From: Michel Pollet <buserror@gmail.com>
Date: Wed, 13 Jun 2012 17:15:58 +0000 (+0100)
Subject: c3algebra: Added ortho matrices
X-Git-Tag: v1.0~82
X-Git-Url: https://git.htl-mechatronik.at/public/?a=commitdiff_plain;h=7bf79ff628dc3c46445a3a5eaf70ac0aa96c927a;p=sx%2Fsimavr.git

c3algebra: Added ortho matrices

Including screen oriented ones

Signed-off-by: Michel Pollet <buserror@gmail.com>
---

diff --git a/examples/shared/libc3/src/c3algebra.c b/examples/shared/libc3/src/c3algebra.c
index 7512346..c78b1fb 100644
--- a/examples/shared/libc3/src/c3algebra.c
+++ b/examples/shared/libc3/src/c3algebra.c
@@ -1033,3 +1033,49 @@ c3mat4	perspective3D(c3f fov, c3f aspect, c3f zNear, c3f zFar)
 
 	return frustum3D(xmin, xmax, ymin, ymax, zNear, zFar);
 }
+
+c3mat4	ortho3D(
+		c3f left, c3f right, c3f bottom, c3f top,
+		c3f near, c3f far)
+{
+	c3f a = 2.0f / (right - left);
+	c3f b = 2.0f / (top - bottom);
+	c3f c = -2.0f / (far - near);
+
+	c3f tx = - (right + left)/(right - left);
+	c3f ty = - (top + bottom)/(top - bottom);
+	c3f tz = - (far + near)/(far - near);
+
+	float ortho[16] = {
+		a, 0, 0, 0,
+		0, b, 0, 0,
+		0, 0, c, 0,
+		tx, ty, tz, 1
+	};
+    return *((c3mat4p)ortho);
+}
+
+/*
+ * Same as previous, but this one is screen aligned, with 0,0 being top,left
+ * instead of bottom,left
+ */
+c3mat4	screen_ortho3D(
+		c3f left, c3f right, c3f bottom, c3f top,
+		c3f near, c3f far)
+{
+	c3f a = 2.0f / (right - left);
+	c3f b = 2.0f / (top - bottom);
+	c3f c = -2.0f / (far - near);
+
+	c3f tx = - (right + left)/(right - left);
+	c3f ty = - (top + bottom)/(top - bottom);
+	c3f tz = - (far + near)/(far - near);
+
+	float ortho[16] = {
+		a, 0, 0, 0,
+		0, -b, 0, 0,
+		0, 0, c, 0,
+		tx, -ty, tz, 1
+	};
+    return *((c3mat4p)ortho);
+}
diff --git a/examples/shared/libc3/src/c3algebra.h b/examples/shared/libc3/src/c3algebra.h
index 98f93bd..9118031 100644
--- a/examples/shared/libc3/src/c3algebra.h
+++ b/examples/shared/libc3/src/c3algebra.h
@@ -216,5 +216,11 @@ c3mat4	frustum3D(
 			c3f left, c3f right, c3f bottom, c3f top,
 			c3f znear, c3f zfar);
 c3mat4	perspective3D(c3f fov, c3f aspect, c3f znear, c3f zfar);
+c3mat4	ortho3D(
+		c3f left, c3f right, c3f bottom, c3f top,
+		c3f near, c3f far);
+c3mat4	screen_ortho3D(
+		c3f left, c3f right, c3f bottom, c3f top,
+		c3f near, c3f far);
 
 #endif /* __C3ALGEBRA_H___ */