# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1420087005 -7200
# Node ID 0d2447b9c512b97a419c72a9c689fd6299962ce9
# Parent  64f874301b53764a871082364e5a5727b12ea60e
did the histogram... doesn't seem to work right

diff -r 64f874301b53 -r 0d2447b9c512 src/viewer.cc
--- a/src/viewer.cc	Wed Dec 31 07:57:42 2014 +0200
+++ b/src/viewer.cc	Thu Jan 01 06:36:45 2015 +0200
@@ -71,6 +71,7 @@
 	if(!xfview_init(xfer)) {
 		return -1;
 	}
+	xfview_set_volume(vol);
 
 	return 0;
 }
diff -r 64f874301b53 -r 0d2447b9c512 src/volume.cc
--- a/src/volume.cc	Wed Dec 31 07:57:42 2014 +0200
+++ b/src/volume.cc	Thu Jan 01 06:36:45 2015 +0200
@@ -94,6 +94,10 @@
 VoxelVolume::VoxelVolume()
 {
 	size[0] = size[1] = size[2] = 0;
+
+	hist_valid = false;
+	hist = 0;
+	num_hist_samples = 0;
 }
 
 VoxelVolume::~VoxelVolume()
@@ -151,6 +155,7 @@
 	}
 
 	size[2] = slices.size();
+	hist_valid = false;
 	fclose(fp);
 	return true;
 }
@@ -223,6 +228,39 @@
 	return slices[z].pixels[y * size[0] + x];
 }
 
+float *VoxelVolume::calc_histogram(int hist_samples)
+{
+	if(hist && hist_samples == num_hist_samples && hist_valid) {
+		return hist;
+	}
+
+	int num_pixels = size[0] * size[1] * size[2];
+	if(!num_pixels) {
+		return 0;
+	}
+
+	delete [] hist;
+	hist = new float[hist_samples];
+	memset(hist, 0, hist_samples * sizeof *hist);
+
+	for(int i=0; i<size[2]; i++) {
+		float *pptr = slices[i].pixels;
+		for(int j=0; j<size[0] * size[1]; j++) {
+			int idx = (int)(*pptr++ * (float)hist_samples);
+
+			hist[idx] += 1.0;
+		}
+	}
+
+	for(int i=0; i<hist_samples; i++) {
+		hist[i] /= (float)num_pixels;
+	}
+
+	hist_valid = true;
+	num_hist_samples = hist_samples;
+	return hist;
+}
+
 static char *strip_space(char *s)
 {
 	while(*s && isspace(*s)) s++;
diff -r 64f874301b53 -r 0d2447b9c512 src/volume.h
--- a/src/volume.h	Wed Dec 31 07:57:42 2014 +0200
+++ b/src/volume.h	Thu Jan 01 06:36:45 2015 +0200
@@ -42,6 +42,10 @@
 	int size[3];
 	std::vector<Image> slices;
 
+	float *hist;
+	int num_hist_samples;
+	bool hist_valid;
+
 public:
 	VoxelVolume();
 	~VoxelVolume();
@@ -52,6 +56,8 @@
 
 	float valuef(float x, float y, float z) const;
 	float valuei(int x, int y, int z) const;
+
+	float *calc_histogram(int hist_samples);
 };
 
 #endif	// VOLUME_H_
diff -r 64f874301b53 -r 0d2447b9c512 src/xfer_view.cc
--- a/src/xfer_view.cc	Wed Dec 31 07:57:42 2014 +0200
+++ b/src/xfer_view.cc	Thu Jan 01 06:36:45 2015 +0200
@@ -20,8 +20,12 @@
 #include "opengl.h"
 #include "xfer_view.h"
 #include "viewer.h"
+#include "volume.h"
+
+static void draw_histogram();
 
 static TransferFunc *xfer;
+static Volume *vol;
 
 static int act_color = -1;
 static int grabbed_handle = -1;
@@ -37,6 +41,11 @@
 {
 }
 
+void xfview_set_volume(Volume *volarg)
+{
+	vol = volarg;
+}
+
 void xfview_draw()
 {
 	float line_color[][3] = {
@@ -64,6 +73,8 @@
 	glVertex2f(-1, 1);
 	glEnd();
 
+	draw_histogram();
+
 	glEnable(GL_LINE_SMOOTH);
 
 	glEnable(GL_BLEND);
@@ -191,6 +202,40 @@
 	glDisable(GL_BLEND);
 }
 
+#define HIST_SAMPLES	256
+
+static void draw_histogram()
+{
+	VoxelVolume *voxvol = dynamic_cast<VoxelVolume*>(vol);
+	if(!voxvol) return;
+
+	float *hist = voxvol->calc_histogram(HIST_SAMPLES);
+	if(!hist) return;
+
+	float max_y = 0.0f;
+	for(int i=0; i<HIST_SAMPLES; i++) {
+		if(hist[i] > max_y) {
+			max_y = hist[i];
+		}
+	}
+
+	float dx = 1.0 / (float)HIST_SAMPLES;
+	glBegin(GL_QUADS);
+	glColor3f(0.6, 0.6, 0.6);
+	for(int i=0; i<HIST_SAMPLES; i++) {
+		float x0 = (float)i / (float)HIST_SAMPLES;
+		float x1 = x0 + dx;
+
+		float y = hist[i] / max_y;
+
+		glVertex2f(x0, 0);
+		glVertex2f(x1, 0);
+		glVertex2f(x1, y);
+		glVertex2f(x0, y);
+	}
+	glEnd();
+}
+
 static int prev_x, prev_y;
 
 void xfview_button(int bn, int press, int x, int y)
diff -r 64f874301b53 -r 0d2447b9c512 src/xfer_view.h
--- a/src/xfer_view.h	Wed Dec 31 07:57:42 2014 +0200
+++ b/src/xfer_view.h	Thu Jan 01 06:36:45 2015 +0200
@@ -18,11 +18,14 @@
 #ifndef XFER_VIEW_H_
 #define XFER_VIEW_H_
 
+#include "volume.h"
 #include "xfermap.h"
 
 bool xfview_init(TransferFunc *xfer);
 void xfview_destroy();
 
+void xfview_set_volume(Volume *vol);
+
 void xfview_draw();
 
 void xfview_button(int bn, int press, int x, int y);