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-rw-r--r--chickadee/math/matrix.scm12
1 files changed, 12 insertions, 0 deletions
diff --git a/chickadee/math/matrix.scm b/chickadee/math/matrix.scm
index 2e94233..cb9f1e1 100644
--- a/chickadee/math/matrix.scm
+++ b/chickadee/math/matrix.scm
@@ -23,6 +23,7 @@
#:use-module (srfi srfi-9 gnu)
#:use-module (srfi srfi-4)
#:use-module (system foreign)
+ #:use-module (chickadee math)
#:use-module (chickadee math vector)
#:export (make-matrix4
make-null-matrix4
@@ -32,6 +33,7 @@
matrix4-identity!
make-identity-matrix4
orthographic-projection
+ perspective-projection
matrix4-translate!
matrix4-translate
matrix4-scale!
@@ -282,6 +284,16 @@ FAR."
(- (/ (+ far near) (- far near)))
1.0))
+(define (perspective-projection field-of-vision aspect-ratio near far)
+ "Return a new matrix4 that represents a perspective projection with
+a FIELD-OF-VISION in degrees, the desired ASPECT-RATIO, and the depth
+clipping plane NEAR and FAR."
+ (let ((f (cotan (/ field-of-vision 2))))
+ (make-matrix4 (/ f aspect-ratio) 0 0 0
+ 0 f 0 0
+ 0 0 (/ (+ far near) (- near far)) -1
+ 0 0 (/ (* 2 far near) (- near far)) 0)))
+
(define (matrix4-translate! matrix v)
(init-matrix4 matrix
1.0 0.0 0.0 0.0