ref: 781eeead92f56bd399624c6f3edc0568935cf9b1
dir: /qw/r_aclip.c/
// r_aclip.c: clip routines for drawing Alias models directly to the screen #include <u.h> #include <libc.h> #include <stdio.h> #include "quakedef.h" static finalvert_t fv[2][8]; static auxvert_t av[8]; void R_AliasProjectFinalVert (finalvert_t *fv, auxvert_t *av); void R_Alias_clip_top (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out); void R_Alias_clip_bottom (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out); void R_Alias_clip_left (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out); void R_Alias_clip_right (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out); /* ================ R_Alias_clip_z pfv0 is the unclipped vertex, pfv1 is the z-clipped vertex ================ */ void R_Alias_clip_z (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out) { float scale; auxvert_t *pav0, *pav1, avout; pav0 = &av[pfv0 - &fv[0][0]]; pav1 = &av[pfv1 - &fv[0][0]]; if (pfv0->v[1] >= pfv1->v[1]) { scale = (ALIAS_Z_CLIP_PLANE - pav0->fv[2]) / (pav1->fv[2] - pav0->fv[2]); avout.fv[0] = pav0->fv[0] + (pav1->fv[0] - pav0->fv[0]) * scale; avout.fv[1] = pav0->fv[1] + (pav1->fv[1] - pav0->fv[1]) * scale; avout.fv[2] = ALIAS_Z_CLIP_PLANE; out->v[2] = pfv0->v[2] + (pfv1->v[2] - pfv0->v[2]) * scale; out->v[3] = pfv0->v[3] + (pfv1->v[3] - pfv0->v[3]) * scale; out->v[4] = pfv0->v[4] + (pfv1->v[4] - pfv0->v[4]) * scale; } else { scale = (ALIAS_Z_CLIP_PLANE - pav1->fv[2]) / (pav0->fv[2] - pav1->fv[2]); avout.fv[0] = pav1->fv[0] + (pav0->fv[0] - pav1->fv[0]) * scale; avout.fv[1] = pav1->fv[1] + (pav0->fv[1] - pav1->fv[1]) * scale; avout.fv[2] = ALIAS_Z_CLIP_PLANE; out->v[2] = pfv1->v[2] + (pfv0->v[2] - pfv1->v[2]) * scale; out->v[3] = pfv1->v[3] + (pfv0->v[3] - pfv1->v[3]) * scale; out->v[4] = pfv1->v[4] + (pfv0->v[4] - pfv1->v[4]) * scale; } R_AliasProjectFinalVert (out, &avout); if (out->v[0] < r_refdef.aliasvrect.x) out->flags |= ALIAS_LEFT_CLIP; if (out->v[1] < r_refdef.aliasvrect.y) out->flags |= ALIAS_TOP_CLIP; if (out->v[0] > r_refdef.aliasvrectright) out->flags |= ALIAS_RIGHT_CLIP; if (out->v[1] > r_refdef.aliasvrectbottom) out->flags |= ALIAS_BOTTOM_CLIP; } void R_Alias_clip_left (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out) { float scale; int i; if (pfv0->v[1] >= pfv1->v[1]) { scale = (float)(r_refdef.aliasvrect.x - pfv0->v[0]) / (pfv1->v[0] - pfv0->v[0]); for (i=0 ; i<6 ; i++) out->v[i] = pfv0->v[i] + (pfv1->v[i] - pfv0->v[i])*scale + 0.5; } else { scale = (float)(r_refdef.aliasvrect.x - pfv1->v[0]) / (pfv0->v[0] - pfv1->v[0]); for (i=0 ; i<6 ; i++) out->v[i] = pfv1->v[i] + (pfv0->v[i] - pfv1->v[i])*scale + 0.5; } } void R_Alias_clip_right (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out) { float scale; int i; if (pfv0->v[1] >= pfv1->v[1]) { scale = (float)(r_refdef.aliasvrectright - pfv0->v[0]) / (pfv1->v[0] - pfv0->v[0]); for (i=0 ; i<6 ; i++) out->v[i] = pfv0->v[i] + (pfv1->v[i] - pfv0->v[i])*scale + 0.5; } else { scale = (float)(r_refdef.aliasvrectright - pfv1->v[0]) / (pfv0->v[0] - pfv1->v[0]); for (i=0 ; i<6 ; i++) out->v[i] = pfv1->v[i] + (pfv0->v[i] - pfv1->v[i])*scale + 0.5; } } void R_Alias_clip_top (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out) { float scale; int i; if (pfv0->v[1] >= pfv1->v[1]) { scale = (float)(r_refdef.aliasvrect.y - pfv0->v[1]) / (pfv1->v[1] - pfv0->v[1]); for (i=0 ; i<6 ; i++) out->v[i] = pfv0->v[i] + (pfv1->v[i] - pfv0->v[i])*scale + 0.5; } else { scale = (float)(r_refdef.aliasvrect.y - pfv1->v[1]) / (pfv0->v[1] - pfv1->v[1]); for (i=0 ; i<6 ; i++) out->v[i] = pfv1->v[i] + (pfv0->v[i] - pfv1->v[i])*scale + 0.5; } } void R_Alias_clip_bottom (finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out) { float scale; int i; if (pfv0->v[1] >= pfv1->v[1]) { scale = (float)(r_refdef.aliasvrectbottom - pfv0->v[1]) / (pfv1->v[1] - pfv0->v[1]); for (i=0 ; i<6 ; i++) out->v[i] = pfv0->v[i] + (pfv1->v[i] - pfv0->v[i])*scale + 0.5; } else { scale = (float)(r_refdef.aliasvrectbottom - pfv1->v[1]) / (pfv0->v[1] - pfv1->v[1]); for (i=0 ; i<6 ; i++) out->v[i] = pfv1->v[i] + (pfv0->v[i] - pfv1->v[i])*scale + 0.5; } } int R_AliasClip (finalvert_t *in, finalvert_t *out, int flag, int count, void(*clip)(finalvert_t *pfv0, finalvert_t *pfv1, finalvert_t *out) ) { int i,j,k; int flags, oldflags; j = count-1; k = 0; for (i=0 ; i<count ; j = i, i++) { oldflags = in[j].flags & flag; flags = in[i].flags & flag; if (flags && oldflags) continue; if (oldflags ^ flags) { clip (&in[j], &in[i], &out[k]); out[k].flags = 0; if (out[k].v[0] < r_refdef.aliasvrect.x) out[k].flags |= ALIAS_LEFT_CLIP; if (out[k].v[1] < r_refdef.aliasvrect.y) out[k].flags |= ALIAS_TOP_CLIP; if (out[k].v[0] > r_refdef.aliasvrectright) out[k].flags |= ALIAS_RIGHT_CLIP; if (out[k].v[1] > r_refdef.aliasvrectbottom) out[k].flags |= ALIAS_BOTTOM_CLIP; k++; } if (!flags) { out[k] = in[i]; k++; } } return k; } /* ================ R_AliasClipTriangle ================ */ void R_AliasClipTriangle (mtriangle_t *ptri) { int i, k, pingpong; mtriangle_t mtri; unsigned clipflags; // copy vertexes and fix seam texture coordinates if (ptri->facesfront) { fv[0][0] = pfinalverts[ptri->vertindex[0]]; fv[0][1] = pfinalverts[ptri->vertindex[1]]; fv[0][2] = pfinalverts[ptri->vertindex[2]]; } else { for (i=0 ; i<3 ; i++) { fv[0][i] = pfinalverts[ptri->vertindex[i]]; if (!ptri->facesfront && (fv[0][i].flags & ALIAS_ONSEAM) ) fv[0][i].v[2] += r_affinetridesc.seamfixupX16; } } // clip clipflags = fv[0][0].flags | fv[0][1].flags | fv[0][2].flags; if (clipflags & ALIAS_Z_CLIP) { for (i=0 ; i<3 ; i++) av[i] = pauxverts[ptri->vertindex[i]]; k = R_AliasClip (fv[0], fv[1], ALIAS_Z_CLIP, 3, R_Alias_clip_z); if (k == 0) return; pingpong = 1; clipflags = fv[1][0].flags | fv[1][1].flags | fv[1][2].flags; } else { pingpong = 0; k = 3; } if (clipflags & ALIAS_LEFT_CLIP) { k = R_AliasClip (fv[pingpong], fv[pingpong ^ 1], ALIAS_LEFT_CLIP, k, R_Alias_clip_left); if (k == 0) return; pingpong ^= 1; } if (clipflags & ALIAS_RIGHT_CLIP) { k = R_AliasClip (fv[pingpong], fv[pingpong ^ 1], ALIAS_RIGHT_CLIP, k, R_Alias_clip_right); if (k == 0) return; pingpong ^= 1; } if (clipflags & ALIAS_BOTTOM_CLIP) { k = R_AliasClip (fv[pingpong], fv[pingpong ^ 1], ALIAS_BOTTOM_CLIP, k, R_Alias_clip_bottom); if (k == 0) return; pingpong ^= 1; } if (clipflags & ALIAS_TOP_CLIP) { k = R_AliasClip (fv[pingpong], fv[pingpong ^ 1], ALIAS_TOP_CLIP, k, R_Alias_clip_top); if (k == 0) return; pingpong ^= 1; } for (i=0 ; i<k ; i++) { if (fv[pingpong][i].v[0] < r_refdef.aliasvrect.x) fv[pingpong][i].v[0] = r_refdef.aliasvrect.x; else if (fv[pingpong][i].v[0] > r_refdef.aliasvrectright) fv[pingpong][i].v[0] = r_refdef.aliasvrectright; if (fv[pingpong][i].v[1] < r_refdef.aliasvrect.y) fv[pingpong][i].v[1] = r_refdef.aliasvrect.y; else if (fv[pingpong][i].v[1] > r_refdef.aliasvrectbottom) fv[pingpong][i].v[1] = r_refdef.aliasvrectbottom; fv[pingpong][i].flags = 0; } // draw triangles mtri.facesfront = ptri->facesfront; r_affinetridesc.ptriangles = &mtri; r_affinetridesc.pfinalverts = fv[pingpong]; // FIXME: do all at once as trifan? mtri.vertindex[0] = 0; for (i=1 ; i<k-1 ; i++) { mtri.vertindex[1] = i; mtri.vertindex[2] = i+1; D_PolysetDraw (); } }