c - 如何在代码块上运行 Raspberry pi 的示例代码

Question

我正在编写 Raspberry PI 3 的示例代码(文件路径为:/opt/vc/src/hello_pi/hello_tiger)。我想在代码块上运行此示例代码。我在代码块上创建了新项目并添加了 main.c 文件和头文件。我编译了这段代码，但出现错误。这是错误:

'rotaten' undeclared(first use in this function).

如果我使用 ./hello_tiger.bin 命令在 LXTerminal 上运行代码，它工作正常。但我想在 Code Blocks 或任何编译器(例如 monodevelop)上运行这段代码。 main.c 文件如下。

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <assert.h>
#include <string.h>
#define UNREF(X) ((void)(X))

//#ifdef HG_FLAT_INCLUDES
#include "/opt/vc/src/hello_pi/libs/vgfont/VG/openvg.h"
#include "/opt/vc/src/hello_pi/libs/vgfont/VG/vgu.h"
#include "/opt/vc/src/hello_pi/libs/vgfont/EGL/egl.h"
/*
#   include "openvg.h"
#   include "vgu.h"
#   include "egl.h" */
/*/#else
#   include "VG/openvg.h"
#   include "VG/vgu.h"
#   include "EGL/egl.h"
#endif
*/
#include "tiger.h"

/*--------------------------------------------------------------*/

#ifdef __RASPBERRYPI__
static float rotateN = 0.0f;
#endif
const float         aspectRatio = 612.0f / 792.0f;
int                 renderWidth = 0;
int                 renderHeight = 0;
EGLDisplay          egldisplay;
EGLConfig           eglconfig;
EGLSurface          eglsurface;
EGLContext          eglcontext;

/*--------------------------------------------------------------*/

typedef struct
{
    VGFillRule      m_fillRule;
    VGPaintMode     m_paintMode;
    VGCapStyle      m_capStyle;
    VGJoinStyle     m_joinStyle;
    float           m_miterLimit;
    float           m_strokeWidth;
    VGPaint         m_fillPaint;
    VGPaint         m_strokePaint;
    VGPath          m_path;
} PathData;

typedef struct
{
    PathData*           m_paths;
    int                 m_numPaths;
} PS;

PS* PS_construct(const char* commands, int commandCount, const float* points, int pointCount)
{
    PS* ps = (PS*)malloc(sizeof(PS));
    int p = 0;
    int c = 0;
    int i = 0;
    int paths = 0;
    int maxElements = 0;
    unsigned char* cmd;
    UNREF(pointCount);

    while(c < commandCount)
    {
        int elements, e;
        c += 4;
        p += 8;
        elements = (int)points[p++];
        assert(elements > 0);
        if(elements > maxElements)
            maxElements = elements;
        for(e=0;e<elements;e++)
        {
            switch(commands[c])
            {
            case 'M': p += 2; break;
            case 'L': p += 2; break;
            case 'C': p += 6; break;
            case 'E': break;
            default:
                assert(0);      //unknown command
            }
            c++;
        }
        paths++;
    }

    ps->m_numPaths = paths;
    ps->m_paths = (PathData*)malloc(paths * sizeof(PathData));
    cmd = (unsigned char*)malloc(maxElements);

    i = 0;
    p = 0;
    c = 0;
    while(c < commandCount)
    {
        int elements, startp, e;
        float color[4];

        //fill type
        int paintMode = 0;
        ps->m_paths[i].m_fillRule = VG_NON_ZERO;
        switch( commands[c] )
        {
        case 'N':
            break;
        case 'F':
            ps->m_paths[i].m_fillRule = VG_NON_ZERO;
            paintMode |= VG_FILL_PATH;
            break;
        case 'E':
            ps->m_paths[i].m_fillRule = VG_EVEN_ODD;
            paintMode |= VG_FILL_PATH;
            break;
        default:
            assert(0);      //unknown command
        }
        c++;

        //stroke
        switch( commands[c] )
        {
        case 'N':
            break;
        case 'S':
            paintMode |= VG_STROKE_PATH;
            break;
        default:
            assert(0);      //unknown command
        }
        ps->m_paths[i].m_paintMode = (VGPaintMode)paintMode;
        c++;

        //line cap
        switch( commands[c] )
        {
        case 'B':
            ps->m_paths[i].m_capStyle = VG_CAP_BUTT;
            break;
        case 'R':
            ps->m_paths[i].m_capStyle = VG_CAP_ROUND;
            break;
        case 'S':
            ps->m_paths[i].m_capStyle = VG_CAP_SQUARE;
            break;
        default:
            assert(0);      //unknown command
        }
        c++;

        //line join
        switch( commands[c] )
        {
        case 'M':
            ps->m_paths[i].m_joinStyle = VG_JOIN_MITER;
            break;
        case 'R':
            ps->m_paths[i].m_joinStyle = VG_JOIN_ROUND;
            break;
        case 'B':
            ps->m_paths[i].m_joinStyle = VG_JOIN_BEVEL;
            break;
        default:
            assert(0);      //unknown command
        }
        c++;

        //the rest of stroke attributes
        ps->m_paths[i].m_miterLimit = points[p++];
        ps->m_paths[i].m_strokeWidth = points[p++];

        //paints
        color[0] = points[p++];
        color[1] = points[p++];
        color[2] = points[p++];
        color[3] = 1.0f;
        ps->m_paths[i].m_strokePaint = vgCreatePaint();
        vgSetParameteri(ps->m_paths[i].m_strokePaint, VG_PAINT_TYPE, VG_PAINT_TYPE_COLOR);
        vgSetParameterfv(ps->m_paths[i].m_strokePaint, VG_PAINT_COLOR, 4, color);

        color[0] = points[p++];
        color[1] = points[p++];
        color[2] = points[p++];
        color[3] = 1.0f;
        ps->m_paths[i].m_fillPaint = vgCreatePaint();
        vgSetParameteri(ps->m_paths[i].m_fillPaint, VG_PAINT_TYPE, VG_PAINT_TYPE_COLOR);
        vgSetParameterfv(ps->m_paths[i].m_fillPaint, VG_PAINT_COLOR, 4, color);

        //read number of elements

        elements = (int)points[p++];
        assert(elements > 0);
        startp = p;
        for(e=0;e<elements;e++)
        {
            switch( commands[c] )
            {
            case 'M':
                cmd[e] = VG_MOVE_TO | VG_ABSOLUTE;
                p += 2;
                break;
            case 'L':
                cmd[e] = VG_LINE_TO | VG_ABSOLUTE;
                p += 2;
                break;
            case 'C':
                cmd[e] = VG_CUBIC_TO | VG_ABSOLUTE;
                p += 6;
                break;
            case 'E':
                cmd[e] = VG_CLOSE_PATH;
                break;
            default:
                assert(0);      //unknown command
            }
            c++;
        }

        ps->m_paths[i].m_path = vgCreatePath(VG_PATH_FORMAT_STANDARD, VG_PATH_DATATYPE_F, 1.0f, 0.0f, 0, 0, (unsigned int)VG_PATH_CAPABILITY_ALL);
        vgAppendPathData(ps->m_paths[i].m_path, elements, cmd, points + startp);
        i++;
    }
    free(cmd);
    return ps;
}

void PS_destruct(PS* ps)
{
    int i;
    assert(ps);
    for(i=0;i<ps->m_numPaths;i++)
    {
        vgDestroyPaint(ps->m_paths[i].m_fillPaint);
        vgDestroyPaint(ps->m_paths[i].m_strokePaint);
        vgDestroyPath(ps->m_paths[i].m_path);
    }
    free(ps->m_paths);
    free(ps);
}

void PS_render(PS* ps)
{
    int i;
    assert(ps);
    vgSeti(VG_BLEND_MODE, VG_BLEND_SRC_OVER);

    for(i=0;i<ps->m_numPaths;i++)
    {
        vgSeti(VG_FILL_RULE, ps->m_paths[i].m_fillRule);
        vgSetPaint(ps->m_paths[i].m_fillPaint, VG_FILL_PATH);

        if(ps->m_paths[i].m_paintMode & VG_STROKE_PATH)
        {
            vgSetf(VG_STROKE_LINE_WIDTH, ps->m_paths[i].m_strokeWidth);
            vgSeti(VG_STROKE_CAP_STYLE, ps->m_paths[i].m_capStyle);
            vgSeti(VG_STROKE_JOIN_STYLE, ps->m_paths[i].m_joinStyle);
            vgSetf(VG_STROKE_MITER_LIMIT, ps->m_paths[i].m_miterLimit);
            vgSetPaint(ps->m_paths[i].m_strokePaint, VG_STROKE_PATH);
        }

        vgDrawPath(ps->m_paths[i].m_path, ps->m_paths[i].m_paintMode);
    }
    assert(vgGetError() == VG_NO_ERROR);
}

PS* tiger = NULL;

/*--------------------------------------------------------------*/

void render(int w, int h)
{
#ifndef __RASPBERRYPI__
    if(renderWidth != w || renderHeight != h)
#endif
    {
        float clearColor[4] = {0,0,0,0};
        float scale = w / (tigerMaxX - tigerMinX);

        eglSwapBuffers(egldisplay, eglsurface); //force EGL to recognize resize

        vgSetfv(VG_CLEAR_COLOR, 4, clearColor);
        vgClear(0, 0, w, h);

        vgLoadIdentity();
#ifdef __RASPBERRYPI__
                vgTranslate(w * 0.5f, h * 0.5f);
                vgRotate(rotateN);
                vgTranslate(-w * 0.5f, -h * 0.5f);
#endif
        vgScale(scale, scale);
        vgTranslate(-tigerMinX, -tigerMinY + 0.5f * (h / scale - (tigerMaxY - tigerMinY)));

        PS_render(tiger);
        assert(vgGetError() == VG_NO_ERROR);

        renderWidth = w;
        renderHeight = h;
    }
#ifndef __RASPBERRYPI__
    eglSwapBuffers(egldisplay, eglsurface);
    assert(eglGetError() == EGL_SUCCESS);
#endif
}

/*--------------------------------------------------------------*/

void init(NativeWindowType window)
{
    static const EGLint s_configAttribs[] =
    {
        EGL_RED_SIZE,       8,
        EGL_GREEN_SIZE,     8,
        EGL_BLUE_SIZE,      8,
        EGL_ALPHA_SIZE,     8,
        EGL_LUMINANCE_SIZE, EGL_DONT_CARE,          //EGL_DONT_CARE
        EGL_SURFACE_TYPE,   EGL_WINDOW_BIT,
        EGL_SAMPLES,        1,
        EGL_NONE
    };
    EGLint numconfigs;

    egldisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
    eglInitialize(egldisplay, NULL, NULL);
    assert(eglGetError() == EGL_SUCCESS);
    eglBindAPI(EGL_OPENVG_API);

    eglChooseConfig(egldisplay, s_configAttribs, &eglconfig, 1, &numconfigs);
    assert(eglGetError() == EGL_SUCCESS);
    assert(numconfigs == 1);

    eglsurface = eglCreateWindowSurface(egldisplay, eglconfig, window, NULL);
    assert(eglGetError() == EGL_SUCCESS);
    eglcontext = eglCreateContext(egldisplay, eglconfig, NULL, NULL);
    assert(eglGetError() == EGL_SUCCESS);
    eglMakeCurrent(egldisplay, eglsurface, eglsurface, eglcontext);
    assert(eglGetError() == EGL_SUCCESS);

    tiger = PS_construct(tigerCommands, tigerCommandCount, tigerPoints, tigerPointCount);
}

/*--------------------------------------------------------------*/

void deinit(void)
{
    PS_destruct(tiger);
    eglMakeCurrent(egldisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
    assert(eglGetError() == EGL_SUCCESS);
    eglTerminate(egldisplay);
    assert(eglGetError() == EGL_SUCCESS);
    eglReleaseThread();
}

#include "/opt/vc/src/hello_pi/libs/vgfont/bcm_host.h"
int main(void)

{
   uint32_t width, height;

   bcm_host_init();

   int s;

   static EGL_DISPMANX_WINDOW_T nativewindow;

   DISPMANX_ELEMENT_HANDLE_T dispman_element;
   DISPMANX_DISPLAY_HANDLE_T dispman_display;
   DISPMANX_UPDATE_HANDLE_T dispman_update;
   VC_RECT_T dst_rect;
   VC_RECT_T src_rect;

   s = graphics_get_display_size(0 /* LCD */, &width, &height);
   assert( s >= 0 );

   dst_rect.x = 0;
   dst_rect.y = 0;
   dst_rect.width = width;
   dst_rect.height = height;

   src_rect.x = 0;
   src_rect.y = 0;
   src_rect.width = width << 16;
   src_rect.height = height << 16;

   dispman_display = vc_dispmanx_display_open( 0 /* LCD */);
   dispman_update = vc_dispmanx_update_start( 0 );

   dispman_element = vc_dispmanx_element_add ( dispman_update, dispman_display,
      1/*layer*/, &dst_rect, 0/*src*/,
      &src_rect, DISPMANX_PROTECTION_NONE, 0 /*alpha*/, 0/*clamp*/, 0/*transform*/);

   nativewindow.element = dispman_element;
   nativewindow.width = width;
   nativewindow.height = height;
   vc_dispmanx_update_submit_sync( dispman_update );

   init(&nativewindow);

   while (1) {
    render(width, height);
    rotateN += 1.0f;  // compiler remarks this line
   }

   deinit();

   return 0;
}

编译器在底部显示注释:

Answer 1

只有定义了宏__RASPBERRYPI__，编译器才能看到rotateN的定义。由于它未在代码或任何包含的头文件或编译器选项中定义，因此您会遇到此错误。