IMX6U-Game/src/Gfx/Draw2D/DrawContext.cpp

#include "DrawContext.h"
#include "FrameBuffer.h"
#include "DepthBuffer.h"
#include "Rasterizer.h"
#include "TriangleRasterizer.h"
#include "Display.h"
#include <algorithm>

namespace Gfx
{
	DrawContext::DrawContext(int32_t width, int32_t height)
	{
		frameBuffer = new Core::FrameBuffer(width, height);
		depthBuffer = new Core::DepthBuffer(width, height);
		rasterizer = new Rasterizer::Rasterizer(frameBuffer, depthBuffer);
		triangleRasterizer = new Rasterizer::TriangleRasterizer(frameBuffer, depthBuffer);
	}

	DrawContext::~DrawContext()
	{
		delete triangleRasterizer;
		delete rasterizer;
		delete depthBuffer;
		delete frameBuffer;
	}

	int32_t DrawContext::get_width() const
	{
		return frameBuffer->get_width();
	}

	int32_t DrawContext::get_height() const
	{
		return frameBuffer->get_height();
	}

	void DrawContext::clear(const RenderData::Color& color)
	{
		frameBuffer->clear(color);
		depthBuffer->clear();
	}

	void DrawContext::clear_depth()
	{
		depthBuffer->clear();
	}

	void DrawContext::draw_line(const Math::Vector2Int& from, const Math::Vector2Int& to, const RenderData::Color& color)
	{
		rasterizer->DrawLine(from, to, color);
	}

	void DrawContext::draw_triangle(const RenderData::Triangle& triangle, const RenderData::Color& color)
	{
		triangleRasterizer->DrawTriangle2D(triangle, color);
	}

	void DrawContext::draw_sprite(int32_t dst_x, int32_t dst_y, const RenderData::Image& img)
	{
		draw_sprite_region(dst_x, dst_y, img, 0, 0, img.width, img.height);
	}

	void DrawContext::draw_sprite_region(int32_t dst_x, int32_t dst_y, const RenderData::Image& img,
	                                     int32_t src_x, int32_t src_y, int32_t src_w, int32_t src_h)
	{
		draw_sprite_ex(dst_x, dst_y, img, src_x, src_y, src_w, src_h, 1, false, false);
	}

	void DrawContext::draw_sprite_ex(int32_t dst_x, int32_t dst_y, const RenderData::Image& img,
	                                 int32_t src_x, int32_t src_y, int32_t src_w, int32_t src_h,
	                                 int32_t scale, bool flip_h, bool flip_v)
	{
		if (scale < 1 || !img.pixels) return;

		const int32_t img_w = img.width;
		const uint32_t* src = img.pixels;
		const bool has_key = img.has_color_key;
		const uint32_t key = img.color_key;

		for (int32_t sy = 0; sy < src_h; ++sy)
		{
			const int32_t read_y = flip_v ? (src_y + src_h - 1 - sy) : (src_y + sy);
			const uint32_t* row = src + read_y * img_w;

			for (int32_t sx = 0; sx < src_w; ++sx)
			{
				const int32_t read_x = flip_h ? (src_x + src_w - 1 - sx) : (src_x + sx);
				const uint32_t pixel = row[read_x];

				if (has_key && pixel == key) continue;

				const int32_t base_x = dst_x + sx * scale;
				const int32_t base_y = dst_y + sy * scale;

				if (scale == 1)
				{
					frameBuffer->set_pixel(base_x, base_y, pixel);
				}
				else
				{
					for (int32_t dy = 0; dy < scale; ++dy)
					{
						for (int32_t dx = 0; dx < scale; ++dx)
						{
							frameBuffer->set_pixel(base_x + dx, base_y + dy, pixel);
						}
					}
				}
			}
		}
	}

	void DrawContext::fill_rect(int32_t x, int32_t y, int32_t w, int32_t h, const RenderData::Color& color)
	{
		const uint32_t rgba = color.to_rgba();
		for (int32_t row = y; row < y + h; ++row)
		{
			for (int32_t col = x; col < x + w; ++col)
			{
				frameBuffer->set_pixel(col, row, rgba);
			}
		}
	}

	void DrawContext::draw_text(const RenderData::BitmapFont& font, int32_t x, int32_t y,
	                            const RenderData::Color& color, const char* text)
	{
		if (!font.atlas.pixels || !text) return;

		const uint32_t rgba = color.to_rgba();
		const int32_t cw = font.char_w;
		const int32_t ch = font.char_h;
		const int32_t atlas_w = font.atlas.width;
		const uint32_t* src = font.atlas.pixels;

		int32_t cursor_x = x;
		for (const char* p = text; *p; ++p)
		{
			const int32_t index = static_cast<int32_t>(*p) - font.first_char;
			if (index < 0) { cursor_x += cw; continue; }

			const int32_t col = index % font.columns;
			const int32_t row = index / font.columns;
			const int32_t src_x = col * cw;
			const int32_t src_y = row * ch;

			for (int32_t sy = 0; sy < ch; ++sy)
			{
				const uint32_t* atlas_row = src + (src_y + sy) * atlas_w;
				const int32_t dst_y_abs = y + sy;
				for (int32_t sx = 0; sx < cw; ++sx)
				{
					const uint32_t pixel = atlas_row[src_x + sx];
					if ((pixel & 0xFF) == 0) continue;
					frameBuffer->set_pixel(cursor_x + sx, dst_y_abs, rgba);
				}
			}
			cursor_x += cw;
		}
	}

	void DrawContext::draw_text(const RenderData::BitmapFont& font, int32_t x, int32_t y,
	                            const RenderData::Color& color, const RenderData::Color& bg_color, const char* text)
	{
		if (!text) return;

		int32_t len = 0;
		for (const char* p = text; *p; ++p) ++len;

		fill_rect(x, y, len * font.char_w, font.char_h, bg_color);
		draw_text(font, x, y, color, text);
	}

	void DrawContext::present(Platform::IDisplay* display)
	{
		display->present(frameBuffer);
	}
}