469 lines
17 KiB
C
469 lines
17 KiB
C
#include "obj.h"
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#include "aliases.h"
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#include "img.h"
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#include "mem_arena.h"
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#include "pam.h"
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#include "typed_list.h"
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#include "utils.h"
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#include <limits.h>
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#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#define TRIANGLE_VERTICES 3
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#define CAMERA_DISTANCE 5.0f
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#define V2(T, ELEM_T, X0, Y0, X1, Y1) \
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((T){(ELEM_T)X1 - (ELEM_T)X0, (ELEM_T)Y1 - (ELEM_T)Y0})
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#define V3(T, ELEM_T, X0, Y0, Z0, X1, Y1, Z1) \
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((T){(ELEM_T)X1 - (ELEM_T)X0, (ELEM_T)Y1 - (ELEM_T)Y0, \
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(ELEM_T)Z1 - (ELEM_T)Z0})
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#define dot_v2(V1, V2) ((f32)V1.x * (f32)V2.x + (f32)V1.y * (f32)V2.y)
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#define dot_v3(V1, V2) \
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((f32)V1.x * (f32)V2.x + (f32)V1.y * (f32)V2.y + (f32)V1.z * (f32)V2.z)
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#define normalise_v3(V) \
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do { \
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f32 magnitude = sqrtf(dot_v3(V, V)); \
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V.x /= magnitude; \
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V.y /= magnitude; \
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V.z /= magnitude; \
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} while (0)
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#define cross_product(V1, V2) \
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((V3f){ \
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.x = V1.y * V2.z - V1.z * V2.y, \
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.y = V1.z * V2.x - V1.x * V2.z, \
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.z = V1.x * V2.y - V1.y * V2.x, \
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})
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#define mat4x4_identity \
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((M4x4f){ \
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.row0 = {1.0f, 0.0f, 0.0f, 0.0f}, \
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.row1 = {0.0f, 1.0f, 0.0f, 0.0f}, \
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.row2 = {0.0f, 0.0f, 1.0f, 0.0f}, \
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.row3 = {0.0f, 0.0f, 0.0f, 1.0f}, \
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})
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#define mat4x4_mul(MAT1, MAT2) \
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((M4x4f){ \
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.row0.x = MAT1.row0.x * MAT2.row0.x + MAT1.row0.y * MAT2.row1.x + \
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MAT1.row0.z * MAT2.row2.x + MAT1.row0.w * MAT2.row3.x, \
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.row0.y = MAT1.row0.x * MAT2.row0.y + MAT1.row0.y * MAT2.row1.y + \
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MAT1.row0.z * MAT2.row2.y + MAT1.row0.w * MAT2.row3.y, \
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.row0.z = MAT1.row0.x * MAT2.row0.z + MAT1.row0.y * MAT2.row1.z + \
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MAT1.row0.z * MAT2.row2.z + MAT1.row0.w * MAT2.row3.z, \
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.row0.w = MAT1.row0.x * MAT2.row0.w + MAT1.row0.y * MAT2.row1.w + \
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MAT1.row0.z * MAT2.row2.w + MAT1.row0.w * MAT2.row3.w, \
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.row1.x = MAT1.row1.x * MAT2.row0.x + MAT1.row1.y * MAT2.row1.x + \
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MAT1.row1.z * MAT2.row2.x + MAT1.row1.w * MAT2.row3.x, \
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.row1.y = MAT1.row1.x * MAT2.row0.y + MAT1.row1.y * MAT2.row1.y + \
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MAT1.row1.z * MAT2.row2.y + MAT1.row1.w * MAT2.row3.y, \
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.row1.z = MAT1.row1.x * MAT2.row0.z + MAT1.row1.y * MAT2.row1.z + \
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MAT1.row1.z * MAT2.row2.z + MAT1.row1.w * MAT2.row3.z, \
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.row1.w = MAT1.row1.x * MAT2.row0.w + MAT1.row1.y * MAT2.row1.w + \
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MAT1.row1.z * MAT2.row2.w + MAT1.row1.w * MAT2.row3.w, \
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.row2.x = MAT1.row2.x * MAT2.row0.x + MAT1.row2.y * MAT2.row1.x + \
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MAT1.row2.z * MAT2.row2.x + MAT1.row2.w * MAT2.row3.x, \
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.row2.y = MAT1.row2.x * MAT2.row0.y + MAT1.row2.y * MAT2.row1.y + \
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MAT1.row2.z * MAT2.row2.y + MAT1.row2.w * MAT2.row3.y, \
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.row2.z = MAT1.row2.x * MAT2.row0.z + MAT1.row2.y * MAT2.row1.z + \
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MAT1.row2.z * MAT2.row2.z + MAT1.row2.w * MAT2.row3.z, \
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.row2.w = MAT1.row2.x * MAT2.row0.w + MAT1.row2.y * MAT2.row1.w + \
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MAT1.row2.z * MAT2.row2.w + MAT1.row2.w * MAT2.row3.w, \
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.row3.x = MAT1.row3.x * MAT2.row0.x + MAT1.row3.y * MAT2.row1.x + \
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MAT1.row3.z * MAT2.row2.x + MAT1.row3.w * MAT2.row3.x, \
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.row3.y = MAT1.row3.x * MAT2.row0.y + MAT1.row3.y * MAT2.row1.y + \
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MAT1.row3.z * MAT2.row2.y + MAT1.row3.w * MAT2.row3.y, \
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.row3.z = MAT1.row3.x * MAT2.row0.z + MAT1.row3.y * MAT2.row1.z + \
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MAT1.row3.z * MAT2.row2.z + MAT1.row3.w * MAT2.row3.z, \
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.row3.w = MAT1.row3.x * MAT2.row0.w + MAT1.row3.y * MAT2.row1.w + \
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MAT1.row3.z * MAT2.row2.w + MAT1.row3.w * MAT2.row3.w, \
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})
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#define mat4x4_mul_vec4(MAT, V) \
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((V4f){ \
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.x = MAT.row0.x * V.x + MAT.row0.y * V.y + MAT.row0.z * V.z + \
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MAT.row0.w * V.w, \
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.y = MAT.row1.x * V.x + MAT.row1.y * V.y + MAT.row1.z * V.z + \
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MAT.row1.w * V.w, \
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.z = MAT.row2.x * V.x + MAT.row2.y * V.y + MAT.row2.z * V.z + \
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MAT.row2.w * V.w, \
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.w = MAT.row3.x * V.x + MAT.row3.y * V.y + MAT.row3.z * V.z + \
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MAT.row3.w * V.w, \
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})
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#define project_vec4(V) ((V3f){.x = V.x / V.w, .y = V.y / V.w, .z = V.z / V.w})
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typedef struct triangle_bbox TriangleBBox;
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struct triangle_bbox {
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u64 x0;
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u64 y0;
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u64 x1;
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u64 y1;
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};
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internal void render_triangle(const Triangle *triangle, const Model *model,
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Render *render, Colour colour, RenderType type,
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ProjectionType projection, M4x4f mv);
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internal void fill_triangle(Render *render, V3f vertices[TRIANGLE_VERTICES],
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V3f normals[TRIANGLE_VERTICES],
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V2f coordinates[TRIANGLE_VERTICES], Colour colour,
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Image *texture, RenderType type);
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internal M4x4f lookat(V3f eye, V3f target, V3f up);
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internal TriangleBBox get_triangle_bbox(const Image *img,
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V3f vertices[TRIANGLE_VERTICES]);
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internal V3f get_barycentric_coords(f32 d00, f32 d01, f32 d11, f32 denom,
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const V2i *ab, const V2i *ac,
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const V2i *ap);
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internal void get_image_coordinates(f32 norm_x, f32 norm_y, const Image *img,
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u64 *x, u64 *y);
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internal u64 ndc_to_image_coordinate(f32 value, u64 max);
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V3f g_light_dir = {0.0f, 0.0f, 1.0f};
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// clang-format off
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M4x4f g_cam_matrix = {
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.row0 = {1.0f, 0.0f, 0.0f, 0.0f},
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.row1 = {0.0f, 1.0f, 0.0f, 0.0f},
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.row2 = {0.0f, 0.0f, 1.0f, 0.0f},
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.row3 = {0.0f, 0.0f, -1.0f / CAMERA_DISTANCE, 1.0f},
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};
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// clang-format on
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V3f g_eye = {0.2f, 0.1f, 0.7f};
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V3f g_target = {0};
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V3f g_up = {0.0f, 1.0f, 0.0f};
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Model load_obj_file(Arena *arena, const char *filename, const char *texture) {
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if (!arena) {
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return INVALID_MODEL;
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}
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FILE *fp = fopen(filename, "r");
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if (!fp) {
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return INVALID_MODEL;
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}
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Model model = (Model){
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.vertices = list_create(V3f, arena),
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.normals = list_create(V3f, arena),
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.texture_coordinates = list_create(V2f, arena),
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.triangles = list_create(Triangle, arena),
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};
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if (!(model.vertices) || !(model.normals) || !(model.texture_coordinates) ||
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!(model.triangles)) {
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return INVALID_MODEL;
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}
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char line[8192];
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char identifier[8];
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V3f vertex;
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V3f normal;
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V2f coord;
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Triangle triangle;
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f32 vx, vy, vz;
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f32 nx, ny, nz;
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f32 u, v;
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u64 fp0, fp1, fp2;
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u64 vn0, vn1, vn2;
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u64 tx0, tx1, tx2;
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while (fgets(line, 8191, fp) != NULL) {
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sscanf(line, "%s", identifier);
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if (strncmp(identifier, "v", 8) == 0) {
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sscanf(line + 2, "%f %f %f", &vx, &vy, &vz);
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vertex.x = vx;
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vertex.y = vy;
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vertex.z = vz;
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list_append(V3f, arena, model.vertices, vertex);
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} else if (strncmp(identifier, "vn", 8) == 0) {
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sscanf(line + 2, "%f %f %f", &nx, &ny, &nz);
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normal.x = nx;
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normal.y = ny;
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normal.z = nz;
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list_append(V3f, arena, model.normals, normal);
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} else if (strncmp(identifier, "vt", 8) == 0) {
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sscanf(line + 2, "%f %f", &u, &v);
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coord.u = u;
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coord.v = v;
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list_append(V2f, arena, model.texture_coordinates, coord);
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} else if (strncmp(identifier, "f", 8) == 0) {
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sscanf(line + 2, "%lu/%lu/%lu %lu/%lu/%lu %lu/%lu/%lu", &fp0, &tx0, &vn0,
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&fp1, &tx1, &vn1, &fp2, &tx2, &vn2);
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// OBJ indices start from 1
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triangle.p0 = fp0 - 1;
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triangle.p1 = fp1 - 1;
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triangle.p2 = fp2 - 1;
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triangle.n0 = vn0 - 1;
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triangle.n1 = vn1 - 1;
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triangle.n2 = vn2 - 1;
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triangle.tx0 = tx0 - 1;
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triangle.tx1 = tx1 - 1;
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triangle.tx2 = tx2 - 1;
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list_append(Triangle, arena, model.triangles, triangle);
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}
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}
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if (texture) {
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model.texture = load_p6_image(arena, texture);
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}
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return model;
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}
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bool init_render(Arena *arena, Render *render, u64 width, u64 height) {
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render->img = (Image){.width = width, .height = height};
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if (!init_buffer(arena, &(render->img))) {
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return false;
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}
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render->depth = (Depth){.width = width, .height = height};
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if (!init_buffer(arena, &(render->depth))) {
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return false;
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}
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f32 inf = -INFINITY;
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clear_buffer(&(render->depth), &inf);
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return true;
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}
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void render_model(const Model *model, Render *render, Colour colour,
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RenderType type, ColourType colour_type,
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ProjectionType projection) {
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Triangle triangle;
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M4x4f model_view = lookat(g_eye, g_target, g_up);
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for (u64 i = 0; i < model->triangles->count; ++i) {
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triangle = list_get(model->triangles, i);
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if (colour_type == COLOUR_TYPE_RANDOM) {
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colour = (Colour){.r = rand() % UINT8_MAX,
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.g = rand() % UINT8_MAX,
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.b = rand() % UINT8_MAX,
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.a = 255};
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}
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render_triangle(&triangle, model, render, colour, type, projection,
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model_view);
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}
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}
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internal void render_triangle(const Triangle *triangle, const Model *model,
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Render *render, Colour colour, RenderType type,
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ProjectionType projection, M4x4f mv) {
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Image *img = &(render->img);
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V3f vertices[TRIANGLE_VERTICES] = {
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list_get(model->vertices, triangle->p0),
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list_get(model->vertices, triangle->p1),
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list_get(model->vertices, triangle->p2),
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};
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V3f normals[TRIANGLE_VERTICES] = {
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list_get(model->normals, triangle->n0),
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list_get(model->normals, triangle->n1),
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list_get(model->normals, triangle->n2),
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};
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V2f coordinates[TRIANGLE_VERTICES] = {
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list_get(model->texture_coordinates, triangle->tx0),
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list_get(model->texture_coordinates, triangle->tx1),
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list_get(model->texture_coordinates, triangle->tx2),
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};
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// Camera
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for (u64 i = 0; i < TRIANGLE_VERTICES; ++i) {
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V4f vertex;
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vertex = (V4f){
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.x = vertices[i].x,
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.y = vertices[i].y,
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.z = vertices[i].z,
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.w = 1.0f,
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};
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vertex = mat4x4_mul_vec4(mv, vertex);
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vertices[i] = project_vec4(vertex);
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}
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// Basic perspective projection
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if (projection == PROJECTION_TYPE_PERSPECTIVE) {
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V4f vertex;
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for (u64 i = 0; i < TRIANGLE_VERTICES; ++i) {
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vertex = (V4f){
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.x = vertices[i].x,
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.y = vertices[i].y,
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.z = vertices[i].z,
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.w = 1.0f,
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};
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vertex = mat4x4_mul_vec4(g_cam_matrix, vertex);
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vertices[i] = project_vec4(vertex);
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}
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}
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if (type == RENDER_TYPE_WIREFRAME) {
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V3f v0, v1;
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u64 x0, y0, x1, y1;
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for (u64 i = 0; i < TRIANGLE_VERTICES; ++i) {
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v0 = vertices[i];
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v1 = vertices[(i + 1) % TRIANGLE_VERTICES];
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get_image_coordinates(v0.x, v0.y, img, &x0, &y0);
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get_image_coordinates(v1.x, v1.y, img, &x1, &y1);
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draw_line(img, x0, y0, x1, y1, colour);
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}
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} else if (type == RENDER_TYPE_FILLED || type == RENDER_TYPE_SHADED) {
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fill_triangle(render, vertices, normals, coordinates, colour,
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model->texture, type);
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}
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}
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internal void fill_triangle(Render *render, V3f vertices[TRIANGLE_VERTICES],
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V3f normals[TRIANGLE_VERTICES],
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V2f coordinates[TRIANGLE_VERTICES], Colour colour,
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Image *texture, RenderType type) {
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Image *img = &(render->img);
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Depth *depth = &(render->depth);
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TriangleBBox bbox = get_triangle_bbox(img, vertices);
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V2u v0, v1, v2;
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get_image_coordinates(vertices[0].x, vertices[0].y, img, &(v0.x), &(v0.y));
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get_image_coordinates(vertices[1].x, vertices[1].y, img, &(v1.x), &(v1.y));
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get_image_coordinates(vertices[2].x, vertices[2].y, img, &(v2.x), &(v2.y));
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V2i ab = V2(V2i, i64, v0.x, v0.y, v1.x, v1.y);
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V2i ac = V2(V2i, i64, v0.x, v0.y, v2.x, v2.y);
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f32 d00 = dot_v2(ab, ab);
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f32 d01 = dot_v2(ab, ac);
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f32 d11 = dot_v2(ac, ac);
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f32 denom = d00 * d11 - d01 * d01;
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V2i ap;
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V3f coords;
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f32 z;
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f32 zbuf;
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f32 nx, ny, nz;
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V3f normal;
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f32 tx_u, tx_v;
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u64 tx_x, tx_y;
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f32 intensity = 1.0f;
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for (u64 y = bbox.y0; y <= bbox.y1; ++y) {
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for (u64 x = bbox.x0; x <= bbox.x1; ++x) {
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ap = V2(V2i, i64, v0.x, v0.y, x, y);
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coords = get_barycentric_coords(d00, d01, d11, denom, &ab, &ac, &ap);
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if (coords.x < 0.0f || coords.y < 0.0f || coords.x + coords.y > 1.0f) {
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continue;
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}
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z = 0.0f;
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z += vertices[0].z * coords.x + vertices[1].z * coords.y +
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vertices[2].z * coords.z;
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zbuf = get_pixel(f32, &(render->depth), x, y);
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if (z > zbuf) {
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if (type == RENDER_TYPE_SHADED) {
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nx = normals[0].x * coords.x + normals[1].x * coords.y +
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normals[2].x * coords.z;
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ny = normals[0].y * coords.x + normals[1].y * coords.y +
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normals[2].y * coords.z;
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nz = normals[0].z * coords.x + normals[1].z * coords.y +
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normals[2].z * coords.z;
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normal = (V3f){nx, ny, nz};
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intensity = dot_v3(normal, g_light_dir);
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}
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if (intensity < 0.0f) {
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intensity = 0.01f;
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}
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if (texture) {
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tx_u = coordinates[0].u * coords.x + coordinates[1].u * coords.y +
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coordinates[2].u * coords.z;
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tx_v = coordinates[0].v * coords.x + coordinates[1].v * coords.y +
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coordinates[2].v * coords.z;
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tx_x = tx_u * texture->width;
|
|
tx_y = (1.0f - tx_v) * texture->height;
|
|
|
|
colour = get_pixel(Colour, texture, tx_x, tx_y);
|
|
}
|
|
|
|
colour.r *= intensity;
|
|
colour.g *= intensity;
|
|
colour.b *= intensity;
|
|
|
|
set_pixel(depth, x, y, &z);
|
|
set_pixel(img, x, y, &colour);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
internal M4x4f lookat(V3f eye, V3f target, V3f up) {
|
|
V3f z = V3(V3f, f32, target.x, target.y, target.z, eye.x, eye.y, eye.z);
|
|
normalise_v3(z);
|
|
V3f x = cross_product(up, z);
|
|
normalise_v3(x);
|
|
V3f y = cross_product(z, x);
|
|
normalise_v3(y);
|
|
|
|
M4x4f rotation = mat4x4_identity;
|
|
rotation.row0.x = x.x;
|
|
rotation.row0.y = x.y;
|
|
rotation.row0.z = x.z;
|
|
rotation.row1.x = y.x;
|
|
rotation.row1.y = y.y;
|
|
rotation.row1.z = y.z;
|
|
rotation.row2.x = z.x;
|
|
rotation.row2.y = z.y;
|
|
rotation.row2.z = z.z;
|
|
|
|
M4x4f translation = mat4x4_identity;
|
|
translation.row0.w = -(eye.x);
|
|
translation.row1.w = -(eye.y);
|
|
translation.row2.w = -(eye.z);
|
|
|
|
return mat4x4_mul(rotation, translation);
|
|
}
|
|
|
|
internal TriangleBBox get_triangle_bbox(const Image *img,
|
|
V3f vertices[TRIANGLE_VERTICES]) {
|
|
f32 x0 = min(vertices[0].x, min(vertices[1].x, vertices[2].x));
|
|
f32 x1 = max(vertices[0].x, max(vertices[1].x, vertices[2].x));
|
|
// NOTE (Abdelrahman): Because y is flipped, we use max for the minimum and
|
|
// min for the maximum
|
|
f32 y0 = max(vertices[0].y, max(vertices[1].y, vertices[2].y));
|
|
f32 y1 = min(vertices[0].y, min(vertices[1].y, vertices[2].y));
|
|
|
|
TriangleBBox bbox = {0};
|
|
get_image_coordinates(x0, y0, img, &(bbox.x0), &(bbox.y0));
|
|
get_image_coordinates(x1, y1, img, &(bbox.x1), &(bbox.y1));
|
|
|
|
return bbox;
|
|
}
|
|
|
|
internal V3f get_barycentric_coords(f32 d00, f32 d01, f32 d11, f32 denom,
|
|
const V2i *ab, const V2i *ac,
|
|
const V2i *ap) {
|
|
if (denom == 0.0f) {
|
|
return (V3f){-INFINITY, -INFINITY, -INFINITY};
|
|
}
|
|
|
|
f32 d20 = dot_v2((*ap), (*ab));
|
|
f32 d21 = dot_v2((*ap), (*ac));
|
|
|
|
f32 v = (d11 * d20 - d01 * d21) / denom;
|
|
f32 w = (d00 * d21 - d01 * d20) / denom;
|
|
f32 u = 1.0f - v - w;
|
|
|
|
return (V3f){v, w, u};
|
|
}
|
|
|
|
internal void get_image_coordinates(f32 norm_x, f32 norm_y, const Image *img,
|
|
u64 *x, u64 *y) {
|
|
*x = ndc_to_image_coordinate(norm_x, img->width);
|
|
*y = ndc_to_image_coordinate(0.0f - norm_y, img->height);
|
|
|
|
if (*x >= img->width) {
|
|
*x = img->width - 1;
|
|
}
|
|
if (*y >= img->height) {
|
|
*y = img->height - 1;
|
|
}
|
|
}
|
|
|
|
internal u64 ndc_to_image_coordinate(f32 value, u64 max) {
|
|
f32 result = (value + 1.0f) * max * 0.5f;
|
|
return clamp((u64)result, 0, max);
|
|
}
|