365 lines
6.7 KiB
C++
365 lines
6.7 KiB
C++
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#include "engine/tinygl/zbuffer.h"
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#define ZCMP(z, zpix) ((z) >= (zpix))
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void ZB_fillTriangleFlatShadowMask(ZBuffer *zb, ZBufferPoint *p0, ZBufferPoint *p1, ZBufferPoint *p2) {
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ZBufferPoint *t, *pr1, *pr2, *l1, *l2;
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float fdx1, fdx2, fdy1, fdy2, fz;
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unsigned char *pm1;
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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, derror;
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int x1, dxdy_min, dxdy_max;
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// warning: x2 is multiplied by 2^16
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int x2, dx2dy2;
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// we sort the vertex with increasing y
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if (p1->y < p0->y) {
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t = p0;
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p0 = p1;
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p1 = t;
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}
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if (p2->y < p0->y) {
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t = p2;
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p2 = p1;
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p1 = p0;
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p0 = t;
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} else if (p2->y < p1->y) {
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t = p1;
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p1 = p2;
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p2 = t;
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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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// screen coordinates
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pm1 = zb->shadow_mask_buf + zb->xsize * p0->y;
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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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}
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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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// generic draw line
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{
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register unsigned char *pm;
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register int n;
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n = (x2 >> 16) - x1;
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pm = pm1 + x1;
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while (n >= 3) {
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for (int a = 0; a <= 3; a++) {
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pm[a] = 0xff;
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}
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pm += 4;
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n -= 4;
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}
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while (n >= 0) {
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pm[0] = 0xff;
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pm += 1;
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n -= 1;
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}
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}
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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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} else {
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x1 += dxdy_min;
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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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pm1 = pm1 + zb->xsize;
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}
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}
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}
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void ZB_fillTriangleFlatShadow(ZBuffer *zb, ZBufferPoint *p0, ZBufferPoint *p1, ZBufferPoint *p2) {
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int color;
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ZBufferPoint *t, *pr1, *pr2, *l1, *l2;
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float fdx1, fdx2, fdy1, fdy2, fz, d1, d2;
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unsigned char *pm1;
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unsigned short *pz1;
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unsigned long *pz2;
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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, derror;
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int x1, dxdy_min, dxdy_max;
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// warning: x2 is multiplied by 2^16
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int x2, dx2dy2;
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int z1, dzdx, dzdy, dzdl_min, dzdl_max;
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// we sort the vertex with increasing y
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if (p1->y < p0->y) {
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t = p0;
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p0 = p1;
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p1 = t;
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}
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if (p2->y < p0->y) {
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t = p2;
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p2 = p1;
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p1 = p0;
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p0 = t;
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} else if (p2->y < p1->y) {
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t = p1;
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p1 = p2;
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p2 = t;
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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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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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// screen coordinates
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pp1 = (PIXEL *)((char *)zb->pbuf + zb->linesize * p0->y);
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pm1 = zb->shadow_mask_buf + p0->y * zb->xsize;
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pz1 = zb->zbuf + p0->y * zb->xsize;
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pz2 = zb->zbuf2 + p0->y * zb->xsize;
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color = RGB_TO_PIXEL(zb->shadow_color_r, zb->shadow_color_g, zb->shadow_color_b);
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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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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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}
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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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// generic draw line
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{
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register PIXEL *pp;
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register unsigned char *pm;
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register int n;
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register unsigned short *pz;
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register unsigned long *pz_2;
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register unsigned int z, zz;
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n = (x2 >> 16) - x1;
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pp = (PIXEL *)((char *)pp1 + x1 * PSZB);
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pm = pm1 + x1;
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pz = pz1 + x1;
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pz_2 = pz2 + x1;
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z = z1;
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while (n >= 3) {
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for (int a = 0; a < 4; a++) {
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zz = z >> ZB_POINT_Z_FRAC_BITS;
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if ((ZCMP(zz, pz[a])) && (ZCMP(z, pz_2[a])) && pm[0]) {
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pp[a] = color;
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pz_2[a] = z;
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}
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z += dzdx;
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}
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pz += 4;
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pz_2 += 4;
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pm += 4;
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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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zz = z >> ZB_POINT_Z_FRAC_BITS;
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if ((ZCMP(zz, pz[0])) && (ZCMP(z, pz_2[0])) && pm[0]) {
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pp[0] = color;
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pz_2[0] = z;
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}
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pz += 1;
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pz_2 += 1;
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pm += 1;
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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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// 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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z1 += dzdl_max;
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} else {
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x1 += dxdy_min;
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z1 += dzdl_min;
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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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pz2 += zb->xsize;
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pm1 += zb->xsize;
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}
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}
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}
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