EGE demo之——【纹理映射】

发表于 2017年8月17日作者 xege

Github URL: https://github.com/wysaid/soft_mesh_mapping

预编译可执行文件: https://raw.githubusercontent.com/wysaid/soft_mesh_mapping/master/soft_mesh_mapping.exe

纹理映射一般用于3d模型贴图，由OpenGL或者DX等底层API以GPU加速的形式实现。

而本demo直接用代码模拟这个过程，软实现（无GPU加速）纹理的uv图映射。

主要意义在于更深层次地理解图形算法, 比如一张纹理图是如何经过底层API(GL, DX等)渲染出来的。

下面是完整源代码: (此次demo直接引用碧波荡漾这个demo的原型，增加了纹理映射.本次demo兼容vc6.0, 直接复制下方代码运行即可)

//By wysaid
//blog: http://wysaid.org
//dependency: Easy Graphics Engine: https://github.com/misakamm/xege/ or http://xege.org
//tips: 本次demo兼容vc6.0, 直接复制下方代码运行即可

#define SHOW_CONSOLE
#define _CRT_SECURE_NO_WARNINGS
#include <graphics.h>
#include <vector>
#include <cmath>
#include <cassert>
#include <cstdio>

#define PRINT_FPS 0

#if PRINT_FPS
#include <chrono>
#endif

using namespace std;

struct Point
{
    Point() : x(0), y(0), dx(0), dy(0) {}
    Point(float _x, float _y, float _u, float _v) : x(_x), y(_y), dx(0), dy(0), u(_u), v(_v) {}
    float x, y;
    float dx, dy;
    float u, v;
};


void my_line(int* data, int width, int height, int pnt1x, int pnt1y, int pnt2x, int pnt2y, int color)
{
    int dx = pnt2x - pnt1x;
    int dy = pnt2y - pnt1y;
    float x = pnt1x;
    float y = pnt1y;
    int step = 0;
    if(abs(dx) > abs(dy))
    {
        step = abs(dx);
    }
    else
    {
        step = abs(dy);
    }
    float xStep = dx / (float)step;
    float yStep = dy / (float)step;
    for(int i = 0; i < step; i++)
    {
        x += xStep;
        y += yStep;
        if(x < 0 || y < 0 || x >= width || y >= height)
            continue;
        data[(int)x + (int)y * width] = color;
    }
}

class Net
{
public:
    Net() : m_index(0), m_intensity(0.2f), m_lastIndex(-1) {}
    ~Net() {}

    void setTextureImage(PIMAGE texture)
    {
        m_texture = texture;
        m_texWidth = getwidth(texture);
        m_texHeight = getheight(texture);
    }

    void setOutputTarget(PIMAGE target)
    {
        m_outputTarget = target;
        m_outputWidth = getwidth(target);
        m_outputHeight = getheight(target);
    }

    bool initNet(int w, int h, PIMAGE inputTexture, PIMAGE outputTarget)
    {
        if(w < 2 || h < 2)
            return false;

        m_texture = inputTexture;
        m_texWidth = getwidth(m_texture);
        m_texHeight = getheight(m_texture);
        m_textureData = (color_t*)getbuffer(m_texture);

        m_outputTarget = outputTarget;
        m_outputWidth = getwidth(m_outputTarget);
        m_outputHeight = getheight(m_outputTarget);

        m_width = w;
        m_height = h;

        m_vec[0].resize(w * h);
        m_vec[1].resize(w * h);
        float widthStep = 1.0f / (w - 1);
        float heightStep = 1.0f / (h - 1);

        for(int i = 0; i != h; ++i)
        {
            const float heightI = i * heightStep;
            int index = w * i;
            for(int j = 0; j != w; ++j)
            {
                const float widthJ = j * widthStep;
                m_vec[0][index] = Point(widthJ, heightI, widthJ, heightI);
                m_vec[1][index] = Point(widthJ, heightI, widthJ, heightI);

                ++index;
            }
        }
        return true;
    }

    void update()
    {
        const float widthStep = 1.0f / (m_width - 1.0f);
        const float heightStep = 1.0f / (m_height - 1.0f);
        int index = (m_index + 1) % 2;

        for(int i = 1; i < m_height - 1; ++i)
        {
            const int k = m_width * i;
            for(int j = 1; j < m_width - 1; ++j)
            {
                const int h = k + j;
                float dx, dy;
                dx = (m_vec[m_index][h - 1].x + m_vec[m_index][h + 1].x - m_vec[m_index][h].x * 2.0f);
                dy = (m_vec[m_index][h - 1].y + m_vec[m_index][h + 1].y - m_vec[m_index][h].y * 2.0f);

                dx += (m_vec[m_index][h - m_width].x + m_vec[m_index][h + m_width].x - m_vec[m_index][h].x * 2.0f);
                dy += (m_vec[m_index][h - m_width].y + m_vec[m_index][h + m_width].y - m_vec[m_index][h].y * 2.0f);

                //模拟能量损失， 当加速度方向与速度方向相反时，加快减速
                if(((unsigned&)dx >> 31) != ((unsigned&)m_vec[m_index][h].dx >> 31))
                    dx *= 1.0f + m_intensity;

                if(((unsigned&)dy >> 31) != ((unsigned&)m_vec[m_index][h].dy >> 31))
                    dy *= 1.0f + m_intensity;

                m_vec[m_index][h].dx += dx * m_intensity;
                m_vec[m_index][h].dy += dy * m_intensity;
                m_vec[index][h].dx = m_vec[m_index][h].dx;
                m_vec[index][h].dy = m_vec[m_index][h].dy;

                m_vec[index][h].x = m_vec[m_index][h].x + m_vec[index][h].dx;
                m_vec[index][h].y = m_vec[m_index][h].y + m_vec[index][h].dy;
            }
        }
        m_index = index;
    }

    void catchPoint(float x, float y)
    {
        int index;

        if(m_lastIndex < 0)
        {
            float mdis = 1e9f;
            for(int i = 1; i < m_height - 1; ++i)
            {
                const int k = m_width * i;
                for(int j = 1; j < m_width - 1; ++j)
                {
                    const int h = k + j;
                    const float dis = fabsf(x - m_vec[m_index][h].x) + fabsf(y - m_vec[m_index][h].y);
                    if(dis < mdis)
                    {
                        index = h;
                        mdis = dis;
                    }
                }
            }
            m_lastIndex = index;
        }
        else
            index = m_lastIndex;

        m_vec[0][index].x = x;
        m_vec[0][index].y = y;
        m_vec[1][index].x = x;
        m_vec[1][index].y = y;
        m_vec[0][index].dx = 0.0f;
        m_vec[0][index].dy = 0.0f;
        m_vec[1][index].dx = 0.0f;
        m_vec[1][index].dy = 0.0f;
    }

    void releasePoint()
    {
        m_lastIndex = -1;
    }

    template<class Type>
    inline void fillTriangle(const Type& v0, const Type& v1, const Type& v2)
    {
        if(v0.y == v2.y)
        {
            _fillSimpleTriangle(v0, v1, v2);
        }
        else if(v1.y == v2.y)
        {
            _fillSimpleTriangle(v1, v0, v2);
        }
        else if(v0.y == v1.y)
        {
            _fillSimpleTriangle(v0, v2, v1);
        }
        else
        {
            _fillNormalTriangle(v0, v1, v2);
        }
    }

    template<class Type>
    inline void _fillSimpleTriangle(const Type& vv0, const Type& v1, const Type& vv2)
    {
        assert(vv0.y == vv2.y);
        bool isOK = (vv0.x < vv2.x);
        const Type& v0 = isOK ? vv0 : vv2;
        const Type& v2 = isOK ? vv2 : vv0;

        float h = v1.y - v0.y;

        float dL = (v1.x - v0.x) / h;
        float dR = (v1.x - v2.x) / h;

        float dUL = (v1.u - v0.u) / h;
        float dUR = (v1.u - v2.u) / h;

        float dVL = (v1.v - v0.v) / h;
        float dVR = (v1.v - v2.v) / h;

        float xL = v0.x, xR = v2.x;
        float uL = v0.u, uR = v2.u;
        float vL = v0.v, vR = v2.v;

        const color_t* data = m_textureData;
        color_t* outputBuffer = (color_t*)getbuffer(m_outputTarget);

        if(v0.y < v1.y)
        {
            for(int i = v0.y; i < v1.y; ++i)
            {
                float len = xR - xL;
                float uLen = uR - uL;
                float vLen = vR - vL;
                for(int j = xL; j < xR; ++j)
                {
                    float percent = (j - xL) / len;
                    float u = uL + uLen * percent;
                    float v = vL + vLen * percent;
                    if(u < 0 || v < 0 || u > 1 || v > 1 || i < 0 || j < 0 || i >= m_outputHeight || j >= m_outputWidth)
                        continue;

                    int ww = u * (m_texWidth - 1);
                    int hh = v * (m_texHeight - 1);
                    int index = ww + hh * m_texWidth;
                    int outputIndex = j + i * m_outputWidth;
                    outputBuffer[outputIndex] = data[index];
                }
                xL += dL;
                xR += dR;
                uL += dUL;
                uR += dUR;
                vL += dVL;
                vR += dVR;
            }
        }
        else
        {
            for(int i = v0.y; i > v1.y; --i)
            {
                float len = xR - xL;
                float uLen = uR - uL;
                float vLen = vR - vL;
                for(int j = xL; j < xR; ++j)
                {
                    float percent = (j - xL) / len;
                    float u = uL + uLen * percent;
                    float v = vL + vLen * percent;
                    if(u < 0 || v < 0 || u > 1 || v > 1 || i < 0 || j < 0 || i >= m_outputHeight || j >= m_outputWidth)
                        continue;
                    int ww = u * (m_texWidth - 1);
                    int hh = v * (m_texHeight - 1);
                    int index = ww + hh * m_texWidth;
                    outputBuffer[j + i * m_outputWidth] = data[index];
                }
                xL -= dL;
                xR -= dR;
                uL -= dUL;
                uR -= dUR;
                vL -= dVL;
                vR -= dVR;
            }
        }
    }

    template<class Type>
    inline void _fillNormalTriangle(const Type& v0, const Type& v1, const Type& v2)
    {
        const Type *pnts[] = {&v0, &v1, &v2};

        if((*pnts[0]).y > (*pnts[1]).y)
            std::swap(pnts[0], pnts[1]);

        if((*pnts[0]).y > (*pnts[2]).y)
            std::swap(pnts[0], pnts[2]);

        if((*pnts[1]).y > (*pnts[2]).y)
            std::swap(pnts[1], pnts[2]);		

        const Type &vv0 = *pnts[0], &vv1 = *pnts[1], &vv2 = *pnts[2];

        Type newPoint;

        float percent = (vv1.y - vv0.y) / (vv2.y - vv0.y);

        newPoint.x = floorf(vv0.x + (vv2.x - vv0.x) * percent);
        newPoint.y = vv1.y;
        newPoint.u = vv0.u + (vv2.u - vv0.u) * percent;
        newPoint.v = vv0.v + (vv2.v - vv0.v) * percent;

        _fillSimpleTriangle(newPoint, vv0, vv1);
        _fillSimpleTriangle(newPoint, vv2, vv1);
    }

    void drawNet()
    {
        std::vector<Point>& vec = m_vec[m_index];
        int sz = vec.size();
        int i; //i变量前置, 方便vc6.0 编译
        m_pointCache.resize(sz);
#if _MSC_VER < 1600 //兼容vc6.0
        Point* v = &m_pointCache[0];
        memcpy(v, &vec[0], sz * sizeof(vec[0]));
#else
        Point* v = m_pointCache.data();
        memcpy(v, vec.data(), sz * sizeof(vec[0]));
#endif

        for(i = 0; i != sz; ++i)
        {
            v[i].x = floorf(v[i].x * m_outputWidth);
            v[i].y = floorf(v[i].y * m_outputHeight);
        }

        for(i = 1; i != m_height; ++i)
        {
            const int k1 = (i - 1) * m_width;
            const int k2 = i * m_width;

            for(int j = 1; j != m_width; ++j)
            {
                const int p1 = k1 + j - 1;
                const int p2 = k1 + j;
                const int p3 = k2 + j - 1;
                const int p4 = k2 + j;

                fillTriangle(v[p1], v[p2], v[p3]);
                fillTriangle(v[p3], v[p2], v[p4]);
            }
        }

        color_t* outputBuffer = (color_t*)getbuffer(m_outputTarget);

        if(m_lastIndex > 0)
        {
            for(i = 0; i != m_height; ++i)
            {
                const int k = i * m_width;
                for(int j = 1; j != m_width; ++j)
                {
                    const int h = k + j;
                    //line(v[h - 1].x, v[h - 1].y, v[h].x, v[h].y, m_outputTarget);
                    my_line((int*)outputBuffer, m_outputWidth, m_outputHeight, v[h - 1].x, v[h - 1].y, v[h].x, v[h].y, 0x00ffff00);
                }
            }

            for(i = 0; i != m_width; ++i)
            {
                for(int j = 1; j != m_height; ++j)
                {
                    const int h2 = j * m_width + i;
                    const int h1 = (j - 1) * m_width + i;
                    //line(v[h1].x, v[h1].y, v[h2].x, v[h2].y, m_outputTarget);
                    my_line((int*)outputBuffer, m_outputWidth, m_outputHeight, v[h1].x, v[h1].y, v[h2].x, v[h2].y, 0x00ffff00);
                }
            }
        }
    }

    void intensityInc(float f)
    {
        m_intensity += f;
        if(m_intensity > 0.3f)
            m_intensity = 0.3f;
    }

    void intensityDec(float f)
    {
        m_intensity -= f;
        if(m_intensity < 0.001f)
            m_intensity = 0.001f;
    }

    float getIntensity()
    {
        return m_intensity;
    }

private:
    vector<Point> m_vec[2];
    vector<Point> m_pointCache;
    int m_index;
    int m_width, m_height;
    float m_intensity;
    int m_lastIndex;

    PIMAGE m_texture;
    int m_texWidth, m_texHeight;
    color_t* m_textureData;

    PIMAGE m_outputTarget;
    int m_outputWidth, m_outputHeight;
};

bool readFileNameDlg(LPSTR filename, LPCSTR title)
{
    OPENFILENAMEA ofna;
    *filename = 0;
    memset(&ofna, 0, sizeof(OPENFILENAMEA));
    ofna.lStructSize = sizeof(OPENFILENAMEA);
    ofna.hwndOwner = getHWnd();
    ofna.hInstance = getHInstance();
    ofna.lpstrFilter = "Image Files(*.jpg;*.png;*.bmp;*.gif)\0*.jpg;*.jpeg;*.png;*.bmp;*.gif\0All Files(*.*)\0*.*\0\0";
    ofna.nMaxFile = MAX_PATH;
    ofna.lpstrDefExt = "jpg";
    ofna.lpstrFile = filename;
    ofna.lpstrTitle = title;
    ofna.Flags = OFN_HIDEREADONLY | OFN_CREATEPROMPT;
    return !!GetOpenFileNameA(&ofna);
}

PIMAGE loadTexture(const char* filename)
{
    char buffer[1024] = {0};
    PIMAGE pimg = NULL;

    if(filename != NULL && *filename != '\0')
    {
        strcpy(buffer, filename);
    }

    setcolor(RED);
    outtextxy(100, 100, "按任意键选择一张图片才能进入下一步");

    do
    {
        getch();

        if(*buffer == '\0')
            readFileNameDlg(buffer, "Please choose an image file!");

        if(*buffer != '\0')
        {
            pimg = newimage();
            int ret = getimage(pimg, buffer);
            if(ret != 0)
            {
                delimage(pimg);
                pimg = NULL;
            }
        }
    }while(pimg == NULL);

    return pimg;
}

int main(int argv, char** argc)
{
    const char* showMsgRule = "使用鼠标拖动可变换网格. 当前网格强度：%g";
    const char* infoMsg = "按'+'或者'-'可以增大或者减小网格弹力！这个版本由wysaid制作， 参见: http://blog.wysaid.org";
    const char* titleMsg = "EGE网格 By wysaid - 2024";

    initgraph(800, 600, INIT_RENDERMANUAL);
    setcaption(titleMsg);

    Net net;
    char buffer[1024];
    PIMAGE pimg = loadTexture(argv > 1 ? argc[1] : NULL);
    PIMAGE target = newimage(getwidth(), getheight());

    setcolor(YELLOW, target);
    sprintf(buffer, showMsgRule, net.getIntensity());
    net.initNet(80, 60, pimg, target);

#if PRINT_FPS
    std::chrono::high_resolution_clock::time_point lastTime = std::chrono::high_resolution_clock::now();
    int frames = 0;
#endif

    for(; is_run(); delay_fps(60))
    {
        cleardevice();

        if(keystate(key_mouse_l))
        {
            int x, y;
            mousepos(&x, &y);
            net.catchPoint(x / 800.0f, y / 600.0f);
        }
        else
        {
            net.releasePoint();
            flushmouse();
        }

        if(kbhit())
        {
            switch(getch())
            {
            case '+':
                net.intensityInc(0.005f);
                break;
            case '-':
                net.intensityDec(0.005f);
                break;
            case 27:
                exit(0);
            }
            flushkey();
            sprintf(buffer, showMsgRule, net.getIntensity());
        }

        setcolor(GREEN);
        net.drawNet();
        net.update();
        putimage(0, 0, target);
        setcolor(0x00ff0000);
        outtextxy(10, 10, infoMsg);
        outtextxy(10, 30, buffer);

#if PRINT_FPS

        ++frames;
        std::chrono::high_resolution_clock::time_point currentTime = std::chrono::high_resolution_clock::now();
        auto dur = (currentTime - lastTime).count() / 1.e6;
        if(dur >= 1000)
        {
            lastTime = currentTime;
            printf("FPS: %d\n", frames);
            frames = 0;
        }
#endif
    }

    delimage(pimg);
    delimage(target);
    closegraph();
    return 0;
}

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//By wysaid

//blog: http://wysaid.org

//dependency: Easy Graphics Engine: https://github.com/misakamm/xege/ or http://xege.org

//tips: 本次demo兼容vc6.0, 直接复制下方代码运行即可

#define SHOW_CONSOLE

#define _CRT_SECURE_NO_WARNINGS

#include <graphics.h>

#include <vector>

#include <cmath>

#include <cassert>

#include <cstdio>

#define PRINT_FPS 0

#if PRINT_FPS

#include <chrono>

#endif

using namespace std;

struct Point

{

Point() : x(0), y(0), dx(0), dy(0) {}

Point(float _x, float _y, float _u, float _v) : x(_x), y(_y), dx(0), dy(0), u(_u), v(_v) {}

float x, y;

float dx, dy;

float u, v;

};

void my_line(int* data, int width, int height, int pnt1x, int pnt1y, int pnt2x, int pnt2y, int color)

{

int dx = pnt2x - pnt1x;

int dy = pnt2y - pnt1y;

float x = pnt1x;

float y = pnt1y;

int step = 0;

if(abs(dx) > abs(dy))

{

step = abs(dx);

}

else

{

step = abs(dy);

}

float xStep = dx / (float)step;

float yStep = dy / (float)step;

for(int i = 0; i < step; i++)

{

x += xStep;

y += yStep;

if(x < 0 || y < 0 || x >= width || y >= height)

continue;

data[(int)x + (int)y * width] = color;

}

class Net

{

public:

Net() : m_index(0), m_intensity(0.2f), m_lastIndex(-1) {}

~Net() {}

void setTextureImage(PIMAGE texture)

{

m_texture = texture;

m_texWidth = getwidth(texture);

m_texHeight = getheight(texture);

}

void setOutputTarget(PIMAGE target)

{

m_outputTarget = target;

m_outputWidth = getwidth(target);

m_outputHeight = getheight(target);

}

bool initNet(int w, int h, PIMAGE inputTexture, PIMAGE outputTarget)

{

if(w < 2 || h < 2)

return false;

m_texture = inputTexture;

m_texWidth = getwidth(m_texture);

m_texHeight = getheight(m_texture);

m_textureData = (color_t*)getbuffer(m_texture);

m_outputTarget = outputTarget;

m_outputWidth = getwidth(m_outputTarget);

m_outputHeight = getheight(m_outputTarget);

m_width = w;

m_height = h;

m_vec[0].resize(w * h);

m_vec[1].resize(w * h);

float widthStep = 1.0f / (w - 1);

float heightStep = 1.0f / (h - 1);

for(int i = 0; i != h; ++i)

{

const float heightI = i * heightStep;

int index = w * i;

for(int j = 0; j != w; ++j)

{

const float widthJ = j * widthStep;

m_vec[0][index] = Point(widthJ, heightI, widthJ, heightI);

m_vec[1][index] = Point(widthJ, heightI, widthJ, heightI);

++index;

}

return true;

}

void update()

{

const float widthStep = 1.0f / (m_width - 1.0f);

const float heightStep = 1.0f / (m_height - 1.0f);

int index = (m_index + 1) % 2;

for(int i = 1; i < m_height - 1; ++i)

{

const int k = m_width * i;

for(int j = 1; j < m_width - 1; ++j)

{

const int h = k + j;

float dx, dy;

dx = (m_vec[m_index][h - 1].x + m_vec[m_index][h + 1].x - m_vec[m_index][h].x * 2.0f);

dy = (m_vec[m_index][h - 1].y + m_vec[m_index][h + 1].y - m_vec[m_index][h].y * 2.0f);

dx += (m_vec[m_index][h - m_width].x + m_vec[m_index][h + m_width].x - m_vec[m_index][h].x * 2.0f);

dy += (m_vec[m_index][h - m_width].y + m_vec[m_index][h + m_width].y - m_vec[m_index][h].y * 2.0f);

//模拟能量损失，当加速度方向与速度方向相反时，加快减速

if(((unsigned&)dx >> 31) != ((unsigned&)m_vec[m_index][h].dx >> 31))

dx *= 1.0f + m_intensity;

if(((unsigned&)dy >> 31) != ((unsigned&)m_vec[m_index][h].dy >> 31))

dy *= 1.0f + m_intensity;

m_vec[m_index][h].dx += dx * m_intensity;

m_vec[m_index][h].dy += dy * m_intensity;

m_vec[index][h].dx = m_vec[m_index][h].dx;

m_vec[index][h].dy = m_vec[m_index][h].dy;

m_vec[index][h].x = m_vec[m_index][h].x + m_vec[index][h].dx;

m_vec[index][h].y = m_vec[m_index][h].y + m_vec[index][h].dy;

}

m_index = index;

}

void catchPoint(float x, float y)

{

int index;

if(m_lastIndex < 0)

{

float mdis = 1e9f;

for(int i = 1; i < m_height - 1; ++i)

{

const int k = m_width * i;

for(int j = 1; j < m_width - 1; ++j)

{

const int h = k + j;

const float dis = fabsf(x - m_vec[m_index][h].x) + fabsf(y - m_vec[m_index][h].y);

if(dis < mdis)

{

index = h;

mdis = dis;

}

m_lastIndex = index;

}

else

index = m_lastIndex;

m_vec[0][index].x = x;

m_vec[0][index].y = y;

m_vec[1][index].x = x;

m_vec[1][index].y = y;

m_vec[0][index].dx = 0.0f;

m_vec[0][index].dy = 0.0f;

m_vec[1][index].dx = 0.0f;

m_vec[1][index].dy = 0.0f;

}

void releasePoint()

{

m_lastIndex = -1;

}

template<class Type>

inline void fillTriangle(const Type& v0, const Type& v1, const Type& v2)

{

if(v0.y == v2.y)

{

_fillSimpleTriangle(v0, v1, v2);

}

else if(v1.y == v2.y)

{

_fillSimpleTriangle(v1, v0, v2);

}

else if(v0.y == v1.y)

{

_fillSimpleTriangle(v0, v2, v1);

}

else

{

_fillNormalTriangle(v0, v1, v2);

}

template<class Type>

inline void _fillSimpleTriangle(const Type& vv0, const Type& v1, const Type& vv2)

{

assert(vv0.y == vv2.y);

bool isOK = (vv0.x < vv2.x);

const Type& v0 = isOK ? vv0 : vv2;

const Type& v2 = isOK ? vv2 : vv0;

float h = v1.y - v0.y;

float dL = (v1.x - v0.x) / h;

float dR = (v1.x - v2.x) / h;

float dUL = (v1.u - v0.u) / h;

float dUR = (v1.u - v2.u) / h;

float dVL = (v1.v - v0.v) / h;

float dVR = (v1.v - v2.v) / h;

float xL = v0.x, xR = v2.x;

float uL = v0.u, uR = v2.u;

float vL = v0.v, vR = v2.v;

const color_t* data = m_textureData;

color_t* outputBuffer = (color_t*)getbuffer(m_outputTarget);

if(v0.y < v1.y)

{

for(int i = v0.y; i < v1.y; ++i)

{

float len = xR - xL;

float uLen = uR - uL;

float vLen = vR - vL;

for(int j = xL; j < xR; ++j)

{

float percent = (j - xL) / len;

float u = uL + uLen * percent;

float v = vL + vLen * percent;

if(u < 0 || v < 0 || u > 1 || v > 1 || i < 0 || j < 0 || i >= m_outputHeight || j >= m_outputWidth)

continue;

int ww = u * (m_texWidth - 1);

int hh = v * (m_texHeight - 1);

int index = ww + hh * m_texWidth;

int outputIndex = j + i * m_outputWidth;

outputBuffer[outputIndex] = data[index];

}

xL += dL;

xR += dR;

uL += dUL;

uR += dUR;

vL += dVL;

vR += dVR;

}

else

{

for(int i = v0.y; i > v1.y; --i)

{

float len = xR - xL;

float uLen = uR - uL;

float vLen = vR - vL;

for(int j = xL; j < xR; ++j)

{

float percent = (j - xL) / len;

float u = uL + uLen * percent;

float v = vL + vLen * percent;

if(u < 0 || v < 0 || u > 1 || v > 1 || i < 0 || j < 0 || i >= m_outputHeight || j >= m_outputWidth)

continue;

int ww = u * (m_texWidth - 1);

int hh = v * (m_texHeight - 1);

int index = ww + hh * m_texWidth;

outputBuffer[j + i * m_outputWidth] = data[index];

}

xL -= dL;

xR -= dR;

uL -= dUL;

uR -= dUR;

vL -= dVL;

vR -= dVR;

}

template<class Type>

inline void _fillNormalTriangle(const Type& v0, const Type& v1, const Type& v2)

{

const Type *pnts[] = {&v0, &v1, &v2};

if((*pnts[0]).y > (*pnts[1]).y)

std::swap(pnts[0], pnts[1]);

if((*pnts[0]).y > (*pnts[2]).y)

std::swap(pnts[0], pnts[2]);

if((*pnts[1]).y > (*pnts[2]).y)

std::swap(pnts[1], pnts[2]);

const Type &vv0 = *pnts[0], &vv1 = *pnts[1], &vv2 = *pnts[2];

Type newPoint;

float percent = (vv1.y - vv0.y) / (vv2.y - vv0.y);

newPoint.x = floorf(vv0.x + (vv2.x - vv0.x) * percent);

newPoint.y = vv1.y;

newPoint.u = vv0.u + (vv2.u - vv0.u) * percent;

newPoint.v = vv0.v + (vv2.v - vv0.v) * percent;

_fillSimpleTriangle(newPoint, vv0, vv1);

_fillSimpleTriangle(newPoint, vv2, vv1);

}

void drawNet()

{

std::vector<Point>& vec = m_vec[m_index];

int sz = vec.size();

int i; //i变量前置, 方便vc6.0 编译

m_pointCache.resize(sz);

#if _MSC_VER < 1600 //兼容vc6.0

Point* v = &m_pointCache[0];

memcpy(v, &vec[0], sz * sizeof(vec[0]));

#else

Point* v = m_pointCache.data();

memcpy(v, vec.data(), sz * sizeof(vec[0]));

#endif

for(i = 0; i != sz; ++i)

{

v[i].x = floorf(v[i].x * m_outputWidth);

v[i].y = floorf(v[i].y * m_outputHeight);

}

for(i = 1; i != m_height; ++i)

{

const int k1 = (i - 1) * m_width;

const int k2 = i * m_width;

for(int j = 1; j != m_width; ++j)

{

const int p1 = k1 + j - 1;

const int p2 = k1 + j;

const int p3 = k2 + j - 1;

const int p4 = k2 + j;

fillTriangle(v[p1], v[p2], v[p3]);

fillTriangle(v[p3], v[p2], v[p4]);

}

color_t* outputBuffer = (color_t*)getbuffer(m_outputTarget);

if(m_lastIndex > 0)

{

for(i = 0; i != m_height; ++i)

{

const int k = i * m_width;

for(int j = 1; j != m_width; ++j)

{

const int h = k + j;

//line(v[h - 1].x, v[h - 1].y, v[h].x, v[h].y, m_outputTarget);

my_line((int*)outputBuffer, m_outputWidth, m_outputHeight, v[h - 1].x, v[h - 1].y, v[h].x, v[h].y, 0x00ffff00);

}

for(i = 0; i != m_width; ++i)

{

for(int j = 1; j != m_height; ++j)

{

const int h2 = j * m_width + i;

const int h1 = (j - 1) * m_width + i;

//line(v[h1].x, v[h1].y, v[h2].x, v[h2].y, m_outputTarget);

my_line((int*)outputBuffer, m_outputWidth, m_outputHeight, v[h1].x, v[h1].y, v[h2].x, v[h2].y, 0x00ffff00);

}

void intensityInc(float f)

{

m_intensity += f;

if(m_intensity > 0.3f)

m_intensity = 0.3f;

}

void intensityDec(float f)

{

m_intensity -= f;

if(m_intensity < 0.001f)

m_intensity = 0.001f;

}

float getIntensity()

{

return m_intensity;

}

private:

vector<Point> m_vec[2];

vector<Point> m_pointCache;

int m_index;

int m_width, m_height;

float m_intensity;

int m_lastIndex;

PIMAGE m_texture;

int m_texWidth, m_texHeight;

color_t* m_textureData;

PIMAGE m_outputTarget;

int m_outputWidth, m_outputHeight;

};

bool readFileNameDlg(LPSTR filename, LPCSTR title)

{

OPENFILENAMEA ofna;

*filename = 0;

memset(&ofna, 0, sizeof(OPENFILENAMEA));

ofna.lStructSize = sizeof(OPENFILENAMEA);

ofna.hwndOwner = getHWnd();

ofna.hInstance = getHInstance();

ofna.lpstrFilter = "Image Files(*.jpg;*.png;*.bmp;*.gif)\0*.jpg;*.jpeg;*.png;*.bmp;*.gif\0All Files(*.*)\0*.*\0\0";

ofna.nMaxFile = MAX_PATH;

ofna.lpstrDefExt = "jpg";

ofna.lpstrFile = filename;

ofna.lpstrTitle = title;

ofna.Flags = OFN_HIDEREADONLY | OFN_CREATEPROMPT;

return !!GetOpenFileNameA(&ofna);

}

PIMAGE loadTexture(const char* filename)

{

char buffer[1024] = {0};

PIMAGE pimg = NULL;

if(filename != NULL && *filename != '\0')

{

strcpy(buffer, filename);

}

setcolor(RED);

outtextxy(100, 100, "按任意键选择一张图片才能进入下一步");

{

getch();

if(*buffer == '\0')

readFileNameDlg(buffer, "Please choose an image file!");

if(*buffer != '\0')

{

pimg = newimage();

int ret = getimage(pimg, buffer);

if(ret != 0)

{

delimage(pimg);

pimg = NULL;

}

}while(pimg == NULL);

return pimg;

}

int main(int argv, char** argc)

{

const char* showMsgRule = "使用鼠标拖动可变换网格. 当前网格强度：%g";

const char* infoMsg = "按'+'或者'-'可以增大或者减小网格弹力！这个版本由wysaid制作，参见: http://blog.wysaid.org";

const char* titleMsg = "EGE网格 By wysaid - 2024";

initgraph(800, 600, INIT_RENDERMANUAL);

setcaption(titleMsg);

Net net;

char buffer[1024];

PIMAGE pimg = loadTexture(argv > 1 ? argc[1] : NULL);

PIMAGE target = newimage(getwidth(), getheight());

setcolor(YELLOW, target);

sprintf(buffer, showMsgRule, net.getIntensity());

net.initNet(80, 60, pimg, target);

#if PRINT_FPS

std::chrono::high_resolution_clock::time_point lastTime = std::chrono::high_resolution_clock::now();

int frames = 0;

#endif

for(; is_run(); delay_fps(60))

{

cleardevice();

if(keystate(key_mouse_l))

{

int x, y;

mousepos(&x, &y);

net.catchPoint(x / 800.0f, y / 600.0f);

}

else

{

net.releasePoint();

flushmouse();

}

if(kbhit())

{

switch(getch())

{

case '+':

net.intensityInc(0.005f);

break;

case '-':

net.intensityDec(0.005f);

break;

case 27:

exit(0);

}

flushkey();

sprintf(buffer, showMsgRule, net.getIntensity());

}

setcolor(GREEN);

net.drawNet();

net.update();

putimage(0, 0, target);

setcolor(0x00ff0000);

outtextxy(10, 10, infoMsg);

outtextxy(10, 30, buffer);

#if PRINT_FPS

++frames;

std::chrono::high_resolution_clock::time_point currentTime = std::chrono::high_resolution_clock::now();

auto dur = (currentTime - lastTime).count() / 1.e6;

if(dur >= 1000)

{

lastTime = currentTime;

printf("FPS: %d\n", frames);

frames = 0;

}

#endif

}

delimage(pimg);

delimage(target);

closegraph();

return 0;

}

文章分类范例标签： 3d, Arithmetic, demo, 纹理映射

EGE demo之——【纹理映射】

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