abdelrahman/arrow-drawing-test
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Add utility functions and fix bug when reallocating lines array

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Abdelrahman Said 2024-01-14 02:44:35 +00:00
parent e4d3024364
commit 13aadb4281
1 changed files with 40 additions and 12 deletions
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52
src/drawing.c
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@ -8,6 +8,22 @@
#define square(x) (x * x)
typedef struct line line_t;
struct line {
point_t p0;
point_t p1;
};
typedef struct triangle triangle_t;
struct triangle {
point_t p0;
point_t p1;
point_t p2;
};
INTERNAL void draw_line(SDL_Renderer *renderer, line_t ln);
INTERNAL void draw_triangle(SDL_Renderer *renderer, triangle_t triangle);
bool init_arrows_arr(arrows_t *lines, u64 capacity) {
u64 size = capacity * sizeof(arrow_t);
@ -36,6 +52,8 @@ void add_arrow(arrows_t *lines, arrow_t ln) {
lines->lines = ptr;
return;
}
lines->capacity = new_capacity;
}
lines->lines[(lines->count)++] = (arrow_t){
@ -57,8 +75,9 @@ INTERNAL f32 vec2_magnitude(const vec2_t *vec) {
return sqrtf((f32)vec->x * vec->x + (f32)vec->y * vec->y);
}
INTERNAL void draw_arrow_head(SDL_Renderer *renderer, const arrow_t *arrow,
const point_t *arrow_end) {
INTERNAL triangle_t calculate_arrow_head(SDL_Renderer *renderer,
const arrow_t *arrow,
const point_t *arrow_end) {
// m = line_slope
// dx = change_in_x
// dy = change_in_y
@ -129,14 +148,7 @@ INTERNAL void draw_arrow_head(SDL_Renderer *renderer, const arrow_t *arrow,
arrow_base_p1.y = arrow_end->y + perpendicular_dy;
}
SDL_RenderDrawLine(renderer, arrow_end->x, arrow_end->y, arrow_base_p0.x,
arrow_base_p0.y);
SDL_RenderDrawLine(renderer, arrow_end->x, arrow_end->y, arrow_base_p1.x,
arrow_base_p1.y);
SDL_RenderDrawLine(renderer, arrow_tip.x, arrow_tip.y, arrow_base_p0.x,
arrow_base_p0.y);
SDL_RenderDrawLine(renderer, arrow_tip.x, arrow_tip.y, arrow_base_p1.x,
arrow_base_p1.y);
return (triangle_t){arrow_tip, arrow_base_p0, arrow_base_p1};
}
void draw_arrow(SDL_Renderer *renderer, const arrow_t *arrow, colour_t colour) {
@ -147,10 +159,26 @@ void draw_arrow(SDL_Renderer *renderer, const arrow_t *arrow, colour_t colour) {
arrow->origin.x + arrow->direction.x,
arrow->origin.y + arrow->direction.y,
};
line_t line = (line_t){arrow->origin, end};
if (vec2_magnitude(&(arrow->direction)) != 0) {
draw_arrow_head(renderer, arrow, &end);
triangle_t triangle = calculate_arrow_head(renderer, arrow, &end);
draw_triangle(renderer, triangle);
}
SDL_RenderDrawLine(renderer, arrow->origin.x, arrow->origin.y, end.x, end.y);
draw_line(renderer, line);
}
INTERNAL void draw_line(SDL_Renderer *renderer, line_t ln) {
SDL_RenderDrawLine(renderer, ln.p0.x, ln.p0.y, ln.p1.x, ln.p1.y);
}
INTERNAL void draw_triangle(SDL_Renderer *renderer, triangle_t triangle) {
line_t ln0 = (line_t){triangle.p0, triangle.p1};
line_t ln1 = (line_t){triangle.p0, triangle.p2};
line_t ln2 = (line_t){triangle.p1, triangle.p2};
draw_line(renderer, ln0);
draw_line(renderer, ln1);
draw_line(renderer, ln2);
}