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#include <sys/types.h>
#include <string.h>
#include <psxgte.h>
#include <psxgpu.h>
#include <inline_c.h>
#include "disp.h"
#include "smd.h"
extern MATRIX lgt_colmtx;
extern SMD *o_world;
extern SMD *o_lightbulb;
void sort_overlay(int showlotl);
void lightdemo() {
/*
The point lighting demo is perhaps the most impressive part of
n00bDEMO. A more streamlined version of this demo where you control
various attributes of the light source such as position, intensity
and color might be made as a dedicated example program in the future.
The point lighting trick is actually not that too complicated. You
basically calculate the distance and direction vector of two points
which are the light source and the vertex of a polygon.
Calculating the normal whose result can later be used to calculate
the distance between two points is achieved with:
vec_dir.vx = lgt_point.vx - pri_vert.vx;
vec_dir.vy = lgt_point.vy - pri_vert.vy;
vec_dir.vz = lgt_point.vz - pri_vert.vz;
The intensity is calculated with (this might not be accurate but this
is faster than applying a square root):
i = 4096 - ( (
(vec_dir.vx*vec_dir.vx) +
(vec_dir.vy*vec_dir.vy) +
(vec_dir.vz*vec_dir.vz) ) >> 7 );
// Clip minimum intensity
if( i < 0 )
i = 0;
This intensity value is then used to set the color of the light source
through the light color matrix.
col_mtx.m[0][0] = i;
col_mtx.m[1][0] = i;
col_mtx.m[2][0] = i;
gte_SetColorMatrix( &col_mtx );
The direction vector can then be used as the direction of the light
source. It is recommended to normalize it first to prevent possible
overflow related issues.
VectorNormalS( &vec_dir, &vec_norm );
lgt_mtx.m[0][0] = vec_norm.vx;
lgt_mtx.m[0][1] = vec_norm.vy;
lgt_mtx.m[0][2] = vec_norm.vz;
gte_SetLightMatrix( &lgt_mtx );
This operation is then performed for each point of a polygon to
achieve a nice smooth shaded point lighting effect. The macros used
are still the same as doing light source calculation with the GTE
the normal way.
3D geometry still requires normal data as with most lighting
processing operations. 'Flat' normals (faces with a single normal
vector) work best on flat surfaces while 'smooth' normals (faces with
normals on each point) work best on round or curved surfaces.
*/
int i,p_ang;
SC_OT s_ot;
SVECTOR rot;
VECTOR pos;
SMD_PRIM s_pri;
VECTOR l_point;
SVECTOR nrm;
MATRIX lmtx,llmtx,omtx;
SVECTOR orot = { 0 };
int timeout = SCENE_TIME;
// Set clear color to black
setRGB0( &draw, 0, 0, 0 );
// Base values for the environment geometry
setVector( &pos, 0, 0, 600 );
setVector( &rot, 512, 0, 0 );
// Set base tpage value for the SMD drawing routines
smdSetBaseTPage( 0x200 );
// Set back or ambient color to black for pure darkness
gte_SetBackColor( 0, 0, 0 );
memset( &llmtx, 0, sizeof(MATRIX) );
// demo loop
while( 1 ) {
char buff[32];
RotMatrix( &rot, &mtx );
TransMatrix( &mtx, &pos );
rot.vy += 4;
gte_SetRotMatrix( &mtx );
gte_SetTransMatrix( &mtx );
setVector( &l_point, (icos( p_ang )>>2)>>2, -350+(icos( p_ang<<1 )>>4), (isin( p_ang )>>2)>>2 );
p_ang += 16;
// Begin parsing the SMD data of the environment
OpenSMD( o_world );
// Prototype point lighting renderer
while( ReadSMD( &s_pri ) ) {
VECTOR v_dir;
SVECTOR v_nrm;
VECTOR v_sqr;
int flg;
if( s_pri.prim_id.texture ) {
POLY_GT4 *pri;
// Perform standard rotate, translate and perspective
// transformation of the geometry
pri = (POLY_GT4*)nextpri;
gte_ldv3(
&o_world->p_verts[s_pri.v0],
&o_world->p_verts[s_pri.v1],
&o_world->p_verts[s_pri.v2] );
gte_rtpt();
gte_nclip(); // Backface culling
gte_stopz( &flg );
if( flg < 0 )
continue;
gte_stsxy3( &pri->x0, &pri->x1, &pri->x2 );
gte_ldv0( &o_world->p_verts[s_pri.v3] );
gte_rtps();
gte_avsz4(); // Depth sort
gte_stotz( &flg );
if( (flg>>2) >= OT_LEN )
continue;
gte_stsxy( &pri->x3 );
// Load base color of polygon to GTE
gte_ldrgb( &s_pri.r0 );
// Load normal of polygon
gte_ldv0( &o_world->p_norms[s_pri.n0] );
// Calculate the direction between the vertex of the
// polygon and the light source
v_dir.vx = l_point.vx - o_world->p_verts[s_pri.v0].vx;
v_dir.vy = l_point.vy - o_world->p_verts[s_pri.v0].vy;
v_dir.vz = l_point.vz - o_world->p_verts[s_pri.v0].vz;
// Calculate distance and light intensity using square
i = 4096 - ( (
(v_dir.vx*v_dir.vx) +
(v_dir.vy*v_dir.vy) +
(v_dir.vz*v_dir.vz) ) >> 7 );
// Clip minimum intensity
if( i < 0 )
i = 0;
// Set intensity to color matrix
llmtx.m[0][0] = i;
llmtx.m[1][0] = i;
llmtx.m[2][0] = i;
gte_SetColorMatrix( &llmtx );
// Normalize light direction and set it to light matrix
VectorNormalS( &v_dir, &v_nrm );
lmtx.m[0][0] = v_nrm.vx;
lmtx.m[0][1] = v_nrm.vy;
lmtx.m[0][2] = v_nrm.vz;
gte_SetLightMatrix( &lmtx );
// Calculate (output is retrieved through gte_strgb)
gte_nccs();
// Repeat process for the next 3 vertices
v_dir.vx = l_point.vx - o_world->p_verts[s_pri.v1].vx;
v_dir.vy = l_point.vy - o_world->p_verts[s_pri.v1].vy;
v_dir.vz = l_point.vz - o_world->p_verts[s_pri.v1].vz;
i = 4096 - ( (
(v_dir.vx*v_dir.vx) +
(v_dir.vy*v_dir.vy) +
(v_dir.vz*v_dir.vz) ) >> 7 );
if( i < 0 )
i = 0;
llmtx.m[0][0] = i;
llmtx.m[1][0] = i;
llmtx.m[2][0] = i;
gte_strgb( &pri->r0 );
gte_SetColorMatrix( &llmtx );
VectorNormalS( &v_dir, &v_nrm );
lmtx.m[0][0] = v_nrm.vx;
lmtx.m[0][1] = v_nrm.vy;
lmtx.m[0][2] = v_nrm.vz;
gte_SetLightMatrix( &lmtx );
gte_nccs();
v_dir.vx = l_point.vx - o_world->p_verts[s_pri.v2].vx;
v_dir.vy = l_point.vy - o_world->p_verts[s_pri.v2].vy;
v_dir.vz = l_point.vz - o_world->p_verts[s_pri.v2].vz;
i = 4096 - ( (
(v_dir.vx*v_dir.vx) +
(v_dir.vy*v_dir.vy) +
(v_dir.vz*v_dir.vz) ) >> 7 );
if( i < 0 )
i = 0;
llmtx.m[0][0] = i;
llmtx.m[1][0] = i;
llmtx.m[2][0] = i;
gte_strgb( &pri->r1 );
gte_SetColorMatrix( &llmtx );
VectorNormalS( &v_dir, &v_nrm );
lmtx.m[0][0] = v_nrm.vx;
lmtx.m[0][1] = v_nrm.vy;
lmtx.m[0][2] = v_nrm.vz;
gte_SetLightMatrix( &lmtx );
gte_nccs();
v_dir.vx = l_point.vx - o_world->p_verts[s_pri.v3].vx;
v_dir.vy = l_point.vy - o_world->p_verts[s_pri.v3].vy;
v_dir.vz = l_point.vz - o_world->p_verts[s_pri.v3].vz;
i = 4096 - ( (
(v_dir.vx*v_dir.vx) +
(v_dir.vy*v_dir.vy) +
(v_dir.vz*v_dir.vz) ) >> 7 );
if( i < 0 )
i = 0;
llmtx.m[0][0] = i;
llmtx.m[1][0] = i;
llmtx.m[2][0] = i;
gte_strgb( &pri->r2 );
gte_SetColorMatrix( &llmtx );
VectorNormalS( &v_dir, &v_nrm );
lmtx.m[0][0] = v_nrm.vx;
lmtx.m[0][1] = v_nrm.vy;
lmtx.m[0][2] = v_nrm.vz;
gte_SetLightMatrix( &lmtx );
gte_nccs();
setUV4( pri,
s_pri.tu0, s_pri.tv0,
s_pri.tu1, s_pri.tv1,
s_pri.tu2, s_pri.tv2,
s_pri.tu3, s_pri.tv3 );
pri->tpage = s_pri.tpage;
pri->clut = s_pri.clut;
setPolyGT4( pri );
addPrim( ot[db]+(flg>>2), pri );
nextpri += sizeof(POLY_GT4);
gte_strgb( &pri->r3 );
} else {
POLY_G4 *pri;
pri = (POLY_G4*)nextpri;
gte_ldv3(
&o_world->p_verts[s_pri.v0],
&o_world->p_verts[s_pri.v1],
&o_world->p_verts[s_pri.v2] );
gte_rtpt();
gte_nclip();
gte_stopz( &flg );
if( flg < 0 )
continue;
gte_stsxy3( &pri->x0, &pri->x1, &pri->x2 );
gte_ldv0( &o_world->p_verts[s_pri.v3] );
gte_rtps();
gte_avsz4();
gte_stotz( &flg );
if( (flg>>2) >= OT_LEN )
continue;
gte_stsxy( &pri->x3 );
gte_ldrgb( &s_pri.r0 );
gte_ldv0( &o_world->p_norms[s_pri.n0] );
v_dir.vx = l_point.vx - o_world->p_verts[s_pri.v0].vx;
v_dir.vy = l_point.vy - o_world->p_verts[s_pri.v0].vy;
v_dir.vz = l_point.vz - o_world->p_verts[s_pri.v0].vz;
i = 4096 - ( (
(v_dir.vx*v_dir.vx) +
(v_dir.vy*v_dir.vy) +
(v_dir.vz*v_dir.vz) ) >> 7 );
if( i < 0 )
i = 0;
llmtx.m[0][0] = i;
llmtx.m[1][0] = i;
llmtx.m[2][0] = i;
gte_SetColorMatrix( &llmtx );
VectorNormalS( &v_dir, &v_nrm );
lmtx.m[0][0] = v_nrm.vx;
lmtx.m[0][1] = v_nrm.vy;
lmtx.m[0][2] = v_nrm.vz;
gte_SetLightMatrix( &lmtx );
gte_nccs();
v_dir.vx = l_point.vx - o_world->p_verts[s_pri.v1].vx;
v_dir.vy = l_point.vy - o_world->p_verts[s_pri.v1].vy;
v_dir.vz = l_point.vz - o_world->p_verts[s_pri.v1].vz;
i = 4096 - ( (
(v_dir.vx*v_dir.vx) +
(v_dir.vy*v_dir.vy) +
(v_dir.vz*v_dir.vz) ) >> 7 );
if( i < 0 )
i = 0;
llmtx.m[0][0] = i;
llmtx.m[1][0] = i;
llmtx.m[2][0] = i;
gte_strgb( &pri->r0 );
gte_SetColorMatrix( &llmtx );
VectorNormalS( &v_dir, &v_nrm );
lmtx.m[0][0] = v_nrm.vx;
lmtx.m[0][1] = v_nrm.vy;
lmtx.m[0][2] = v_nrm.vz;
gte_SetLightMatrix( &lmtx );
gte_nccs();
v_dir.vx = l_point.vx - o_world->p_verts[s_pri.v2].vx;
v_dir.vy = l_point.vy - o_world->p_verts[s_pri.v2].vy;
v_dir.vz = l_point.vz - o_world->p_verts[s_pri.v2].vz;
i = 4096 - ( (
(v_dir.vx*v_dir.vx) +
(v_dir.vy*v_dir.vy) +
(v_dir.vz*v_dir.vz) ) >> 7 );
if( i < 0 )
i = 0;
llmtx.m[0][0] = i;
llmtx.m[1][0] = i;
llmtx.m[2][0] = i;
gte_strgb( &pri->r1 );
gte_SetColorMatrix( &llmtx );
VectorNormalS( &v_dir, &v_nrm );
lmtx.m[0][0] = v_nrm.vx;
lmtx.m[0][1] = v_nrm.vy;
lmtx.m[0][2] = v_nrm.vz;
gte_SetLightMatrix( &lmtx );
gte_nccs();
v_dir.vx = l_point.vx - o_world->p_verts[s_pri.v3].vx;
v_dir.vy = l_point.vy - o_world->p_verts[s_pri.v3].vy;
v_dir.vz = l_point.vz - o_world->p_verts[s_pri.v3].vz;
i = 4096 - ( (
(v_dir.vx*v_dir.vx) +
(v_dir.vy*v_dir.vy) +
(v_dir.vz*v_dir.vz) ) >> 7 );
if( i < 0 )
i = 0;
llmtx.m[0][0] = i;
llmtx.m[1][0] = i;
llmtx.m[2][0] = i;
gte_strgb( &pri->r2 );
gte_SetColorMatrix( &llmtx );
VectorNormalS( &v_dir, &v_nrm );
lmtx.m[0][0] = v_nrm.vx;
lmtx.m[0][1] = v_nrm.vy;
lmtx.m[0][2] = v_nrm.vz;
gte_SetLightMatrix( &lmtx );
gte_nccs();
setPolyG4( pri );
addPrim( ot[db]+(flg>>2), pri );
nextpri += sizeof(POLY_G4);
gte_strgb( &pri->r3 );
}
}
// Sort the light bulb to represent the position of the light source
orot.vx += 32;
orot.vy += 32;
orot.vz += 32;
RotMatrix( &orot, &omtx );
TransMatrix( &omtx, &l_point );
CompMatrixLV( &mtx, &omtx, &mtx );
gte_SetRotMatrix( &mtx );
gte_SetTransMatrix( &mtx );
s_ot.ot = ot[db];
s_ot.otlen = OT_LEN;
s_ot.zdiv = 2;
s_ot.zoff = 0;
nextpri = smdSortModel( &s_ot, nextpri, o_lightbulb );
// Sort overlay and display
sort_overlay( 1 );
display();
timeout--;
if( timeout < 0 )
break;
}
}
|
