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authorDavid Thompson <dthompson2@worcester.edu>2017-01-19 09:24:19 -0500
committerDavid Thompson <dthompson2@worcester.edu>2017-01-19 09:30:18 -0500
commit3227d8393d857f8df221e5df9383ca203ad418f8 (patch)
treeca659ea439b286dfd19f20f4d2e1d7433ae22b5d
parent084c80a0fcfc28af7fff5c85dced7e8350d56252 (diff)
render: Add viewports.
-rw-r--r--Makefile.am1
-rw-r--r--chickadee.scm18
-rw-r--r--chickadee/render.scm13
-rw-r--r--chickadee/render/viewport.scm106
4 files changed, 131 insertions, 7 deletions
diff --git a/Makefile.am b/Makefile.am
index 7838b0b..fa84dd6 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -53,6 +53,7 @@ SOURCES = \
chickadee/render/texture.scm \
chickadee/render/shader.scm \
chickadee/render/vertex-buffer.scm \
+ chickadee/render/viewport.scm \
chickadee/render/shapes.scm \
chickadee/render/sprite.scm \
chickadee/render.scm \
diff --git a/chickadee.scm b/chickadee.scm
index b9996e1..41a3d90 100644
--- a/chickadee.scm
+++ b/chickadee.scm
@@ -20,9 +20,12 @@
#:use-module (sdl2)
#:use-module (sdl2 events)
#:use-module (sdl2 input text)
+ #:use-module (chickadee color)
#:use-module (chickadee window)
+ #:use-module (chickadee render)
#:use-module (chickadee render gl)
#:use-module (chickadee render gpu)
+ #:use-module (chickadee render viewport)
#:export (load-hook
update-hook
before-draw-hook
@@ -142,7 +145,13 @@
(controller-axis-event-axis event)
(/ (controller-axis-event-value event) 32768.0)))))
(with-window window
- (let ((update-interval (round (/ 1000 update-hz))))
+ (let ((update-interval (round (/ 1000 update-hz)))
+ (default-viewport
+ (make-viewport 0 0 window-width window-height
+ ;; Just a fun color from the Dawnbringer
+ ;; 32-color palette instead of boring old
+ ;; black.
+ #:clear-color (rgb #x45283c))))
(call-with-prompt game-loop-prompt-tag
(lambda ()
;; Catch SIGINT and kill the loop.
@@ -170,11 +179,8 @@
(begin
;; Render a frame.
(run-hook before-draw-hook)
- (gl-clear-color 0.267 0.141 0.204 1.0)
- (gl-clear (logior (attrib-mask color-buffer)
- (attrib-mask depth-buffer)
- (attrib-mask stencil-buffer)))
- (run-hook draw-hook (/ lag update-interval))
+ (with-viewport default-viewport
+ (run-hook draw-hook (/ lag update-interval)))
(swap-buffers window)
(run-hook after-draw-hook)
(loop current-time lag)))))))
diff --git a/chickadee/render.scm b/chickadee/render.scm
index d55c76e..efb5004 100644
--- a/chickadee/render.scm
+++ b/chickadee/render.scm
@@ -29,10 +29,13 @@
#:use-module (chickadee render shader)
#:use-module (chickadee render texture)
#:use-module (chickadee render vertex-buffer)
- #:export (current-blend-mode
+ #:use-module (chickadee render viewport)
+ #:export (current-viewport
+ current-blend-mode
current-depth-test
current-texture
current-projection
+ with-viewport
with-blend-mode
with-depth-test
with-texture
@@ -40,11 +43,15 @@
gpu-apply
gpu-apply*))
+(define *current-viewport* null-viewport)
(define *current-blend-mode* 'replace)
(define *current-depth-test* #f)
(define *current-texture* null-texture)
(define *current-projection* (make-identity-matrix4))
+(define (current-viewport)
+ *current-viewport*)
+
(define (current-blend-mode)
*current-blend-mode*)
@@ -64,6 +71,9 @@
(lambda () body ...)
(lambda () (set! name prev)))))
+(define-syntax-rule (with-viewport viewport body ...)
+ (with (*current-viewport* viewport) body ...))
+
(define-syntax-rule (with-blend-mode blend-mode body ...)
(with (*current-blend-mode* blend-mode) body ...))
@@ -123,6 +133,7 @@
(define-syntax-rule (gpu-apply* shader vertex-array count . uniforms)
(begin
+ (gpu-state-set! *viewport-state* (current-viewport))
(gpu-state-set! *blend-mode-state* (current-blend-mode))
(gpu-state-set! *depth-test-state* (current-depth-test))
(gpu-state-set! *texture-state* (current-texture))
diff --git a/chickadee/render/viewport.scm b/chickadee/render/viewport.scm
new file mode 100644
index 0000000..5768406
--- /dev/null
+++ b/chickadee/render/viewport.scm
@@ -0,0 +1,106 @@
+;;; Chickadee Game Toolkit
+;;; Copyright © 2017 David Thompson <davet@gnu.org>
+;;;
+;;; Chickadee 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.
+;;;
+;;; Chickadee 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:
+;;
+;; Viewports specify the renderable section of a window.
+;;
+;;; Code:
+
+(define-module (chickadee render viewport)
+ #:use-module (ice-9 match)
+ #:use-module (srfi srfi-9)
+ #:use-module (gl)
+ #:use-module (chickadee utils)
+ #:use-module (chickadee render gl)
+ #:use-module (chickadee render gpu)
+ #:use-module (chickadee color)
+ #:export (make-viewport
+ viewport?
+ viewport-x
+ viewport-y
+ viewport-width
+ viewport-height
+ viewport-clear-color
+ viewport-clear-flags
+ null-viewport
+ %standard-clear-flags
+ apply-viewport
+ *viewport-state*))
+
+(define-record-type <viewport>
+ (%make-viewport x y width height clear-color clear-flags)
+ viewport?
+ (x viewport-x)
+ (y viewport-y)
+ (width viewport-width)
+ (height viewport-height)
+ (clear-color viewport-clear-color)
+ (clear-flags viewport-clear-flags))
+
+(define %standard-clear-flags '(color-buffer depth-buffer))
+
+(define (assert-non-negative-integer n)
+ (if (and (integer? n) (>= n 0))
+ n
+ (error "expecting non-negative integer:" n)))
+
+(define* (make-viewport x y width height #:key (clear-color black)
+ (clear-flags %standard-clear-flags))
+ "Create a viewport that covers an area of the window starting from
+coordinates (X, Y) and spanning WIDTH x HEIGHT pixels. Fill the
+viewport with CLEAR-COLOR when clearing the screen. Clear the buffers
+denoted by the list of symbols in CLEAR-FLAGS. Possible values for
+CLEAR-FLAGS are 'color-buffer', 'depth-buffer', 'accum-buffer', and
+'stencil-buffer'."
+ (%make-viewport (assert-non-negative-integer x)
+ (assert-non-negative-integer y)
+ (assert-non-negative-integer width)
+ (assert-non-negative-integer height)
+ clear-color
+ clear-flags))
+
+(define null-viewport (make-viewport 0 0 0 0))
+
+(define clear-buffer-mask
+ (memoize
+ (lambda (flags)
+ (apply logior
+ ;; Map symbols to OpenGL constants.
+ (map (match-lambda
+ ('depth-buffer 256)
+ ('accum-buffer 512)
+ ('stencil-buffer 1024)
+ ('color-buffer 16384))
+ flags)))))
+
+(define (apply-viewport viewport)
+ "Set the OpenGL state for VIEWPORT. Clip rendering to the viewport
+area, set the clear color, and clear necessary buffers."
+ (let ((x (viewport-x viewport))
+ (y (viewport-y viewport))
+ (w (viewport-width viewport))
+ (h (viewport-height viewport))
+ (c (viewport-clear-color viewport)))
+ (gl-enable (enable-cap scissor-test))
+ (gl-viewport x y w h)
+ (gl-scissor x y w h)
+ (gl-clear-color (color-r c) (color-g c) (color-b c) (color-a c))
+ (gl-clear (clear-buffer-mask (viewport-clear-flags viewport)))))
+
+(define *viewport-state*
+ (make-gpu-state apply-viewport null-viewport))