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cleanup and document current code. Also catch a couple of possible bugs in the 

process
This commit is contained in:
Bill Currie 2000-11-15 18:43:19 +00:00
parent 293d2bcc13
commit c604d261f7
1 changed files with 119 additions and 64 deletions
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183
source/gl_sky_clip.c
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@ -33,10 +33,32 @@
#include "console.h"
#include "glquake.h"
// Set to true if a valid skybox is loaded --KB
extern qboolean skyloaded;
extern vec5_t skyvec[6][4];
/* cube face to sky texture offset conversion */
static const int skytex_offs[] = {3, 0, 4, 1, 2, 5};
/* clockwise loop through the cube faces adjoining the current face */
static const int face_loop[6][5] = {
{1, 2, 4, 5, 1},
{0, 5, 3, 2, 0},
{0, 1, 3, 4, 0},
{1, 5, 4, 2, 1},
{0, 2, 3, 5, 0},
{0, 4, 3, 1, 0},
};
/* axis the cube face cuts (also index into vec3_t for) */
static const int face_axis[] = {0, 1, 2, 0, 1, 2};
/* offset on the axis the cube face cuts */
static const vec_t face_offset[] = {1024, 1024, 1024, -1024, -1024, -1024};
/* our cube */
struct box_def {
int tex, enter, leave;
glpoly_t poly;
float verts[32][VERTEXSIZE];
};
/*
determine_face
@ -67,8 +89,10 @@ determine_face (vec3_t v)
m = a[2];
i = 2;
}
if (!m)
if (!m) {
Con_Printf ("%s speared by sky poly edge\n", name->string);
abort();
}
if (v[i] < 0)
i += 3;
VectorScale (v, 1024/m, v);
@ -123,12 +147,14 @@ find_intersect (int face1, vec3_t x1, int face2, vec3_t x2, vec3_t y)
VectorSubtract (x, t, y);
}
struct box_def {
int tex, enter, leave;
glpoly_t poly;
float verts[32][VERTEXSIZE];
};
/*
set_vertex
add the vertex to the polygon describing the face of the cube. Offsets
the vertex relative to r_refdef.vieworg so the cube is always centered
on the player and also calculates the texture coordinates of the vertex
(wish I could find a cleaner way of calculating s and t).
*/
static void
set_vertex (struct box_def *box, vec3_t v, int face)
{
@ -168,7 +194,9 @@ set_vertex (struct box_def *box, vec3_t v, int face)
get the coords of the vertex common to the three specified faces of the
cube. NOTE: this WILL break if the three faces do not share a common
vertex.
vertex. ie works = ((face1 % 3 != face2 % 3)
&& (face2 % 3 != face3 % 3)
&& (face1 % 3 != face3 % 3))
*/
static void
find_cube_vertex (int face1, int face2, int face3, vec3_t v)
@ -178,6 +206,12 @@ find_cube_vertex (int face1, int face2, int face3, vec3_t v)
v[face3 % 3] = 1024 * (1 - 2 * (face3 / 3));
}
/*
enter_face
if we left this face on an adjoining face with a common vertex, add
that vertex to the cube face polygon.
*/
static void
enter_face (struct box_def *box, int prev_face, int face)
{
@ -192,6 +226,12 @@ enter_face (struct box_def *box, int prev_face, int face)
box[face].leave = -1;
}
/*
leave_face
if we entered this face on an adjoining face with a common vertex, add
that vertex to the cube face polygon.
*/
static void
leave_face (struct box_def *box, int prev_face, int face)
{
@ -206,6 +246,11 @@ leave_face (struct box_def *box, int prev_face, int face)
box[prev_face].enter = -1;
}
/*
render_box
draws all faces of the cube with 3 or more vertexen.
*/
static void
render_box (struct box_def *box)
{
@ -224,15 +269,66 @@ render_box (struct box_def *box)
}
}
/*
fixup_center_face
add the vertexen of the cube face that should be draw but was not
clipped by the sky polygon because it was fully enclosed by the
polygon. Also adds the missing vertexen to the surrounding cube faces.
*/
static void
fixup_center_face (struct box_def *box, int c_face)
{
vec3_t v[4];
int i;
for (i = 0; i < 4; i++) {
find_cube_vertex (c_face, face_loop[c_face][i],
face_loop[c_face][i + 1], v[i]);
set_vertex(box, v[i], c_face);
}
for (i = 0; i < 4; i++) {
set_vertex (box, v[i], face_loop[c_face][i]);
set_vertex (box, v[(i - 1) & 3], face_loop[c_face][i]);
}
}
/*
cross_cube_edge
add the vertex formed by the poly edge crossing the cube edge to the
polygon for the two faces on that edge. Actually, the two faces define
the edge :). The poly edge is going from face 1 to face 2 (for
enter/leave purposes).
*/
void
cross_cube_edge (struct box_def *box, int face1, vec3_t v1, int face2,
vec3_t v2)
{
vec3_t l;
find_intersect (face1, v1, face2, v2, l);
set_vertex(box, l, face1);
leave_face (box, face1, face2);
enter_face (box, face1, face2);
set_vertex(box, l, face2);
}
void
R_DrawSkyBoxPoly (glpoly_t *poly)
{
static const int skytex_offs[] = {3, 0, 4, 1, 2, 5};
vec3_t v, last_v;
vec3_t center = {0, 0, 0};
struct box_def box[6];
int i;
int face, prev_face, c_face;
struct box_def box[6];
/* projected vertex and face of the previous sky poly vertex */
vec3_t last_v;
int prev_face;
/* projected vertex and face of the current sky poly vertex */
vec3_t v;
int face;
/* projected vertex and face of the center of the sky poly */
vec3_t center = {0, 0, 0};
int c_face;
memset (box, 0, sizeof (box));
for (i = 0; i < 6; i++) {
@ -245,49 +341,26 @@ R_DrawSkyBoxPoly (glpoly_t *poly)
abort();
}
for (i = 0; i < poly->numverts; i++) {
VectorAdd (poly->verts[i], center, center);
VectorSubtract (center, r_refdef.vieworg, center);
}
VectorScale (center, 1.0/poly->numverts, center);
c_face = determine_face (center);
VectorSubtract (poly->verts[poly->numverts - 1], r_refdef.vieworg, v);
prev_face = determine_face (v);
VectorCopy (v, last_v);
VectorSubtract (poly->verts[poly->numverts - 1], r_refdef.vieworg, last_v);
prev_face = determine_face (last_v);
for (i=0; i< poly->numverts; i++) {
VectorSubtract (poly->verts[i], r_refdef.vieworg, v);
VectorAdd (v, center, center);
face = determine_face (v);
if (face != prev_face) {
if ((face % 3) == (prev_face % 3)) {
vec3_t l, x;
vec3_t x;
int x_face;
VectorAdd (v, last_v, x);
VectorScale (x, 0.5, x);
x_face = determine_face (x);
find_intersect (prev_face, last_v, x_face, v, l);
set_vertex(box, l, prev_face);
leave_face (box, prev_face, x_face);
enter_face (box, prev_face, x_face);
find_intersect (x_face, last_v, face, v, l);
leave_face (box, x_face, face);
enter_face (box, x_face, face);
set_vertex(box, l, face);
cross_cube_edge (box, prev_face, last_v, x_face, x);
cross_cube_edge (box, x_face, x, face, v);
} else {
vec3_t l;
find_intersect (prev_face, last_v, face, v, l);
set_vertex(box, l, prev_face);
leave_face (box, prev_face, face);
enter_face (box, prev_face, face);
set_vertex(box, l, face);
cross_cube_edge (box, prev_face, last_v, face, v);
}
}
set_vertex(box, v, face);
@ -295,28 +368,10 @@ R_DrawSkyBoxPoly (glpoly_t *poly)
VectorCopy (v, last_v);
prev_face = face;
}
c_face = determine_face (center);
if (box[c_face].poly.numverts == 0) {
vec3_t v;
static const int face_loop[6][5] = {
{1, 2, 4, 5, 1},
{0, 5, 3, 2, 0},
{0, 1, 3, 4, 0},
{1, 5, 4, 2, 1},
{0, 2, 3, 5, 0},
{0, 4, 3, 1, 0},
};
for (i = 0; i < 4; i++) {
find_cube_vertex (c_face, face_loop[c_face][i],
face_loop[c_face][i + 1], v);
set_vertex(box, v, c_face);
}
for (i = 0; i < 4; i++) {
set_vertex (box, box[c_face].poly.verts[i], face_loop[c_face][i]);
set_vertex (box, box[c_face].poly.verts[(i - 1) & 3],
face_loop[c_face][i]);
}
}
if (box[c_face].poly.numverts == 0)
fixup_center_face (box, c_face);
render_box (box);
}