mirror of
https://github.com/libretro/scummvm.git
synced 2025-01-10 11:51:52 +00:00
363 lines
6.7 KiB
C
363 lines
6.7 KiB
C
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// We draw a triangle with various interpolations
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{
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ZBufferPoint *tp, *pr1 = 0, *pr2 = 0, *l1 = 0, *l2 = 0;
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float fdx1, fdx2, fdy1, fdy2, fz, d1, d2;
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unsigned int *pz1;
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PIXEL *pp1;
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int part, update_left, update_right;
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int nb_lines, dx1, dy1, tmp, dx2, dy2;
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int error = 0, derror = 0;
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int x1 = 0, dxdy_min = 0, dxdy_max = 0;
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// warning: x2 is multiplied by 2^16
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int x2 = 0, dx2dy2 = 0;
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#ifdef INTERP_Z
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int z1 = 0, dzdx, dzdy, dzdl_min = 0, dzdl_max = 0;
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#endif
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#ifdef INTERP_RGB
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int r1 = 0, drdx, drdy, drdl_min = 0, drdl_max = 0;
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int g1 = 0, dgdx, dgdy, dgdl_min = 0, dgdl_max = 0;
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int b1 = 0, dbdx, dbdy, dbdl_min = 0, dbdl_max = 0;
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#endif
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#ifdef INTERP_ST
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int s1 = 0, dsdx, dsdy, dsdl_min = 0, dsdl_max = 0;
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int t1 = 0, dtdx, dtdy, dtdl_min = 0, dtdl_max = 0;
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#endif
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#ifdef INTERP_STZ
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float sz1, dszdx, dszdy, dszdl_min, dszdl_max;
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float tz1, dtzdx, dtzdy, dtzdl_min, dtzdl_max;
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#endif
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// we sort the vertex with increasing y
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if (p1->y < p0->y) {
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tp = p0;
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p0 = p1;
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p1 = tp;
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}
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if (p2->y < p0->y) {
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tp = p2;
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p2 = p1;
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p1 = p0;
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p0 = tp;
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} else if (p2->y < p1->y) {
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tp = p1;
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p1 = p2;
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p2 = tp;
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}
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// we compute dXdx and dXdy for all interpolated values
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fdx1 = (float)(p1->x - p0->x);
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fdy1 = (float)(p1->y - p0->y);
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fdx2 = (float)(p2->x - p0->x);
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fdy2 = (float)(p2->y - p0->y);
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fz = fdx1 * fdy2 - fdx2 * fdy1;
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if (fz == 0)
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return;
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fz = (float)(1.0 / fz);
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fdx1 *= fz;
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fdy1 *= fz;
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fdx2 *= fz;
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fdy2 *= fz;
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#ifdef INTERP_Z
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d1 = (float)(p1->z - p0->z);
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d2 = (float)(p2->z - p0->z);
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dzdx = (int)(fdy2 * d1 - fdy1 * d2);
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dzdy = (int)(fdx1 * d2 - fdx2 * d1);
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#endif
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#ifdef INTERP_RGB
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d1 = (float)(p1->r - p0->r);
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d2 = (float)(p2->r - p0->r);
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drdx = (int)(fdy2 * d1 - fdy1 * d2);
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drdy = (int)(fdx1 * d2 - fdx2 * d1);
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d1 = (float)(p1->g - p0->g);
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d2 = (float)(p2->g - p0->g);
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dgdx = (int)(fdy2 * d1 - fdy1 * d2);
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dgdy = (int)(fdx1 * d2 - fdx2 * d1);
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d1 = (float)(p1->b - p0->b);
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d2 = (float)(p2->b - p0->b);
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dbdx = (int)(fdy2 * d1 - fdy1 * d2);
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dbdy = (int)(fdx1 * d2 - fdx2 * d1);
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#endif
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#ifdef INTERP_ST
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d1 = (float)(p1->s - p0->s);
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d2 = (float)(p2->s - p0->s);
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dsdx = (int)(fdy2 * d1 - fdy1 * d2);
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dsdy = (int)(fdx1 * d2 - fdx2 * d1);
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d1 = (float)(p1->t - p0->t);
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d2 = (float)(p2->t - p0->t);
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dtdx = (int)(fdy2 * d1 - fdy1 * d2);
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dtdy = (int)(fdx1 * d2 - fdx2 * d1);
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#endif
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#ifdef INTERP_STZ
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{
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float zz;
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zz = (float)p0->z;
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p0->sz = (float)p0->s * zz;
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p0->tz = (float)p0->t * zz;
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zz = (float)p1->z;
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p1->sz = (float)p1->s * zz;
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p1->tz = (float)p1->t * zz;
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zz=(float) p2->z;
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p2->sz = (float)p2->s * zz;
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p2->tz = (float)p2->t * zz;
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d1 = p1->sz - p0->sz;
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d2 = p2->sz - p0->sz;
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dszdx = (fdy2 * d1 - fdy1 * d2);
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dszdy = (fdx1 * d2 - fdx2 * d1);
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d1 = p1->tz - p0->tz;
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d2 = p2->tz - p0->tz;
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dtzdx = (fdy2 * d1 - fdy1 * d2);
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dtzdy = (fdx1 * d2 - fdx2 * d1);
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}
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#endif
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// screen coordinates
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pp1 = (PIXEL *)((char *)zb->pbuf.getRawBuffer() + zb->linesize * p0->y);
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pz1 = zb->zbuf + p0->y * zb->xsize;
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DRAW_INIT();
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for (part = 0; part < 2; part++) {
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if (part == 0) {
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if (fz > 0) {
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update_left = 1;
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update_right = 1;
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l1 = p0;
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l2 = p2;
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pr1 = p0;
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pr2 = p1;
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} else {
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update_left = 1;
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update_right = 1;
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l1 = p0;
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l2 = p1;
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pr1 = p0;
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pr2 = p2;
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}
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nb_lines = p1->y - p0->y;
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} else {
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// second part
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if (fz > 0) {
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update_left = 0;
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update_right = 1;
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pr1 = p1;
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pr2 = p2;
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} else {
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update_left = 1;
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update_right = 0;
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l1 = p1;
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l2 = p2;
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}
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nb_lines = p2->y - p1->y + 1;
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}
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// compute the values for the left edge
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if (update_left) {
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dy1 = l2->y - l1->y;
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dx1 = l2->x - l1->x;
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if (dy1 > 0)
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tmp = (dx1 << 16) / dy1;
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else
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tmp = 0;
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x1 = l1->x;
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error = 0;
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derror = tmp & 0x0000ffff;
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dxdy_min = tmp >> 16;
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dxdy_max = dxdy_min + 1;
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#ifdef INTERP_Z
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z1 = l1->z;
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dzdl_min = (dzdy + dzdx * dxdy_min);
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dzdl_max = dzdl_min + dzdx;
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#endif
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#ifdef INTERP_RGB
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r1 = l1->r;
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drdl_min = (drdy + drdx * dxdy_min);
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drdl_max = drdl_min + drdx;
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g1 = l1->g;
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dgdl_min = (dgdy + dgdx * dxdy_min);
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dgdl_max = dgdl_min + dgdx;
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b1 = l1->b;
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dbdl_min = (dbdy + dbdx * dxdy_min);
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dbdl_max = dbdl_min + dbdx;
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#endif
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#ifdef INTERP_ST
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s1 = l1->s;
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dsdl_min = (dsdy + dsdx * dxdy_min);
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dsdl_max = dsdl_min + dsdx;
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t1 = l1->t;
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dtdl_min = (dtdy + dtdx * dxdy_min);
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dtdl_max = dtdl_min + dtdx;
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#endif
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#ifdef INTERP_STZ
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sz1 = l1->sz;
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dszdl_min = (dszdy + dszdx * dxdy_min);
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dszdl_max = dszdl_min + dszdx;
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tz1 = l1->tz;
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dtzdl_min = (dtzdy + dtzdx * dxdy_min);
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dtzdl_max = dtzdl_min + dtzdx;
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#endif
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}
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// compute values for the right edge
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if (update_right) {
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dx2 = (pr2->x - pr1->x);
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dy2 = (pr2->y - pr1->y);
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if (dy2>0)
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dx2dy2 = ( dx2 << 16) / dy2;
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else
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dx2dy2 = 0;
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x2 = pr1->x << 16;
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}
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// we draw all the scan line of the part
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while (nb_lines>0) {
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nb_lines--;
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#ifndef DRAW_LINE
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// generic draw line
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{
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register PIXEL *pp;
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register int n;
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#ifdef INTERP_Z
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register unsigned int *pz;
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register unsigned int z;
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#endif
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#ifdef INTERP_RGB
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register unsigned int or1, og1, ob1;
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#endif
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#ifdef INTERP_ST
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register unsigned int s, t;
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#endif
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#ifdef INTERP_STZ
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float sz, tz;
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#endif
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n = (x2 >> 16) - x1;
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pp = (PIXEL *)((char *)pp1 + x1 * PSZB);
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#ifdef INTERP_Z
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pz = pz1 + x1;
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z = z1;
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#endif
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#ifdef INTERP_RGB
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or1 = r1;
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og1 = g1;
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ob1 = b1;
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#endif
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#ifdef INTERP_ST
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s = s1;
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t = t1;
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#endif
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#ifdef INTERP_STZ
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sz = sz1;
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tz = tz1;
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#endif
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while (n >= 3) {
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PUT_PIXEL(0);
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PUT_PIXEL(1);
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PUT_PIXEL(2);
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PUT_PIXEL(3);
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#ifdef INTERP_Z
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pz += 4;
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#endif
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pp = (PIXEL *)((char *)pp + 4 * PSZB);
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n -= 4;
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}
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while (n >= 0) {
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PUT_PIXEL(0);
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#ifdef INTERP_Z
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pz += 1;
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#endif
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pp = (PIXEL *)((char *)pp + PSZB);
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n -= 1;
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}
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}
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#else
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DRAW_LINE();
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#endif
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// left edge
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error += derror;
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if (error > 0) {
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error -= 0x10000;
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x1 += dxdy_max;
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#ifdef INTERP_Z
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z1 += dzdl_max;
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#endif
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#ifdef INTERP_RGB
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r1 += drdl_max;
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g1 += dgdl_max;
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b1 += dbdl_max;
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#endif
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#ifdef INTERP_ST
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s1 += dsdl_max;
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t1 += dtdl_max;
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#endif
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#ifdef INTERP_STZ
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sz1 += dszdl_max;
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tz1 += dtzdl_max;
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#endif
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} else {
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x1 += dxdy_min;
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#ifdef INTERP_Z
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z1 += dzdl_min;
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#endif
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#ifdef INTERP_RGB
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r1 += drdl_min;
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g1 += dgdl_min;
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b1 += dbdl_min;
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#endif
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#ifdef INTERP_ST
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s1 += dsdl_min;
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t1 += dtdl_min;
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#endif
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#ifdef INTERP_STZ
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sz1 += dszdl_min;
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tz1 += dtzdl_min;
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#endif
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}
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// right edge
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x2 += dx2dy2;
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// screen coordinates
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pp1 = (PIXEL *)((char *)pp1 + zb->linesize);
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pz1 += zb->xsize;
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}
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}
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}
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#undef INTERP_Z
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#undef INTERP_RGB
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#undef INTERP_ST
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#undef INTERP_STZ
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#undef DRAW_INIT
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#undef DRAW_LINE
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#undef PUT_PIXEL
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