render and culling options

scripts/display.c

@@ -95,7 +95,7 @@ void draw_line(int x0, int y0, int x1, int y1, uint32_t color) {
     float current_x = x0;
     float current_y = y0;
 
-    for (int i = 0; i < longest_side_length; i++) {
+    for (int i = 0; i <= longest_side_length; i++) {
         draw_pixel(round(current_x), round(current_y), color);
         current_x += x_inc;
         current_y += y_inc;

scripts/display.h

@@ -17,6 +17,18 @@ extern SDL_Texture* color_buffer_texture;
 extern int window_width;
 extern int window_height;
 
+enum render_methods {
+    RENDER_WIRE_VERTEX,
+    RENDER_WIRE,
+    RENDER_FILL_TRIANGLE,
+    RENDER_FILL_TRIANGLE_LINE,
+};
+
+enum cull_methods {
+    CULL_NONE,
+    CULL_BACKFACE,
+};
+
 bool initialize_window(void); 
 void draw_grid(void);
 void draw_pixel(int x, int y, uint32_t color);

scripts/main.c

@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <stdint.h>
 #include <stdbool.h>
+#include <math.h>
 #include <SDL.h>
 #include <SDL_ttf.h>
 #include "display.h"
@@ -32,6 +33,10 @@ vec3_t camera_position = { 0, 0, 0 };
 float fov_factor = 640;
 
 bool is_running = false;
+
+int cull_method = CULL_BACKFACE;
+int render_method = RENDER_WIRE_VERTEX;
+
 uint32_t previous_frame_time = 0;
 
 void setup(void) {
@@ -71,6 +76,26 @@ void process_input(void) {
             if (event.key.keysym.sym == SDLK_RIGHT)
                 mesh.rotation.y += STEP;
             break;
+        case SDL_KEYUP:
+            SDL_Keycode key = event.key.keysym.sym;
+            if (key == SDLK_c) {
+                cull_method = !cull_method;
+            }
+
+            if (key == SDLK_1) {
+                render_method = RENDER_WIRE_VERTEX;
+            }
+            if (key == SDLK_2) {
+                render_method = RENDER_WIRE;
+            }
+            if (key == SDLK_3) {
+                render_method = RENDER_FILL_TRIANGLE;
+            }
+            if (key == SDLK_4) {
+                render_method = RENDER_FILL_TRIANGLE_LINE;
+            }
+
+            break;
 
 
 
@@ -82,8 +107,8 @@ void process_input(void) {
 ////////////////////////////////////////////////////////////////////////////////
 vec2_t project(vec3_t point) {
     vec2_t projected_point = {
-        .x = (fov_factor * point.x) / point.z,
-        .y = (fov_factor * point.y) / point.z,
+        .x = round((fov_factor * point.x) / point.z),
+        .y = round((fov_factor * point.y) / point.z),
     };
     return projected_point;
 }
@@ -131,29 +156,31 @@ void update(void) {
             transformed_vertices[j] = transformed_vertex;
         }
 
-        // check backface culling
-        vec3_t vector_a = transformed_vertices[0]; /*   A    */
-        vec3_t vector_b = transformed_vertices[1]; /*  / \   */
-        vec3_t vector_c = transformed_vertices[2]; /* C---B  */
+        if (cull_method == CULL_BACKFACE) {
+            // check backface culling
+            vec3_t vector_a = transformed_vertices[0]; /*   A    */
+            vec3_t vector_b = transformed_vertices[1]; /*  / \   */
+            vec3_t vector_c = transformed_vertices[2]; /* C---B  */
 
-        // get the vector subtraction of B-A and C-A
-        vec3_t vector_ab = vec3_subtract(vector_b, vector_a);
-        vec3_t vector_ac = vec3_subtract(vector_c, vector_a);
-        vec3_normalize(&vector_ab);
-        vec3_normalize(&vector_ac);
+            // get the vector subtraction of B-A and C-A
+            vec3_t vector_ab = vec3_subtract(vector_b, vector_a);
+            vec3_t vector_ac = vec3_subtract(vector_c, vector_a);
+            vec3_normalize(&vector_ab);
+            vec3_normalize(&vector_ac);
 
-        // compute the face normal using the cross product to find perpindicular
-        vec3_t normal = vec3_cross(vector_ab, vector_ac);
-        vec3_normalize(&normal);
+            // compute the face normal using the cross product to find perpindicular
+            vec3_t normal = vec3_cross(vector_ab, vector_ac);
+            vec3_normalize(&normal);
 
-        // find the vector between a point in the triangle and the camera origin
-        vec3_t camera_ray = vec3_subtract(camera_position, vector_a);
+            // find the vector between a point in the triangle and the camera origin
+            vec3_t camera_ray = vec3_subtract(camera_position, vector_a);
 
-        // calculate how aligned the camera ray is with the face normal
-        float dot_normal_camera = vec3_dot(normal, camera_ray);
+            // calculate how aligned the camera ray is with the face normal
+            float dot_normal_camera = vec3_dot(normal, camera_ray);
 
-        if (dot_normal_camera < 0) {
-            continue;
+            if (dot_normal_camera < 0) {
+                continue;
+            }
         }
 
         triangle_t projected_triangle;
@@ -177,19 +204,6 @@ void update(void) {
 
         triangle_t normal_triangle;
 
-        for (int j = 0; j < 3; j++) {
-            // project the current vertex
-            vec2_t projected_point = project(transformed_vertices[j]);
-
-            // scale and translate the projected points to the center of the screen
-            projected_point.x += (window_width / 2);
-            projected_point.y += (window_height / 2);
-
-            normal_triangle.points[j] = projected_point;
-        }
-
-        array_push(triangles_to_render, normal_triangle);
-
     }
 }
 
@@ -200,18 +214,29 @@ void render(void) {
 
     for (int i = 0; i < array_length(triangles_to_render); i++) {
         triangle_t triangle = triangles_to_render[i];
-        draw_filled_triangle(triangle, colors[i]);
-        //draw_triangle(triangle, 0xFFFF0000);
-        //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);
-    }
 
-    triangle_t t;
-    t.points[0] = (vec2_t){ 100, 100 };
-    t.points[1] = (vec2_t){ 100, 200.1 };
-    t.points[2] = (vec2_t){ 300, 200.5};
-    draw_filled_triangle(t, 0xFF00FF00);
+        switch (render_method) {
+            case RENDER_WIRE:
+                draw_triangle(triangle, 0x0000ff);
+                break;
+            case RENDER_WIRE_VERTEX:
+                draw_triangle(triangle, 0x000055);
+                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);
+                break;
+            case RENDER_FILL_TRIANGLE_LINE:
+                draw_filled_triangle(triangle, 0xff00);
+                draw_triangle(triangle, 0x0000ff);
+                break;
+            default:
+                break;
+        }
+
+    }
 
     //vec2_t m = triangle_midpoint(t);
     //draw_rect(m.x, m.y, 10, 10, 0xFFFF0000);

scripts/mesh.c

@@ -75,7 +75,7 @@ void load_file(void) {
     FILE* fp;
     char* tok;
 
-    fp = fopen("..\\assets\\cube.obj", "r");
+    fp = fopen("..\\assets\\f22.obj", "r");
 
     if (fp == NULL) {
         exit(EXIT_FAILURE);

scripts/triangle.c

@@ -13,8 +13,8 @@ int compare_vec2_t(const void* a, const void* b) {
     return 0;
 }
 
-#define FUNC ceilf
-#define FUNC2 floorf
+#define FUNC (int)ceilf
+#define FUNC2 (int)floorf
 
 uint32_t invert_rgb(uint32_t color) {
     uint32_t a = color & 0xFF000000;          // Alpha channel
@@ -29,9 +29,9 @@ void fill_flat_bottom_triangle(const triangle_t* triangle, uint32_t color) {
 
     float x_start = triangle->points[0].x, x_end = triangle->points[0].x;
 
-    for (int x = FUNC(triangle->points[0].y); x < FUNC(triangle->points[2].y); x++) {
+    for (int x = FUNC(triangle->points[0].y); x <= FUNC2(triangle->points[2].y); x++) {
         //draw_rect((int)triangle->points[0].x, i, 1, 1, 0xFFFF0000);
-        draw_line(FUNC2(x_start), x, FUNC2(x_end), x, color);
+        draw_line(FUNC(x_start), x, FUNC2(x_end), x, color);
         x_start += inv_slope_1;
         x_end += inv_slope_2;
     }
@@ -43,9 +43,9 @@ void fill_flat_top_triangle(const triangle_t* triangle, uint32_t color) {
 
     float x_start = triangle->points[2].x, x_end = triangle->points[2].x;
 
-    for (int y = FUNC(triangle->points[2].y); y > FUNC(triangle->points[0].y); y--) {
+    for (int y = FUNC2(triangle->points[2].y); y >= FUNC(triangle->points[0].y); y--) {
         //draw_rect((int)triangle->points[0].x, i, 1, 1, 0xFFFF0000);
-        draw_line(FUNC2(x_start), y, FUNC2(x_end), y, color);
+        draw_line(FUNC(x_start), y, FUNC2(x_end), y, color);
         x_start -= inv_slope_1;
         x_end -= inv_slope_2;
     }

scripts/triangle.h

@@ -10,6 +10,11 @@ typedef struct {
     int c;
 } face_t;
 
+typedef struct {
+    int x;
+    int y;
+} int_vec2_t;
+
 typedef struct {
     vec2_t points[3];
 } triangle_t;