#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <iostream>

#define SDL_MAIN_USE_CALLBACKS 1  /* use the callbacks instead of main() */
#include <SDL3/SDL.h>
#include <SDL3/SDL_main.h>
#include <SDL3/SDL_opengl.h>

#include "math/dvc_vector2.h"
#include "math/dvc_vector3.h"

#include "dvr_triangle.h"
#include "dvr_canvas.h"
#include "rasterizer/dvc_rasterizer_triangle.h"

using namespace davinci;

enum MouseAction
{
	MT_NULL,
	MT_FIRST_LINE,
	MT_TRIANGLE,

	MT_PAN,
};

const float		MIN_SCALE = 4.f;
const float		MAX_SCALE = 120.f;
const float		TRIANGLE_BORDER_WIDTH = 1.5f;
const float		ACTION_WIDTH = 1.f;
const fVector3	GRID_BORDER_COLOR = fVector3(0.f, 0.f, 0.f);
const fVector3	GRID_CROSS_COLOR = fVector3(0.1f, 0.1f, 0.1f);
const fVector3	TRIANGLE_BORDER_COLOR = fVector3(0.f, 0.f, 0.f);
const fVector3	ACTION_COLOR = fVector3(1.f, 0.f, 0.f);
const int32_t	CANVAS_WIDTH = 512;
const int32_t	CANVAS_HEIGHT = 256;

int32_t		g_viewWidth = 2048;
int32_t		g_viewHeight = 1440;
float32_t	g_scale = MAX_SCALE/2.0f;
int32_t		g_lbCorner_x = 20;
int32_t		g_lbCorner_y = 20;
int32_t		g_nDrawGridLevel = 0; //0:all 1:fine+coarse+tile  2:coarse+tile 3: tile 
int32_t		g_screenMousePosX = 0, g_screenMousePosY = 0;
float32_t	g_mousePosX, g_mousePosY;
bool		g_bSnapMode = true;
float		g_fSnapSize = 0.25f;
MouseAction	g_currentAction = MT_NULL;
bool		g_bDrawExtension = false;

int32_t		g_nStartPanX, g_nStartPanY;
int32_t		g_nPanX, g_nPanY;

Triangle			g_currentTriangle(INT_MAX, ACTION_COLOR);
TriangleArray		g_allTriangles;
Canvas				g_canvas;
AntiAliasingTech	g_aaTech = AntiAliasingTech::AA_None;

SDL_Window*		g_window = NULL;
SDL_Renderer*	g_renderer = NULL;

#define trans_w2s_x(x) ((float32_t)(x) * g_scale + g_lbCorner_x + g_nPanX)
#define trans_w2s_y(y) ((float32_t)g_viewHeight - ((float32_t)(y) * g_scale + g_lbCorner_y + g_nPanY))

#define trans_s2w_x(x) ((float32_t)(x - g_lbCorner_x - g_nPanX) / g_scale)
#define trans_s2w_y(y) ((float32_t)(g_viewHeight - y - g_lbCorner_y - g_nPanY) / g_scale)

void _onFramebufferSize(int32_t w, int32_t h)
{
	g_viewWidth = w;
	g_viewHeight = h > 0 ? h : 1;

	if (g_scale < 10.f) g_nDrawGridLevel = 3;
	else if (g_scale < 20.f) g_nDrawGridLevel = 2;
	else if (g_scale < 50.f) g_nDrawGridLevel = 1;
	else g_nDrawGridLevel = 0;
}

static void _drawGrid(void)
{
	int32_t horLength = (int32_t)floorf(g_viewWidth / g_scale);
	int32_t verLength = (int32_t)floorf(g_viewHeight / g_scale);

	// draw canvas background
	SDL_FRect rect;
	rect.x = trans_w2s_x(0);
	rect.y = trans_w2s_y(0);
	rect.w = g_canvas.width() * g_scale;
	rect.h = -g_canvas.height() * g_scale;
	SDL_SetRenderDrawColorFloat(g_renderer, 255, 255, 255, SDL_ALPHA_OPAQUE_FLOAT);
	SDL_RenderFillRect(g_renderer, &rect);

	fVector3 lineColor[] = { fVector3(0.f, 0.f, 0.f), fVector3(0.5f, 0.5f, 0.5f), fVector3(0.7f,0.7f,0.7f), fVector3(0.9f, 0.9f,0.9f) };

	// Horizontal lines
	for (int32_t i = (int32_t)trans_s2w_y(0); ; i--)
	{
		if (i > g_canvas.height()) continue;
		if (i < 0) break;

		float32_t screenY = trans_w2s_y(i);
		if (screenY < 0) continue;
		if (screenY > g_viewHeight) break;

		int32_t level = 3;

		if (i % 64 == 0)level = 0;
		else if (i % 16 == 0) level = 1;
		else if (i % 4 == 0) level = 2;
		if (level > 3 - g_nDrawGridLevel) continue;

		SDL_SetRenderDrawColorFloat(g_renderer, lineColor[level].x, lineColor[level].y, lineColor[level].z, SDL_ALPHA_OPAQUE_FLOAT);
		SDL_RenderLine(g_renderer, trans_w2s_x(0), screenY, trans_w2s_x(g_canvas.width()), screenY);
	}

	// Vertical lines
	for (int32_t j = (int32_t)trans_s2w_x(0); ; j++)
	{
		if (j < 0) continue;
		if (j > g_canvas.width()) break;

		float32_t screenX = trans_w2s_x(j);
		if (screenX < 0) continue;
		if (screenX > g_viewWidth) break;

		int32_t level = 3;

		if (j % 64 == 0)level = 0;
		else if (j % 16 == 0) level = 1;
		else if (j % 4 == 0) level = 2;
		if (level > 3 - g_nDrawGridLevel) continue;

		SDL_SetRenderDrawColorFloat(g_renderer, lineColor[level].x, lineColor[level].y, lineColor[level].z, SDL_ALPHA_OPAQUE_FLOAT);
		SDL_RenderLine(g_renderer, screenX, trans_w2s_y(0), screenX, trans_w2s_y(g_canvas.height()));
	}
}

void _drawTriangleBorder(const Triangle& triangle, const fVector3& color, float lineWidth)
{
	SDL_SetRenderDrawColorFloat(g_renderer, color[0], color[1], color[2], SDL_ALPHA_OPAQUE_FLOAT);

	SDL_FPoint points[4] = {
		{trans_w2s_x(triangle.m_p0.x), trans_w2s_y(triangle.m_p0.y)},
		{trans_w2s_x(triangle.m_p1.x), trans_w2s_y(triangle.m_p1.y)},
		{trans_w2s_x(triangle.m_p2.x), trans_w2s_y(triangle.m_p2.y)},
		{trans_w2s_x(triangle.m_p0.x), trans_w2s_y(triangle.m_p0.y)}
	};
	SDL_RenderLines(g_renderer, points, 4);
}

void _drawCanvasPixel()
{
	SDL_SetRenderDrawBlendMode(g_renderer, SDL_BLENDMODE_BLEND);

	for (int32_t y = 0; y < g_canvas.height(); y++)
	{
		for (int32_t x = 0; x < g_canvas.width(); x++)
		{
			const Canvas::Pixel& pixel = g_canvas.pixel(x, y);
			if (pixel.fragementID < 0) continue;

			SDL_FRect rect;
			rect.x = trans_w2s_x(x);
			rect.y = trans_w2s_y(y);
			rect.w = g_scale;
			rect.h = -g_scale;
			SDL_SetRenderDrawColorFloat(g_renderer, pixel.color.x, pixel.color.y, pixel.color.z, pixel.alpha);
			SDL_RenderFillRect(g_renderer, &rect);
		}
	}
}

void _drawTriangles(void)
{
	_drawCanvasPixel();

	for (const auto& triangle : g_allTriangles) 
	{
		_drawTriangleBorder(triangle, TRIANGLE_BORDER_COLOR, TRIANGLE_BORDER_WIDTH);
	}
}

void _drawSegmentInAABB(const fVector2& p0, const fVector2& p1, float xMin, float xMax, float yMin, float yMax)
{
	float32_t dx = p1.x - p0.x;
	float32_t dy = p1.y - p0.y;
	if (std::abs(dx) > std::abs(dy)) 
	{
		float _ymin = (xMin - p0.x) * dy / dx + p0.y;
		float _ymax = (xMax - p0.x) * dy / dx + p0.y;

		if (dx > 0) {
			SDL_RenderLine(g_renderer, trans_w2s_x(xMin), trans_w2s_y(_ymin), trans_w2s_x(p0.x), trans_w2s_y(p0.y) );
			SDL_RenderLine(g_renderer, trans_w2s_x(p1.x), trans_w2s_y(p1.y), trans_w2s_x(xMax), trans_w2s_y(_ymax) );
		}
		else {
			SDL_RenderLine(g_renderer, trans_w2s_x(xMin), trans_w2s_y(_ymin), trans_w2s_x(p1.x), trans_w2s_y(p1.y));
			SDL_RenderLine(g_renderer, trans_w2s_x(p0.x), trans_w2s_y(p0.y), trans_w2s_x(xMax), trans_w2s_y(_ymax));
		}
	}
	else {
		float _xmin = (yMin - p0.y) * dx / dy + p0.x;
		float _xmax = (yMax - p0.y) * dx / dy + p0.x;

		if (dy > 0) {
			SDL_RenderLine(g_renderer, trans_w2s_x(_xmin), trans_w2s_y(yMin), trans_w2s_x(p0.x), trans_w2s_y(p0.y));
			SDL_RenderLine(g_renderer, trans_w2s_x(p1.x), trans_w2s_y(p1.y), trans_w2s_x(_xmax), trans_w2s_y(yMax));
		}
		else {
			SDL_RenderLine(g_renderer, trans_w2s_x(_xmin), trans_w2s_y(yMin), trans_w2s_x(p1.x), trans_w2s_y(p1.y));
			SDL_RenderLine(g_renderer, trans_w2s_x(p0.x), trans_w2s_y(p0.y), trans_w2s_x(_xmax), trans_w2s_y(yMax));
		}
	}
}

void _drawAction(void)
{
	if (g_bDrawExtension) {
		SDL_SetRenderDrawColorFloat(g_renderer, ACTION_COLOR.x/2.f, ACTION_COLOR.y/2.f, ACTION_COLOR.z/2.f, SDL_ALPHA_OPAQUE_FLOAT);

		_drawSegmentInAABB(g_currentTriangle.m_p0.xy(), g_currentTriangle.m_p1.xy(), 
			0, (float)g_canvas.width(), 0, (float)g_canvas.height());
		_drawSegmentInAABB(g_currentTriangle.m_p1.xy(), g_currentTriangle.m_p2.xy(), 
			0, (float)g_canvas.width(), 0, (float)g_canvas.height());
		_drawSegmentInAABB(g_currentTriangle.m_p2.xy(), g_currentTriangle.m_p0.xy(), 
			0, (float)g_canvas.width(), 0, (float)g_canvas.height());
	}

	SDL_SetRenderDrawColorFloat(g_renderer, ACTION_COLOR.x, ACTION_COLOR.y, ACTION_COLOR.z, SDL_ALPHA_OPAQUE_FLOAT);
	switch (g_currentAction)
	{
	case MT_FIRST_LINE:
	{
		SDL_RenderLine(g_renderer, 
			trans_w2s_x(g_currentTriangle.m_p0.x), trans_w2s_y(g_currentTriangle.m_p0.y),
			trans_w2s_x(g_currentTriangle.m_p1.x), trans_w2s_y(g_currentTriangle.m_p1.y)
		);
	}
	break;

	case MT_TRIANGLE:
	{
		_drawTriangleBorder(g_currentTriangle, ACTION_COLOR, ACTION_WIDTH);
	}
	break;

	default:
		break;
	}
}

void _drawPixelSample()
{
	const float crossLength = 0.2f;

	//sample cross
	if (g_nDrawGridLevel < 3)
	{
		SDL_SetRenderDrawColorFloat(g_renderer, GRID_CROSS_COLOR.x, GRID_CROSS_COLOR.y, GRID_CROSS_COLOR.z, SDL_ALPHA_OPAQUE_FLOAT);

		for (int32_t i = 0; i < g_canvas.height(); i++)
		{
			for (int32_t j = 0; j < g_canvas.width(); j++)
			{
				const Canvas::Pixel& pixel = g_canvas.pixel(j, i);
				if (pixel.fragementID < 0) continue;

				if (g_aaTech == AntiAliasingTech::AA_None)
				{
					SDL_RenderLine(g_renderer,
						trans_w2s_x(j + 0.5f - crossLength), trans_w2s_y(i + 0.5f - crossLength),
						trans_w2s_x(j + 0.5f + crossLength), trans_w2s_y(i + 0.5f + crossLength)
					);

					SDL_RenderLine(g_renderer,
						trans_w2s_x(j + 0.5f - crossLength), trans_w2s_y(i + 0.5f + crossLength),
						trans_w2s_x(j + 0.5f + crossLength), trans_w2s_y(i + 0.5f - crossLength)
					);
				}
				else if (g_aaTech == AntiAliasingTech::AA_MSAA_2X2)
				{
					for (int32_t ii = 0; ii < 2; ii++)
					{
						for (int32_t jj = 0; jj < 2; jj++)
						{
							int32_t maskOffset = ii * 2 + jj;
							if (((pixel.mask >> maskOffset) & 1) == 0U) continue;

							SDL_RenderLine(g_renderer,
								trans_w2s_x(j + 0.25f + jj * 0.5f - crossLength / 2), trans_w2s_y(i + 0.25f + ii * 0.5f - crossLength / 2),
								trans_w2s_x(j + 0.25f + jj * 0.5f + crossLength / 2), trans_w2s_y(i + 0.25f + ii * 0.5f + crossLength / 2)
							);

							SDL_RenderLine(g_renderer,
								trans_w2s_x(j + 0.25f + jj * 0.5f - crossLength / 2), trans_w2s_y(i + 0.25f + ii * 0.5f + crossLength / 2),
								trans_w2s_x(j + 0.25f + jj * 0.5f + crossLength / 2), trans_w2s_y(i + 0.25f + ii * 0.5f - crossLength / 2)
							);
						}
					}
				}
				else if (g_aaTech == AntiAliasingTech::AA_MSAA_4X4)
				{
					for (int32_t ii = 0; ii < 4; ii++)
					{
						for (int32_t jj = 0; jj < 4; jj++)
						{
							int32_t maskOffset = ii * 4 + jj;
							if (((pixel.mask >> maskOffset) & 1) == 0U) continue;

							SDL_RenderLine(g_renderer,
								trans_w2s_x(j + 0.125f + jj * 0.25f - crossLength/4), trans_w2s_y(i + 0.125f + ii * 0.25f - crossLength/4),
								trans_w2s_x(j + 0.125f + jj * 0.25f + crossLength/4), trans_w2s_y(i + 0.125f + ii * 0.25f + crossLength/4)
							);

							SDL_RenderLine(g_renderer,
								trans_w2s_x(j + 0.125f + jj * 0.25f - crossLength/4), trans_w2s_y(i + 0.125f + ii * 0.25f + crossLength/4),
								trans_w2s_x(j + 0.125f + jj * 0.25f + crossLength/4), trans_w2s_y(i + 0.125f + ii * 0.25f - crossLength/4)
							);

						}
					}
				}

			}
		}

		//for (int32_t i = (int32_t)trans_s2w_y(0); ; i--)
		//{
		//	if (i > g_canvas.height()) continue;
		//	if (i < 0) break;

		//}

		//float crossLength = 0.2f;
		//for (int i = 0; i < verLength; i++)
		//{
		//	for (int j = 0; j < horLength; j++)
		//	{
		//		SDL_RenderLine(g_renderer,
		//			trans_w2s_x(j + 0.5f - crossLength), trans_w2s_y(i + 0.5f - crossLength),
		//			trans_w2s_x(j + 0.5f + crossLength), trans_w2s_y(i + 0.5f + crossLength)
		//		);

		//		SDL_RenderLine(g_renderer,
		//			trans_w2s_x(j + 0.5f - crossLength), trans_w2s_y(i + 0.5f + crossLength),
		//			trans_w2s_x(j + 0.5f + crossLength), trans_w2s_y(i + 0.5f - crossLength)
		//		);
		//	}
		//}
	}
}

void _drawMouseCursor(void)
{
	if (g_bSnapMode && g_currentAction!=MT_PAN)
	{
		SDL_SetRenderDrawColorFloat(g_renderer, 0, 0, 0, SDL_ALPHA_OPAQUE_FLOAT);

		const float32_t CursorLength = 10.f / g_scale;

		SDL_RenderLine(g_renderer,
			trans_w2s_x(g_mousePosX - CursorLength), trans_w2s_y(g_mousePosY),
			trans_w2s_x(g_mousePosX + CursorLength), trans_w2s_y(g_mousePosY)
		);

		SDL_RenderLine(g_renderer,
			trans_w2s_x(g_mousePosX), trans_w2s_y(g_mousePosY - CursorLength),
			trans_w2s_x(g_mousePosX), trans_w2s_y(g_mousePosY + CursorLength)
		);
	}
}

void _drawDebugText()
{
	const float32_t TextHeight = (float32_t)SDL_DEBUG_TEXT_FONT_CHARACTER_SIZE*1.5;

	SDL_SetRenderDrawColorFloat(g_renderer, 0, 0, 0, SDL_ALPHA_OPAQUE_FLOAT);

	SDL_SetRenderScale(g_renderer, 1.5f, 1.5f);
	SDL_RenderDebugText(g_renderer, 20, 20, "Press 'S' to turn on/off snap mode.");
	SDL_RenderDebugText(g_renderer, 20, 20 + TextHeight, "Click 'LeftMouseButton' to draw new triangle.");

	SDL_SetRenderScale(g_renderer, 1.0f, 1.0f);
}

inline float _snapPosition(float pos)
{
	if (g_fSnapSize < 1) {
		int invSize = (int)(1.f / g_fSnapSize);

		float x_f = floorf(((pos - floorf(pos)) * invSize + 0.5f)) / (float)invSize;
		return floorf(pos) + x_f;
	}
	else {
		return floorf(pos - floorf(pos / g_fSnapSize) + 0.5f) * g_fSnapSize;
	}
}

void _onMouseMove(float32_t x, float32_t y)
{
	g_screenMousePosX = (int32_t)x;
	g_screenMousePosY = (int32_t)y;
	g_mousePosX = trans_s2w_x(x);
	g_mousePosY = trans_s2w_y(y);

	if (g_bSnapMode && g_currentAction != MT_PAN) 
	{
		g_mousePosX = _snapPosition(g_mousePosX);
		g_mousePosY = _snapPosition(g_mousePosY);
	}

	switch (g_currentAction)
	{
	case MT_FIRST_LINE:
	{
		g_currentTriangle.m_p1 = fVector3(g_mousePosX, g_mousePosY, 0);
	}
	break;

	case MT_TRIANGLE:
	{
		g_currentTriangle.m_p2 = fVector3(g_mousePosX, g_mousePosY, 0);
		g_currentTriangle.build(g_canvas.width(), g_canvas.height(), g_aaTech);

		g_canvas.update(g_aaTech, g_allTriangles, &g_currentTriangle);
	}
	break;

	case MT_PAN:
	{
		g_nPanX = g_screenMousePosX - g_nStartPanX;
		g_nPanY = -(g_screenMousePosY - g_nStartPanY);
	}
	break;

	default: break;
	}
}

void _onMouseWheel(float32_t x, float32_t y)
{
	g_scale += (float)y * g_scale * 0.05f;
	if (g_scale < MIN_SCALE) g_scale = MIN_SCALE;
	if (g_scale > MAX_SCALE) g_scale = MAX_SCALE;

	_onFramebufferSize(g_viewWidth, g_viewHeight);
}

void _onKeyDown(SDL_Keycode key)
{
	if (SDLK_S == key)
	{
		g_bSnapMode = !g_bSnapMode;
	}
	else if (SDLK_A == key)
	{
		if (g_currentAction == MT_NULL)
		{
			if (g_aaTech == AntiAliasingTech::AA_None)
			{
				g_aaTech = AntiAliasingTech::AA_MSAA_2X2;
			}
			else if (g_aaTech == AntiAliasingTech::AA_MSAA_2X2)
			{
				g_aaTech = AntiAliasingTech::AA_MSAA_4X4;
			}
			else if (g_aaTech == AntiAliasingTech::AA_MSAA_4X4)
			{
				g_aaTech = AntiAliasingTech::AA_None;
			}
			for (auto& triangle : g_allTriangles)
			{
				triangle.build(g_canvas.width(), g_canvas.height(), g_aaTech);
			}
			g_canvas.update(g_aaTech, g_allTriangles);
		}
	}
	else if (SDLK_ESCAPE == key)
	{
		g_currentAction = MT_NULL;
		g_bDrawExtension = false;
	}
}

void _onMouseDown(Uint8 button)
{
	if (button == SDL_BUTTON_MIDDLE)
	{
		if (g_currentAction == MT_NULL)
		{
			g_currentAction = MT_PAN;

			g_nStartPanX = g_screenMousePosX;
			g_nStartPanY = g_screenMousePosY;
			g_nPanX = g_nPanY = 0;
		}
	}
}

void _onMouseUp(Uint8 button)
{
	if (button == SDL_BUTTON_LEFT)
	{
		switch (g_currentAction)
		{
		case MT_NULL:
		{
			g_currentTriangle.m_p0 = g_currentTriangle.m_p1 = fVector3(g_mousePosX, g_mousePosY, 0);
			g_currentAction = MT_FIRST_LINE;
			g_bDrawExtension = false;
		}
		break;

		case MT_FIRST_LINE:
		{
			g_currentTriangle.m_p1 = g_currentTriangle.m_p2 = fVector3(g_mousePosX, g_mousePosY, 0);
			g_currentAction = MT_TRIANGLE;
			g_bDrawExtension = true;
		}
		break;

		case MT_TRIANGLE:
		{
			g_currentTriangle.m_p2 = fVector3(g_mousePosX, g_mousePosY, 0);
			g_currentAction = MT_NULL;

			//build triangle
			Triangle newTriangle(Triangle::nextID(), Triangle::randomColor());
			newTriangle.m_p0 = g_currentTriangle.m_p0;
			newTriangle.m_p1 = g_currentTriangle.m_p1;
			newTriangle.m_p2 = g_currentTriangle.m_p2;
			newTriangle.build(g_canvas.width(), g_canvas.height(), g_aaTech);
			g_allTriangles.push_back(std::move(newTriangle));
			g_canvas.update(g_aaTech, g_allTriangles);
			g_bDrawExtension = true;
		}
		break;

		default:
			break;
		}
	}
	else if (button== SDL_BUTTON_RIGHT)
	{
		g_currentAction = MT_NULL;
		g_bDrawExtension = false;
		g_canvas.update(g_aaTech, g_allTriangles);
	}
	else if (button == SDL_BUTTON_MIDDLE)
	{
		if (g_currentAction == MT_PAN)
		{
			g_currentAction = MT_NULL;
			g_lbCorner_x += g_nPanX;
			g_lbCorner_y += g_nPanY;
			g_nPanX = g_nPanY = 0;
		}
	}
}

void _buildDemoTriangles(void)
{
	// https://msdn.microsoft.com/en-us/library/windows/desktop/cc627092(v=vs.85).aspx

	float32_t triangleData[] = {
		1, 2,7, 4,5, 2,
		5, 2,7, 4,8, 1,
		8, 1,7, 4,9.5f, 2.5f,
		1, 7,6, 6,2, 4,
		5.25f, 6.75f, 6.25f, 7.75,6.25f, 6.75f,
		6.5f, 5.5f,7.5f, 7.5f,7.5f, 6.5f,
		11.5f, 1.5f,11.5f, 3.5f, 12.5f, 2.5f,
		13.5f, 0.5f,13.5f, 2.5f, 15.5f, 2.5f,
		13.5f, 0.5f,15.5f, 2.5f, 15.5f, 0.5f,
		13.5f, 6.5f,14.5f, 5.5f, 14.5f, 3.5f,
		13.5f, 6.5f,15, 8, 14.5f, 5.5f,
		9.5f, 0.5f, 10.5f, 0.5f,9.5f, -1.5f,
		7.6f, 5.5f,9.75f, 7.25f, 11.6f, 5.5f,
		7.6f, 5.5f, 11.6f, 5.5f, 9.5f, 2.6f,
	};

	size_t triangleCounts = sizeof(triangleData) / (6 * sizeof(float));
	for (size_t i = 0; i < triangleCounts; i++) {

		fVector3 p0(triangleData[i * 6 + 0], triangleData[i * 6 + 1], 0.f);
		fVector3 p1(triangleData[i * 6 + 2], triangleData[i * 6 + 3], 0.f);
		fVector3 p2(triangleData[i * 6 + 4], triangleData[i * 6 + 5], 0.f);

		Triangle triangle(Triangle::nextID(), Triangle::randomColor());
		triangle.m_p0 = p0;
		triangle.m_p1 = p1;
		triangle.m_p2 = p2;
		triangle.build(g_canvas.width(), g_canvas.height(), g_aaTech);
		g_allTriangles.emplace_back(triangle);
	}
}

SDL_AppResult SDL_AppInit(void** appstate, int argc, char* argv[])
{
	// Setup SDL
	SDL_SetAppMetadata("Davinci Rasterization Test Program", "1.0", "com.thecodeway.davinci");

	if (!SDL_Init(SDL_INIT_VIDEO | SDL_INIT_GAMEPAD))
	{
		printf("Error: SDL_Init(): %s\n", SDL_GetError());
		return SDL_APP_FAILURE;
	}

	if (!SDL_CreateWindowAndRenderer("Davinci Rasterization Test Program", g_viewWidth, g_viewHeight, SDL_WINDOW_RESIZABLE, &g_window, &g_renderer))
	{
		SDL_Log("Couldn't create window/renderer: %s", SDL_GetError());
		return SDL_APP_FAILURE;
	}

	g_canvas.reset(CANVAS_WIDTH, CANVAS_HEIGHT);

	_onFramebufferSize(g_viewWidth, g_viewHeight);
	_buildDemoTriangles();

	g_canvas.update(g_aaTech, g_allTriangles);

	return SDL_APP_CONTINUE;  /* carry on with the program! */
}

/* This function runs when a new event (mouse input, keypresses, etc) occurs. */
SDL_AppResult SDL_AppEvent(void* appstate, SDL_Event* event)
{
	switch (event->type)
	{
	case SDL_EVENT_QUIT:
		return SDL_APP_SUCCESS;
		break;

	case SDL_EVENT_WINDOW_RESIZED:
	{
		_onFramebufferSize(event->window.data1, event->window.data2);
	}
	break;

	case SDL_EVENT_MOUSE_MOTION:
	{
		_onMouseMove(event->motion.x, event->motion.y);
	}
	break;

	case SDL_EVENT_MOUSE_WHEEL:
	{
		_onMouseWheel(event->wheel.x, event->wheel.y);
	}
	break;

	case SDL_EVENT_KEY_DOWN:
	{
		_onKeyDown(event->key.key);
	}
	break;

	case SDL_EVENT_MOUSE_BUTTON_DOWN:
	{
		_onMouseDown(event->button.button);
	}
	break;
	case SDL_EVENT_MOUSE_BUTTON_UP:
	{
		_onMouseUp(event->button.button);
	}
	break;
	}
	return SDL_APP_CONTINUE;
}

SDL_AppResult SDL_AppIterate(void* appstate)
{
	SDL_FRect rect;

	SDL_SetRenderDrawColor(g_renderer, 0, 99, 177, SDL_ALPHA_OPAQUE);
	SDL_RenderClear(g_renderer);

	_drawGrid();
	_drawTriangles();
	_drawAction();
	_drawPixelSample();
	_drawMouseCursor();
	_drawDebugText();

	SDL_RenderPresent(g_renderer);  /* put it all on the screen! */
	return SDL_APP_CONTINUE;
}

/* This function runs once at shutdown. */
void SDL_AppQuit(void* appstate, SDL_AppResult result)
{
}