ref: 712ee8d9e10b050b55d8903799c8922cf13d7cf8
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) static inline void gl_transform_to_viewport_clip_c(GLVertex* v) { //MARK: NOT_INLINED_IN_OG GLContext* c = gl_get_context(); /* coordinates */ { GLfloat winv = 1.0 / v->pc.W; v->zp.x = (GLint)(v->pc.X * winv * c->viewport.scale.X + c->viewport.trans.X); v->zp.y = (GLint)(v->pc.Y * winv * c->viewport.scale.Y + c->viewport.trans.Y); v->zp.z = (GLint)(v->pc.Z * winv * c->viewport.scale.Z + c->viewport.trans.Z); } /* color */ v->zp.r = (GLuint)(v->color.v[0] * COLOR_CORRECTED_MULT_MASK + COLOR_MIN_MULT) & COLOR_MASK; v->zp.g = (GLuint)(v->color.v[1] * COLOR_CORRECTED_MULT_MASK + COLOR_MIN_MULT) & COLOR_MASK; v->zp.b = (GLuint)(v->color.v[2] * COLOR_CORRECTED_MULT_MASK + COLOR_MIN_MULT) & COLOR_MASK; /* texture */ if (c->texture_2d_enabled) { v->zp.s = (GLint)(v->tex_coord.X * (ZB_POINT_S_MAX - ZB_POINT_S_MIN) + ZB_POINT_S_MIN); //MARKED v->zp.t = (GLint)(v->tex_coord.Y * (ZB_POINT_T_MAX - ZB_POINT_T_MIN) + ZB_POINT_T_MIN); //MARKED } } /* //MARK <POSSIBLE_PERF_BONUS> #define clip_func(name, sign, dir, dir1, dir2) GLfloat name(V4* c, V4* a, V4* b); //MARK <POSSIBLE_PERF_BONUS> clip_func(clip_xmin, -, X, Y, Z) clip_func(clip_xmax, +, X, Y, Z) clip_func(clip_ymin, -, Y, X, Z) clip_func(clip_ymax, +, Y, X, Z) //MARK <POSSIBLE_PERF_BONUS> clip_func(clip_zmin, -, Z, X, Y) clip_func(clip_zmax, +, Z, X, Y) extern GLfloat (*clip_proc[6])(V4*, V4*, V4*);// = {clip_xmin, clip_xmax, clip_ymin, clip_ymax, clip_zmin, clip_zmax}; */ #define clip_funcdef(name, sign, dir, dir1, dir2) \ static 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) static GLfloat (*clip_proc[6])(V4*, V4*, V4*) = {clip_xmin, clip_xmax, clip_ymin, clip_ymax, clip_zmin, clip_zmax}; /* point */ #if TGL_FEATURE_ALT_RENDERMODES == 1 static void gl_add_select1(GLint z1, GLint z2, GLint z3) { GLint min, max; min = max = z1; if (z2 < min) min = z2; if (z3 < min) min = z3; if (z2 > max) max = z2; if (z3 > max) max = z3; gl_add_select(0xffffffff - min, 0xffffffff - max); } #else #define gl_add_select1(a, b, c) /*a comment*/ #endif void gl_draw_point(GLVertex* p0) { GLContext* c = gl_get_context(); if (p0->clip_code == 0) { #if TGL_FEATURE_ALT_RENDERMODES == 1 if (c->render_mode == GL_SELECT) { gl_add_select(p0->zp.z, p0->zp.z); }else if (c->render_mode == GL_FEEDBACK){ gl_add_feedback(GL_POINT_TOKEN,p0,NULL,NULL,0); } else #endif { ZB_plot(c->zb, &p0->zp); } } } /* line */ //Used only for lines. /* * Line Clipping */ static inline void GLinterpolate(GLVertex* q, GLVertex* p0, GLVertex* p1, GLfloat t) { //MARK: INLINED_IN_OG q->pc.X = p0->pc.X + (p1->pc.X - p0->pc.X) * t; q->pc.Y = p0->pc.Y + (p1->pc.Y - p0->pc.Y) * t; q->pc.Z = p0->pc.Z + (p1->pc.Z - p0->pc.Z) * t; q->pc.W = p0->pc.W + (p1->pc.W - p0->pc.W) * t; for(int i = 0; i < 3; i++) q->color.v[i] = p0->color.v[i] + (p1->color.v[i] - p0->color.v[i]) * t; } /* Line Clipping algorithm from 'Computer Graphics', Principles and Practice */ static inline GLint ClipLine1(GLfloat denom, GLfloat num, GLfloat* tmin, GLfloat* tmax) { GLfloat t; if (denom > 0) { t = num / denom; if (t > *tmax) return 0; if (t > *tmin) *tmin = t; } else if (denom < 0) { t = num / denom; if (t < *tmin) return 0; if (t < *tmax) *tmax = t; } else if (num > 0) return 0; return 1; } void gl_draw_line(GLVertex* p1, GLVertex* p2) {GLContext* c = gl_get_context(); GLfloat dx, dy, dz, dw, x1, y1, z1, w1; GLVertex q1, q2; GLint cc1, cc2; cc1 = p1->clip_code; cc2 = p2->clip_code; if ((cc1 | cc2) == 0) { #if TGL_FEATURE_ALT_RENDERMODES == 1 if (c->render_mode == GL_SELECT) { gl_add_select1(p1->zp.z, p2->zp.z, p2->zp.z); }else if (c->render_mode == GL_FEEDBACK){ gl_add_feedback( GL_LINE_TOKEN, p1, p2, NULL, 0 ); } else #endif { if (c->zb->depth_test) ZB_line_z(c->zb, &p1->zp, &p2->zp); else ZB_line(c->zb, &p1->zp, &p2->zp); } } else if ((cc1 & cc2) != 0) { return; } else { dx = p2->pc.X - p1->pc.X; dy = p2->pc.Y - p1->pc.Y; dz = p2->pc.Z - p1->pc.Z; dw = p2->pc.W - p1->pc.W; x1 = p1->pc.X; y1 = p1->pc.Y; z1 = p1->pc.Z; w1 = p1->pc.W; GLfloat tmin = 0; GLfloat tmax = 1; if (ClipLine1(dx + dw, -x1 - w1, &tmin, &tmax) && ClipLine1(-dx + dw, x1 - w1, &tmin, &tmax) && ClipLine1(dy + dw, -y1 - w1, &tmin, &tmax) && ClipLine1(-dy + dw, y1 - w1, &tmin, &tmax) && ClipLine1(dz + dw, -z1 - w1, &tmin, &tmax) && ClipLine1(-dz + dw, z1 - w1, &tmin, &tmax)) { GLinterpolate(&q1, p1, p2, tmin); GLinterpolate(&q2, p1, p2, tmax); gl_transform_to_viewport_clip_c(&q1); gl_transform_to_viewport_clip_c(&q2); #if TGL_FEATURE_ALT_RENDERMODES == 1 if (c->render_mode == GL_SELECT) { gl_add_select1(q1.zp.z, q2.zp.z, q2.zp.z); }else if (c->render_mode == GL_FEEDBACK){ gl_add_feedback( GL_LINE_TOKEN, &q1, &q2, NULL, 0 ); } else #endif { if (c->zb->depth_test) ZB_line_z(c->zb, &q1.zp, &q2.zp); else ZB_line(c->zb, &q1.zp, &q2.zp); } } } } //inline void gl_draw_point(GLContext* c, GLVertex* p0); /*Triangles*/ static inline void updateTmp(GLVertex* q, GLVertex* p0, GLVertex* p1, GLfloat t) { //MARK: INLINED_IN_OG GLContext* c = gl_get_context(); { q->color.v[0] = p0->color.v[0] + (p1->color.v[0] - p0->color.v[0]) * t; q->color.v[1] = p0->color.v[1] + (p1->color.v[1] - p0->color.v[1]) * t; q->color.v[2] = p0->color.v[2] + (p1->color.v[2] - p0->color.v[2]) * t; } // */ if (c->texture_2d_enabled) { q->tex_coord.X = p0->tex_coord.X + (p1->tex_coord.X - p0->tex_coord.X) * t; q->tex_coord.Y = p0->tex_coord.Y + (p1->tex_coord.Y - p0->tex_coord.Y) * t; } q->clip_code = gl_clipcode(q->pc.X, q->pc.Y, q->pc.Z, q->pc.W); if (q->clip_code == 0) gl_transform_to_viewport_clip_c(q); } //DO NOT INLINE!!! DO NOT INLINE!!! DO NOT INLINE!!! static void gl_draw_triangle_clip(GLVertex* p0, GLVertex* p1, GLVertex* p2, GLint clip_bit);//MARK: NOT_INLINED_IN_OG void gl_draw_triangle(GLVertex* p0, GLVertex* p1, GLVertex* p2) {GLContext* c = gl_get_context(); GLint co, cc[3], front; cc[0] = p0->clip_code; cc[1] = p1->clip_code; cc[2] = p2->clip_code; co = cc[0] | cc[1] | cc[2]; /* we handle the non clipped case here to go faster */ if (co == 0) { GLfloat norm; norm = (GLfloat)(p1->zp.x - p0->zp.x) * (GLfloat)(p2->zp.y - p0->zp.y) - (GLfloat)(p2->zp.x - p0->zp.x) * (GLfloat)(p1->zp.y - p0->zp.y); if (norm == 0) //MARK <POSSIBLE_PERF_BONUS> return; front = norm < 0.0; front = front ^ c->current_front_face; //I don't know how this works, but it does, GL_CCW is 0x901 and CW is 900. /* back face culling */ if (c->cull_face_enabled) { /* most used case first */ if (c->current_cull_face == GL_BACK) { if (front == 0) return; c->draw_triangle_front(p0, p1, p2); } else if (c->current_cull_face == GL_FRONT) { if (front != 0) return; c->draw_triangle_back(p0, p1, p2); } else { return; } } else { /* no culling */ if (front) { c->draw_triangle_front(p0, p1, p2); } else { c->draw_triangle_back(p0, p1, p2); } } } else { //GLint c_and = cc[0] & cc[1] & cc[2]; if ((cc[0] & cc[1] & cc[2]) == 0) { // Don't draw a triangle with no points gl_draw_triangle_clip(p0, p1, p2, 0); } } } static void gl_draw_triangle_clip(GLVertex* p0, GLVertex* p1, GLVertex* p2, GLint clip_bit) { //GLContext* c = gl_get_context(); GLint co, c_and, co1, cc[3], edge_flag_tmp, clip_mask; //GLVertex tmp1, tmp2, *q[3]; GLVertex *q[3]; cc[0] = p0->clip_code; cc[1] = p1->clip_code; cc[2] = p2->clip_code; co = cc[0] | cc[1] | cc[2]; if (co == 0) { gl_draw_triangle(p0, p1, p2); } else { c_and = cc[0] & cc[1] & cc[2]; /* the triangle is completely outside */ if (c_and != 0) return; /* find the next direction to clip */ while (clip_bit < 6 && (co & (1 << clip_bit)) == 0) { clip_bit++; } /* this test can be true only in case of rounding errors */ if (clip_bit == 6) { //The 2 bit and the 4 bit. #if 0 tgl_warning("Error:\n");tgl_warning("%f %f %f %f\n",p0->pc.X,p0->pc.Y,p0->pc.Z,p0->pc.W);tgl_warning("%f %f %f %f\n",p1->pc.X,p1->pc.Y,p1->pc.Z,p1->pc.W);tgl_warning("%f %f %f %f\n",p2->pc.X,p2->pc.Y,p2->pc.Z,p2->pc.W); #endif return; } clip_mask = 1 << clip_bit; co1 = (cc[0] ^ cc[1] ^ cc[2]) & clip_mask; if (co1) { /* one point outside */ if (cc[0] & clip_mask) { q[0] = p0; q[1] = p1; q[2] = p2; } else if (cc[1] & clip_mask) { q[0] = p1; q[1] = p2; q[2] = p0; } else { q[0] = p2; q[1] = p0; q[2] = p1; } {GLVertex tmp1, tmp2;GLfloat tt; tt = clip_proc[clip_bit](&tmp1.pc, &q[0]->pc, &q[1]->pc); updateTmp(&tmp1, q[0], q[1], tt); tt = clip_proc[clip_bit](&tmp2.pc, &q[0]->pc, &q[2]->pc); updateTmp(&tmp2, q[0], q[2], tt); tmp1.edge_flag = q[0]->edge_flag; edge_flag_tmp = q[2]->edge_flag; q[2]->edge_flag = 0; gl_draw_triangle_clip(&tmp1, q[1], q[2], clip_bit + 1); tmp2.edge_flag = 1; tmp1.edge_flag = 0; q[2]->edge_flag = edge_flag_tmp; gl_draw_triangle_clip(&tmp2, &tmp1, q[2], clip_bit + 1); } } else { /* two points outside */ if ((cc[0] & clip_mask) == 0) { q[0] = p0; q[1] = p1; q[2] = p2; } else if ((cc[1] & clip_mask) == 0) { q[0] = p1; q[1] = p2; q[2] = p0; } else { q[0] = p2; q[1] = p0; q[2] = p1; } {GLVertex tmp1, tmp2;GLfloat tt; tt = clip_proc[clip_bit](&tmp1.pc, &q[0]->pc, &q[1]->pc); updateTmp(&tmp1, q[0], q[1], tt); tt = clip_proc[clip_bit](&tmp2.pc, &q[0]->pc, &q[2]->pc); updateTmp(&tmp2, q[0], q[2], tt); tmp1.edge_flag = 1; tmp2.edge_flag = q[2]->edge_flag; gl_draw_triangle_clip(q[0], &tmp1, &tmp2, clip_bit + 1); } } } } //see vertex.c to see how the draw functions are assigned. void gl_draw_triangle_select(GLVertex* p0, GLVertex* p1, GLVertex* p2) { gl_add_select1(p0->zp.z, p1->zp.z, p2->zp.z); } void gl_draw_triangle_feedback(GLVertex* p0, GLVertex* p1, GLVertex* p2){ gl_add_feedback( 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( GLVertex* p0, GLVertex* p1, GLVertex* p2) { //Must be function pointer! GLContext* c = gl_get_context(); 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(GLVertex* p0, GLVertex* p1, GLVertex* p2) { GLContext* c = gl_get_context(); 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(GLVertex* p0, GLVertex* p1, GLVertex* p2) { GLContext* c = gl_get_context(); 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); }