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fix circle rendering over new impl

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veclav talica
2024-10-19 19:16:18 +03:00
parent 399b199266
commit a7b09b9f39
4 changed files with 24 additions and 12 deletions
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20
src/rendering/twn_circles.c
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@ -27,8 +27,10 @@ void create_circle_geometry(Vec2 position,
size_t num_vertices,
Vec2 vertices[])
{
SDL_assert(num_vertices <= CIRCLE_VERTICES_MAX);
/* the angle (in radians) to rotate by on each iteration */
float seg_rotation_angle = (360.0f / (float)num_vertices) * ((float)M_PI / 180);
float seg_rotation_angle = (360.0f / (float)(num_vertices - 2)) * ((float)M_PI / 180);
vertices[0].x = (float)position.x;
vertices[0].y = (float)position.y;
@ -37,7 +39,7 @@ void create_circle_geometry(Vec2 position,
float start_x = 0.0f - radius;
float start_y = 0.0f;
for (size_t i = 1; i < num_vertices + 1; ++i) {
for (size_t i = 1; i < num_vertices - 1; ++i) {
float final_seg_rotation_angle = (float)i * seg_rotation_angle;
float c, s;
@ -49,4 +51,18 @@ void create_circle_geometry(Vec2 position,
vertices[i].x += position.x;
vertices[i].y += position.y;
}
// place a redundant vertex to make proper circling over shared element buffer
{
float final_seg_rotation_angle = (float)1 * seg_rotation_angle;
float c, s;
sincosf(final_seg_rotation_angle, &s, &c);
vertices[num_vertices - 1].x = c * start_x - s * start_y;
vertices[num_vertices - 1].y = c * start_y + s * start_x;
vertices[num_vertices - 1].x += position.x;
vertices[num_vertices - 1].y += position.y;
}
}