diff --git a/include/rasteriser/rasteriser.h b/include/rasteriser/rasteriser.h
index 012a4ea..3e994f7 100644
--- a/include/rasteriser/rasteriser.h
+++ b/include/rasteriser/rasteriser.h
@@ -22,6 +22,7 @@ typedef struct {
colour_t colour;
} scene_triangle_t;
+MAKE_LIST_TYPE(u64);
MAKE_LIST_TYPE(f32);
MAKE_LIST_TYPE(vec2i_t);
MAKE_LIST_TYPE(vec3f_t);
@@ -33,6 +34,8 @@ typedef enum {
RASTERISER_RENDER_WIREFRAME,
RASTERISER_RENDER_FILLED,
RASTERISER_RENDER_SHADED,
+
+ COUNT_RASTERISER_RENDER,
} render_type_t;
typedef struct {
diff --git a/src/rasteriser/main.c b/src/rasteriser/main.c
index 10b2d5f..7233bc6 100644
--- a/src/rasteriser/main.c
+++ b/src/rasteriser/main.c
@@ -159,6 +159,8 @@ int main(void) {
return EXIT_FAILURE;
}
+ render_type_t type = RASTERISER_RENDER_FILLED;
+
while (running) {
while (SDL_PollEvent(&event)) {
switch (event.type) {
@@ -174,6 +176,8 @@ int main(void) {
camera.rotation.y += 1.0f;
} else if (event.key.keysym.sym == SDLK_a) {
camera.rotation.y -= 1.0f;
+ } else if (event.key.keysym.sym == SDLK_e) {
+ type = (type + 1) % COUNT_RASTERISER_RENDER;
}
break;
}
@@ -181,7 +185,7 @@ int main(void) {
clear_window(&window, bg);
- render_scene(&window, frame_arena, &scene, RASTERISER_RENDER_FILLED);
+ render_scene(&window, frame_arena, &scene, type);
swap_buffers(&window);
diff --git a/src/rasteriser/rasteriser.c b/src/rasteriser/rasteriser.c
index 09d2578..778c9c6 100644
--- a/src/rasteriser/rasteriser.c
+++ b/src/rasteriser/rasteriser.c
@@ -11,12 +11,20 @@
#include <string.h>
#include <sys/mman.h>
+#define CULL_ENABLED 0
+
internal void render_instance(window_t *wnd, const rasteriser_scene_t *scene,
Arena *arena, mat4x4f_t camera_matrix,
mat3x4f_t projection_matrix,
const instance_t *instance, render_type_t type);
internal void clip_instance(Arena *arena, model_t *model,
const rasteriser_scene_t *scene);
+
+#if CULL_ENABLED
+internal void cull_back_faces(Arena *arena, const rasteriser_scene_t *scene,
+ model_t *model);
+#endif
+
internal void clip_instance_against_plane(Arena *arena, model_t *model,
const bounding_sphere_t *sphere,
const clipping_plane_t *plane);
@@ -26,6 +34,13 @@ internal void clip_triangle_against_plane(Arena *arena, model_t *model,
i64 triangle_index,
const clipping_plane_t *plane);
internal list_float *interpolate(Arena *arena, i32 i0, f32 d0, i32 i1, f32 d1);
+
+#if CULL_ENABLED
+internal inline vec3f_t
+calculate_triangle_normal(const model_t *model,
+ const scene_triangle_t *triangle);
+#endif
+
internal inline void order_triangle_points(triangle_t *triangle);
internal inline bounding_sphere_t
get_bounding_sphere(const list_vertex_t *vertices);
@@ -57,11 +72,9 @@ internal void render_instance(window_t *wnd, const rasteriser_scene_t *scene,
mat3x4f_t projection_matrix,
const instance_t *instance, render_type_t type) {
list_vertex_t *transformed = list_create_with_capacity(
- vertex_t, arena,
- (instance->model->vertices->count + 10) * sizeof(vertex_t));
+ vertex_t, arena, instance->model->vertices->count + 10);
list_scene_triangle_t *triangles = list_create_with_capacity(
- scene_triangle_t, arena,
- (instance->model->triangles->count + 10) * sizeof(scene_triangle_t));
+ scene_triangle_t, arena, instance->model->triangles->count + 10);
if (!transformed || !triangles) {
return;
}
@@ -94,13 +107,17 @@ internal void render_instance(window_t *wnd, const rasteriser_scene_t *scene,
}
model_t model = {transformed, triangles};
+#if CULL_ENABLED
+ cull_back_faces(arena, scene, &model);
+#endif
+
clip_instance(arena, &model, scene);
if (is_null_model(&model)) {
return;
}
list_vec2i_t *projected = list_create_with_capacity(
- vec2i_t, arena, instance->model->vertices->count * sizeof(vec2i_t));
+ vec2i_t, arena, instance->model->vertices->count);
if (!projected) {
return;
}
@@ -151,6 +168,8 @@ internal void render_instance(window_t *wnd, const rasteriser_scene_t *scene,
case RASTERISER_RENDER_SHADED:
draw_shaded_triangle(wnd, arena, tri);
break;
+ default:
+ return;
}
}
}
@@ -390,6 +409,36 @@ internal void clip_instance(Arena *arena, model_t *model,
}
}
+#if CULL_ENABLED
+internal void cull_back_faces(Arena *arena, const rasteriser_scene_t *scene,
+ model_t *model) {
+ list_uint64_t *to_remove =
+ list_create_with_capacity(u64, arena, model->triangles->count);
+ vec3f_t normal;
+ scene_triangle_t triangle;
+ vertex_t v0;
+ vec3f_t viewing_vector;
+ f32 dot_product;
+
+ for (u64 i = 0; i < model->triangles->count; ++i) {
+ triangle = list_get(model->triangles, i);
+ v0 = list_get(model->vertices, triangle.idx0);
+ normal = calculate_triangle_normal(model, &triangle);
+ viewing_vector = vec_sub(vec3f_t, v0.position, scene->camera->position);
+ dot_product = vec_dot(vec3f_t, normal, viewing_vector);
+
+ if (dot_product <= 0.0f) {
+ list_append(u64, arena, to_remove, i);
+ }
+ }
+
+ for (u64 i = 0; i < to_remove->count; ++i) {
+ u64 idx = list_get(to_remove, i);
+ list_remove(model->triangles, idx);
+ }
+}
+#endif
+
internal void clip_instance_against_plane(Arena *arena, model_t *model,
const bounding_sphere_t *sphere,
const clipping_plane_t *plane) {
@@ -536,6 +585,21 @@ internal list_float *interpolate(Arena *arena, i32 i0, f32 d0, i32 i1, f32 d1) {
return values;
}
+#if CULL_ENABLED
+internal inline vec3f_t
+calculate_triangle_normal(const model_t *model,
+ const scene_triangle_t *triangle) {
+ vertex_t v0 = list_get(model->vertices, triangle->idx0);
+ vertex_t v1 = list_get(model->vertices, triangle->idx1);
+ vertex_t v2 = list_get(model->vertices, triangle->idx2);
+
+ vec3f_t ba = vec_sub(vec3f_t, v1.position, v0.position);
+ vec3f_t ca = vec_sub(vec3f_t, v2.position, v0.position);
+
+ return vec_cross(vec3f_t, ba, ca);
+}
+#endif
+
internal inline void order_triangle_points(triangle_t *triangle) {
if (triangle->p1.y < triangle->p0.y) {
swap(vec2i_t, triangle->p0, triangle->p1);