embedded-game-programming/game/src/text.c

#include "font.h"
#include "odroid/display.h"
#include "text.h"


static const int MAX_GLYPHS_PER_ROW = LCD_WIDTH / GLYPH_WIDTH;
static const int MAX_GLYPHS_PER_COL = LCD_HEIGHT / GLYPH_HEIGHT;

void DrawText(uint16_t* framebuffer, char* string, int length, int x, int y, uint16_t color)
{
	assert(x + length <= MAX_GLYPHS_PER_ROW);
	assert(y <= MAX_GLYPHS_PER_COL);

	for (int charIndex = 0; charIndex < length; ++charIndex)
	{
		char c = string[charIndex];

		if (c == ' ')
		{
			continue;
		}

		int xStart = GLYPH_WIDTH * (x + charIndex);
		int yStart = GLYPH_HEIGHT * y;

		for (int row = 0; row < GLYPH_HEIGHT; ++row)
		{
			for (int col = 0; col < GLYPH_WIDTH; ++col)
			{
				int bitPosition = 1U << (15U - col);
				int glyphIndex = GetGlyphIndex(c);

				uint16_t pixel = glyphMap[glyphIndex][row] & bitPosition;

				if (pixel)
				{
					int screenX = xStart + col;
					int screenY = yStart + row;

					framebuffer[screenY * LCD_WIDTH + screenX] = color;
				}
			}
		}
	}
}