ref: 6fcd6697335c8180e4571e435eb68d9fc22540e7
dir: /src/render_software.c/
#include "system.h"
#include "render.h"
#include "mem.h"
#include "utils.h"
#include "platform.h"
#define NEAR_PLANE 16.0
#define FAR_PLANE (RENDER_FADEOUT_FAR)
#define TEXTURES_MAX 1024
typedef struct {
vec2i_t size;
rgba_t *pixels;
} render_texture_t;
static void line(vec2i_t p0, vec2i_t p1, rgba_t color);
static rgba_t *screen_buffer;
static int32_t screen_pitch;
static int32_t screen_ppr;
static vec2i_t screen_size;
static mat4_t view_mat = mat4_identity();
static mat4_t mvp_mat = mat4_identity();
static mat4_t projection_mat = mat4_identity();
static mat4_t sprite_mat = mat4_identity();
static render_texture_t textures[TEXTURES_MAX];
static uint32_t textures_len;
uint16_t RENDER_NO_TEXTURE;
void render_init(vec2i_t screen_size) {
render_set_screen_size(screen_size);
textures_len = 0;
rgba_t white_pixels[4] = {
rgba(128,128,128,255), rgba(128,128,128,255),
rgba(128,128,128,255), rgba(128,128,128,255)
};
RENDER_NO_TEXTURE = render_texture_create(2, 2, white_pixels);
}
void render_cleanup() {}
void render_set_screen_size(vec2i_t size) {
screen_size = size;
float aspect = (float)size.x / (float)size.y;
float fov = (73.75 / 180.0) * 3.14159265358;
float f = 1.0 / tan(fov / 2);
float nf = 1.0 / (NEAR_PLANE - FAR_PLANE);
projection_mat = mat4(
f / aspect, 0, 0, 0,
0, f, 0, 0,
0, 0, (FAR_PLANE + NEAR_PLANE) * nf, -1,
0, 0, 2 * FAR_PLANE * NEAR_PLANE * nf, 0
);
}
void render_set_resolution(render_resolution_t res) {}
void render_set_post_effect(render_post_effect_t post) {}
vec2i_t render_size() {
return screen_size;
}
void render_frame_prepare() {
screen_buffer = platform_get_screenbuffer(&screen_pitch);
screen_ppr = screen_pitch / sizeof(rgba_t);
rgba_t color = rgba(0, 0, 0, 255);
for (uint32_t y = 0; y < screen_size.y; y++) {
for (uint32_t x = 0; x < screen_size.x; x++) {
screen_buffer[y * screen_ppr + x] = color;
}
}
}
void render_frame_end() {}
void render_set_view(vec3_t pos, vec3_t angles) {
view_mat = mat4_identity();
mat4_set_translation(&view_mat, vec3(0, 0, 0));
mat4_set_roll_pitch_yaw(&view_mat, vec3(angles.x, -angles.y + M_PI, angles.z + M_PI));
mat4_translate(&view_mat, vec3_inv(pos));
mat4_set_yaw_pitch_roll(&sprite_mat, vec3(-angles.x, angles.y - M_PI, 0));
render_set_model_mat(&mat4_identity());
}
void render_set_view_2d() {
float near = -1;
float far = 1;
float left = 0;
float right = screen_size.x;
float bottom = screen_size.y;
float top = 0;
float lr = 1 / (left - right);
float bt = 1 / (bottom - top);
float nf = 1 / (near - far);
mvp_mat = mat4(
-2 * lr, 0, 0, 0,
0, -2 * bt, 0, 0,
0, 0, 2 * nf, 0,
(left + right) * lr, (top + bottom) * bt, (far + near) * nf, 1
);
}
void render_set_model_mat(mat4_t *m) {
mat4_t vm_mat;
mat4_mul(&vm_mat, &view_mat, m);
mat4_mul(&mvp_mat, &projection_mat, &vm_mat);
}
void render_set_depth_write(bool enabled) {}
void render_set_depth_test(bool enabled) {}
void render_set_depth_offset(float offset) {}
void render_set_screen_position(vec2_t pos) {}
void render_set_blend_mode(render_blend_mode_t mode) {}
void render_set_cull_backface(bool enabled) {}
vec3_t render_transform(vec3_t pos) {
return vec3_transform(vec3_transform(pos, &view_mat), &projection_mat);
}
void render_push_tris(tris_t tris, uint16_t texture_index) {
float w2 = screen_size.x * 0.5;
float h2 = screen_size.y * 0.5;
vec3_t p0 = vec3_transform(tris.vertices[0].pos, &mvp_mat);
vec3_t p1 = vec3_transform(tris.vertices[1].pos, &mvp_mat);
vec3_t p2 = vec3_transform(tris.vertices[2].pos, &mvp_mat);
if (p0.z >= 1.0 || p1.z >= 1.0 || p2.z >= 1.0) {
return;
}
vec2i_t sc0 = vec2i(p0.x * w2 + w2, h2 - p0.y * h2);
vec2i_t sc1 = vec2i(p1.x * w2 + w2, h2 - p1.y * h2);
vec2i_t sc2 = vec2i(p2.x * w2 + w2, h2 - p2.y * h2);
rgba_t color = tris.vertices[0].color;
color.as_rgba.r = min(color.as_rgba.r * 2, 255);
color.as_rgba.g = min(color.as_rgba.g * 2, 255);
color.as_rgba.b = min(color.as_rgba.b * 2, 255);
color.as_rgba.a = clamp(color.as_rgba.a * (1.0-p0.z) * FAR_PLANE * (2.0/255.0), 0, 255);
line(sc0, sc1, color);
line(sc1, sc2, color);
line(sc2, sc0, color);
}
void render_push_sprite(vec3_t pos, vec2i_t size, rgba_t color, uint16_t texture_index) {
error_if(texture_index >= textures_len, "Invalid texture %d", texture_index);
vec3_t p0 = vec3_add(pos, vec3_transform(vec3(-size.x * 0.5, -size.y * 0.5, 0), &sprite_mat));
vec3_t p1 = vec3_add(pos, vec3_transform(vec3( size.x * 0.5, -size.y * 0.5, 0), &sprite_mat));
vec3_t p2 = vec3_add(pos, vec3_transform(vec3(-size.x * 0.5, size.y * 0.5, 0), &sprite_mat));
vec3_t p3 = vec3_add(pos, vec3_transform(vec3( size.x * 0.5, size.y * 0.5, 0), &sprite_mat));
render_texture_t *t = &textures[texture_index];
render_push_tris((tris_t){
.vertices = {
{.pos = p0, .uv = {0, 0}, .color = color},
{.pos = p1, .uv = {0 + t->size.x ,0}, .color = color},
{.pos = p2, .uv = {0, 0 + t->size.y}, .color = color},
}
}, texture_index);
render_push_tris((tris_t){
.vertices = {
{.pos = p2, .uv = {0, 0 + t->size.y}, .color = color},
{.pos = p1, .uv = {0 + t->size.x, 0}, .color = color},
{.pos = p3, .uv = {0 + t->size.x, 0 + t->size.y}, .color = color},
}
}, texture_index);
}
void render_push_2d(vec2i_t pos, vec2i_t size, rgba_t color, uint16_t texture_index) {
render_push_2d_tile(pos, vec2i(0, 0), render_texture_size(texture_index), size, color, texture_index);
}
void render_push_2d_tile(vec2i_t pos, vec2i_t uv_offset, vec2i_t uv_size, vec2i_t size, rgba_t color, uint16_t texture_index) {
error_if(texture_index >= textures_len, "Invalid texture %d", texture_index);
render_push_tris((tris_t){
.vertices = {
{.pos = {pos.x, pos.y + size.y, 0}, .uv = {uv_offset.x , uv_offset.y + uv_size.y}, .color = color},
{.pos = {pos.x + size.x, pos.y, 0}, .uv = {uv_offset.x + uv_size.x, uv_offset.y}, .color = color},
{.pos = {pos.x, pos.y, 0}, .uv = {uv_offset.x , uv_offset.y}, .color = color},
}
}, texture_index);
render_push_tris((tris_t){
.vertices = {
{.pos = {pos.x + size.x, pos.y + size.y, 0}, .uv = {uv_offset.x + uv_size.x, uv_offset.y + uv_size.y}, .color = color},
{.pos = {pos.x + size.x, pos.y, 0}, .uv = {uv_offset.x + uv_size.x, uv_offset.y}, .color = color},
{.pos = {pos.x, pos.y + size.y, 0}, .uv = {uv_offset.x , uv_offset.y + uv_size.y}, .color = color},
}
}, texture_index);
}
uint16_t render_texture_create(uint32_t width, uint32_t height, rgba_t *pixels) {
error_if(textures_len >= TEXTURES_MAX, "TEXTURES_MAX reached");
uint32_t byte_size = width * height * sizeof(rgba_t);
uint16_t texture_index = textures_len;
textures[texture_index] = (render_texture_t){{width, height}, NULL};
// textures[texture_index] = (render_texture_t){{width, height}, mem_bump(byte_size)};
// memcpy(textures[texture_index].pixels, pixels, byte_size);
textures_len++;
return texture_index;
}
vec2i_t render_texture_size(uint16_t texture_index) {
error_if(texture_index >= textures_len, "Invalid texture %d", texture_index);
return textures[texture_index].size;
}
void render_texture_replace_pixels(int16_t texture_index, rgba_t *pixels) {
error_if(texture_index >= textures_len, "Invalid texture %d", texture_index);
render_texture_t *t = &textures[texture_index];
// memcpy(t->pixels, pixels, t->size.x * t->size.y * sizeof(rgba_t));
}
uint16_t render_textures_len() {
return textures_len;
}
void render_textures_reset(uint16_t len) {
error_if(len > textures_len, "Invalid texture reset len %d >= %d", len, textures_len);
textures_len = len;
}
void render_textures_dump(const char *path) {}
// -----------------------------------------------------------------------------
static inline rgba_t color_mix(rgba_t in, rgba_t out) {
return rgba(
lerp(in.as_rgba.r, out.as_rgba.r, out.as_rgba.a/255.0),
lerp(in.as_rgba.g, out.as_rgba.g, out.as_rgba.a/255.0),
lerp(in.as_rgba.b, out.as_rgba.b, out.as_rgba.a/255.0),
1
);
}
typedef enum {
CLIP_INSIDE = 0,
CLIP_LEFT = (1<<0),
CLIP_RIGHT = (1<<1),
CLIP_BOTTOM = (1<<2),
CLIP_TOP = (1<<3),
} clip_code_t;
static inline clip_code_t clip_code(vec2i_t p) {
clip_code_t cc = CLIP_INSIDE;
if (p.x < 0) {
flags_add(cc, CLIP_LEFT);
}
else if (p.x >= screen_size.x) {
flags_add(cc, CLIP_RIGHT);
}
if (p.y < 0) {
flags_add(cc, CLIP_BOTTOM);
}
else if (p.y >= screen_size.y) {
flags_add(cc, CLIP_TOP);
}
return cc;
}
static void line(vec2i_t p0, vec2i_t p1, rgba_t color) {
// Cohen Sutherland Line Clipping
clip_code_t cc0 = clip_code(p0);
clip_code_t cc1 = clip_code(p1);
bool accept = false;
vec2i_t ss = vec2i(screen_size.x-1, screen_size.y-1);
while (true) {
if (!(cc0 | cc1)) {
accept = true;
break;
}
else if (cc0 & cc1) {
break;
}
else {
vec2i_t r = p0;
clip_code_t cc_out = cc0 ? cc0 : cc1;
if (flags_is(cc_out, CLIP_TOP)) {
r.x = p0.x + (p1.x - p0.x) * (ss.y - p0.y) / (p1.y - p0.y);
r.y = ss.y;
}
else if (flags_is(cc_out, CLIP_BOTTOM)) {
r.x = p0.x + (p1.x - p0.x) * (-p0.y) / (p1.y - p0.y);
r.y = 0;
}
else if (flags_is(cc_out, CLIP_RIGHT)) {
r.y = p0.y + (p1.y - p0.y) * (ss.x - p0.x) / (p1.x - p0.x);
r.x = ss.x;
}
else if (flags_is(cc_out, CLIP_LEFT)) {
r.y = p0.y + (p1.y - p0.y) * (-p0.x) / (p1.x - p0.x);
r.x = 0;
}
if (cc_out == cc0) {
p0.x = r.x;
p0.y = r.y;
cc0 = clip_code(p0);
}
else {
p1.x = r.x;
p1.y = r.y;
cc1 = clip_code(p1);
}
}
}
if (!accept) {
return;
}
// Bresenham's line algorithm
bool steep = false;
if (abs(p0.x - p1.x) < abs(p0.y - p1.y)) {
swap(p0.x, p0.y);
swap(p1.x, p1.y);
steep = true;
}
if (p0.x > p1.x) {
swap(p0.x, p1.x);
swap(p0.y, p1.y);
}
int32_t dx = p1.x - p0.x;
int32_t dy = p1.y - p0.y;
int32_t derror2 = abs(dy) * 2;
int32_t error2 = 0;
int32_t y = p0.y;
int32_t ydir = (p1.y > p0.y ? 1 : -1);
if (steep) {
for (int32_t x = p0.x; x <= p1.x; x++) {
screen_buffer[x * screen_ppr + y] = color_mix(screen_buffer[x * screen_ppr + y], color);
error2 += derror2;
if (error2 > dx) {
y += ydir;
error2 -= dx * 2;
}
}
}
else {
for (int32_t x = p0.x; x <= p1.x; x++) {
screen_buffer[y * screen_ppr + x] = color_mix(screen_buffer[y * screen_ppr + x], color);
error2 += derror2;
if (error2 > dx) {
y += ydir;
error2 -= dx * 2;
}
}
}
}