:: commit 0daf11eccae8b5f4a88d4cfcc8ac0175f43b9bcd
gterm: refactor genloop()
diff --git a/stage23/lib/gterm.c b/stage23/lib/gterm.c
index 5439852a..c15b71a2 100644
--- a/stage23/lib/gterm.c
+++ b/stage23/lib/gterm.c
@@ -105,78 +105,100 @@ static uint32_t blend_gradient_from_box(int x, int y, uint32_t bg_px, uint32_t h
return colour_blend((hex & 0xffffff) | (new_alpha << 24), bg_px);
}
+typedef int fixedp6; // the last 6 bits are the fixed point part
+static int fixedp6_to_int(fixedp6 value) { return value / 64; }
+static fixedp6 int_to_fixedp6(int value) { return value * 64; }
+
// Draw rect at coordinates, copying from the image to the fb and canvas, applying fn on every pixel
-#define genloop(xstart, xend, ystart, yend, fn) \
- switch (background->type) { \
- case IMAGE_TILED: \
- for (int y = (ystart); y < (yend); y++) { \
- int yb = y % img_height, xb = (xstart) % img_width; \
- const size_t off = img_pitch * (img_height - 1 - yb), coff = gterm_width * y, goff = gterm_pitch / 4 * y; \
- for (int x = (xstart); x < (xend); x++) { \
- uint32_t i = *(uint32_t*)(img + xb * colsize + off); i = fn; /* xb = (x % img_width) */ \
- bg_canvas[coff + x] = i; gterm_framebuffer[goff + x] = i; \
- if (xb++ == img_width) xb = 0; \
- } \
- } \
- break; \
- case IMAGE_CENTERED: \
- for (int y = (ystart); y < (yend); y++) { \
- int yb = y - background->y_displacement; \
- const size_t off = img_pitch * (img_height - 1 - yb), coff = gterm_width * y, goff = gterm_pitch / 4 * y; \
- if ((yb < 0) || (yb > background->y_size)) { /* external part */ \
- for (int x = (xstart); x < (xend); x++) { \
- uint32_t i = background->back_colour; i = fn; \
- bg_canvas[coff + x] = i; gterm_framebuffer[goff + x] = i; \
- } \
- } \
- else { /* internal part */ \
- for (int x = (xstart); x < (xend); x++) { \
- int xb = (x - background->x_displacement); \
- uint32_t i = ((xb < 0) || (xb > background->x_size)) ? background->back_colour : *(uint32_t*)(img + xb * colsize + off); i = fn; \
- bg_canvas[coff + x] = i; gterm_framebuffer[goff + x] = i; \
- } \
- } \
- } \
- break; \
- case IMAGE_STRETCHED: \
- for (int y = (ystart); y < (yend); y++) { \
- int counter = x16_x_delta * (xstart); \
- const size_t imgy = (y * img_height) / gterm_height, off = img_pitch * (img_height - 1 - imgy), coff = gterm_width * y, goff = gterm_pitch / 4 * y; \
- for (int x = (xstart); x < (xend); x++) { \
- uint32_t i = *(uint32_t*)(img + (counter / 16) * colsize + off); i = fn; /* counter/16 = (x * img_width) / gterm_width */ \
- bg_canvas[coff + x] = i; gterm_framebuffer[goff + x] = i; \
- counter += x16_x_delta; \
- } \
- } \
- break; \
+__attribute__((always_inline)) static inline void genloop(int xstart, int xend, int ystart, int yend, uint32_t (*blend)(int x, int y, uint32_t orig)) {
+ uint8_t *img = background->img;
+ const int img_width = background->img_width, img_height = background->img_height, img_pitch = background->pitch, colsize = background->bpp / 8;
+
+ switch (background->type) {
+ case IMAGE_TILED:
+ for (int y = ystart; y < yend; y++) {
+ int image_y = y % img_height, image_x = xstart % img_width;
+ const size_t off = img_pitch * (img_height - 1 - image_y);
+ int canvas_off = gterm_width * y, fb_off = gterm_pitch / 4 * y;
+ for (int x = xstart; x < xend; x++) {
+ uint32_t img_pixel = *(uint32_t*)(img + image_x * colsize + off);
+ uint32_t i = blend(x, y, img_pixel);
+ bg_canvas[canvas_off + x] = i; gterm_framebuffer[fb_off + x] = i;
+ if (image_x++ == img_width) image_x = 0; // image_x = x % img_width, but modulo is too expensive
+ }
+ }
+ break;
+
+ case IMAGE_CENTERED:
+ for (int y = ystart; y < yend; y++) {
+ int image_y = y - background->y_displacement;
+ const size_t off = img_pitch * (img_height - 1 - image_y);
+ int canvas_off = gterm_width * y, fb_off = gterm_pitch / 4 * y;
+ if ((image_y < 0) || (image_y >= background->y_size)) { /* external part */
+ for (int x = xstart; x < xend; x++) {
+ uint32_t i = blend(x, y, background->back_colour);
+ bg_canvas[canvas_off + x] = i; gterm_framebuffer[fb_off + x] = i;
+ }
+ }
+ else { /* internal part */
+ for (int x = xstart; x < xend; x++) {
+ int image_x = (x - background->x_displacement);
+ bool x_external = (image_x < 0) || (image_x >= background->x_size);
+ uint32_t img_pixel = *(uint32_t*)(img + image_x * colsize + off);
+ uint32_t i = blend(x, y, x_external ? background->back_colour : img_pixel);
+ bg_canvas[canvas_off + x] = i; gterm_framebuffer[fb_off + x] = i;
+ }
+ }
+ }
+ break;
+ // For every pixel, ratio = img_width / gterm_width, img_x = x * ratio, x = (xstart + i)
+ // hence x = xstart * ratio + i * ratio
+ // so you can set x = xstart * ratio, and increment by ratio at each iteration
+ case IMAGE_STRETCHED:
+ for (int y = ystart; y < yend; y++) {
+ int img_y = y * img_width / gterm_width; // calculate Y with full precision
+ int off = img_pitch * (img_height - 1 - img_y);
+ int canvas_off = gterm_width * y, fb_off = gterm_pitch / 4 * y;
+
+ size_t ratio = int_to_fixedp6(img_width) / gterm_width;
+ fixedp6 img_x = ratio * xstart;
+ for (int x = xstart; x < xend; x++) {
+ uint32_t img_pixel = *(uint32_t*)(img + fixedp6_to_int(img_x) * colsize + off);
+ uint32_t i = blend(x, y, img_pixel);
+ bg_canvas[canvas_off + x] = i; gterm_framebuffer[fb_off + x] = i;
+ img_x += ratio;
+ }
+ }
+ break;
}
+}
+static uint32_t blend_external(int x, int y, uint32_t orig) { (void)x; (void)y; return orig; }
+static uint32_t blend_internal(int x, int y, uint32_t orig) { (void)x; (void)y; return colour_blend(ansi_colours[8], orig); }
+static uint32_t blend_margin(int x, int y, uint32_t orig) { return blend_gradient_from_box(x, y, orig, ansi_colours[8]); }
+
+static void loop_external(int xstart, int xend, int ystart, int yend) { genloop(xstart, xend, ystart, yend, blend_external); }
+static void loop_margin(int xstart, int xend, int ystart, int yend) { genloop(xstart, xend, ystart, yend, blend_margin); }
+static void loop_internal(int xstart, int xend, int ystart, int yend) { genloop(xstart, xend, ystart, yend, blend_internal); }
void gterm_generate_canvas(void) {
if (background) {
- // Instead of executing blend_gradient_from_box for every pixel in the fb, just run it for the margin
- uint8_t *img = background->img;
- const int img_width = background->img_width, x16_x_delta = (img_width * 16) / gterm_width,
- img_height = background->img_height, img_pitch = background->pitch, colsize = background->bpp / 8;
const int frame_height_end = frame_height + VGA_FONT_HEIGHT * rows, frame_width_end = frame_width + VGA_FONT_WIDTH * cols;
const int fheight = frame_height - margin_gradient, fheight_end = frame_height_end + margin_gradient,
fwidth = frame_width - margin_gradient, fwidth_end = frame_width_end + margin_gradient;
- // Draw the part of the image outside the margin
- genloop(0, gterm_width, 0, fheight, i);
- genloop(0, gterm_width, fheight_end, gterm_height, i);
- genloop(0, fwidth, fheight, fheight_end, i);
- genloop(fwidth_end, gterm_width, fheight, fheight_end, i);
+ loop_external(0, gterm_width, 0, fheight);
+ loop_external(0, gterm_width, fheight_end, gterm_height);
+ loop_external(0, fwidth, fheight, fheight_end);
+ loop_external(fwidth_end, gterm_width, fheight, fheight_end);
- // Draw margin
if (margin_gradient) {
- genloop(fwidth, fwidth_end, fheight, frame_height, blend_gradient_from_box(x, y, i, ansi_colours[8]));
- genloop(fwidth, fwidth_end, frame_height_end, fheight_end, blend_gradient_from_box(x, y, i, ansi_colours[8]));
- genloop(fwidth, frame_width, frame_height, frame_height_end, blend_gradient_from_box(x, y, i, ansi_colours[8]));
- genloop(frame_width_end, fwidth_end, frame_height, frame_height_end, blend_gradient_from_box(x, y, i, ansi_colours[8]));
+ loop_margin(fwidth, fwidth_end, fheight, frame_height);
+ loop_margin(fwidth, fwidth_end, frame_height_end, fheight_end);
+ loop_margin(fwidth, frame_width, frame_height, frame_height_end);
+ loop_margin(frame_width_end, fwidth_end, frame_height, frame_height_end);
}
- // Draw inner frame
- genloop(frame_width, frame_width_end, frame_height, frame_height_end, colour_blend(ansi_colours[8], i));
+ loop_internal(frame_width, frame_width_end, frame_height, frame_height_end);
} else {
for (int y = 0; y < gterm_height; y++) {
for (int x = 0; x < gterm_width; x++) {
