Graphics/3D/Env_Mapping/source/main.cpp

#include <nds.h>


#include "teapot_bin.h"
#include "cafe_bin.h"


static void get_pen_delta( int *dx, int *dy )
{
    static int prev_pen[2] = { 0x7FFFFFFF, 0x7FFFFFFF };
    touchPosition touchXY;
    
    u32 keys = keysHeld();

    if( keys & KEY_TOUCH )
    {
        
        touchRead(&touchXY);

        if( prev_pen[0] != 0x7FFFFFFF )
        {
            *dx = (prev_pen[0] - touchXY.rawx);
            *dy = (prev_pen[1] - touchXY.rawy);
        }

        prev_pen[0] = touchXY.rawx;
        prev_pen[1] = touchXY.rawy;
    }
    else
    {
        prev_pen[0] = prev_pen[1] = 0x7FFFFFFF;
        *dx = *dy = 0;
    }
}


int main()
{

    int rotateX = 0;
    int rotateY = 0;

    //set mode 0, enable BG0 and set it to 3D
    videoSetMode(MODE_0_3D);

    // intialize gl
    glInit();
    
    // enable antialiasing
    glEnable(GL_ANTIALIAS);
    
    // setup the rear plane
    glClearColor(0,0,0,31); // BG must be opaque for AA to work
    glClearPolyID(63); // BG must have a unique polygon ID for AA to work
    glClearDepth(0x7FFF);

    //this should work the same as the normal gl call
    glViewport(0,0,255,191);

    vramSetBankA(VRAM_A_TEXTURE);
    glEnable(GL_TEXTURE_2D);
    
    int cafe_texid;
    glGenTextures( 1, &cafe_texid );
    glBindTexture( 0, cafe_texid );
    glTexImage2D( 0, 0, GL_RGB, TEXTURE_SIZE_128 , TEXTURE_SIZE_128, 0, GL_TEXTURE_WRAP_S|GL_TEXTURE_WRAP_T|TEXGEN_NORMAL, (u8*)cafe_bin );

    
    //any floating point gl call is being converted to fixed prior to being implemented
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(70, 256.0 / 192.0, 0.1, 40);
    
    while(1)
    {
        //TEXGEN_NORMAL helpfully pops our normals into this matrix and uses the result as texcoords
        glMatrixMode(GL_TEXTURE);
        glLoadIdentity();
        GLvector tex_scale = { 64<<16, -64<<16, 1<<16 };
        glScalev( &tex_scale );     //scale normals up from (-1,1) range into texcoords
        glRotateXi(rotateX);        //rotate texture-matrix to match the camera
        glRotateYi(rotateY);


        glMatrixMode(GL_POSITION);
        glLoadIdentity();
        glTranslatef32(0, 0, floattof32(-3));
        glRotateXi(rotateX);
        glRotateYi(rotateY);

        glMaterialf(GL_EMISSION, RGB15(31,31,31));

        glPolyFmt(POLY_ALPHA(31) | POLY_CULL_BACK );

        scanKeys();
        u32 keys = keysHeld();

        if( keys & KEY_UP ) rotateX += 3<<3;
        if( keys & KEY_DOWN ) rotateX -= 3<<3;
        if( keys & KEY_LEFT ) rotateY += 3<<3;
        if( keys & KEY_RIGHT ) rotateY -= 3<<3;

        int pen_delta[2];
        get_pen_delta( &pen_delta[0], &pen_delta[1] );
        rotateY -= pen_delta[0];
        rotateX -= pen_delta[1];


        glBindTexture( 0, cafe_texid );
        glCallList((u32*)teapot_bin);

        glFlush(0);
    }

    return 0;
}//end main