nanovg/example/demo.c

#include "demo.h"
#include <stdio.h>
#include <string.h>
#include <math.h>
#ifdef NANOVG_GLEW
#  include <GL/glew.h>
#endif
#include <GLFW/glfw3.h>
#include "nanovg.h"
#define STB_IMAGE_WRITE_IMPLEMENTATION
#include "stb_image_write.h"


#ifdef _MSC_VER
#define snprintf _snprintf
#elif !defined(__MINGW32__)
#include <iconv.h>
#endif

#define ICON_SEARCH 0x1F50D
#define ICON_CIRCLED_CROSS 0x2716
#define ICON_CHEVRON_RIGHT 0xE75E
#define ICON_CHECK 0x2713
#define ICON_LOGIN 0xE740
#define ICON_TRASH 0xE729

//static float minf(float a, float b) { return a < b ? a : b; }
static float maxf(float a, float b) { return a > b ? a : b; }
//static float absf(float a) { return a >= 0.0f ? a : -a; }
static float clampf(float a, float mn, float mx) { return a < mn ? mn : (a > mx ? mx : a); }

// Returns 1 if col.rgba is 0.0f,0.0f,0.0f,0.0f, 0 otherwise
int isBlack( struct NVGcolor col )
{
	if( col.r == 0.0f && col.g == 0.0f && col.b == 0.0f && col.a == 0.0f )
	{
		return 1;
	}
	return 0;
}

static char* cpToUTF8(int cp, char* str)
{
	int n = 0;
	if (cp < 0x80) n = 1;
	else if (cp < 0x800) n = 2;
	else if (cp < 0x10000) n = 3;
	else if (cp < 0x200000) n = 4;
	else if (cp < 0x4000000) n = 5;
	else if (cp <= 0x7fffffff) n = 6;
	str[n] = '\0';
	switch (n) {
	case 6: str[5] = 0x80 | (cp & 0x3f); cp = cp >> 6; cp |= 0x4000000;
	case 5: str[4] = 0x80 | (cp & 0x3f); cp = cp >> 6; cp |= 0x200000;
	case 4: str[3] = 0x80 | (cp & 0x3f); cp = cp >> 6; cp |= 0x10000;
	case 3: str[2] = 0x80 | (cp & 0x3f); cp = cp >> 6; cp |= 0x800;
	case 2: str[1] = 0x80 | (cp & 0x3f); cp = cp >> 6; cp |= 0xc0;
	case 1: str[0] = cp;
	}
	return str;
}


void drawWindow(struct NVGcontext* vg, const char* title, float x, float y, float w, float h)
{
	float cornerRadius = 3.0f;
	struct NVGpaint shadowPaint;
	struct NVGpaint headerPaint;

	nvgSave(vg);
//	nvgClearState(vg);

	// Window
	nvgBeginPath(vg);
	nvgRoundedRect(vg, x,y, w,h, cornerRadius);
	nvgFillColor(vg, nvgRGBA(28,30,34,192));
//	nvgFillColor(vg, nvgRGBA(0,0,0,128));
	nvgFill(vg);

	// Drop shadow
	shadowPaint = nvgBoxGradient(vg, x,y+2, w,h, cornerRadius*2, 10, nvgRGBA(0,0,0,128), nvgRGBA(0,0,0,0));
	nvgBeginPath(vg);
	nvgRect(vg, x-10,y-10, w+20,h+30);
	nvgRoundedRect(vg, x,y, w,h, cornerRadius);
	nvgPathWinding(vg, NVG_HOLE);
	nvgFillPaint(vg, shadowPaint);
	nvgFill(vg);

	// Header
	headerPaint = nvgLinearGradient(vg, x,y,x,y+15, nvgRGBA(255,255,255,8), nvgRGBA(0,0,0,16));
	nvgBeginPath(vg);
	nvgRoundedRect(vg, x+1,y+1, w-2,30, cornerRadius-1);
	nvgFillPaint(vg, headerPaint);
	nvgFill(vg);
	nvgBeginPath(vg);
	nvgMoveTo(vg, x+0.5f, y+0.5f+30);
	nvgLineTo(vg, x+0.5f+w-1, y+0.5f+30);
	nvgStrokeColor(vg, nvgRGBA(0,0,0,32));
	nvgStroke(vg);

	nvgFontSize(vg, 18.0f);
	nvgFontFace(vg, "sans-bold");
	nvgTextAlign(vg,NVG_ALIGN_CENTER|NVG_ALIGN_MIDDLE);

	nvgFontBlur(vg,2);
	nvgFillColor(vg, nvgRGBA(0,0,0,128));
	nvgText(vg, x+w/2,y+16+1, title, NULL);

	nvgFontBlur(vg,0);
	nvgFillColor(vg, nvgRGBA(220,220,220,160));
	nvgText(vg, x+w/2,y+16, title, NULL);

	nvgRestore(vg);
}

void drawSearchBox(struct NVGcontext* vg, const char* text, float x, float y, float w, float h)
{
	struct NVGpaint bg;
	char icon[8];
	float cornerRadius = h/2-1;

	// Edit
	bg = nvgBoxGradient(vg, x,y+1.5f, w,h, h/2,5, nvgRGBA(0,0,0,16), nvgRGBA(0,0,0,92));
	nvgBeginPath(vg);
	nvgRoundedRect(vg, x,y, w,h, cornerRadius);
	nvgFillPaint(vg, bg);
	nvgFill(vg);

/*	nvgBeginPath(vg);
	nvgRoundedRect(vg, x+0.5f,y+0.5f, w-1,h-1, cornerRadius-0.5f);
	nvgStrokeColor(vg, nvgRGBA(0,0,0,48));
	nvgStroke(vg);*/

	nvgFontSize(vg, h*1.3f);
	nvgFontFace(vg, "icons");
	nvgFillColor(vg, nvgRGBA(255,255,255,64));
	nvgTextAlign(vg,NVG_ALIGN_CENTER|NVG_ALIGN_MIDDLE);
	nvgText(vg, x+h*0.55f, y+h*0.55f, cpToUTF8(ICON_SEARCH,icon), NULL);

	nvgFontSize(vg, 20.0f);
	nvgFontFace(vg, "sans");
	nvgFillColor(vg, nvgRGBA(255,255,255,32));

	nvgTextAlign(vg,NVG_ALIGN_LEFT|NVG_ALIGN_MIDDLE);
	nvgText(vg, x+h*1.05f,y+h*0.5f,text, NULL);

	nvgFontSize(vg, h*1.3f);
	nvgFontFace(vg, "icons");
	nvgFillColor(vg, nvgRGBA(255,255,255,32));
	nvgTextAlign(vg,NVG_ALIGN_CENTER|NVG_ALIGN_MIDDLE);
	nvgText(vg, x+w-h*0.55f, y+h*0.55f, cpToUTF8(ICON_CIRCLED_CROSS,icon), NULL);
}

void drawDropDown(struct NVGcontext* vg, const char* text, float x, float y, float w, float h)
{
	struct NVGpaint bg;
	char icon[8];
	float cornerRadius = 4.0f;

	bg = nvgLinearGradient(vg, x,y,x,y+h, nvgRGBA(255,255,255,16), nvgRGBA(0,0,0,16));
	nvgBeginPath(vg);
	nvgRoundedRect(vg, x+1,y+1, w-2,h-2, cornerRadius-1);
	nvgFillPaint(vg, bg);
	nvgFill(vg);

	nvgBeginPath(vg);
	nvgRoundedRect(vg, x+0.5f,y+0.5f, w-1,h-1, cornerRadius-0.5f);
	nvgStrokeColor(vg, nvgRGBA(0,0,0,48));
	nvgStroke(vg);

	nvgFontSize(vg, 20.0f);
	nvgFontFace(vg, "sans");
	nvgFillColor(vg, nvgRGBA(255,255,255,160));
	nvgTextAlign(vg,NVG_ALIGN_LEFT|NVG_ALIGN_MIDDLE);
	nvgText(vg, x+h*0.3f,y+h*0.5f,text, NULL);

	nvgFontSize(vg, h*1.3f);
	nvgFontFace(vg, "icons");
	nvgFillColor(vg, nvgRGBA(255,255,255,64));
	nvgTextAlign(vg,NVG_ALIGN_CENTER|NVG_ALIGN_MIDDLE);
	nvgText(vg, x+w-h*0.5f, y+h*0.5f, cpToUTF8(ICON_CHEVRON_RIGHT,icon), NULL);
}

void drawLabel(struct NVGcontext* vg, const char* text, float x, float y, float w, float h)
{
	NVG_NOTUSED(w);

	nvgFontSize(vg, 18.0f);
	nvgFontFace(vg, "sans");
	nvgFillColor(vg, nvgRGBA(255,255,255,128));

	nvgTextAlign(vg,NVG_ALIGN_LEFT|NVG_ALIGN_MIDDLE);
	nvgText(vg, x,y+h*0.5f,text, NULL);
}

void drawEditBoxBase(struct NVGcontext* vg, float x, float y, float w, float h)
{
	struct NVGpaint bg;
	// Edit
	bg = nvgBoxGradient(vg, x+1,y+1+1.5f, w-2,h-2, 3,4, nvgRGBA(255,255,255,32), nvgRGBA(32,32,32,32));
	nvgBeginPath(vg);
	nvgRoundedRect(vg, x+1,y+1, w-2,h-2, 4-1);
	nvgFillPaint(vg, bg);
	nvgFill(vg);

	nvgBeginPath(vg);
	nvgRoundedRect(vg, x+0.5f,y+0.5f, w-1,h-1, 4-0.5f);
	nvgStrokeColor(vg, nvgRGBA(0,0,0,48));
	nvgStroke(vg);
}

void drawEditBox(struct NVGcontext* vg, const char* text, float x, float y, float w, float h)
{

	drawEditBoxBase(vg, x,y, w,h);

	nvgFontSize(vg, 20.0f);
	nvgFontFace(vg, "sans");
	nvgFillColor(vg, nvgRGBA(255,255,255,64));
	nvgTextAlign(vg,NVG_ALIGN_LEFT|NVG_ALIGN_MIDDLE);
	nvgText(vg, x+h*0.3f,y+h*0.5f,text, NULL);
}

void drawEditBoxNum(struct NVGcontext* vg,
					const char* text, const char* units, float x, float y, float w, float h)
{
	float uw;

	drawEditBoxBase(vg, x,y, w,h);

	uw = nvgTextBounds(vg, 0,0, units, NULL, NULL);

	nvgFontSize(vg, 18.0f);
	nvgFontFace(vg, "sans");
	nvgFillColor(vg, nvgRGBA(255,255,255,64));
	nvgTextAlign(vg,NVG_ALIGN_RIGHT|NVG_ALIGN_MIDDLE);
	nvgText(vg, x+w-h*0.3f,y+h*0.5f,units, NULL);

	nvgFontSize(vg, 20.0f);
	nvgFontFace(vg, "sans");
	nvgFillColor(vg, nvgRGBA(255,255,255,128));
	nvgTextAlign(vg,NVG_ALIGN_RIGHT|NVG_ALIGN_MIDDLE);
	nvgText(vg, x+w-uw-h*0.5f,y+h*0.5f,text, NULL);
}

void drawCheckBox(struct NVGcontext* vg, const char* text, float x, float y, float w, float h)
{
	struct NVGpaint bg;
	char icon[8];
	NVG_NOTUSED(w);

	nvgFontSize(vg, 18.0f);
	nvgFontFace(vg, "sans");
	nvgFillColor(vg, nvgRGBA(255,255,255,160));

	nvgTextAlign(vg,NVG_ALIGN_LEFT|NVG_ALIGN_MIDDLE);
	nvgText(vg, x+28,y+h*0.5f,text, NULL);

	bg = nvgBoxGradient(vg, x+1,y+(int)(h*0.5f)-9+1, 18,18, 3,3, nvgRGBA(0,0,0,32), nvgRGBA(0,0,0,92));
	nvgBeginPath(vg);
	nvgRoundedRect(vg, x+1,y+(int)(h*0.5f)-9, 18,18, 3);
	nvgFillPaint(vg, bg);
	nvgFill(vg);

	nvgFontSize(vg, 40);
	nvgFontFace(vg, "icons");
	nvgFillColor(vg, nvgRGBA(255,255,255,128));
	nvgTextAlign(vg,NVG_ALIGN_CENTER|NVG_ALIGN_MIDDLE);
	nvgText(vg, x+9+2, y+h*0.5f, cpToUTF8(ICON_CHECK,icon), NULL);
}

void drawButton(struct NVGcontext* vg, int preicon, const char* text, float x, float y, float w, float h, struct NVGcolor col)
{
	struct NVGpaint bg;
	char icon[8];
	float cornerRadius = 4.0f;
	float tw = 0, iw = 0;

	bg = nvgLinearGradient(vg, x,y,x,y+h, nvgRGBA(255,255,255,isBlack(col)?16:32), nvgRGBA(0,0,0,isBlack(col)?16:32));
	nvgBeginPath(vg);
	nvgRoundedRect(vg, x+1,y+1, w-2,h-2, cornerRadius-1);
	if (!isBlack(col)) {
		nvgFillColor(vg, col);
		nvgFill(vg);
	}
	nvgFillPaint(vg, bg);
	nvgFill(vg);

	nvgBeginPath(vg);
	nvgRoundedRect(vg, x+0.5f,y+0.5f, w-1,h-1, cornerRadius-0.5f);
	nvgStrokeColor(vg, nvgRGBA(0,0,0,48));
	nvgStroke(vg);

	nvgFontSize(vg, 20.0f);
	nvgFontFace(vg, "sans-bold");
	tw = nvgTextBounds(vg, 0,0, text, NULL, NULL);
	if (preicon != 0) {
		nvgFontSize(vg, h*1.3f);
		nvgFontFace(vg, "icons");
		iw = nvgTextBounds(vg, 0,0, cpToUTF8(preicon,icon), NULL, NULL);
		iw += h*0.15f;
	}

	if (preicon != 0) {
		nvgFontSize(vg, h*1.3f);
		nvgFontFace(vg, "icons");
		nvgFillColor(vg, nvgRGBA(255,255,255,96));
		nvgTextAlign(vg,NVG_ALIGN_LEFT|NVG_ALIGN_MIDDLE);
		nvgText(vg, x+w*0.5f-tw*0.5f-iw*0.75f, y+h*0.5f, cpToUTF8(preicon,icon), NULL);
	}

	nvgFontSize(vg, 20.0f);
	nvgFontFace(vg, "sans-bold");
	nvgTextAlign(vg,NVG_ALIGN_LEFT|NVG_ALIGN_MIDDLE);
	nvgFillColor(vg, nvgRGBA(0,0,0,160));
	nvgText(vg, x+w*0.5f-tw*0.5f+iw*0.25f,y+h*0.5f-1,text, NULL);
	nvgFillColor(vg, nvgRGBA(255,255,255,160));
	nvgText(vg, x+w*0.5f-tw*0.5f+iw*0.25f,y+h*0.5f,text, NULL);
}

void drawSlider(struct NVGcontext* vg, float pos, float x, float y, float w, float h)
{
	struct NVGpaint bg, knob;
	float cy = y+(int)(h*0.5f);
	float kr = (int)(h*0.25f);

	nvgSave(vg);
//	nvgClearState(vg);

	// Slot
	bg = nvgBoxGradient(vg, x,cy-2+1, w,4, 2,2, nvgRGBA(0,0,0,32), nvgRGBA(0,0,0,128));
	nvgBeginPath(vg);
	nvgRoundedRect(vg, x,cy-2, w,4, 2);
	nvgFillPaint(vg, bg);
	nvgFill(vg);

	// Knob Shadow
	bg = nvgRadialGradient(vg, x+(int)(pos*w),cy+1, kr-3,kr+3, nvgRGBA(0,0,0,64), nvgRGBA(0,0,0,0));
	nvgBeginPath(vg);
	nvgRect(vg, x+(int)(pos*w)-kr-5,cy-kr-5,kr*2+5+5,kr*2+5+5+3);
	nvgCircle(vg, x+(int)(pos*w),cy, kr);
	nvgPathWinding(vg, NVG_HOLE);
	nvgFillPaint(vg, bg);
	nvgFill(vg);

	// Knob
	knob = nvgLinearGradient(vg, x,cy-kr,x,cy+kr, nvgRGBA(255,255,255,16), nvgRGBA(0,0,0,16));
	nvgBeginPath(vg);
	nvgCircle(vg, x+(int)(pos*w),cy, kr-1);
	nvgFillColor(vg, nvgRGBA(40,43,48,255));
	nvgFill(vg);
	nvgFillPaint(vg, knob);
	nvgFill(vg);

	nvgBeginPath(vg);
	nvgCircle(vg, x+(int)(pos*w),cy, kr-0.5f);
	nvgStrokeColor(vg, nvgRGBA(0,0,0,92));
	nvgStroke(vg);

	nvgRestore(vg);
}

void drawEyes(struct NVGcontext* vg, float x, float y, float w, float h, float mx, float my, float t)
{
	struct NVGpaint gloss, bg;
	float ex = w *0.23f;
	float ey = h * 0.5f;
	float lx = x + ex;
	float ly = y + ey;
	float rx = x + w - ex;
	float ry = y + ey;
	float dx,dy,d;
	float br = (ex < ey ? ex : ey) * 0.5f;
	float blink = 1 - pow(sinf(t*0.5f),200)*0.8f;

	bg = nvgLinearGradient(vg, x,y+h*0.5f,x+w*0.1f,y+h, nvgRGBA(0,0,0,32), nvgRGBA(0,0,0,16));
	nvgBeginPath(vg);
	nvgEllipse(vg, lx+3.0f,ly+16.0f, ex,ey);
	nvgEllipse(vg, rx+3.0f,ry+16.0f, ex,ey);
	nvgFillPaint(vg, bg);
	nvgFill(vg);

	bg = nvgLinearGradient(vg, x,y+h*0.25f,x+w*0.1f,y+h, nvgRGBA(220,220,220,255), nvgRGBA(128,128,128,255));
	nvgBeginPath(vg);
	nvgEllipse(vg, lx,ly, ex,ey);
	nvgEllipse(vg, rx,ry, ex,ey);
	nvgFillPaint(vg, bg);
	nvgFill(vg);

	dx = (mx - rx) / (ex * 10);
	dy = (my - ry) / (ey * 10);
	d = sqrtf(dx*dx+dy*dy);
	if (d > 1.0f) {
		dx /= d; dy /= d;
	}
	dx *= ex*0.4f;
	dy *= ey*0.5f;
	nvgBeginPath(vg);
	nvgEllipse(vg, lx+dx,ly+dy+ey*0.25f*(1-blink), br,br*blink);
	nvgFillColor(vg, nvgRGBA(32,32,32,255));
	nvgFill(vg);

	dx = (mx - rx) / (ex * 10);
	dy = (my - ry) / (ey * 10);
	d = sqrtf(dx*dx+dy*dy);
	if (d > 1.0f) {
		dx /= d; dy /= d;
	}
	dx *= ex*0.4f;
	dy *= ey*0.5f;
	nvgBeginPath(vg);
	nvgEllipse(vg, rx+dx,ry+dy+ey*0.25f*(1-blink), br,br*blink);
	nvgFillColor(vg, nvgRGBA(32,32,32,255));
	nvgFill(vg);

	gloss = nvgRadialGradient(vg, lx-ex*0.25f,ly-ey*0.5f, ex*0.1f,ex*0.75f, nvgRGBA(255,255,255,128), nvgRGBA(255,255,255,0));
	nvgBeginPath(vg);
	nvgEllipse(vg, lx,ly, ex,ey);
	nvgFillPaint(vg, gloss);
	nvgFill(vg);

	gloss = nvgRadialGradient(vg, rx-ex*0.25f,ry-ey*0.5f, ex*0.1f,ex*0.75f, nvgRGBA(255,255,255,128), nvgRGBA(255,255,255,0));
	nvgBeginPath(vg);
	nvgEllipse(vg, rx,ry, ex,ey);
	nvgFillPaint(vg, gloss);
	nvgFill(vg);
}

void drawGraph(struct NVGcontext* vg, float x, float y, float w, float h, float t)
{
	struct NVGpaint bg;
	float samples[6];
	float sx[6], sy[6];
	float dx = w/5.0f;
	int i;

	samples[0] = (1+sinf(t*1.2345f+cosf(t*0.33457f)*0.44f))*0.5f;
	samples[1] = (1+sinf(t*0.68363f+cosf(t*1.3f)*1.55f))*0.5f;
	samples[2] = (1+sinf(t*1.1642f+cosf(t*0.33457)*1.24f))*0.5f;
	samples[3] = (1+sinf(t*0.56345f+cosf(t*1.63f)*0.14f))*0.5f;
	samples[4] = (1+sinf(t*1.6245f+cosf(t*0.254f)*0.3f))*0.5f;
	samples[5] = (1+sinf(t*0.345f+cosf(t*0.03f)*0.6f))*0.5f;

	for (i = 0; i < 6; i++) {
		sx[i] = x+i*dx;
		sy[i] = y+h*samples[i]*0.8f;
	}

	// Graph background
	bg = nvgLinearGradient(vg, x,y,x,y+h, nvgRGBA(0,160,192,0), nvgRGBA(0,160,192,64));
	nvgBeginPath(vg);
	nvgMoveTo(vg, sx[0], sy[0]);
	for (i = 1; i < 6; i++)
		nvgBezierTo(vg, sx[i-1]+dx*0.5f,sy[i-1], sx[i]-dx*0.5f,sy[i], sx[i],sy[i]);
	nvgLineTo(vg, x+w, y+h);
	nvgLineTo(vg, x, y+h);
	nvgFillPaint(vg, bg);
	nvgFill(vg);

	// Graph line
	nvgBeginPath(vg);
	nvgMoveTo(vg, sx[0], sy[0]+2);
	for (i = 1; i < 6; i++)
		nvgBezierTo(vg, sx[i-1]+dx*0.5f,sy[i-1]+2, sx[i]-dx*0.5f,sy[i]+2, sx[i],sy[i]+2);
	nvgStrokeColor(vg, nvgRGBA(0,0,0,32));
	nvgStrokeWidth(vg, 3.0f);
	nvgStroke(vg);

	nvgBeginPath(vg);
	nvgMoveTo(vg, sx[0], sy[0]);
	for (i = 1; i < 6; i++)
		nvgBezierTo(vg, sx[i-1]+dx*0.5f,sy[i-1], sx[i]-dx*0.5f,sy[i], sx[i],sy[i]);
	nvgStrokeColor(vg, nvgRGBA(0,160,192,255));
	nvgStrokeWidth(vg, 3.0f);
	nvgStroke(vg);

	// Graph sample pos
	for (i = 0; i < 6; i++) {
		bg = nvgRadialGradient(vg, sx[i],sy[i]+2, 3.0f,8.0f, nvgRGBA(0,0,0,32), nvgRGBA(0,0,0,0));
		nvgBeginPath(vg);
		nvgRect(vg, sx[i]-10, sy[i]-10+2, 20,20);
		nvgFillPaint(vg, bg);
		nvgFill(vg);
	}

	nvgBeginPath(vg);
	for (i = 0; i < 6; i++)
		nvgCircle(vg, sx[i], sy[i], 4.0f);
	nvgFillColor(vg, nvgRGBA(0,160,192,255));
	nvgFill(vg);
	nvgBeginPath(vg);
	for (i = 0; i < 6; i++)
		nvgCircle(vg, sx[i], sy[i], 2.0f);
	nvgFillColor(vg, nvgRGBA(220,220,220,255));
	nvgFill(vg);

	nvgStrokeWidth(vg, 1.0f);
}

void drawSpinner(struct NVGcontext* vg, float cx, float cy, float r, float t)
{
	float a0 = 0.0f + t*6;
	float a1 = NVG_PI + t*6;
	float r0 = r;
	float r1 = r * 0.75f;
	float ax,ay, bx,by;
	struct NVGpaint paint;

	nvgSave(vg);

	nvgBeginPath(vg);
	nvgArc(vg, cx,cy, r0, a0, a1, NVG_CW);
	nvgArc(vg, cx,cy, r1, a1, a0, NVG_CCW);
	nvgClosePath(vg);
	ax = cx + cosf(a0) * (r0+r1)*0.5f;
	ay = cy + sinf(a0) * (r0+r1)*0.5f;
	bx = cx + cosf(a1) * (r0+r1)*0.5f;
	by = cy + sinf(a1) * (r0+r1)*0.5f;
	paint = nvgLinearGradient(vg, ax,ay, bx,by, nvgRGBA(0,0,0,0), nvgRGBA(0,0,0,128));
	nvgFillPaint(vg, paint);
	nvgFill(vg);

	nvgRestore(vg);
}

void drawThumbnails(struct NVGcontext* vg, float x, float y, float w, float h, const int* images, int nimages, float t)
{
	float cornerRadius = 3.0f;
	struct NVGpaint shadowPaint, imgPaint, fadePaint;
	float ix,iy,iw,ih;
	float thumb = 60.0f;
	float arry = 30.5f;
	int imgw, imgh;
	float stackh = (nimages/2) * (thumb+10) + 10;
	int i;
	float u = (1+cosf(t*0.5f))*0.5f;
	float u2 = (1-cosf(t*0.2f))*0.5f;
	float scrollh, dv;

	nvgSave(vg);
//	nvgClearState(vg);

	// Drop shadow
	shadowPaint = nvgBoxGradient(vg, x,y+4, w,h, cornerRadius*2, 20, nvgRGBA(0,0,0,128), nvgRGBA(0,0,0,0));
	nvgBeginPath(vg);
	nvgRect(vg, x-10,y-10, w+20,h+30);
	nvgRoundedRect(vg, x,y, w,h, cornerRadius);
	nvgPathWinding(vg, NVG_HOLE);
	nvgFillPaint(vg, shadowPaint);
	nvgFill(vg);

	// Window
	nvgBeginPath(vg);
	nvgRoundedRect(vg, x,y, w,h, cornerRadius);
	nvgMoveTo(vg, x-10,y+arry);
	nvgLineTo(vg, x+1,y+arry-11);
	nvgLineTo(vg, x+1,y+arry+11);
	nvgFillColor(vg, nvgRGBA(200,200,200,255));
	nvgFill(vg);

	nvgSave(vg);
	nvgScissor(vg, x,y,w,h);
	nvgTranslate(vg, 0, -(stackh - h)*u);

	dv = 1.0f / (float)(nimages-1);

	for (i = 0; i < nimages; i++) {
		float tx, ty, v, a;
		tx = x+10;
		ty = y+10;
		tx += (i%2) * (thumb+10);
		ty += (i/2) * (thumb+10);
		nvgImageSize(vg, images[i], &imgw, &imgh);
		if (imgw < imgh) {
			iw = thumb;
			ih = iw * (float)imgh/(float)imgw;
			ix = 0;
			iy = -(ih-thumb)*0.5f;
		} else {
			ih = thumb;
			iw = ih * (float)imgw/(float)imgh;
			ix = -(iw-thumb)*0.5f;
			iy = 0;
		}

		v = i * dv;
		a = clampf((u2-v) / dv, 0, 1);

		if (a < 1.0f)
			drawSpinner(vg, tx+thumb/2,ty+thumb/2, thumb*0.25f, t);

		imgPaint = nvgImagePattern(vg, tx+ix, ty+iy, iw,ih, 0.0f/180.0f*NVG_PI, images[i], NVG_NOREPEAT, a);
		nvgBeginPath(vg);
		nvgRoundedRect(vg, tx,ty, thumb,thumb, 5);
		nvgFillPaint(vg, imgPaint);
		nvgFill(vg);

		shadowPaint = nvgBoxGradient(vg, tx-1,ty, thumb+2,thumb+2, 5, 3, nvgRGBA(0,0,0,128), nvgRGBA(0,0,0,0));
		nvgBeginPath(vg);
		nvgRect(vg, tx-5,ty-5, thumb+10,thumb+10);
		nvgRoundedRect(vg, tx,ty, thumb,thumb, 6);
		nvgPathWinding(vg, NVG_HOLE);
		nvgFillPaint(vg, shadowPaint);
		nvgFill(vg);

		nvgBeginPath(vg);
		nvgRoundedRect(vg, tx+0.5f,ty+0.5f, thumb-1,thumb-1, 4-0.5f);
		nvgStrokeWidth(vg,1.0f);
		nvgStrokeColor(vg, nvgRGBA(255,255,255,192));
		nvgStroke(vg);
	}
	nvgRestore(vg);

	// Hide fades
	fadePaint = nvgLinearGradient(vg, x,y,x,y+6, nvgRGBA(200,200,200,255), nvgRGBA(200,200,200,0));
	nvgBeginPath(vg);
	nvgRect(vg, x+4,y,w-8,6);
	nvgFillPaint(vg, fadePaint);
	nvgFill(vg);

	fadePaint = nvgLinearGradient(vg, x,y+h,x,y+h-6, nvgRGBA(200,200,200,255), nvgRGBA(200,200,200,0));
	nvgBeginPath(vg);
	nvgRect(vg, x+4,y+h-6,w-8,6);
	nvgFillPaint(vg, fadePaint);
	nvgFill(vg);

	// Scroll bar
	shadowPaint = nvgBoxGradient(vg, x+w-12+1,y+4+1, 8,h-8, 3,4, nvgRGBA(0,0,0,32), nvgRGBA(0,0,0,92));
	nvgBeginPath(vg);
	nvgRoundedRect(vg, x+w-12,y+4, 8,h-8, 3);
	nvgFillPaint(vg, shadowPaint);
//	nvgFillColor(vg, nvgRGBA(255,0,0,128));
	nvgFill(vg);

	scrollh = (h/stackh) * (h-8);
	shadowPaint = nvgBoxGradient(vg, x+w-12-1,y+4+(h-8-scrollh)*u-1, 8,scrollh, 3,4, nvgRGBA(220,220,220,255), nvgRGBA(128,128,128,255));
	nvgBeginPath(vg);
	nvgRoundedRect(vg, x+w-12+1,y+4+1 + (h-8-scrollh)*u, 8-2,scrollh-2, 2);
	nvgFillPaint(vg, shadowPaint);
//	nvgFillColor(vg, nvgRGBA(0,0,0,128));
	nvgFill(vg);

	nvgRestore(vg);
}

void drawColorwheel(struct NVGcontext* vg, float x, float y, float w, float h, float t)
{
	int i;
	float r0, r1, ax,ay, bx,by, cx,cy, aeps, r;
	float hue = sinf(t * 0.12f);
	struct NVGpaint paint;

	nvgSave(vg);

/*	nvgBeginPath(vg);
	nvgRect(vg, x,y,w,h);
	nvgFillColor(vg, nvgRGBA(255,0,0,128));
	nvgFill(vg);*/

	cx = x + w*0.5f;
	cy = y + h*0.5f;
	r1 = (w < h ? w : h) * 0.5f - 5.0f;
	r0 = r1 - 20.0f;
	aeps = 0.5f / r1;	// half a pixel arc length in radians (2pi cancels out).

	for (i = 0; i < 6; i++) {
		float a0 = (float)i / 6.0f * NVG_PI * 2.0f - aeps;
		float a1 = (float)(i+1.0f) / 6.0f * NVG_PI * 2.0f + aeps;
		nvgBeginPath(vg);
		nvgArc(vg, cx,cy, r0, a0, a1, NVG_CW);
		nvgArc(vg, cx,cy, r1, a1, a0, NVG_CCW);
		nvgClosePath(vg);
		ax = cx + cosf(a0) * (r0+r1)*0.5f;
		ay = cy + sinf(a0) * (r0+r1)*0.5f;
		bx = cx + cosf(a1) * (r0+r1)*0.5f;
		by = cy + sinf(a1) * (r0+r1)*0.5f;
		paint = nvgLinearGradient(vg, ax,ay, bx,by, nvgHSLA(a0/(NVG_PI*2),1.0f,0.55f,255), nvgHSLA(a1/(NVG_PI*2),1.0f,0.55f,255));
		nvgFillPaint(vg, paint);
		nvgFill(vg);
	}

	nvgBeginPath(vg);
	nvgCircle(vg, cx,cy, r0-0.5f);
	nvgCircle(vg, cx,cy, r1+0.5f);
	nvgStrokeColor(vg, nvgRGBA(0,0,0,64));
	nvgStrokeWidth(vg, 1.0f);
	nvgStroke(vg);

	// Selector
	nvgSave(vg);
	nvgTranslate(vg, cx,cy);
	nvgRotate(vg, hue*NVG_PI*2);

	// Marker on
	nvgStrokeWidth(vg, 2.0f);
	nvgBeginPath(vg);
	nvgRect(vg, r0-1,-3,r1-r0+2,6);
	nvgStrokeColor(vg, nvgRGBA(255,255,255,192));
	nvgStroke(vg);

	paint = nvgBoxGradient(vg, r0-3,-5,r1-r0+6,10, 2,4, nvgRGBA(0,0,0,128), nvgRGBA(0,0,0,0));
	nvgBeginPath(vg);
	nvgRect(vg, r0-2-10,-4-10,r1-r0+4+20,8+20);
	nvgRect(vg, r0-2,-4,r1-r0+4,8);
	nvgPathWinding(vg, NVG_HOLE);
	nvgFillPaint(vg, paint);
	nvgFill(vg);

	// Center triangle
	r = r0 - 6;
	ax = cosf(120.0f/180.0f*NVG_PI) * r;
	ay = sinf(120.0f/180.0f*NVG_PI) * r;
	bx = cosf(-120.0f/180.0f*NVG_PI) * r;
	by = sinf(-120.0f/180.0f*NVG_PI) * r;
	nvgBeginPath(vg);
	nvgMoveTo(vg, r,0);
	nvgLineTo(vg, ax,ay);
	nvgLineTo(vg, bx,by);
	nvgClosePath(vg);
	paint = nvgLinearGradient(vg, r,0, ax,ay, nvgHSLA(hue,1.0f,0.5f,255), nvgRGBA(255,255,255,255));
	nvgFillPaint(vg, paint);
	nvgFill(vg);
	paint = nvgLinearGradient(vg, (r+ax)*0.5f,(0+ay)*0.5f, bx,by, nvgRGBA(0,0,0,0), nvgRGBA(0,0,0,255));
	nvgFillPaint(vg, paint);
	nvgFill(vg);
	nvgStrokeColor(vg, nvgRGBA(0,0,0,64));
	nvgStroke(vg);

	// Select circle on triangle
	ax = cosf(120.0f/180.0f*NVG_PI) * r*0.3f;
	ay = sinf(120.0f/180.0f*NVG_PI) * r*0.4f;
	nvgStrokeWidth(vg, 2.0f);
	nvgBeginPath(vg);
	nvgCircle(vg, ax,ay,5);
	nvgStrokeColor(vg, nvgRGBA(255,255,255,192));
	nvgStroke(vg);

	paint = nvgRadialGradient(vg, ax,ay, 7,9, nvgRGBA(0,0,0,64), nvgRGBA(0,0,0,0));
	nvgBeginPath(vg);
	nvgRect(vg, ax-20,ay-20,40,40);
	nvgCircle(vg, ax,ay,7);
	nvgPathWinding(vg, NVG_HOLE);
	nvgFillPaint(vg, paint);
	nvgFill(vg);

	nvgRestore(vg);

	nvgRestore(vg);
}

void drawLines(struct NVGcontext* vg, float x, float y, float w, float h, float t)
{
	int i, j;
	float pad = 5.0f, s = w/9.0f - pad*2;
	float pts[4*2], fx, fy;
	int joins[3] = {NVG_MITER, NVG_ROUND, NVG_BEVEL};
	int caps[3] = {NVG_BUTT, NVG_ROUND, NVG_SQUARE};
	NVG_NOTUSED(h);

	nvgSave(vg);
	pts[0] = -s*0.25f + cosf(t*0.3f) * s*0.5f;
	pts[1] = sinf(t*0.3f) * s*0.5f;
	pts[2] = -s*0.25;
	pts[3] = 0;
	pts[4] = s*0.25f;
	pts[5] = 0;
	pts[6] = s*0.25f + cosf(-t*0.3f) * s*0.5f;
	pts[7] = sinf(-t*0.3f) * s*0.5f;

	for (i = 0; i < 3; i++) {
		for (j = 0; j < 3; j++) {
			fx = x + s*0.5f + (i*3+j)/9.0f*w + pad;
			fy = y - s*0.5f + pad;

			nvgLineCap(vg, caps[i]);
			nvgLineJoin(vg, joins[j]);

			nvgStrokeWidth(vg, s*0.3f);
			nvgStrokeColor(vg, nvgRGBA(0,0,0,160));
			nvgBeginPath(vg);
			nvgMoveTo(vg, fx+pts[0], fy+pts[1]);
			nvgLineTo(vg, fx+pts[2], fy+pts[3]);
			nvgLineTo(vg, fx+pts[4], fy+pts[5]);
			nvgLineTo(vg, fx+pts[6], fy+pts[7]);
			nvgStroke(vg);

			nvgLineCap(vg, NVG_BUTT);
			nvgLineJoin(vg, NVG_BEVEL);

			nvgStrokeWidth(vg, 1.0f);
			nvgStrokeColor(vg, nvgRGBA(0,192,255,255));
			nvgBeginPath(vg);
			nvgMoveTo(vg, fx+pts[0], fy+pts[1]);
			nvgLineTo(vg, fx+pts[2], fy+pts[3]);
			nvgLineTo(vg, fx+pts[4], fy+pts[5]);
			nvgLineTo(vg, fx+pts[6], fy+pts[7]);
			nvgStroke(vg);
		}
	}


	nvgRestore(vg);
}

int loadDemoData(struct NVGcontext* vg, struct DemoData* data)
{
	int i;

	if (vg == NULL)
		return -1;

	for (i = 0; i < 12; i++) {
		char file[128];
		snprintf(file, 128, "../example/images/image%d.jpg", i+1);
		data->images[i] = nvgCreateImage(vg, file, 0);
		if (data->images[i] == 0) {
			printf("Could not load %s.\n", file);
			return -1;
		}
	}

	data->fontIcons = nvgCreateFont(vg, "icons", "../example/entypo.ttf");
	if (data->fontIcons == -1) {
		printf("Could not add font icons.\n");
		return -1;
	}
	data->fontNormal = nvgCreateFont(vg, "sans", "../example/Roboto-Regular.ttf");
	if (data->fontNormal == -1) {
		printf("Could not add font italic.\n");
		return -1;
	}
	data->fontBold = nvgCreateFont(vg, "sans-bold", "../example/Roboto-Bold.ttf");
	if (data->fontBold == -1) {
		printf("Could not add font bold.\n");
		return -1;
	}

	return 0;
}

void freeDemoData(struct NVGcontext* vg, struct DemoData* data)
{
	int i;

	if (vg == NULL)
		return;

	for (i = 0; i < 12; i++)
		nvgDeleteImage(vg, data->images[i]);
}

void drawParagraph(struct NVGcontext* vg, float x, float y, float width, float height, float mx, float my)
{
	struct NVGtextRow rows[3];
	struct NVGglyphPosition glyphs[100];
	const char* text = "This is longer chunk of text.\n  \n  Would have used lorem ipsum but she    was busy jumping over the lazy dog with the fox and all the men who came to the aid of the party.";
	const char* start;
	const char* end;
	int nrows, i, nglyphs, j, lnum = 0;
	float lineh;
	float caretx, px;
	float bounds[4];
	float a;
	float gx,gy;
	int gutter = 0;
	NVG_NOTUSED(height);

	nvgSave(vg);

	nvgFontSize(vg, 18.0f);
	nvgFontFace(vg, "sans");
	nvgTextAlign(vg, NVG_ALIGN_LEFT|NVG_ALIGN_TOP);
	nvgTextMetrics(vg, NULL, NULL, &lineh);

	// The text break API can be used to fill a large buffer of rows,
	// or to iterate over the text just few lines (or just one) at a time.
	// The "next" variable of the last returned item tells where to continue.
	start = text;
	end = text + strlen(text);
	while ((nrows = nvgTextBreakLines(vg, start, end, width, rows, 3))) {
		for (i = 0; i < nrows; i++) {
			struct NVGtextRow* row = &rows[i];
			int hit = mx > x && mx < (x+width) && my >= y && my < (y+lineh);

			nvgBeginPath(vg);
			nvgFillColor(vg, nvgRGBA(255,255,255,hit?64:16));
			nvgRect(vg, x, y, row->width, lineh);
			nvgFill(vg);

			nvgFillColor(vg, nvgRGBA(255,255,255,255));
			nvgText(vg, x, y, row->start, row->end);

			if (hit) {
				caretx = (mx < x+row->width/2) ? x : x+row->width;
				px = x;
				nglyphs = nvgTextGlyphPositions(vg, x, y, row->start, row->end, glyphs, 100);
				for (j = 0; j < nglyphs; j++) {
					float x0 = glyphs[j].x;
					float x1 = (j+1 < nglyphs) ? glyphs[j+1].x : x+row->width;
					float gx = x0 * 0.3f + x1 * 0.7f;
					if (mx >= px && mx < gx)
						caretx = glyphs[j].x;
					px = gx;
				}
				nvgBeginPath(vg);
				nvgFillColor(vg, nvgRGBA(255,192,0,255));
				nvgRect(vg, caretx, y, 1, lineh);
				nvgFill(vg);

				gutter = lnum+1;
				gx = x - 10;
				gy = y + lineh/2;
			}
			lnum++;
			y += lineh;
		}
		// Keep going...
		start = rows[nrows-1].next;
	}

	if (gutter) {
		char txt[16];
		snprintf(txt, sizeof(txt), "%d", gutter);
		nvgFontSize(vg, 13.0f);
		nvgTextAlign(vg, NVG_ALIGN_RIGHT|NVG_ALIGN_MIDDLE);

		nvgTextBounds(vg, gx,gy, txt, NULL, bounds);

		nvgBeginPath(vg);
		nvgFillColor(vg, nvgRGBA(255,192,0,255));
		nvgRoundedRect(vg, (int)bounds[0]-4,(int)bounds[1]-2, (int)(bounds[2]-bounds[0])+8, (int)(bounds[3]-bounds[1])+4, ((int)(bounds[3]-bounds[1])+4)/2-1);
		nvgFill(vg);

		nvgFillColor(vg, nvgRGBA(32,32,32,255));
		nvgText(vg, gx,gy, txt, NULL);
	}

	y += 20.0f;

	nvgFontSize(vg, 13.0f);
	nvgTextAlign(vg, NVG_ALIGN_LEFT|NVG_ALIGN_TOP);
	nvgTextLineHeight(vg, 1.2f);

	nvgTextBoxBounds(vg, x,y, 150, "Hover your mouse over the text to see calculated caret position.", NULL, bounds);

	// Fade the tooltip out when close to it.
	gx = fabsf((mx - (bounds[0]+bounds[2])*0.5f) / (bounds[0] - bounds[2]));
	gy = fabsf((my - (bounds[1]+bounds[3])*0.5f) / (bounds[1] - bounds[3]));
	a = maxf(gx, gy) - 0.5f;
	a = clampf(a, 0, 1);
	nvgGlobalAlpha(vg, a);

	nvgBeginPath(vg);
	nvgFillColor(vg, nvgRGBA(220,220,220,255));
	nvgRoundedRect(vg, bounds[0]-2,bounds[1]-2, (int)(bounds[2]-bounds[0])+4, (int)(bounds[3]-bounds[1])+4, 3);
	px = (int)((bounds[2]+bounds[0])/2);
	nvgMoveTo(vg, px,bounds[1] - 10);
	nvgLineTo(vg, px+7,bounds[1]+1);
	nvgLineTo(vg, px-7,bounds[1]+1);
	nvgFill(vg);

	nvgFillColor(vg, nvgRGBA(0,0,0,220));
	nvgTextBox(vg, x,y, 150, "Hover your mouse over the text to see calculated caret position.", NULL);

	nvgRestore(vg);
}

void drawWidths(struct NVGcontext* vg, float x, float y, float width)
{
	int i;

	nvgSave(vg);

	nvgStrokeColor(vg, nvgRGBA(0,0,0,255));

	for (i = 0; i < 20; i++) {
		float w = (i+0.5f)*0.1f;
		nvgStrokeWidth(vg, w);
		nvgBeginPath(vg);
		nvgMoveTo(vg, x,y);
		nvgLineTo(vg, x+width,y+width*0.3f);
		nvgStroke(vg);
		y += 10;
	}

	nvgRestore(vg);
}

void drawCaps(struct NVGcontext* vg, float x, float y, float width)
{
	int i;
	int caps[3] = {NVG_BUTT, NVG_ROUND, NVG_SQUARE};
	float lineWidth = 8.0f;

	nvgSave(vg);

	nvgBeginPath(vg);
	nvgRect(vg, x-lineWidth/2, y, width+lineWidth, 40);
	nvgFillColor(vg, nvgRGBA(255,255,255,32));
	nvgFill(vg);

	nvgBeginPath(vg);
	nvgRect(vg, x, y, width, 40);
	nvgFillColor(vg, nvgRGBA(255,255,255,32));
	nvgFill(vg);

	nvgStrokeWidth(vg, lineWidth);
	for (i = 0; i < 3; i++) {
		nvgLineCap(vg, caps[i]);
		nvgStrokeColor(vg, nvgRGBA(0,0,0,255));
		nvgBeginPath(vg);
		nvgMoveTo(vg, x, y + i*10 + 5);
		nvgLineTo(vg, x+width, y + i*10 + 5);
		nvgStroke(vg);
	}

	nvgRestore(vg);
}

void renderDemo(struct NVGcontext* vg, float mx, float my, float width, float height,
				float t, int blowup, struct DemoData* data)
{
	float x,y,popy;

	drawEyes(vg, width - 250, 50, 150, 100, mx, my, t);
	drawParagraph(vg, width - 450, 50, 150, 100, mx, my);
	drawGraph(vg, 0, height/2, width, height/2, t);
	drawColorwheel(vg, width - 300, height - 300, 250.0f, 250.0f, t);

	// Line joints
	drawLines(vg, 50, height-50, 600, 50, t);

	// Line caps
	drawWidths(vg, 10, 50, 30);

	// Line caps
	drawCaps(vg, 10, 300, 30);

	nvgSave(vg);
	if (blowup) {
		nvgRotate(vg, sinf(t*0.3f)*5.0f/180.0f*NVG_PI);
		nvgScale(vg, 2.0f, 2.0f);
	}

	// Widgets
	drawWindow(vg, "Widgets `n Stuff", 50, 50, 300, 400);
	x = 60; y = 95;
	drawSearchBox(vg, "Search", x,y,280,25);
	y += 40;
	drawDropDown(vg, "Effects", x,y,280,28);
	popy = y + 14;
	y += 45;

	// Form
	drawLabel(vg, "Login", x,y, 280,20);
	y += 25;
	drawEditBox(vg, "Email",  x,y, 280,28);
	y += 35;
	drawEditBox(vg, "Password", x,y, 280,28);
	y += 38;
	drawCheckBox(vg, "Remember me", x,y, 140,28);
	drawButton(vg, ICON_LOGIN, "Sign in", x+138, y, 140, 28, nvgRGBA(0,96,128,255));
	y += 45;

	// Slider
	drawLabel(vg, "Diameter", x,y, 280,20);
	y += 25;
	drawEditBoxNum(vg, "123.00", "px", x+180,y, 100,28);
	drawSlider(vg, 0.4f, x,y, 170,28);
	y += 55;

	drawButton(vg, ICON_TRASH, "Delete", x, y, 160, 28, nvgRGBA(128,16,8,255));
	drawButton(vg, 0, "Cancel", x+170, y, 110, 28, nvgRGBA(0,0,0,0));

	// Thumbnails box
	drawThumbnails(vg, 365, popy-30, 160, 300, data->images, 12, t);

	nvgRestore(vg);
}

static int mini(int a, int b) { return a < b ? a : b; }

static void unpremultiplyAlpha(unsigned char* image, int w, int h, int stride)
{
	int x,y;

	// Unpremultiply
	for (y = 0; y < h; y++) {
		unsigned char *row = &image[y*stride];
		for (x = 0; x < w; x++) {
			int r = row[0], g = row[1], b = row[2], a = row[3];
			if (a != 0) {
				row[0] = (int)mini(r*255/a, 255);
				row[1] = (int)mini(g*255/a, 255);
				row[2] = (int)mini(b*255/a, 255);
			}
			row += 4;
		}
	}

	// Defringe
	for (y = 0; y < h; y++) {
		unsigned char *row = &image[y*stride];
		for (x = 0; x < w; x++) {
			int r = 0, g = 0, b = 0, a = row[3], n = 0;
			if (a == 0) {
				if (x-1 > 0 && row[-1] != 0) {
					r += row[-4];
					g += row[-3];
					b += row[-2];
					n++;
				}
				if (x+1 < w && row[7] != 0) {
					r += row[4];
					g += row[5];
					b += row[6];
					n++;
				}
				if (y-1 > 0 && row[-stride+3] != 0) {
					r += row[-stride];
					g += row[-stride+1];
					b += row[-stride+2];
					n++;
				}
				if (y+1 < h && row[stride+3] != 0) {
					r += row[stride];
					g += row[stride+1];
					b += row[stride+2];
					n++;
				}
				if (n > 0) {
					row[0] = r/n;
					row[1] = g/n;
					row[2] = b/n;
				}
			}
			row += 4;
		}
	}
}

static void setAlpha(unsigned char* image, int w, int h, int stride, unsigned char a)
{
	int x, y;
	for (y = 0; y < h; y++) {
		unsigned char* row = &image[y*stride];
		for (x = 0; x < w; x++)
			row[x*4+3] = a;
	}
}

static void flipHorizontal(unsigned char* image, int w, int h, int stride)
{
	int i = 0, j = h-1, k;
	while (i < j) {
		unsigned char* ri = &image[i * stride];		
		unsigned char* rj = &image[j * stride];		
		for (k = 0; k < w*4; k++) {
			unsigned char t = ri[k];
			ri[k] = rj[k];
			rj[k] = t;
		}
		i++;
		j--;
	}
}

void saveScreenShot(int w, int h, int premult, const char* name)
{
	unsigned char* image = (unsigned char*)malloc(w*h*4);
	if (image == NULL)
		return;
	glReadPixels(0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, image);
	if (premult)
		unpremultiplyAlpha(image, w, h, w*4);
	else
		setAlpha(image, w, h, w*4, 255);
	flipHorizontal(image, w, h, w*4);
 	stbi_write_png(name, w, h, 4, image, w*4);
 	free(image);
}