Improve performance of `ren_draw_rect` (#935)

We color a 1x1 `SDL_Surface` with the desired color. This surface is 
then stretched over the area we need to cover using `SDL_BlitScaled`.
This way we avoid having to do the blending ourselves.
This commit is contained in:
Guldoman 2022-04-20 23:13:42 +02:00 committed by GitHub
parent bbac7e479c
commit 1439b59d65
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1 changed files with 11 additions and 16 deletions

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@ -18,6 +18,9 @@
static RenWindow window_renderer = {0};
static FT_Library library;
// draw_rect_surface is used as a 1x1 surface to simplify ren_draw_rect with blending
static SDL_Surface *draw_rect_surface;
static void* check_alloc(void *ptr) {
if (!ptr) {
fprintf(stderr, "Fatal error: memory allocation failed\n");
@ -370,31 +373,21 @@ void ren_draw_rect(RenRect rect, RenColor color) {
y2 = y2 > clip.y + clip.height ? clip.y + clip.height : y2;
SDL_Surface *surface = renwin_get_surface(&window_renderer);
uint32_t *d = surface->pixels;
d += x1 + y1 * surface->w;
int dr = surface->w - (x2 - x1);
SDL_Rect dest_rect = { x1, y1, x2 - x1, y2 - y1 };
if (color.a == 0xff) {
uint32_t translated = SDL_MapRGB(surface->format, color.r, color.g, color.b);
SDL_Rect rect = { x1, y1, x2 - x1, y2 - y1 };
SDL_FillRect(surface, &rect, translated);
SDL_FillRect(surface, &dest_rect, translated);
} else {
RenColor current_color;
RenColor blended_color;
for (int j = y1; j < y2; j++) {
for (int i = x1; i < x2; i++, d++)
{
SDL_GetRGB(*d, surface->format, &current_color.r, &current_color.g, &current_color.b);
blended_color = blend_pixel(current_color, color);
*d = SDL_MapRGB(surface->format, blended_color.r, blended_color.g, blended_color.b);
}
d += dr;
}
uint32_t *pixel = (uint32_t *)draw_rect_surface->pixels;
*pixel = SDL_MapRGBA(draw_rect_surface->format, color.r, color.g, color.b, color.a);
SDL_BlitScaled(draw_rect_surface, NULL, surface, &dest_rect);
}
}
/*************** Window Management ****************/
void ren_free_window_resources() {
renwin_free(&window_renderer);
SDL_FreeSurface(draw_rect_surface);
}
void ren_init(SDL_Window *win) {
@ -407,6 +400,8 @@ void ren_init(SDL_Window *win) {
window_renderer.window = win;
renwin_init_surface(&window_renderer);
renwin_clip_to_surface(&window_renderer);
draw_rect_surface = SDL_CreateRGBSurface(0, 1, 1, 32,
0xFF000000, 0x00FF0000, 0x0000FF00, 0x000000FF);
}