update README with text

Makefile

@@ -3,13 +3,14 @@ LIBS := `pkg-config --libs sdl3`
 INC := `pkg-config --cflags sdl3` -I./include
 SRC := src/engine/engine.c \
 	src/engine/engine_init.c \
-	src/engine/render.c
+	src/engine/render.c \
+	src/engine/text.c
 OUT := build/main
 SNAKE_SRC := src/examples/snake.c $(SRC)
 SNAKE := build/snake
 
 build:
-	$(CC) -o $(OUT) $(SRC) $(INC) $(LIBS)
+	$(CC) -o $(OUT) src/main.c $(SRC) $(INC) $(LIBS)
 
 run:
 	$(OUT)

README.md

@@ -7,7 +7,7 @@
 1. Put Pixel - Lets you color one given pixel in the framebuffer.
 
 ```c
-void put_pixel(unsigned int x, unsigned int y, uint32_t color);
+void put_pixel(uint32_t x, uint32_t y, uint32_t color);
 ```
 
 2. Clear Framebuffer - Lets you fill the entire framebuffer with one color.
@@ -16,6 +16,22 @@ void put_pixel(unsigned int x, unsigned int y, uint32_t color);
 void clear_framebuffer(uint32_t color);
 ```
 
+3. Put String - Lets you display multiline text with a size, foreground and background color on a given (x,y). You can specify the spacing between letters and lines. Supported characters are in `text.c` - feel free to add some if you want to.
+```c
+void
+put_string(
+    const char *text,
+    uint32_t x,
+    uint32_t y,
+    uint32_t size,
+    uint32_t spacing,
+    uint32_t line_spacing,
+    uint32_t fg_color,
+    uint32_t bg_color
+);
+```
+
+
 #### Usage
 
 The main function of a program that uses this engine should look something like this:

include/engine.h

@@ -11,6 +11,8 @@
 #define DEFAULT_WINDOW_NAME "Dangerzone"
 #define WINDOW_NAME_LENGTH 128
 #define TARGET_FRAME 1.0 / 60.0
+#define FONT_ROWS 7
+#define FONT_COLS 5
 
 typedef struct {
 	char window_name[WINDOW_NAME_LENGTH];
@@ -91,5 +93,19 @@ put_char(
 	char c,
 	uint32_t x, 
 	uint32_t y,
-	uint8_t size
+	uint32_t size,
+	uint32_t fg_color,
+	uint32_t bg_color
+);
+
+void
+put_string(
+    const char *text,
+    uint32_t x,
+    uint32_t y,
+    uint32_t size,
+    uint32_t spacing,
+    uint32_t line_spacing,
+    uint32_t fg_color,
+    uint32_t bg_color
 );

src/engine/render.c

@@ -1,5 +1,6 @@
 #include "engine.h"
 #include "error.h"
+#include <stdint.h>
 
 // alter a pixel at an imaginary x & y coordinates
 void 

src/engine/text.c

@@ -0,0 +1,141 @@
+// rendering characters in the framebuffer
+
+#include "engine.h"
+#include <stdint.h>
+
+/*
+ * each character has 8 rows
+ * only the lower 4 bits of each byte are used
+ */
+static const uint8_t font[128][FONT_ROWS] = {
+    [' '] = { 0, 0, 0, 0, 0, 0, 0 },
+
+    ['A'] = { 0x0E, 0x11, 0x11, 0x1F, 0x11, 0x11, 0x11 },
+    ['B'] = { 0x1E, 0x11, 0x11, 0x1E, 0x11, 0x11, 0x1E },
+    ['C'] = { 0x0F, 0x10, 0x10, 0x10, 0x10, 0x10, 0x0F },
+    ['D'] = { 0x1E, 0x11, 0x11, 0x11, 0x11, 0x11, 0x1E },
+    ['E'] = { 0x1F, 0x10, 0x10, 0x1E, 0x10, 0x10, 0x1F },
+    ['F'] = { 0x1F, 0x10, 0x10, 0x1E, 0x10, 0x10, 0x10 },
+    ['G'] = { 0x0F, 0x10, 0x10, 0x17, 0x11, 0x11, 0x0F },
+    ['H'] = { 0x11, 0x11, 0x11, 0x1F, 0x11, 0x11, 0x11 },
+    ['I'] = { 0x1F, 0x04, 0x04, 0x04, 0x04, 0x04, 0x1F },
+    ['J'] = { 0x01, 0x01, 0x01, 0x01, 0x11, 0x11, 0x0E },
+    ['K'] = { 0x11, 0x12, 0x14, 0x18, 0x14, 0x12, 0x11 },
+    ['L'] = { 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x1F },
+    ['M'] = { 0x11, 0x1B, 0x15, 0x15, 0x11, 0x11, 0x11 },
+    ['N'] = { 0x11, 0x19, 0x15, 0x13, 0x11, 0x11, 0x11 },
+    ['O'] = { 0x0E, 0x11, 0x11, 0x11, 0x11, 0x11, 0x0E },
+    ['P'] = { 0x1E, 0x11, 0x11, 0x1E, 0x10, 0x10, 0x10 },
+    ['Q'] = { 0x0E, 0x11, 0x11, 0x11, 0x15, 0x12, 0x0D },
+    ['R'] = { 0x1E, 0x11, 0x11, 0x1E, 0x14, 0x12, 0x11 },
+    ['S'] = { 0x0F, 0x10, 0x10, 0x0E, 0x01, 0x01, 0x1E },
+    ['T'] = { 0x1F, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04 },
+    ['U'] = { 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x0E },
+    ['V'] = { 0x11, 0x11, 0x11, 0x11, 0x11, 0x0A, 0x04 },
+    ['W'] = { 0x11, 0x11, 0x11, 0x15, 0x15, 0x15, 0x0A },
+    ['X'] = { 0x11, 0x11, 0x0A, 0x04, 0x0A, 0x11, 0x11 },
+    ['Y'] = { 0x11, 0x11, 0x0A, 0x04, 0x04, 0x04, 0x04 },
+    ['Z'] = { 0x1F, 0x01, 0x02, 0x04, 0x08, 0x10, 0x1F },
+
+    ['0'] = { 0x0E, 0x11, 0x13, 0x15, 0x19, 0x11, 0x0E },
+    ['1'] = { 0x04, 0x0C, 0x04, 0x04, 0x04, 0x04, 0x0E },
+    ['2'] = { 0x0E, 0x11, 0x01, 0x02, 0x04, 0x08, 0x1F },
+    ['3'] = { 0x1E, 0x01, 0x01, 0x0E, 0x01, 0x01, 0x1E },
+    ['4'] = { 0x02, 0x06, 0x0A, 0x12, 0x1F, 0x02, 0x02 },
+    ['5'] = { 0x1F, 0x10, 0x10, 0x1E, 0x01, 0x01, 0x1E },
+    ['6'] = { 0x0E, 0x10, 0x10, 0x1E, 0x11, 0x11, 0x0E },
+    ['7'] = { 0x1F, 0x01, 0x02, 0x04, 0x08, 0x08, 0x08 },
+    ['8'] = { 0x0E, 0x11, 0x11, 0x0E, 0x11, 0x11, 0x0E },
+    ['9'] = { 0x0E, 0x11, 0x11, 0x0F, 0x01, 0x01, 0x0E },
+
+    ['.'] = { 0, 0, 0, 0, 0, 0x0C, 0x0C },
+    [','] = { 0, 0, 0, 0, 0, 0x0C, 0x08 },
+    [':'] = { 0, 0x0C, 0x0C, 0, 0, 0x0C, 0x0C },
+    [';'] = { 0, 0x0C, 0x0C, 0, 0, 0x0C, 0x08 },
+    ['!'] = { 0x04, 0x04, 0x04, 0x04, 0x04, 0, 0x04 },
+    ['?'] = { 0x0E, 0x11, 0x01, 0x02, 0x04, 0, 0x04 },
+    ['-'] = { 0, 0, 0, 0x1F, 0, 0, 0 },
+    ['_'] = { 0, 0, 0, 0, 0, 0, 0x1F },
+    ['+'] = { 0, 0x04, 0x04, 0x1F, 0x04, 0x04, 0 },
+    ['='] = { 0, 0x1F, 0, 0, 0x1F, 0, 0 },
+    ['/'] = { 0x01, 0x01, 0x02, 0x04, 0x08, 0x10, 0x10 },
+    ['\\'] = { 0x10, 0x10, 0x08, 0x04, 0x02, 0x01, 0x01 },
+    ['('] = { 0x02, 0x04, 0x08, 0x08, 0x08, 0x04, 0x02 },
+    [')'] = { 0x08, 0x04, 0x02, 0x02, 0x02, 0x04, 0x08 },
+    ['['] = { 0x0E, 0x08, 0x08, 0x08, 0x08, 0x08, 0x0E },
+    [']'] = { 0x0E, 0x02, 0x02, 0x02, 0x02, 0x02, 0x0E },
+    ['<'] = { 0x02, 0x04, 0x08, 0x10, 0x08, 0x04, 0x02 },
+    ['>'] = { 0x08, 0x04, 0x02, 0x01, 0x02, 0x04, 0x08 },
+    ['*'] = { 0, 0x15, 0x0E, 0x1F, 0x0E, 0x15, 0 },
+    ['#'] = { 0x0A, 0x0A, 0x1F, 0x0A, 0x1F, 0x0A, 0x0A },
+    ['%'] = { 0x19, 0x19, 0x02, 0x04, 0x08, 0x13, 0x13 },
+    ['@'] = { 0x0E, 0x11, 0x17, 0x15, 0x17, 0x10, 0x0F }
+};
+
+/**
+ * put a char 'c' on 'x' and 'y' in the framebuffer
+ * with a foreground color of 'color'
+ */
+void
+put_char(
+    char c,
+    uint32_t x,
+    uint32_t y,
+    uint32_t size,
+    uint32_t fg_color,
+    uint32_t bg_color
+) {
+    // convert lowercase letters to uppercase
+    if (c >= 'a' && c <= 'z') {
+        c -= 'a' - 'A';
+    }
+
+    // avoid indexing outside font[128]
+    if ((unsigned char)c >= 128) {
+        c = '?';
+    }
+
+    for (uint32_t row = 0; row < FONT_ROWS; row++) {
+        uint8_t bits = font[(unsigned char)c][row];
+
+        for (uint32_t col = 0; col < FONT_COLS; col++) {
+            uint32_t color =
+                bits & (1u << (FONT_COLS - 1 - col))
+                    ? fg_color : bg_color;
+
+            put_rect(
+                x + col * size,
+                y + row * size,
+                size,
+                size,
+                color
+            );
+        }
+    }
+}
+
+void
+put_string(
+    const char *text,
+    uint32_t x,
+    uint32_t y,
+    uint32_t size,
+    uint32_t spacing,
+    uint32_t line_spacing,
+    uint32_t fg_color,
+    uint32_t bg_color
+) {
+    uint32_t start_x = x;
+
+    while (*text) {
+        if (*text == '\n') {
+            x = start_x;
+            y += (FONT_ROWS + line_spacing) * size;
+        } else {
+            put_char(*text, x, y, size, fg_color, bg_color);
+            x += (FONT_COLS + spacing) * size;
+        }
+
+        text++;
+    }
+}

src/examples/snake.c

@@ -88,25 +88,6 @@ client_poll_event()
 	} 
 }
 
-/**
- * draws a rectangle with its left-top corner at (x,y) with
- * a width of 'w' and height of 'h' filled with color 'color'
- */ 
-void
-put_rect(
-	unsigned int x, 
-	unsigned int y, 
-	unsigned int w, 
-	unsigned int h,
-	uint32_t color
-) {
-	for (int i = x; i < x + w; i++) {
-		for (int j = y; j < y + h; j++) {
-			put_pixel(i, j, color);
-		}
-	}
-}
-
 // a wrapper function for put_rect using a v2 struct
 void
 put_rect_v2(

src/main.c

@@ -18,7 +18,7 @@ client_poll_event()
 		default:
 			break;
 		}
-	} 
+	}
 }
 
 /**
@@ -31,6 +31,11 @@ client_update_framebuffer()
 {
 	// single green demo pixel
 	game_state->framebuffer[0] = 0x00FF00;
+
+	put_rect(0, 0, 1100, 200, 0xFFFF00);
+	put_string("Hello, traveller. You have come\nto the right place!",
+		20, 20, 2, 2, 3, 0x000000, 0xFFFF00
+	);
 }
 
 int