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;;; Sly
;;; Copyright (C) 2014 David Thompson <davet@gnu.org>
;;;
;;; Sly is free software: you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation, either version 3 of the License, or
;;; (at your option) any later version.
;;;
;;; Sly is distributed in the hope that it will be useful, but WITHOUT
;;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
;;; or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
;;; License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with this program. If not, see
;;; <http://www.gnu.org/licenses/>.
;;; Commentary:
;;
;; OpenGL renderer.
;;
;;; Code:
(define-module (sly render renderer)
#:use-module (system foreign)
#:use-module (ice-9 match)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-26)
#:use-module (gl)
#:use-module (gl low-level)
#:use-module (sly shader)
#:use-module (sly texture)
#:use-module (sly transform)
#:use-module (sly math vector)
#:use-module (sly render utils)
#:use-module (sly render vertex-array)
#:export (make-render-op render-op?
render-op-transform render-op-vertex-array
render-op-texture render-op-shader
render-op-blend-mode render-op-uniforms
transform-render-op
make-renderer renderer?
renderer-ops
render))
;; Representation of a single OpenGL render call.
(define-record-type <render-op>
(%make-render-op transform vertex-array texture shader uniforms
blend-mode depth-test?)
render-op?
(transform render-op-transform)
(vertex-array render-op-vertex-array)
(texture render-op-texture)
(shader render-op-shader)
(uniforms render-op-uniforms)
(blend-mode render-op-blend-mode)
(depth-test? render-op-depth-test?))
(define* (make-render-op #:optional #:key (transform identity-transform)
(vertex-array #f) (texture #f) (shader #f)
(uniforms '()) (blend-mode default-blend-mode)
(depth-test? #t))
"Create a new render operation object. Optional arguments include:
TRANSFORM, a model transformation matrix. VERTEX-ARRAY, the geometry
container. TEXTURE, the texture object to bind. SHADER, the shader
program to bind. UNIFORMS, the variables to be passed to the shader.
And DEPTH-TEST?, a flag that determines whether the depth buffer is
activated or not."
(%make-render-op transform vertex-array texture shader uniforms
blend-mode depth-test?))
(define* (transform-render-op op transform)
"Return a new render operation object that is the same as OP, but
with its transformation matrix multiplied by TRANSFORM."
(match op
(($ <render-op> local-transform vertex-array texture shader uniforms
blend-mode depth-test?)
(%make-render-op (transform* transform local-transform) vertex-array
texture shader uniforms blend-mode depth-test?))))
(define-syntax-rule (with-texture-maybe texture body ...)
(if texture
(with-texture texture body ...)
(begin body ...)))
(define (apply-render-op op)
"Render OP by applying its texture, shader, vertex array, uniforms,
blend mode, etc.."
(match op
(($ <render-op> transform vertex-array texture shader uniforms
blend-mode depth-test?)
(when depth-test?
(gl-enable (enable-cap depth-test)))
(if blend-mode
(begin
(gl-enable (enable-cap blend))
(apply-blend-mode blend-mode))
(gl-disable (enable-cap blend)))
(with-shader-program shader
(for-each (lambda (uniform)
(match uniform
((name value)
(uniform-set! shader name value))))
`(("mvp" ,transform)
,@uniforms))
(with-vertex-array vertex-array
(with-texture-maybe texture
(glDrawElements (begin-mode triangles)
(vertex-array-length vertex-array)
(data-type unsigned-int)
%null-pointer))))
(when depth-test?
(gl-disable (enable-cap depth-test))))))
(define-record-type <renderer>
(make-renderer ops)
renderer?
(ops renderer-ops))
(define (render renderer)
"Apply all of the render operations in RENDERER. The render
operations are applied once for each camera."
(for-each (cut apply-render-op <>)
(renderer-ops renderer)))
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