add an overdraw buffer to allow for layered rendering

include/dangerzone/engine.h

@@ -4,13 +4,22 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+typedef enum {
+    BASE,
+    OVERDRAW
+} framebuffer_e;
+
 typedef struct {
 	SDL_Event event;
 	bool is_running;
-	bool framebuffer_dirty;
+	bool framebuffer_base_dirty;
+	bool framebuffer_overdraw_dirty;
 	SDL_Rect dirty_rect;
 	uint16_t width, height;
-	uint32_t *framebuffer;
+    // base layer ~ layer 0
+	uint32_t *framebuffer_base; 
+    // layer on top of that ~ layer 1
+    uint32_t *framebuffer_overdraw; 
 } game_state_t;
 
 extern game_state_t *game_state;
@@ -28,4 +37,4 @@ void
 engine_start();
 
 void
-engine_stop();
+engine_stop();

include/dangerzone/render/anim.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <stdint.h>
+
+/**
+ * animate a rectangle's position changing over time
+ * => x0 -> x1, y0 -> y1, all else stays the same
+ */
+void
+anim_rect_pos(
+    uint32_t x0,
+    uint32_t y0,
+    uint32_t x1,
+    uint32_t y1,
+    uint32_t w,
+    uint32_t h,
+    uint32_t color
+);

include/dangerzone/render/misc.h

@@ -1,9 +1,12 @@
 #pragma once
 
+#include <dangerzone/engine.h>
+
 #include <stdint.h>
 
 void 
 put_pixel(
+    framebuffer_e framebuffer,
 	unsigned int x, 
 	unsigned int y, 
 	uint32_t color
@@ -11,5 +14,6 @@ put_pixel(
 
 void 
 clear_framebuffer(
+    framebuffer_e framebuffer,
 	uint32_t color
-);
+);

include/dangerzone/render/rect.h

@@ -1,9 +1,12 @@
 #pragma once
 
+#include <dangerzone/engine.h>
+
 #include <stdint.h>
 
 void
 put_rect(
+    framebuffer_e framebuffer,
 	uint32_t x, 
 	uint32_t y, 
 	uint32_t w, 
@@ -11,8 +14,9 @@ put_rect(
 	uint32_t color
 );
 
+// TODO: remove, deprecated, you can use put_rect for the same thing
 void
 clear_rect(int x, int y, int w, int h, uint32_t color);
 
 void
-mark_dirty_rect(int x, int y, int w, int h);
+mark_dirty_rect(int x, int y, int w, int h);

include/dangerzone/render/text.h

@@ -1,9 +1,12 @@
 #pragma once
 
+#include <dangerzone/engine.h>
+
 #include <stdint.h>
 
 void
 put_char(
+    framebuffer_e framebuffer,
 	char c,
 	uint32_t x, 
 	uint32_t y,
@@ -14,6 +17,7 @@ put_char(
 
 void
 put_string(
+    framebuffer_e framebuffer,
     const char *text,
     uint32_t x,
     uint32_t y,
@@ -22,4 +26,4 @@ put_string(
     uint32_t line_spacing,
     uint32_t fg_color,
     uint32_t bg_color
-);
+);