Create text module for displaying messages

text.c

@@ -0,0 +1,117 @@
+#include "text.h"
+
+#include "renderer.h"
+
+#include <assert.h>
+
+#define NELEMS(arr) (sizeof(arr) / sizeof(arr[0]))
+
+#define MAX_LINES 2
+
+#define TEXT_HEIGHT 8
+#define TEXT_SCALE 0.025
+#define LETTER_WIDTH 3
+#define SPACE_WIDTH 1
+
+typedef struct {
+	unsigned line_count;
+	unsigned line_lens[MAX_LINES];
+	vec2_t lines[MAX_LINES][MAX_VERTS];
+} glyph_t;
+
+static const mat3_t text_transform = {
+	{ TEXT_SCALE, 0, 0 },
+	{ 0, TEXT_SCALE, 0 },
+	{ 0, 0, 1 },
+};
+
+static const glyph_t font[] = {
+	['A'] = {
+		.line_count = 2,
+		.line_lens = { 3, 2 },
+		.lines = {
+			{ { -1, -4 }, { 0, 4 }, { 1, -4 } },
+			{ { -0.75, -2 }, { 0.75, -2 } },
+		},
+	},
+	['E'] = {
+		.line_count = 2,
+		.line_lens = { 4, 2 },
+		.lines = {
+			{ { 1, 4 }, { -1, 4 }, { -1, -4 }, { 1, -4 } },
+			{ { -1, -2 }, { 0, -2 } },
+		},
+	},
+	['G'] = {
+		.line_count = 1,
+		.line_lens = { 5 },
+		.lines = {
+			{ { 1, 4 }, { -1, 4 }, { -1, -4 }, { 1, -4 }, { 1, -2 } },
+		},
+	},
+	['M'] = {
+		.line_count = 1,
+		.line_lens = { 5 },
+		.lines = {
+			{ { -1, -4 }, { -1, 4 }, { 0, -4 }, { 1, 4 }, { 1, -4 } },
+		},
+	},
+	['O'] = {
+		.line_count = 1,
+		.line_lens = { 5 },
+		.lines = {
+			{ { -1, 4 }, { -1, -4 }, { 1, -4 }, { 1, 4 }, { -1, 4 } },
+		},
+	},
+	['R'] = {
+		.line_count = 1,
+		.line_lens = { 6 },
+		.lines = {
+			{
+				{ -1, -4 }, { -1, 4 }, { 1, 4 },
+				{ 1, -2 }, { -1, -2 }, { 1, -4 },
+			},
+		},
+	},
+	['V'] = {
+		.line_count = 1,
+		.line_lens = { 3 },
+		.lines = {
+			{ { -1, 4 }, { 0, -4 }, { 1, 4 } },
+		},
+	},
+};
+
+void text_draw(const char *s)
+{
+	int width = 0;
+	for (const char *p = s; *p != '\0'; ++p)
+		width += *p == ' ' ? SPACE_WIDTH : LETTER_WIDTH;
+	--width;
+
+	const vec2_t bg_size = {
+		.x = TEXT_SCALE * (width + 2),
+		.y = TEXT_SCALE * (TEXT_HEIGHT + 2),
+	};
+	renderer_clear_rect((vec2_t) { 0, 0 }, bg_size);
+
+	int x = -width / 2 + 1;
+	for (const char *p = s; *p != '\0'; ++p) {
+		if (*p == ' ') {
+			x += SPACE_WIDTH;
+		} else {
+			const unsigned c = (unsigned)*p;
+			assert(c < NELEMS(font) && font[c].line_count != 0);
+			const glyph_t *g = font + c;
+
+			const vec2_t t = { .x = x };
+			const mat3_t m
+			    = mat3_mul_mat3(text_transform, mat3_translation(t));
+
+			for (unsigned i = 0; i < g->line_count; ++i)
+				renderer_draw(g->lines[i], g->line_lens[i], m, false);
+
+			x += LETTER_WIDTH;
+		}
+	}
+}