depth sorting

scripts/main.c

@@ -36,6 +36,7 @@ bool is_running = false;
 
 int cull_method = CULL_BACKFACE;
 int render_method = RENDER_WIRE_VERTEX;
+bool sort_faces = true;
 
 uint32_t previous_frame_time = 0;
 
@@ -53,7 +54,8 @@ void setup(void) {
     );
 
     // load cube mesh data
-    load_file();
+    //load_file("..\\assets\\tank.obj");
+    load_cube_mesh_data();
 
 }
 
@@ -82,6 +84,10 @@ void process_input(void) {
                 cull_method = !cull_method;
             }
 
+            if (key == SDLK_s) {
+                sort_faces = !sort_faces;
+            }
+
             if (key == SDLK_1) {
                 render_method = RENDER_WIRE_VERTEX;
             }
@@ -196,6 +202,10 @@ void update(void) {
             projected_triangle.points[j] = projected_point;
         }
 
+        // calculate the average depth of the triangle
+        projected_triangle.average_depth = (transformed_vertices[0].z + transformed_vertices[1].z + transformed_vertices[2].z) / 3.0f;
+
+        projected_triangle.color = mesh_face.color;// | 0xFF00FF00;
         //vec2_t midpoint = triangle_midpoint(projected_triangle);
         //draw_rect(midpoint.x, midpoint.y, 10, 10, 0xFFFF0000);
 
@@ -207,12 +217,25 @@ void update(void) {
     }
 }
 
+int depth_comp(const void* a, const void* b) {
+    triangle_t arg_a = *(const triangle_t*)a;
+    triangle_t arg_b = *(const triangle_t*)b;
+
+    if (arg_a.average_depth < arg_b.average_depth) return -1;
+    if (arg_a.average_depth > arg_b.average_depth) return 1;
+    return 0;
+}
+
 void render(void) {
     draw_grid();
     //uint32_t colors[] = { 0xFFFF0000, 0xFF00FF00, 0xFF0000FF, 0xFF757500, 0xFF007575, 0xFF750075 };
     // Loop all projected points and render them
+    size_t arr_length = array_length(triangles_to_render);
 
-    for (int i = 0; i < array_length(triangles_to_render); i++) {
+    // sort triangles
+    if (sort_faces) qsort(triangles_to_render, arr_length, sizeof(triangle_t), depth_comp);
+
+    for (int i = 0; i < arr_length; i++) {
         triangle_t triangle = triangles_to_render[i];
 
         switch (render_method) {
@@ -220,16 +243,16 @@ void render(void) {
                 draw_triangle(triangle, 0x0000ff);
                 break;
             case RENDER_WIRE_VERTEX:
-                draw_triangle(triangle, 0x000055);
+                draw_triangle(triangle, 0x0000ff);
                 draw_rect(triangle.points[0].x, triangle.points[0].y, 3, 3, 0xFFFFFF00);
                 draw_rect(triangle.points[1].x, triangle.points[1].y, 3, 3, 0xFFFFFF00);
                 draw_rect(triangle.points[2].x, triangle.points[2].y, 3, 3, 0xFFFFFF00);
                 break;
             case RENDER_FILL_TRIANGLE:
-                draw_filled_triangle(triangle, 0x0000ff);
+                draw_filled_triangle(triangle);
                 break;
             case RENDER_FILL_TRIANGLE_LINE:
-                draw_filled_triangle(triangle, 0xff00);
+                draw_filled_triangle(triangle);
                 draw_triangle(triangle, 0x0000ff);
                 break;
             default:

scripts/mesh.c

@@ -27,23 +27,23 @@ vec3_t cube_vertices[N_CUBE_VERTICES] = {
 
 face_t cube_faces[N_CUBE_FACES] = {
     // front
-    { .a = 1, .b = 2, .c = 3 },
-    { .a = 1, .b = 3, .c = 4 },
+    { .a = 1, .b = 2, .c = 3 , .color = COLOR_ORANGE},
+    { .a = 1, .b = 3, .c = 4, .color  = COLOR_ORANGE},
     // right
-    { .a = 4, .b = 3, .c = 5 },
-    { .a = 4, .b = 5, .c = 6 },
+    { .a = 4, .b = 3, .c = 5, .color = COLOR_TEAL_GREEN },
+    { .a = 4, .b = 5, .c = 6, .color = COLOR_TEAL_GREEN},
     // back
-    { .a = 6, .b = 5, .c = 7 },
-    { .a = 6, .b = 7, .c = 8 },
+    { .a = 6, .b = 5, .c = 7, .color = COLOR_RED },
+    { .a = 6, .b = 7, .c = 8, .color = COLOR_RED },
     // left
-    { .a = 8, .b = 7, .c = 2 },
-    { .a = 8, .b = 2, .c = 1 },
+    { .a = 8, .b = 7, .c = 2, .color = COLOR_PURPLE },
+    { .a = 8, .b = 2, .c = 1, .color = COLOR_PURPLE },
     // top
-    { .a = 2, .b = 7, .c = 5 },
-    { .a = 2, .b = 5, .c = 3 },
+    { .a = 2, .b = 7, .c = 5, .color = COLOR_GREY },
+    { .a = 2, .b = 5, .c = 3, .color = COLOR_GREY },
     // bottom
-    { .a = 6, .b = 8, .c = 1 },
-    { .a = 6, .b = 1, .c = 4 }
+    { .a = 6, .b = 8, .c = 1, .color = COLOR_LIGHT_GREEN_BLUE },
+    { .a = 6, .b = 1, .c = 4, .color = COLOR_LIGHT_GREEN_BLUE }
 };
 
 void load_cube_mesh_data(void) {
@@ -71,11 +71,11 @@ void parse_face(const char* buffer, face_t* face) {
     face->c = token ? atoi(token) : -1;
 }
 
-void load_file(void) {
+void load_file(const char* filename) {
     FILE* fp;
     char* tok;
 
-    fp = fopen("..\\assets\\f22.obj", "r");
+    fp = fopen(filename, "r");
 
     if (fp == NULL) {
         exit(EXIT_FAILURE);

scripts/mesh.h

@@ -12,6 +12,21 @@
 extern vec3_t cube_vertices[N_CUBE_VERTICES];
 extern face_t cube_faces[N_CUBE_FACES];
 
+typedef enum {
+    COLOR_PURPLE      = 0xFF6A2EFF,
+    COLOR_SAND_YELLOW = 0xFFE9C46A,
+    COLOR_TEAL_GREEN  = 0xFF2A9D8F,
+    COLOR_ORANGE      = 0xFFF4A261,
+    COLOR_DARK_BLUE_GREY = 0xFF264653,
+    COLOR_MAUVE       = 0xFFB5838D,
+    COLOR_RED         = 0xFFD7263D,
+    COLOR_TURQUOISE   = 0xFF38A3A5,
+    COLOR_GREY        = 0xFF757575,
+    COLOR_LIGHT_GREEN_BLUE = 0xFF70C1B3,
+    COLOR_YELLOW      = 0xFFFFC300,
+    COLOR_DEEP_PURPLE = 0xFF5D2E8C
+} color_enum_t;
+
 typedef struct mesh_t mesh_t;
 struct mesh_t {
     vec3_t* vertices;
@@ -24,6 +39,6 @@ extern mesh_t mesh;
 void parse_face(const char* buffer, face_t* face);
 
 void load_cube_mesh_data(void);
-void load_file(void);
+void load_file(const char* filename);
 
 #endif

scripts/triangle.c

@@ -23,7 +23,7 @@ uint32_t invert_rgb(uint32_t color) {
     return a | rgb;
 }
 
-void fill_flat_bottom_triangle(const triangle_t* triangle, uint32_t color) {
+void fill_flat_bottom_triangle(const triangle_t* triangle, color_t color) {
     float inv_slope_1 = (triangle->points[1].x - triangle->points[0].x) / (triangle->points[1].y - triangle->points[0].y);
     float inv_slope_2 = (triangle->points[2].x - triangle->points[0].x) / (triangle->points[2].y - triangle->points[0].y);;
 
@@ -37,7 +37,7 @@ void fill_flat_bottom_triangle(const triangle_t* triangle, uint32_t color) {
     }
 }
 
-void fill_flat_top_triangle(const triangle_t* triangle, uint32_t color) {
+void fill_flat_top_triangle(const triangle_t* triangle, color_t color) {
     float inv_slope_1 = (triangle->points[2].x - triangle->points[0].x) / (triangle->points[2].y - triangle->points[0].y);
     float inv_slope_2 = (triangle->points[2].x - triangle->points[1].x) / (triangle->points[2].y - triangle->points[1].y);;
 
@@ -51,7 +51,7 @@ void fill_flat_top_triangle(const triangle_t* triangle, uint32_t color) {
     }
 }
 
-void draw_filled_triangle(triangle_t triangle, uint32_t color) {
+void draw_filled_triangle(triangle_t triangle) {
     // sort by y
     int temp = 0, min_idx = 0, mid_idx = 1, max_idx = 2;
 
@@ -65,6 +65,8 @@ void draw_filled_triangle(triangle_t triangle, uint32_t color) {
         temp = mid_idx; mid_idx = max_idx; max_idx = temp;
     }
 
+    color_t color = triangle.color ? triangle.color : 0xFF00FF00; // Default to 0xFF00FF00 if not setr; // Default color if not set
+
     if (triangle.points[mid_idx].y == triangle.points[max_idx].y) {
         fill_flat_bottom_triangle(&triangle, color);
     } else if (triangle.points[min_idx].y == triangle.points[mid_idx].y) {

scripts/triangle.h

@@ -4,10 +4,13 @@
 #include <stdint.h>
 #include "vector.h"
 
+typedef uint32_t color_t;
+
 typedef struct {
     int a;
     int b;
     int c;
+    color_t color;
 } face_t;
 
 typedef struct {
@@ -17,8 +20,10 @@ typedef struct {
 
 typedef struct {
     vec2_t points[3];
+    color_t color;
+    float average_depth;
 } triangle_t;
 
-void draw_filled_triangle(triangle_t triangle, uint32_t color);
+void draw_filled_triangle(triangle_t triangle);
 
 #endif