///////////////////////////////////////////////////////////////////////////////////// /// /// ### Things to do: /// /// - [x] Drawing triangles /// - [x] Drawing cubes and lines for testing /// - [x] Y up coordinate system, left handed /// - [x] Drawing a cube with perspective /// - [x] Culling triangles facing away from camera /// - [x] Texture mapping /// - [x] Basic linear transformations - rotation, translation, scaling /// - [x] Bilinear filtering of textures /// - [x] Nearest filtering /// - [x] Fix the gaps between triangles (it also improved look of triangle edges) /// - [ ] Perspective matrix vs simple perspective /// - [x] Perspective correct interpolation /// - [x] Depth buffer /// - [x] Gamma correct blending - converting to almost linear space /// - [x] Alpha blending /// - [x] Premultiplied alpha /// - [x] Merge with base /// - [ ] Lightning /// - [x] GLOBAL Ilumination /// - [x] LookAt Camera /// - [x] FPS Camera /// - [x] Reading OBJ models /// - [ ] Reading more OBJ formats /// - [ ] Reading OBJ .mtl files /// - [x] Reading complex obj models (sponza) /// - [ ] Reading PMX files /// - [ ] Rendering multiple objects, queue renderer /// - [x] Simple function to render a mesh /// - [x] Clipping /// - [x] Triagnle rectangle bound clipping /// - [x] A way of culling Z out triangles /// - [x] Simple test z clipping /// - [x] Maybe should clip a triangle on znear zfar plane? /// - [x] Maybe should clip out triangles that are fully z out before draw_triangle /// - [ ] Subpixel precision of triangle edges /// - [x] Simple profiling tooling /// - [x] Statistics based on profiler data, distribution information /// - [x] Find cool profilers - ExtraSleepy, Vtune /// - [ ] Optimizations /// - [ ] Inline edge function /// - [ ] Expand edge functions to more optimized version /// - [ ] Test 4x2 bitmap layout? /// - [ ] Edge function to integer /// - [ ] Use integer bit operations to figure out if plus. (edge1|edge2|edge3)>=0 /// - [ ] SIMD /// - [ ] Multithreading /// /// - [ ] Text rendering /// - [ ] Basic UI /// - [ ] Gamma correct and alpha blending /// #define _CRT_SECURE_NO_WARNINGS #define PREMULTIPLIED_ALPHA_BLENDING 1 #define PLATFORM #include "kpl.h" #include "profile.cpp" #include "math.h" struct R_Vertex { Vec3 pos; Vec2 tex; Vec3 norm; }; struct R_Render { Mat4 camera; Mat4 projection; Mat4 transform; Vec3 camera_pos; Vec3 camera_direction; Vec3 camera_forward_velocity; Vec2 camera_yaw; Vec3 camera_target; Bitmap img; Bitmap screen320; F32 *depth320; }; #include "obj_parser.cpp" #include "stb_image.h" #include GLOBAL bool draw_rects = 0; GLOBAL bool draw_wireframe = 0; FUNCTION void draw_rect(Bitmap* dst, F32 X, F32 Y, F32 w, F32 h, U32 color) { int max_x = (int)(MIN(X + w, dst->x) + 0.5f); int max_y = (int)(MIN(Y + h, dst->y) + 0.5f); int min_x = (int)(MAX(0, X) + 0.5f); int min_y = (int)(MAX(0, Y) + 0.5f); for (int y = min_y; y < max_y; y++) { for (int x = min_x; x < max_x; x++) { dst->pixels[x + y * dst->x] = color; } } } FUNCTION F32 edge_function(Vec4 vecp0, Vec4 vecp1, Vec4 p) { F32 result = (vecp1.y - vecp0.y) * (p.x - vecp0.x) - (vecp1.x - vecp0.x) * (p.y - vecp0.y); return result; } FUNCTION Vec4 srgb_to_almost_linear(Vec4 a) { Vec4 result = {a.r*a.r, a.g*a.g, a.b*a.b, a.a}; return result; // @Note: Linear would be to power of 2.2 } FUNCTION Vec4 almost_linear_to_srgb(Vec4 a) { Vec4 result = { sqrtf(a.r), sqrtf(a.g), sqrtf(a.b), a.a }; return result; } FUNCTION void draw_bitmap(Bitmap* dst, Bitmap* src, Vec2 pos) { I64 minx = (I64)(pos.x + 0.5); I64 miny = (I64)(pos.y + 0.5); I64 maxx = minx + src->x; I64 maxy = miny + src->y; I64 offsetx = 0; I64 offsety = 0; if (maxx > dst->x) { maxx = dst->x; } if (maxy > dst->y) { maxy = dst->y; } if (minx < 0) { offsetx = -minx; minx = 0; } if (miny < 0) { offsety = -miny; miny = 0; } for (I64 y = miny; y < maxy; y++) { for (I64 x = minx; x < maxx; x++) { I64 tx = x - minx + offsetx; I64 ty = y - miny + offsety; U32 *dst_pixel = dst->pixels + (x + y * dst->x); U32 *pixel = src->pixels + (tx + ty * src->x); Vec4 result_color = srgb_to_almost_linear(vec4abgr(*pixel)); Vec4 dst_color = srgb_to_almost_linear(vec4abgr(*dst_pixel)); result_color.r = result_color.r + (1-result_color.a) * dst_color.r; result_color.g = result_color.g + (1-result_color.a) * dst_color.g; result_color.b = result_color.b + (1-result_color.a) * dst_color.b; result_color.a = result_color.a + dst_color.a - result_color.a*dst_color.a; result_color = almost_linear_to_srgb(result_color); U32 color32 = vec4_to_u32abgr(result_color); *dst_pixel = color32; } } } FUNCTION void draw_triangle_nearest(Bitmap* dst, F32 *depth_buffer, Bitmap *src, F32 light, Vec4 p0, Vec4 p1, Vec4 p2, Vec2 tex0, Vec2 tex1, Vec2 tex2) { if(os.frame > 60) PROFILE_BEGIN(draw_triangle); F32 min_x1 = (F32)(MIN(p0.x, MIN(p1.x, p2.x))); F32 min_y1 = (F32)(MIN(p0.y, MIN(p1.y, p2.y))); F32 max_x1 = (F32)(MAX(p0.x, MAX(p1.x, p2.x))); F32 max_y1 = (F32)(MAX(p0.y, MAX(p1.y, p2.y))); I64 min_x = (I64)MAX(0, floor(min_x1)); I64 min_y = (I64)MAX(0, floor(min_y1)); I64 max_x = (I64)MIN(dst->x, ceil(max_x1)); I64 max_y = (I64)MIN(dst->y, ceil(max_y1)); F32 area = edge_function(p0, p1, p2); for (I64 y = min_y; y < max_y; y++) { for (I64 x = min_x; x < max_x; x++) { F32 edge1 = edge_function(p0, p1, { (F32)x,(F32)y }); F32 edge2 = edge_function(p1, p2, { (F32)x,(F32)y }); F32 edge3 = edge_function(p2, p0, { (F32)x,(F32)y }); if (edge1 >= 0 && edge2 >= 0 && edge3 >= 0) { F32 w1 = edge2 / area; F32 w2 = edge3 / area; F32 w3 = edge1 / area; F32 interpolated_w = (1.f / p0.w) * w1 + (1.f / p1.w) * w2 + (1.f / p2.w) * w3; F32 u = tex0.x * (w1 / p0.w) + tex1.x * (w2 / p1.w) + tex2.x * (w3 / p2.w); F32 v = tex0.y * (w1 / p0.w) + tex1.y * (w2 / p1.w) + tex2.y * (w3 / p2.w); u /= interpolated_w; v /= interpolated_w; // @Note: We could do: interpolated_w = 1.f / interpolated_w to get proper depth // but why waste an instruction, the smaller the depth value the farther the object F32* depth = depth_buffer + (x + y * dst->x); if (*depth < interpolated_w) { *depth = interpolated_w; u = u * (src->x - 2); v = v * (src->y - 2); I64 ui = (I64)(u); I64 vi = (I64)(v); F32 udiff = u - (F32)ui; F32 vdiff = v - (F32)vi; // Origin UV (0,0) is in bottom left U32 *dst_pixel = dst->pixels + (x + y * dst->x); U32 *pixel = src->pixels + (ui + (src->y - 1ll - vi) * src->x); #if PREMULTIPLIED_ALPHA_BLENDING Vec4 result_color = srgb_to_almost_linear(vec4abgr(*pixel)); Vec4 dst_color = srgb_to_almost_linear(vec4abgr(*dst_pixel)); result_color.r *= light; result_color.g *= light; result_color.b *= light; result_color.r = result_color.r + (1-result_color.a) * dst_color.r; result_color.g = result_color.g + (1-result_color.a) * dst_color.g; result_color.b = result_color.b + (1-result_color.a) * dst_color.b; result_color.a = result_color.a + dst_color.a - result_color.a*dst_color.a; result_color = almost_linear_to_srgb(result_color); U32 color32 = vec4_to_u32abgr(result_color); #else U32 color32 = *pixel; #endif *dst_pixel = color32; } } } } if (draw_rects) { draw_rect(dst, p0.x-4, p0.y-4, 8,8, 0x00ff0000); draw_rect(dst, p1.x-4, p1.y-4, 8,8, 0x0000ff00); draw_rect(dst, p2.x-4, p2.y-4, 8,8, 0x000000ff); } if(os.frame > 60) PROFILE_END(draw_triangle); } FUNCTION void draw_triangle_subpixel(Bitmap* dst, F32 *depth_buffer, Bitmap *src, F32 light, Vec4 p0, Vec4 p1, Vec4 p2, Vec2 tex0, Vec2 tex1, Vec2 tex2) { F32 min_x1 = (F32)(MIN(p0.x, MIN(p1.x, p2.x))); F32 min_y1 = (F32)(MIN(p0.y, MIN(p1.y, p2.y))); F32 max_x1 = (F32)(MAX(p0.x, MAX(p1.x, p2.x))); F32 max_y1 = (F32)(MAX(p0.y, MAX(p1.y, p2.y))); I64 min_x = (I64)MAX(0, floor(min_x1)); I64 min_y = (I64)MAX(0, floor(min_y1)); I64 max_x = (I64)MIN(dst->x, ceil(max_x1)); I64 max_y = (I64)MIN(dst->y, ceil(max_y1)); F32 area = edge_function(p0, p1, p2); for (I64 y = min_y; y < max_y; y++) { for (I64 x = min_x; x < max_x; x++) { F32 edge1 = edge_function(p0, p1, { (F32)x,(F32)y }); F32 edge2 = edge_function(p1, p2, { (F32)x,(F32)y }); F32 edge3 = edge_function(p2, p0, { (F32)x,(F32)y }); if (edge1 >= 0 && edge2 >= 0 && edge3 >= 0) { F32 w1 = edge2 / area; F32 w2 = edge3 / area; F32 w3 = edge1 / area; F32 interpolated_w = (1.f / p0.w) * w1 + (1.f / p1.w) * w2 + (1.f / p2.w) * w3; F32 u = tex0.x * (w1 / p0.w) + tex1.x * (w2 / p1.w) + tex2.x * (w3 / p2.w); F32 v = tex0.y * (w1 / p0.w) + tex1.y * (w2 / p1.w) + tex2.y * (w3 / p2.w); u /= interpolated_w; v /= interpolated_w; // @Note: We could do: interpolated_w = 1.f / interpolated_w to get proper depth // but why waste an instruction, the smaller the depth value the farther the object F32* depth = depth_buffer + (x + y * dst->x); if (*depth < interpolated_w && interpolated_w > 0.1f) { *depth = interpolated_w; u = u * (src->x - 2); v = v * (src->y - 2); I64 ui = (I64)(u); I64 vi = (I64)(v); F32 udiff = u - (F32)ui; F32 vdiff = v - (F32)vi; // Origin UV (0,0) is in bottom left U32 *pixel = src->pixels + (ui + (src->y - 1ll - vi) * src->x); U32 *dst_pixel = dst->pixels + (x + y * dst->x); Vec4 pixelx1y1 = vec4abgr(*pixel); Vec4 pixelx2y1 = vec4abgr(*(pixel + 1)); Vec4 pixelx1y2 = vec4abgr(*(pixel - src->x)); Vec4 pixelx2y2 = vec4abgr(*(pixel + 1 - src->x)); pixelx1y1 = srgb_to_almost_linear(pixelx1y1); pixelx2y1 = srgb_to_almost_linear(pixelx2y1); pixelx1y2 = srgb_to_almost_linear(pixelx1y2); pixelx2y2 = srgb_to_almost_linear(pixelx2y2); Vec4 blendx1 = lerp(pixelx1y1, pixelx2y1, udiff); Vec4 blendx2 = lerp(pixelx1y2, pixelx2y2, udiff); Vec4 result_color = lerp(blendx1, blendx2, vdiff); result_color.r *= light; result_color.g *= light; result_color.b *= light; #if PREMULTIPLIED_ALPHA_BLENDING Vec4 dst_color = vec4abgr(*dst_pixel); dst_color = srgb_to_almost_linear(dst_color); result_color.r = result_color.r + (1-result_color.a) * dst_color.r; result_color.g = result_color.g + (1-result_color.a) * dst_color.g; result_color.b = result_color.b + (1-result_color.a) * dst_color.b; result_color.a = result_color.a + dst_color.a - result_color.a*dst_color.a; #endif // PREMULTIPLIED_ALPHA_BLENDING result_color = almost_linear_to_srgb(result_color); U32 color32 = vec4_to_u32abgr(result_color); *dst_pixel = color32; } } } } if (draw_rects) { draw_rect(dst, p0.x-4, p0.y-4, 8,8, 0x00ff0000); draw_rect(dst, p1.x-4, p1.y-4, 8,8, 0x0000ff00); draw_rect(dst, p2.x-4, p2.y-4, 8,8, 0x000000ff); } } FUNCTION void draw_line(Bitmap *dst, F32 x0, F32 y0, F32 x1, F32 y1) { F32 delta_x = (x1 - x0); F32 delta_y = (y1 - y0); F32 longest_side_length = (ABS(delta_x) >= ABS(delta_y)) ? ABS(delta_x) : ABS(delta_y); F32 x_inc = delta_x / (F32)longest_side_length; F32 y_inc = delta_y / (F32)longest_side_length; F32 current_x = (F32)x0; F32 current_y = (F32)y0; for (int i = 0; i <= longest_side_length; i++) { int x = (int)(current_x + 0.5f); int y = (int)(current_y + 0.5f); dst->pixels[x + y * dst->x] = 0xffffffff; current_x += x_inc; current_y += y_inc; } } FUNCTION Bitmap load_image(const char* path) { int x, y, n; unsigned char* data = stbi_load(path, &x, &y, &n, 4); Bitmap result = { (U32*)data, x, y }; #if PREMULTIPLIED_ALPHA_BLENDING U32 *p = result.pixels; for (int Y = 0; Y < y; Y++) { for (int X = 0; X < x; X++) { Vec4 color = vec4abgr(*p); color.r *= color.a; color.g *= color.a; color.b *= color.a; *p++ = vec4_to_u32abgr(color); } } #endif return result; } S8 scenario_name = string_null; FN void r_draw_mesh(R_Render *r, ObjMesh *mesh, Vec3 *vertices, Vec2 *tex_coords, Vec3 *normals) { for (int i = 0; i < mesh->indices.len; i++) { ObjIndex *index = mesh->indices.e + i; R_Vertex vert[] = { { vertices[index->vertex[0] - 1], tex_coords[index->tex[0] - 1], normals[index->normal[0] - 1], }, { vertices[index->vertex[1] - 1], tex_coords[index->tex[1] - 1], normals[index->normal[1] - 1], }, { vertices[index->vertex[2] - 1], tex_coords[index->tex[2] - 1], normals[index->normal[2] - 1], }, }; //@Note: Transform for (int j = 0; j < 3; j++) { vert[j].pos = r->transform * vert[j].pos; } Vec3 p0_to_camera = r->camera_pos - vert[0].pos; Vec3 p0_to_p1 = vert[1].pos - vert[0].pos; Vec3 p0_to_p2 = vert[2].pos - vert[0].pos; Vec3 normal = normalize(cross(p0_to_p1, p0_to_p2)); Vec3 light_direction = mat4_rotation_y(45) * vec3(0, 0, 1); F32 light = -dot(normal, light_direction); light = CLAMP(0.05f, light, 1.f); if (dot(normal, p0_to_camera) > 0) { //@Note: Backface culling /// ## Clipping /// /// There are 3 clipping stages, 2 clipping stages in 3D space against zfar and znear and 1 clipping /// stage in 2D against left, bottom, right, top(2D image bounds). /// /// First the triangles get clipped against the zfar plane, /// if a triangle has even one vertex outside the clipping region, the entire triangle gets cut. /// So far I didn't have problems with that. It simplifies the computations and splitting triangles /// on zfar seems like a waste of power. /// /// The second clipping stage is znear plane. Triangles get fully and nicely clipped against znear. /// Every time a triangle gets partially outside the clipping region it gets cut to the znear and /// either one or two new triangles get derived from the old one. /// /// Last clipping stage is performed in the 2D image space. Every triangle has a corresponding AABB /// box. In this box every pixel gets tested to see if it's in the triangle. In this clipping stage /// the box is clipped to the image metrics - 0, 0, width, height. /// /// // @Note: Zfar B32 vertex_is_outside = false; Vec3 zfar_normal = vec3(0, 0, -1); Vec3 zfar_pos = vec3(0, 0, 10000.f); for (I32 j = 0; j < 3; j++) { // @Note: Camera vert[j].pos = r->camera * vert[j].pos; // @Note: Skip triangle if even one vertex gets outside the clipping plane if ((dot(zfar_normal, vert[j].pos - zfar_pos) < 0)) { vertex_is_outside = true; break; } } if (vertex_is_outside) { continue; } // @Note: Znear, clip triangles to the near clipping plane Vec3 znear_normal = vec3(0, 0, 1); Vec3 znear_pos = vec3(0, 0, 1.f); struct _R_Vertex { Vec4 pos; Vec2 tex; } in[4]; I32 in_count = 0; R_Vertex *prev = vert + 2; R_Vertex *curr = vert; F32 prev_dot = dot(znear_normal, prev->pos - znear_pos); F32 curr_dot = 0; for (int j = 0; j < 3; j++) { curr_dot = dot(znear_normal, curr->pos - znear_pos); if (curr_dot * prev_dot < 0) { F32 t = prev_dot / (prev_dot - curr_dot); in[in_count].pos = vec4(lerp(prev->pos, curr->pos, t), 1); in[in_count++].tex = lerp(prev->tex, curr->tex, t); } if (curr_dot > 0) { in[in_count].pos = vec4(vert[j].pos, 1); in[in_count++].tex = vert[j].tex; } prev = curr++; prev_dot = curr_dot; } if (in_count == 0) { continue; } for(I64 j = 0; j < in_count; j++) { //@Note: Perspective in[j].pos = r->projection * in[j].pos; in[j].pos.x = in[j].pos.x / in[j].pos.w; in[j].pos.y = in[j].pos.y / in[j].pos.w; in[j].pos.z = in[j].pos.z / in[j].pos.w; //@Note: To pixel space in[j].pos.x *= r->screen320.x / 2; in[j].pos.y *= r->screen320.y / 2; in[j].pos.x += r->screen320.x / 2; in[j].pos.y += r->screen320.y / 2; } draw_triangle_nearest(&r->screen320, r->depth320, &r->img, light, in[0].pos, in[1].pos, in[2].pos, in[0].tex, in[1].tex, in[2].tex); if (in_count > 3) { draw_triangle_nearest(&r->screen320, r->depth320, &r->img, light, in[0].pos, in[2].pos, in[3].pos, in[0].tex, in[2].tex, in[3].tex); } #if 1 ProfileScope *scope = profile_scopes + ProfileScopeName_draw_triangle; LOCAL_PERSIST B32 profile_flag; if (!profile_flag && scope->i > 2000) { profile_flag = 1; save_profile_data(scope, scenario_name); } #endif if (draw_wireframe) { draw_line(&r->screen320, vert[0].pos.x, vert[0].pos.y, vert[1].pos.x, vert[1].pos.y); draw_line(&r->screen320, vert[1].pos.x, vert[1].pos.y, vert[2].pos.x, vert[2].pos.y); draw_line(&r->screen320, vert[2].pos.x, vert[2].pos.y, vert[0].pos.x, vert[0].pos.y); } } } } int main() { os.window_size.x = 1920; os.window_size.y = 1080; os.window_resizable = 1; os_init().error_is_fatal(); S8List list = {}; string_push(os.frame_arena, &list, LIT("main.cpp")); generate_documentation(list, LIT("README.md")); //scenario_name = LIT("assets/f22.obj"); //scenario_name = LIT("assets/AnyConv.com__White.obj"); scenario_name = LIT("assets/sponza/sponza.obj"); Obj obj = load_obj(scenario_name); Vec3* vertices = (Vec3 *)obj.vertices.e; Vec2* tex_coords = (Vec2*)obj.texture_coordinates.e; Vec3 *normals = (Vec3 *)obj.normals.e; ObjMesh *mesh = obj.mesh.e; F32 speed = 5.f; F32 rotation = 0; int screen_x = 320; int screen_y = 180; R_Render r = {}; r.camera_pos = {0,0,-2}; r.screen320 = {(U32 *)PUSH_SIZE(os.perm_arena, screen_x*screen_y*sizeof(U32)), screen_x, screen_y}; r.depth320 = (F32 *)PUSH_SIZE(os.perm_arena, sizeof(F32) * screen_x * screen_y); r.img = load_image("assets/bricksx64.png"); while (os_game_loop()) { r.camera_yaw.x += os.delta_mouse_pos.x * (F32)os.delta_time * 0.2f; r.camera_yaw.y += os.delta_mouse_pos.y * (F32)os.delta_time * 0.2f; if (os.key[Key_Escape].pressed) os_quit(); if (os.key[Key_O].down) rotation += 0.05f; if (os.key[Key_P].down) rotation -= 0.05f; if (os.key[Key_F1].pressed) draw_rects = !draw_rects; if (os.key[Key_F2].pressed) draw_wireframe = !draw_wireframe; if (os.key[Key_A].down) r.camera_pos.x -= speed * (F32)os.delta_time; if (os.key[Key_D].down) r.camera_pos.x += speed * (F32)os.delta_time; if (os.key[Key_W].down) { r.camera_forward_velocity = r.camera_direction * speed * (F32)os.delta_time; r.camera_pos = r.camera_pos + r.camera_forward_velocity; } if (os.key[Key_S].down) { r.camera_forward_velocity = r.camera_direction * speed * (F32)os.delta_time; r.camera_pos = r.camera_pos - r.camera_forward_velocity; } if (os.key[Key_R].down) r.camera_pos.y += speed * (F32)os.delta_time; if (os.key[Key_F].down) r.camera_pos.y -= speed * (F32)os.delta_time; U32* p = r.screen320.pixels; for (int y = 0; y < r.screen320.y; y++) { for (int x = 0; x < r.screen320.x; x++) { *p++ = 0x33333333; } } F32* dp = r.depth320; for (int y = 0; y < r.screen320.y; y++) { for (int x = 0; x < r.screen320.x; x++) { *dp++ = -FLT_MAX; } } Mat4 camera_rotation = mat4_rotation_y(r.camera_yaw.x) * mat4_rotation_x(r.camera_yaw.y); r.camera_direction = (camera_rotation * vec4(0,0,1,1)).xyz; Vec3 target = r.camera_pos + r.camera_direction; r.camera = mat4_look_at(r.camera_pos, target, vec3(0, 1, 0)); r.projection = mat4_perspective(60.f, (F32)os.screen->x, (F32)os.screen->y, 0.1f, 1000.f); r.transform = mat4_rotation_z(rotation); r.transform = r.transform * mat4_rotation_y(rotation); for (int i = 0; i < obj.mesh.len; i++) { r_draw_mesh(&r, mesh+i, vertices, tex_coords, normals); } // @Note: Draw 320screen to OS screen U32* ptr = os.screen->pixels; for (int y = 0; y < os.screen->y; y++) { for (int x = 0; x < os.screen->x; x++) { F32 u = (F32)x / (F32)os.screen->x; F32 v = (F32)y / (F32)os.screen->y; int tx = (int)(u * r.screen320.x ); int ty = (int)(v * r.screen320.y ); *ptr++ = r.screen320.pixels[tx + ty * (r.screen320.x)]; } } } } /// ### Resources that helped me build the rasterizer (Might be helpful to you too): /// /// * Algorithm I used for triangle rasterization by Juan Pineda: https://www.cs.drexel.edu/~david/Classes/Papers/comp175-06-pineda.pdf /// * Casey Muratori's series on making a game from scratch(including a 2D software rasterizer(episode ~82) and 3d gpu renderer): https://hero.handmade.network/episode/code# /// * Fabian Giessen's "Optimizing Software Occlusion Culling": https://fgiesen.wordpress.com/2013/02/17/optimizing-sw-occlusion-culling-index/ /// * Fabian Giessen's optimized software renderer: https://github.com/rygorous/intel_occlusion_cull/tree/blog/SoftwareOcclusionCulling /// * Fabian Giessen's javascript triangle rasterizer: https://gist.github.com/rygorous/2486101 /// * Fabian Giessen's C++ triangle rasterizer: https://github.com/rygorous/trirast/blob/master/main.cpp /// * Joy's Kenneth lectures about computer graphics: https://www.youtube.com/playlist?list=PL_w_qWAQZtAZhtzPI5pkAtcUVgmzdAP8g /// * Joy's Kenneth article on clipping: https://import.cdn.thinkific.com/167815/JoyKennethClipping-200905-175314.pdf /// * A bunch of helpful notes and links to resources: https://nlguillemot.wordpress.com/2016/07/10/rasterizer-notes/ /// * Very nice paid course on making a software rasterizer using a scanline method: https://pikuma.com/courses/learn-3d-computer-graphics-programming /// * Reference for obj loader: https://github.com/tinyobjloader/tinyobjloader/blob/master/tiny_obj_loader.h /// * /// * /// * /// /// ### To read /// /// * http://ce-publications.et.tudelft.nl/publications/1362_hardware_algorithms_for_tilebased_realtime_rendering.pdf