implemented distance maps

CMakeLists.txt

@@ -5,4 +5,5 @@ set(CMAKE_C_STANDARD 99)
 
 add_executable(Juniorcamp main.c)
 
-target_link_libraries(Juniorcamp imago)
+target_link_libraries(Juniorcamp imago m)
+target_link_directories(Juniorcamp PRIVATE /usr/local/lib/)

main.c

@@ -1,26 +1,150 @@
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
+#include <math.h>
+#include <memory.h>
 #include <imago2.h>
 
+#define DEBUG_BUILD 0
+
 typedef struct {
     uint32_t    width;
     uint32_t    height;
-    uint8_t*    buffer;
+    uint32_t*   buffer;
+    uint32_t*   dist_buffer;
 } image_T;
 
+uint32_t pixel_distance(uint32_t pixel_a, uint32_t pixel_b) {
+    uint8_t r_a = (pixel_a)       & 0xFF;
+    uint8_t g_a = (pixel_a >> 8)  & 0xFF;
+    uint8_t b_a = (pixel_a >> 16) & 0xFF;
+
+    uint8_t r_b = (pixel_b)       & 0xFF;
+    uint8_t g_b = (pixel_b >> 8)  & 0xFF;
+    uint8_t b_b = (pixel_b >> 16) & 0xFF;
+
+    uint32_t dist = (uint32_t)sqrt(pow(r_a - r_b, 2) +
+                                      pow(g_a - g_b, 2) +
+                                      pow(b_a - b_b, 2));
+
+    #if DEBUG_BUILD
+        printf("    %x %x %x  --> %x %x %x  =  %d\n", r_a, g_a, b_a, r_b, g_b, b_b, dist);
+    #endif
+
+    return dist;
+}
+
+image_T* image_load(const char* filename) {
+    printf("loading '%s'...\n", filename);
+
+    image_T* image     = malloc(sizeof(image_T));
+    image->buffer      = img_load_pixels(filename, (int*)&image->width, (int*)&image->height, IMG_FMT_RGBA32);
+    image->dist_buffer = calloc(image->width * image->height, sizeof(uint32_t));
+}
+
+void image_destruct(image_T* image) {
+    printf("destructing resources\n");
+
+    img_free_pixels(image->buffer);
+    free(image->dist_buffer);
+    free(image);
+}
+
+void image_calculate_dist_buffer(image_T* image) {
+    memset(image->dist_buffer, 0, image->height * image->width * sizeof(uint32_t));
+
+    uint32_t* last_row       = image->buffer;
+    uint32_t* pixel_row      = &last_row[image->height+1];
+    uint32_t* dist_last_row  = image->dist_buffer;
+    uint32_t* dist_pixel_row = &dist_last_row[image->height+1];
+
+    for (int y = 1; y < image->height; y++) {
+        #if DEBUG_BUILD
+                printf("  Y\n");
+        #endif
+        for (int x = 0; x < image->width; x++) {
+            uint32_t pixel = pixel_row[x];
+
+            #if DEBUG_BUILD
+                printf("  X\n");
+            #endif
+
+            int32_t shortest_dist = -1;
+            for (int i = (x > 0 ? -1 : 0); i < (x < image->width-1 ? 2 : 1); i++) {
+                uint32_t dist = pixel_distance(pixel, last_row[x + i]) + dist_last_row[x + i];
+
+                if (shortest_dist == -1 || shortest_dist > dist) {
+                    shortest_dist = (int32_t)dist;
+                }
+
+                #if DEBUG_BUILD
+                    printf("    0x%x  -  %d\n", dist, x+i);
+                #endif
+            }
+            #if DEBUG_BUILD
+                printf("        0x%x\n", shortest_dist);
+            #endif
+
+            dist_pixel_row[x] = shortest_dist;
+        }
+
+        last_row       = pixel_row;
+        pixel_row      = &last_row[image->height+1];
+        dist_last_row  = dist_pixel_row;
+        dist_pixel_row = &dist_last_row[image->height+1];
+    }
+}
+
+void image_dump(image_T* image) {
+    printf("Pixels:\n");
+    for (int y = 0; y < image->height; y++) {
+        uint32_t* pixel_row = &image->buffer[y * (image->height+1)];
+
+        printf("  ");
+        for (int x = 0; x < image->width; x++) {
+            printf("%x ", pixel_row[x]);
+        }
+
+        printf("\n");
+    }
+
+    printf("Distances:\n");
+    for (int y = 0; y < image->height; y++) {
+        uint32_t* dist_row = &image->dist_buffer[y * (image->height+1)];
+
+        printf("  ");
+        for (int x = 0; x < image->width; x++) {
+            printf("%x ", dist_row[x]);
+        }
+
+        printf("\n");
+    }
+}
+
+uint32_t test_array[12] = {
+        0x00000001, 0x00000003, 0x00000005, 0x00000001,
+        0x00000001, 0x00000007, 0x00000001, 0x00000002,
+        0x0000000A, 0x00000003, 0x00000002, 0x00000005
+};
+
 int main() {
     printf("Line Cutter - Juniorcamp Informatik\n");
 
-    const char* filename = "../paris.png";
+//    image_T* image = image_load("../paris.png");
 
-    printf("loading '%s'...\n", filename);
-    image_T image;
-    image.buffer = img_load_pixels(filename, (int*)&image.width, (int*)&image.height, IMG_FMT_RGBA32);
+    image_T* image     = malloc(sizeof(image_T));
+    image->height      = 3;
+    image->width       = 4;
+    image->buffer      = test_array;
+    image->dist_buffer = calloc(image->width * image->height, sizeof(uint32_t));
+
+    image_calculate_dist_buffer(image);
+    image_dump(image);
 
 
-    printf("destructing resources\n");
-    img_free_pixels(image.buffer);
+//    image_destruct(image);
+    free(image->dist_buffer);
+    free(image);
 
     return 0;
 }