oblique_mc

Commit: e1220f4880f5d3b5942f1a4d99514ee32408c2b0
Parent: dfdab8960742c55dad0cce904bf6e9019b5413e1
Author: Randy Palamar
Date:   Sat, 30 Mar 2024 11:59:01 -0600

specify output extent instead of dx and dy

Diffstat:
M
config.def.h
 | 
10
++++++++--
M
mcml.c
 | 
12
++++++++++--

2 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/config.def.h b/config.def.h
@@ -1,6 +1,6 @@
 /* global data that will not be modified after startup */
 static struct {
-	f64 dx, dy;     /* cm */
+	Rect extent;    /* extent [cm] */
 	u32 Nx, Ny;
 	u32 N_photons;
 
@@ -12,8 +12,14 @@ static struct {
 
 	f64 mu_t;
 	f64 xoff, yoff;
+	f64 dx, dy;
 } gctx =  {
-	.dx = 0.05, .dy = 0.05,
+	.extent = (Rect){
+		.top   = 1.5,
+		.bot   = -1.5,
+		.left  = -1.5,
+		.right = 1.5
+	},
 	.Nx = 61, .Ny = 61,
 	.N_photons = 10e6,
 
diff --git a/mcml.c b/mcml.c
@@ -32,6 +32,10 @@ typedef struct {
 } Vec3;
 
 typedef struct {
+	f64 top, bot, left, right;
+} Rect;
+
+typedef struct {
 	u32 Nx, Ny;
 	f64 *b;
 } Mat2;
@@ -66,8 +70,12 @@ die(const char *fmt, ...)
 static void
 init(void)
 {
-	gctx.xoff = gctx.dx * gctx.Nx / 2;
-	gctx.yoff = gctx.dy * gctx.Ny / 2;
+	f64 w = gctx.extent.right - gctx.extent.left;
+	f64 h = gctx.extent.top - gctx.extent.bot;
+	gctx.dx = w / gctx.Nx;
+	gctx.dy = h / gctx.Ny;
+	gctx.xoff = w / 2;
+	gctx.yoff = h / 2;
 	gctx.mu_t = gctx.mu_a + gctx.mu_s;
 	gctx.theta_i = gctx.theta_i * M_PI / 180;
 }