convert demo noise generator to procedural approach, optimize a bit

util/demo_noise.h

@@ -1,38 +1,35 @@
 #pragma once
-#define _USE_MATH_DEFINES
+
 #include <math.h>
-#include <cstdlib>
 
 namespace trnr {
-template <typename t_sample>
-class demo_noise {
-public:
-    void set_samplerate(double _samplerate) {
-        samplerate = _samplerate;
+
+struct demo_noise {
+	double samplerate;
+	int counter;
+};
+
+inline void demo_nose_init(demo_noise& d, double samplerate)
+{
+	d.samplerate = samplerate;
+	d.samplerate = 0;
 }
 
-    void process_block(t_sample** samples, long sample_frames) {
+inline void process_block(demo_noise& d, float** samples, int blocksize)
+{
+	for (int s = 0; s < blocksize; s++) {
+		d.counter++;
 
-        for (int s = 0; s < sample_frames; s++) {
-            demo_counter++;
+		if (d.counter == d.samplerate * 20) { d.counter = 0; }
+		if (d.counter > d.samplerate * 17) {
+			float r1 = static_cast<float>(rand()) / static_cast<float>(RAND_MAX);
+			float r2 = static_cast<float>(rand()) / static_cast<float>(RAND_MAX);
 
-            if (demo_counter == samplerate * 20) {
-                demo_counter = 0;
-            }
-            if (demo_counter > samplerate * 17) {
-                t_sample r1 = static_cast<t_sample>(rand()) / static_cast<t_sample>(RAND_MAX);
-                t_sample r2 = static_cast<t_sample>(rand()) / static_cast<t_sample>(RAND_MAX);
-
-                t_sample noise = static_cast<t_sample>(sqrt(-2.0 * log(r1)) * cos(2.0 * M_PI * r2));
+			float noise = static_cast<float>(sqrt(-2.0 * log(r1)) * cos(2.0 * M_PI * r2));
 
 			samples[0][s] = noise / 10.0;
 			samples[1][s] = noise / 10.0;
 		}
 	}
 }
-
-private:
-    double samplerate = 44100;
-    int demo_counter = 0;
-};
-}
+} // namespace trnr