From b34220f5df6ab917f191ee4bc0189ba85065199c Mon Sep 17 00:00:00 2001
From: iamcheeseman <dev@iamcheeseman.net>
Date: Mon, 11 May 2026 21:24:49 -0400
Subject: allow the user to change the render target

---
 teensy/teensy.h          |  2 ++
 teensy/teensy_renderer.c | 50 +++++++++++++++++++++++++++++-------------------
 2 files changed, 32 insertions(+), 20 deletions(-)

(limited to 'teensy')

diff --git a/teensy/teensy.h b/teensy/teensy.h
index 568430c..13216a8 100644
--- a/teensy/teensy.h
+++ b/teensy/teensy.h
@@ -123,6 +123,8 @@ void ty_img_set_pixel(
 void ty_font_add_glyph(struct ty_font *font, uint8_t c, struct ty_image img);
 int ty_font_width(struct ty_font *font, const char *fmt, ...);
 
+// Pass NULL to restore the screen.
+void ty_draw_set_target(const struct ty_image *img);
 void ty_draw_clear(struct ty_color col);
 void ty_draw_image(struct ty_image img, struct ty_vec2i pos);
 void ty_draw_image_ex(
diff --git a/teensy/teensy_renderer.c b/teensy/teensy_renderer.c
index da35738..d457ef6 100644
--- a/teensy/teensy_renderer.c
+++ b/teensy/teensy_renderer.c
@@ -48,6 +48,7 @@ void ty_init_renderer(void)
         ctx.hints.scr_height,
         NULL
     );
+    r.target = r.screen;
 }
 
 void ty_deinit_renderer(void)
@@ -119,20 +120,29 @@ int ty_font_width(struct ty_font *font, const char *fmt, ...)
     return width;
 }
 
+void ty_draw_set_target(const struct ty_image *img)
+{
+    if (!img) {
+        r.target = r.screen;
+        return;
+    }
+    memcpy(&r.target, img, sizeof(r.target));
+}
+
 void ty_draw_clear(struct ty_color col)
 {
     assert(is_renderer_init());
-    for (int i = 0; i < r.screen.width * r.screen.height; i++) {
-        r.screen.data[i] = col;
+    for (int i = 0; i < r.target.width * r.target.height; i++) {
+        r.target.data[i] = col;
     }
 }
 
 void ty_draw_image(struct ty_image img, struct ty_vec2i pos)
 {
-    int x1 = fmin(fmax(pos.x, 0), r.screen.width);
-    int y1 = fmin(fmax(pos.y, 0), r.screen.height);
-    int x2 = fmin(fmax(pos.x + img.width, 0), r.screen.width);
-    int y2 = fmin(fmax(pos.y + img.height, 0), r.screen.height);
+    int x1 = fmin(fmax(pos.x, 0), r.target.width);
+    int y1 = fmin(fmax(pos.y, 0), r.target.height);
+    int x2 = fmin(fmax(pos.x + img.width, 0), r.target.width);
+    int y2 = fmin(fmax(pos.y + img.height, 0), r.target.height);
 
     for (int dy = y1; dy < y2; dy++) {
         for (int dx = x1; dx < x2; dx++) {
@@ -143,7 +153,7 @@ void ty_draw_image(struct ty_image img, struct ty_vec2i pos)
             if (memcmp(&px, &BLEND_COLOR, sizeof(px)) == 0)
                 continue;
             ty_img_set_pixel(
-                r.screen,
+                r.target,
                 ty_vec2i(dx, dy),
                 px
             );
@@ -156,10 +166,10 @@ void ty_draw_image_ex(
     struct ty_recti src,
     struct ty_recti dst
 ) {
-    int x1 = fmin(fmax(dst.x, 0), r.screen.width);
-    int y1 = fmin(fmax(dst.y, 0), r.screen.height);
-    int x2 = fmin(fmax(dst.x + dst.w, 0), r.screen.width);
-    int y2 = fmin(fmax(dst.y + dst.h, 0), r.screen.height);
+    int x1 = fmin(fmax(dst.x, 0), r.target.width);
+    int y1 = fmin(fmax(dst.y, 0), r.target.height);
+    int x2 = fmin(fmax(dst.x + dst.w, 0), r.target.width);
+    int y2 = fmin(fmax(dst.y + dst.h, 0), r.target.height);
 
     for (int dy = y1; dy < y2; dy++) {
         for (int dx = x1; dx < x2; dx++) {
@@ -170,7 +180,7 @@ void ty_draw_image_ex(
                 continue;
 
             ty_img_set_pixel(
-                r.screen,
+                r.target,
                 ty_vec2i(dx, dy),
                 px
             );
@@ -210,23 +220,23 @@ void ty_draw_image_rot(
                 continue;
 
             struct ty_color px = ty_img_get_pixel(img, ty_vec2i(dx, dy));
-            ty_img_set_pixel(r.screen, ty_vec2i(pos.x + img_x, pos.y + img_y), px);
+            ty_img_set_pixel(r.target, ty_vec2i(pos.x + img_x, pos.y + img_y), px);
         }
     }
 }
 
 void ty_draw_rect(struct ty_recti rect, struct ty_color color)
 {
-    int x1 = fmin(fmax(rect.x, 0), r.screen.width);
-    int y1 = fmin(fmax(rect.y, 0), r.screen.height);
+    int x1 = fmin(fmax(rect.x, 0), r.target.width);
+    int y1 = fmin(fmax(rect.y, 0), r.target.height);
 
-    int x2 = fmin(fmax(rect.x + rect.w, 0), r.screen.width);
-    int y2 = fmin(fmax(rect.y + rect.h, 0), r.screen.height);
+    int x2 = fmin(fmax(rect.x + rect.w, 0), r.target.width);
+    int y2 = fmin(fmax(rect.y + rect.h, 0), r.target.height);
 
     for (int dy = y1; dy < y2; dy++) {
         for (int dx = x1; dx < x2; dx++) {
             ty_img_set_pixel(
-                r.screen,
+                r.target,
                 ty_vec2i(dx, dy),
                 color
             );
@@ -257,7 +267,7 @@ void ty_draw_line(
             int y = start.y + dy * (x - start.x) / dx;
 
             ty_img_set_pixel(
-                r.screen,
+                r.target,
                 ty_vec2i(x, y),
                 color
             );
@@ -277,7 +287,7 @@ void ty_draw_line(
             int x = start.x + dx * (y - start.y) / dy;
 
             ty_img_set_pixel(
-                r.screen,
+                r.target,
                 ty_vec2i(x, y),
                 color
             );
-- 
cgit v1.3-2-g0d8e