ref: 522b4cd3a8ecf8bd0833a7d41daa408c6493829f
dir: /src/clip.c/
#include "msghandling.h"
#include "zgl.h"
/* fill triangle profile */
/* #define PROFILE */
#define CLIP_XMIN (1 << 0)
#define CLIP_XMAX (1 << 1)
#define CLIP_YMIN (1 << 2)
#define CLIP_YMAX (1 << 3)
#define CLIP_ZMIN (1 << 4)
#define CLIP_ZMAX (1 << 5)
#define clip_funcdef(name, sign, dir, dir1, dir2) \
GLfloat name(V4* c, V4* a, V4* b) { \
GLfloat t, dX, dY, dZ, dW, den; \
dX = (b->X - a->X); \
dY = (b->Y - a->Y); \
dZ = (b->Z - a->Z); \
dW = (b->W - a->W); \
den = -(sign d##dir) + dW; \
if (den == 0) \
t = 0; \
else \
t = (sign a->dir - a->W) / den; \
c->dir1 = a->dir1 + t * d##dir1; \
c->dir2 = a->dir2 + t * d##dir2; \
c->W = a->W + t * dW; \
c->dir = sign c->W; \
return t; \
}
//MARK <POSSIBLE_PERF_BONUS>
clip_funcdef(clip_xmin, -, X, Y, Z)
clip_funcdef(clip_xmax, +, X, Y, Z)
clip_funcdef(clip_ymin, -, Y, X, Z)
clip_funcdef(clip_ymax, +, Y, X, Z)
//MARK <POSSIBLE_PERF_BONUS>
clip_funcdef(clip_zmin, -, Z, X, Y)
clip_funcdef(clip_zmax, +, Z, X, Y)
GLfloat (*clip_proc[6])(V4*, V4*, V4*) = {clip_xmin, clip_xmax, clip_ymin, clip_ymax, clip_zmin, clip_zmax};
/* point */
/* line */
//Used only for lines.
/*
* Line Clipping
*/
/* Line Clipping algorithm from 'Computer Graphics', Principles and
Practice */
//see vertex.c to see how the draw functions are assigned.
void gl_draw_triangle_select(GLContext* c, GLVertex* p0, GLVertex* p1, GLVertex* p2) {
gl_add_select1(c, p0->zp.z, p1->zp.z, p2->zp.z);
}
void gl_draw_triangle_feedback(GLContext* c, GLVertex* p0, GLVertex* p1, GLVertex* p2){
gl_add_feedback(
c, GL_POLYGON_TOKEN,
p0,
p1,
p2,
0
);
}
#ifdef PROFILE
int count_triangles, count_triangles_textured, count_pixels;
#warning "Compile with PROFILE slows down everything"
#endif
//see vertex.c to see how the draw functions are assigned.
void gl_draw_triangle_fill(GLContext* c, GLVertex* p0, GLVertex* p1, GLVertex* p2) { //Must be function pointer!
if (c->texture_2d_enabled) {
//if(c->current_texture)
#if TGL_FEATURE_LIT_TEXTURES == 1
if(c->current_shade_model != GL_SMOOTH){
p1->zp.r = p2->zp.r;
p1->zp.g = p2->zp.g;
p1->zp.b = p2->zp.b;
p0->zp.r = p2->zp.r;
p0->zp.g = p2->zp.g;
p0->zp.b = p2->zp.b;
}
#endif
//#ifdef PROFILE
// count_triangles_textured++;
//#endif
ZB_setTexture(c->zb, c->current_texture->images[0].pixmap);
#if TGL_FEATURE_BLEND == 1
if(c->zb->enable_blend)
ZB_fillTriangleMappingPerspective(c->zb, &p0->zp, &p1->zp, &p2->zp);
else
ZB_fillTriangleMappingPerspectiveNOBLEND(c->zb, &p0->zp, &p1->zp, &p2->zp);
#else
ZB_fillTriangleMappingPerspectiveNOBLEND(c->zb, &p0->zp, &p1->zp, &p2->zp);
#endif
} else if (c->current_shade_model == GL_SMOOTH) {
//ZB_fillTriangleSmooth(c->zb, &p0->zp, &p1->zp, &p2->zp);
#if TGL_FEATURE_BLEND == 1
if(c->zb->enable_blend)
ZB_fillTriangleSmooth(c->zb, &p0->zp, &p1->zp, &p2->zp);
else
ZB_fillTriangleSmoothNOBLEND(c->zb, &p0->zp, &p1->zp, &p2->zp);
#else
ZB_fillTriangleSmoothNOBLEND(c->zb, &p0->zp, &p1->zp, &p2->zp);
#endif
} else {
//ZB_fillTriangleFlat(c->zb, &p0->zp, &p1->zp, &p2->zp);
#if TGL_FEATURE_BLEND == 1
if(c->zb->enable_blend)
ZB_fillTriangleFlat(c->zb, &p0->zp, &p1->zp, &p2->zp);
else
ZB_fillTriangleFlatNOBLEND(c->zb, &p0->zp, &p1->zp, &p2->zp);
#else
ZB_fillTriangleFlatNOBLEND(c->zb, &p0->zp, &p1->zp, &p2->zp);
#endif
}
}
/* Render a clipped triangle in line mode */
void gl_draw_triangle_line(GLContext* c, GLVertex* p0, GLVertex* p1, GLVertex* p2) {
if (c->zb->depth_test) {
if (p0->edge_flag)
ZB_line_z(c->zb, &p0->zp, &p1->zp);
if (p1->edge_flag)
ZB_line_z(c->zb, &p1->zp, &p2->zp);
if (p2->edge_flag)
ZB_line_z(c->zb, &p2->zp, &p0->zp);
} else {
if (p0->edge_flag)
ZB_line(c->zb, &p0->zp, &p1->zp);
if (p1->edge_flag)
ZB_line(c->zb, &p1->zp, &p2->zp);
if (p2->edge_flag)
ZB_line(c->zb, &p2->zp, &p0->zp);
}
}
/* Render a clipped triangle in point mode */
void gl_draw_triangle_point(GLContext* c, GLVertex* p0, GLVertex* p1, GLVertex* p2) {
if (p0->edge_flag)
ZB_plot(c->zb, &p0->zp);
if (p1->edge_flag)
ZB_plot(c->zb, &p1->zp);
if (p2->edge_flag)
ZB_plot(c->zb, &p2->zp);
}