render/mesh.scm @@ -25,18 +25,21 @@ #:use-module (ice-9 format) #:use-module (ice-9 match) #:use-module (rnrs bytevectors) + #:use-module (srfi srfi-4) #:use-module (srfi srfi-9) #:use-module (srfi srfi-9 gnu) #:use-module (srfi srfi-43) #:use-module (system foreign) #:use-module (gl) #:use-module (gl low-level) + #:use-module (gl enums) #:use-module (sly utils) #:use-module (sly wrappers gl) #:use-module (sly math vector) #:use-module (sly render color) #:use-module (sly render shader) - #:export (make-vertex-buffer + #:export (make-streaming-vertex-buffer + make-vertex-buffer bytevector->vertex-buffer vector->vertex-buffer vertex-buffer? @@ -46,8 +49,11 @@ vertex-buffer-usage vertex-buffer-data vertex-buffer-length + vertex-buffer-element-length vertex-buffer-attribute-size apply-vertex-buffer + map-vertex-buffer! + unmap-vertex-buffer! generate-vertex-array vertex-attrib-pointer @@ -68,17 +74,18 @@ ;;; (define-record-type <vertex-buffer> - (%make-vertex-buffer id type usage data) + (%make-vertex-buffer id type usage length data) vertex-buffer? (id vertex-buffer-id) (type vertex-buffer-type) (usage vertex-buffer-usage) - (data vertex-buffer-data)) + (length vertex-buffer-length) + (data vertex-buffer-data set-vertex-buffer-data!)) (set-record-type-printer! <vertex-buffer> (lambda (vbo port) (format port - "#<vertex-buffer id: ~d type: ~a usage: ~a" + "#<vertex-buffer id: ~d type: ~a usage: ~a>" (vertex-buffer-id vbo) (vertex-buffer-type vbo) (vertex-buffer-usage vbo)))) @@ -173,7 +180,7 @@ (arb-vertex-buffer-object element-array-buffer-arb) (arb-vertex-buffer-object array-buffer-arb))) -(define (vertex-buffer-length vbo) +(define (vertex-buffer-element-length vbo) (/ (bytevector-length (vertex-buffer-data vbo)) (* (vertex-buffer-attribute-size vbo) 4))) @@ -184,13 +191,22 @@ ('stream (arb-vertex-buffer-object stream-draw-arb)))) -(define (init-vertex-buffer-data! vbo) - (let ((data (vertex-buffer-data vbo))) +(define (make-streaming-vertex-buffer type length) + "Return a new vertex buffer of LENGTH elements suitable for +streaming data to the GPU every frame. TYPE is a symbol specifying +the element type, either 'float', 'index', 'vec2', 'vec3', or 'vec4'." + (let ((vbo (%make-vertex-buffer (generate-vertex-buffer) + type + 'stream + ;; All numbers are 32 bits e.g. 4 bytes + (* (type-size type) length 4) + #f))) (with-vertex-buffer vbo (glBufferData (vertex-buffer-target vbo) - (bytevector-length data) - (bytevector->pointer data) - (vertex-buffer-usage-gl vbo))))) + length + %null-pointer + (vertex-buffer-usage-gl vbo))) + vbo)) (define (make-vertex-buffer type usage length) (let ((data (if (eq? type 'index) @@ -199,8 +215,16 @@ (bytevector->vertex-buffer type usage data))) (define (bytevector->vertex-buffer type usage bv) - (let ((vbo (%make-vertex-buffer (generate-vertex-buffer) type usage bv))) - (init-vertex-buffer-data! vbo) + (let ((vbo (%make-vertex-buffer (generate-vertex-buffer) + type + usage + (bytevector-length bv) + bv))) + (with-vertex-buffer vbo + (glBufferData (vertex-buffer-target vbo) + (bytevector-length bv) + (bytevector->pointer bv) + (vertex-buffer-usage-gl vbo))) vbo)) (define* (vector->vertex-buffer vertices #:optional (index? #f) (usage 'static)) @@ -210,6 +234,25 @@ (attribute-type (vector-ref vertices 0))))) (bytevector->vertex-buffer type usage data))) +(define (map-vertex-buffer! vbo) + "Map the memory space for VBO from GPU to the CPU, which is then +accessible via the vertex-buffer-data procedure. This technique +allows vertex buffers to be updated with new vertex data." + (let ((target (vertex-buffer-target vbo)) + (length (vertex-buffer-length vbo)) + (usage (vertex-buffer-usage-gl vbo))) + (with-vertex-buffer vbo + ;; Orphan the buffer to avoid implicit synchronization. + ;; See: https://www.opengl.org/wiki/Buffer_Object_Streaming#Buffer_re-specification + (glBufferData target length %null-pointer usage) + (let ((ptr (glMapBuffer target (version-1-5 read-write)))) + (set-vertex-buffer-data! vbo (pointer->bytevector ptr length)))))) + +(define (unmap-vertex-buffer! vbo) + "Return the mapped vertex data for VBO to the GPU." + (with-vertex-buffer vbo + (glUnmapBuffer (vertex-buffer-target vbo)))) + ;;; ;;; Mesh ;;; @@ -258,7 +301,7 @@ (define (make-mesh index-buffer position-buffer texture-buffer) (let ((mesh (%make-mesh (generate-vertex-array) - (vertex-buffer-length index-buffer) + (vertex-buffer-element-length index-buffer) `((index . ,index-buffer) (position . ,position-buffer) (texture . ,texture-buffer))))) |