ref: 4219f692b155bf650c0918bffbbfa8d41dd670b6
dir: /d_part.c/
// d_part.c: software driver module for drawing particles #include <u.h> #include <libc.h> #include <stdio.h> #include "quakedef.h" /* ============== D_EndParticles ============== */ void D_EndParticles (void) { // not used by software driver } /* ============== D_StartParticles ============== */ void D_StartParticles (void) { // not used by software driver } /* ============== D_DrawParticle ============== */ void D_DrawParticle (particle_t *pparticle) { vec3_t local, transformed; float zi; byte *pdest; short *pz; int i, izi, pix, count, u, v; // transform point VectorSubtract (pparticle->org, r_origin, local); transformed[0] = DotProduct(local, r_pright); transformed[1] = DotProduct(local, r_pup); transformed[2] = DotProduct(local, r_ppn); if (transformed[2] < PARTICLE_Z_CLIP) return; // project the point // FIXME: preadjust xcenter and ycenter zi = 1.0 / transformed[2]; u = (int)(xcenter + zi * transformed[0] + 0.5); v = (int)(ycenter - zi * transformed[1] + 0.5); if ((v > d_vrectbottom_particle) || (u > d_vrectright_particle) || (v < d_vrecty) || (u < d_vrectx)) { return; } pz = d_pzbuffer + (d_zwidth * v) + u; pdest = d_viewbuffer + d_scantable[v] + u; izi = (int)(zi * 0x8000); pix = izi >> d_pix_shift; if (pix < d_pix_min) pix = d_pix_min; else if (pix > d_pix_max) pix = d_pix_max; switch (pix) { case 1: count = 1 << d_y_aspect_shift; for ( ; count ; count--, pz += d_zwidth, pdest += screenwidth) { if (pz[0] <= izi) { pz[0] = izi; pdest[0] = pparticle->color; } } break; case 2: count = 2 << d_y_aspect_shift; for ( ; count ; count--, pz += d_zwidth, pdest += screenwidth) { if (pz[0] <= izi) { pz[0] = izi; pdest[0] = pparticle->color; } if (pz[1] <= izi) { pz[1] = izi; pdest[1] = pparticle->color; } } break; case 3: count = 3 << d_y_aspect_shift; for ( ; count ; count--, pz += d_zwidth, pdest += screenwidth) { if (pz[0] <= izi) { pz[0] = izi; pdest[0] = pparticle->color; } if (pz[1] <= izi) { pz[1] = izi; pdest[1] = pparticle->color; } if (pz[2] <= izi) { pz[2] = izi; pdest[2] = pparticle->color; } } break; case 4: count = 4 << d_y_aspect_shift; for ( ; count ; count--, pz += d_zwidth, pdest += screenwidth) { if (pz[0] <= izi) { pz[0] = izi; pdest[0] = pparticle->color; } if (pz[1] <= izi) { pz[1] = izi; pdest[1] = pparticle->color; } if (pz[2] <= izi) { pz[2] = izi; pdest[2] = pparticle->color; } if (pz[3] <= izi) { pz[3] = izi; pdest[3] = pparticle->color; } } break; default: count = pix << d_y_aspect_shift; for ( ; count ; count--, pz += d_zwidth, pdest += screenwidth) { for (i=0 ; i<pix ; i++) { if (pz[i] <= izi) { pz[i] = izi; pdest[i] = pparticle->color; } } } break; } }