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optimize case of sequential shared radius circle drawing by reusing the geometry by just offsetting it

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This commit is contained in:
veclavtalica 2024-11-03 22:33:18 +03:00
parent e4da4a8b7f
commit 26c75ffd7c
2 changed files with 23 additions and 5 deletions
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4
apps/demos/platformer/player.c
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@ -255,6 +255,10 @@ static void drawdef(Player *player) {
draw_circle((Vec2) { 256, 128 },
24,
(Color) { 255, 0, 0, 255 });
draw_circle((Vec2) { 304, 128 },
24,
(Color) { 255, 0, 0, 255 });
}

16
src/rendering/twn_gl_15_rendering.c
View File

@ -911,12 +911,26 @@ static void load_cubemap_side(const char *path, GLenum target) {
void render_circle(const CirclePrimitive *circle) {
static Vec2 vertices[CIRCLE_VERTICES_MAX];
int num_vertices = MIN((int)circle->radius, CIRCLE_VERTICES_MAX);
static int prev_num_vertices = 0;
static Vec2 prev_position = {0};
int const num_vertices = MIN((int)circle->radius, CIRCLE_VERTICES_MAX);
if (prev_num_vertices != num_vertices) {
create_circle_geometry(circle->position,
circle->radius,
num_vertices,
vertices);
prev_num_vertices = num_vertices;
prev_position = circle->position;
} else {
/* reuse the data, but offset it by difference with previously generated position */
/* no evil cos sin ops this way, if radius is shared in sequential calls */
Vec2 const d = { prev_position.x - circle->position.x, prev_position.y - circle->position.y };
for (int i = 0; i < num_vertices; ++i)
vertices[i] = (Vec2){ vertices[i].x - d.x, vertices[i].y - d.y };
prev_position = circle->position;
}
VertexBuffer buffer = get_scratch_vertex_array();
specify_vertex_buffer(buffer, vertices, sizeof (Vec2) * num_vertices);