Setup buildsystem for c apps

Added fbcp to repo
Added setup-apps.sh
Disable non runtable apps

apps/c-src/CMakeLists.txt

@@ -0,0 +1,11 @@
+cmake_minimum_required(VERSION 2.8)
+
+SET(COMPILE_DEFINITIONS -Werror -Wall)
+
+
+set(CMAKE_C_FLAGS "-O3")
+
+add_executable(fbcp fbcp.c)
+target_link_libraries(fbcp m)
+
+add_executable(flicker flicker.c)

apps/c-src/fbcp.c

@@ -0,0 +1,136 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <linux/fb.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <termios.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdlib.h>
+
+volatile sig_atomic_t flag = 0;
+
+void Error(const char * format, ...) {
+    fprintf(stderr, "Error: ");
+    va_list args;
+    va_start(args, format);
+    vfprintf(stderr, format, args);
+    va_end(args);
+    fprintf(stderr, "\n");
+}
+
+// fast and only approximate
+void DownsampleFrameBufferBGRA2RGB(uint8_t *in, int xin, int yin, uint8_t* out, int xout, int yout){
+    int sx = xin/xout;
+    int sy = yin/yout;
+    int size = sx*sy;
+    for(int y = 0; y != yout; y++){
+        for(int x = 0; x != xout; x++){
+            int xmin = x*xin/xout;
+            int ymin = y*yin/yout;
+            int xmax = xmin+sx;
+            int ymax = ymin+sy;
+            
+            int r = 0, g = 0, b = 0;
+            int idx = xmin+ymin*xin;
+            uint8_t *mem = in+4*idx;
+            for (int yp = ymin; yp != ymax; yp++ ){
+                for (int xp =xmin; xp != xmax; xp++ ){
+                    b += *mem++;
+                    g += *mem++;
+                    r += *mem++;
+                    mem++;
+                }
+                mem += 4*(xin-sx);
+            }
+            *out++ = r/size;
+            *out++ = g/size;
+            *out++ = b/size;
+        }
+    }
+}
+
+
+
+void SignalHandler(int sig){
+    flag = 1;
+}
+
+int main(int argc, char **argv) {
+    //DISPMANX_RESOURCE_HANDLE_T screen_resource;
+    uint32_t                   image_prt;
+    //VC_RECT_T                  rect1;
+    int ret;
+    int fbfd = 0;
+    char *framebuffer_gbra = 0;
+
+    struct fb_var_screeninfo vinfo;
+    struct fb_fix_screeninfo finfo;
+    int serial;
+    int x = atoi(argv[2]);
+    int y = atoi(argv[3]);
+    uint8_t * out_rgb = malloc(x*y*3+1);
+
+    signal(SIGINT, SignalHandler); 
+
+    if (argc < 4){
+        fprintf(stderr, "Wrong number of parameters, should be:\n\n");
+        fprintf(stderr, " fbcp <framebuffer> <sizex> <sizey>\n\n");
+        fprintf(stderr, "i.e. fbcp /dev/fb0\n");
+        goto exit;
+    }
+
+
+    fbfd = open(argv[1], O_RDWR);
+    if (fbfd == -1) {
+        Error("Unable to open display %s", argv[2]);
+        goto clean1_1;
+    }
+    if (ioctl(fbfd, FBIOGET_FSCREENINFO, &finfo)) {
+        Error("Unable to get display information");
+        goto clean2;
+    }
+    if (ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)) {
+        Error("Unable to get display information");
+        goto clean2;
+    }
+
+    fprintf(stderr, "Display is %d x %d %dbps\n", vinfo.xres, vinfo.yres, vinfo.bits_per_pixel);
+
+    if (vinfo.bits_per_pixel != 32){
+        Error("Display has %i bits per pixel. This program only works for 32.", vinfo.bits_per_pixel);
+    }
+
+    framebuffer_gbra = (char*) mmap(0, finfo.smem_len, PROT_READ | PROT_WRITE, MAP_SHARED, fbfd, 0);
+    if (framebuffer_gbra <= 0) {
+        Error("Unable to create framebuffer memory mapping");
+        goto clean3;
+    }
+
+    FILE *logfile = fopen("out.log", "w");
+    int frame = 0;
+    while(!flag) {
+
+       // vc_dispmanx_resource_read_data(screen_resource, &rect1, framebuffer_gbra, vinfo.xres * vinfo.bits_per_pixel / 8);
+        fflush(logfile);
+        uint8_t* out = out_rgb;
+        *out++ = 1; // Begin of frame marker
+        DownsampleFrameBufferBGRA2RGB(framebuffer_gbra, vinfo.xres, vinfo.yres, out, x, y);
+        write(1, out_rgb+1, x*y*3);
+
+        frame++;
+    }
+    
+clean4:
+    munmap(framebuffer_gbra, finfo.smem_len);
+clean3:
+clean2:
+    close(fbfd);
+clean1_1:
+clean1:
+exit:
+    return 0;
+}
+

apps/c-src/flicker.c

@@ -0,0 +1,79 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <unistd.h>
+
+// Here I use a lcg RNG with a specificaly crafted period to enumerate all pixels
+// and color them by cycling a colormap in a randomish order
+// Same approch as in DOOM (1993)
+// see: Knuth - The Art of Computer Programming, Volume 2: Seminumerical Algorithms
+
+uint32_t hash32(uint32_t d) {
+    // DJB Hash
+    uint32_t h = 0x811c9dc5;
+    h = (h * 16777619) ^ ((d >>  0) & 0xff);
+    h = (h * 16777619) ^ ((d >>  8) & 0xff);
+    h = (h * 16777619) ^ ((d >> 16) & 0xff);
+    h = (h * 16777619) ^ ((d >> 24) & 0xff);
+    return h;
+}
+
+// must be the next prime after NUM_TOTAL_LEDS
+#define IDLE_PRIME 3203 
+// must be a primitive element of the prime residue field |N/IDLE_PRIM
+#define IDLE_PRIM_ELEM 777
+
+int IDLE_rand(int *seed){
+    return *seed = (*seed * IDLE_PRIM_ELEM ) % IDLE_PRIME;
+}
+
+int IDLE_last_pixel   = 34;
+int IDLE_color_offset = 2;
+
+uint32_t IDLE_colors[5] ={
+    0xd31719,
+    0x0f6851,
+    0xd4772e,
+    0xd84b23,
+    0x3d89a7
+};
+
+
+int Nx, Ny;
+uint8_t *buf;
+
+void SetPixel(int x, int y, uint8_t r, uint8_t g, uint8_t b){
+    buf[3*(x+Nx*y)+0] = r;
+    buf[3*(x+Nx*y)+1] = g;
+    buf[3*(x+Nx*y)+2] = b;
+}
+
+void IDLE_set_pixel(){
+    int i = IDLE_rand(&IDLE_last_pixel)-1;
+    int x = i%Nx;
+    int y = i/Nx;
+    if (i == IDLE_color_offset){
+        IDLE_color_offset++;
+        if (IDLE_color_offset > 100)
+            IDLE_color_offset=2;
+    } 
+    if (i >= Nx*Ny) return;
+    int color_count = sizeof(IDLE_colors)/sizeof(IDLE_colors[0]);
+
+    int color = IDLE_colors[hash32(i+IDLE_color_offset)%color_count];
+    SetPixel(x, y, (color>>16)&0xff, (color>>8)&0xff, (color>>0)&0xff);
+}
+
+int main(int argc, char **argv) {
+    Nx = atoi(argv[1]);
+    Ny = atoi(argv[2]);
+    buf = malloc(Nx*Ny*3);
+    int sleepms = atoi(argv[3]);
+    if (sleepms == 0) sleepms = 30;
+
+    while(1) {
+        IDLE_set_pixel();
+        write(1, buf, Nx*Ny*3);
+        usleep(1000*sleepms);
+
+    }
+}