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-rw-r--r--examples/demos/n00bdemo/lightdemo.c494
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diff --git a/examples/demos/n00bdemo/lightdemo.c b/examples/demos/n00bdemo/lightdemo.c
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+++ b/examples/demos/n00bdemo/lightdemo.c
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+#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;
+
+ }
+
+} \ No newline at end of file
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