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5251c12b8e0545bae341cf80ba61a6087c0e7181
software_rasterizer/main.cpp
Krzosa Karol 5251c12b8e save_profile_data
2022-02-26 11:23:57 +01:00

620 lines
22 KiB
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/////////////////////////////////////////////////////////////////////////////////////
///
/// ### 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 <float.h>
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
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