/* * libcaca Colour ASCII-Art library * Copyright (c) 2002-2006 Sam Hocevar * All Rights Reserved * * $Id$ * * This library is free software. It comes without any warranty, to * the extent permitted by applicable law. You can redistribute it * and/or modify it under the terms of the Do What The Fuck You Want * To Public License, Version 2, as published by Sam Hocevar. See * http://sam.zoy.org/wtfpl/COPYING for more details. */ /* * This file contains triangle drawing functions, both filled and outline. */ #include "config.h" #if !defined(__KERNEL__) # include #endif #include "caca.h" #include "caca_internals.h" /** \brief Draw a triangle on the canvas using the given character. * * This function never fails. * * \param cv The handle to the libcaca canvas. * \param x1 X coordinate of the first point. * \param y1 Y coordinate of the first point. * \param x2 X coordinate of the second point. * \param y2 Y coordinate of the second point. * \param x3 X coordinate of the third point. * \param y3 Y coordinate of the third point. * \param ch UTF-32 character to be used to draw the triangle outline. * \return This function always returns 0. */ int caca_draw_triangle(caca_canvas_t * cv, int x1, int y1, int x2, int y2, int x3, int y3, uint32_t ch) { caca_draw_line(cv, x1, y1, x2, y2, ch); caca_draw_line(cv, x2, y2, x3, y3, ch); caca_draw_line(cv, x3, y3, x1, y1, ch); return 0; } /** \brief Draw a thin triangle on the canvas. * * This function never fails. * * \param cv The handle to the libcaca canvas. * \param x1 X coordinate of the first point. * \param y1 Y coordinate of the first point. * \param x2 X coordinate of the second point. * \param y2 Y coordinate of the second point. * \param x3 X coordinate of the third point. * \param y3 Y coordinate of the third point. * \return This function always returns 0. */ int caca_draw_thin_triangle(caca_canvas_t * cv, int x1, int y1, int x2, int y2, int x3, int y3) { caca_draw_thin_line(cv, x1, y1, x2, y2); caca_draw_thin_line(cv, x2, y2, x3, y3); caca_draw_thin_line(cv, x3, y3, x1, y1); return 0; } /** \brief Fill a triangle on the canvas using the given character. * * This function never fails. * * \param cv The handle to the libcaca canvas. * \param x1 X coordinate of the first point. * \param y1 Y coordinate of the first point. * \param x2 X coordinate of the second point. * \param y2 Y coordinate of the second point. * \param x3 X coordinate of the third point. * \param y3 Y coordinate of the third point. * \param ch UTF-32 character to be used to fill the triangle. * \return This function always returns 0. */ int caca_fill_triangle(caca_canvas_t * cv, int x1, int y1, int x2, int y2, int x3, int y3, uint32_t ch) { int x, y, xmin, xmax, ymin, ymax; int xx1, xx2, xa, xb, sl21, sl31, sl32; /* Bubble-sort y1 <= y2 <= y3 */ if (y1 > y2) return caca_fill_triangle(cv, x2, y2, x1, y1, x3, y3, ch); if (y2 > y3) return caca_fill_triangle(cv, x1, y1, x3, y3, x2, y2, ch); /* Compute slopes and promote precision */ sl21 = (y2 == y1) ? 0 : (x2 - x1) * 0x10000 / (y2 - y1); sl31 = (y3 == y1) ? 0 : (x3 - x1) * 0x10000 / (y3 - y1); sl32 = (y3 == y2) ? 0 : (x3 - x2) * 0x10000 / (y3 - y2); x1 *= 0x10000; x2 *= 0x10000; x3 *= 0x10000; ymin = y1 < 0 ? 0 : y1; ymax = y3 + 1 < cv->height ? y3 + 1 : cv->height; if (ymin < y2) { xa = x1 + sl21 * (ymin - y1); xb = x1 + sl31 * (ymin - y1); } else if (ymin == y2) { xa = x2; xb = (y1 == y3) ? x3 : x1 + sl31 * (ymin - y1); } else /* (ymin > y2) */ { xa = x3 + sl32 * (ymin - y3); xb = x3 + sl31 * (ymin - y3); } /* Rasterize our triangle */ for (y = ymin; y < ymax; y++) { /* Rescale xa and xb, recentering the division */ if (xa < xb) { xx1 = (xa + 0x800) / 0x10000; xx2 = (xb + 0x801) / 0x10000; } else { xx1 = (xb + 0x800) / 0x10000; xx2 = (xa + 0x801) / 0x10000; } xmin = xx1 < 0 ? 0 : xx1; xmax = xx2 + 1 < cv->width ? xx2 + 1 : cv->width; for (x = xmin; x < xmax; x++) caca_put_char(cv, x, y, ch); xa += y < y2 ? sl21 : sl32; xb += sl31; } return 0; } /* This function actually renders the triangle, but is not exported due to sam's pedantic will. */ static int caca_fill_triangle_textured_l(caca_canvas_t * cv, int x1, int y1, int x2, int y2, int x3, int y3, caca_canvas_t * tex, float u1, float v1, float u2, float v2, float u3, float v3) { uint32_t savedattr; #define SWAP_F(a, b) {float c = a; a = b; b = c; } /* (very) Naive and (very) float-based affine and (very) non-clipped and (very) non-corrected triangle mapper Accepts arbitrary texture sizes Coordinates clamped to [0.0 - 1.0] (no repeat) */ if (!cv || !tex) return -1; /* Bubble-sort y1 <= y2 <= y3 */ if (y1 > y2) return caca_fill_triangle_textured_l(cv, x2, y2, x1, y1, x3, y3, tex, u2, v2, u1, v1, u3, v3); if (y2 > y3) return caca_fill_triangle_textured_l(cv, x1, y1, x3, y3, x2, y2, tex, u1, v1, u3, v3, u2, v2); savedattr = caca_get_attr(cv, -1, -1); /* Clip texture coordinates */ if (u1 < 0.0f) u1 = 0.0f; if (v1 < 0.0f) v1 = 0.0f; if (u2 < 0.0f) u2 = 0.0f; if (v2 < 0.0f) v2 = 0.0f; if (u3 < 0.0f) u3 = 0.0f; if (v3 < 0.0f) v3 = 0.0f; if (u1 > 1.0f) u1 = 1.0f; if (v1 > 1.0f) v1 = 1.0f; if (u2 > 1.0f) u2 = 1.0f; if (v2 > 1.0f) v2 = 1.0f; if (u3 > 1.0f) u3 = 1.0f; if (v3 > 1.0f) v3 = 1.0f; /* Convert relative tex coordinates to absolute */ int tw = caca_get_canvas_width(tex); int th = caca_get_canvas_height(tex); u1 *= (float)tw; u2 *= (float)tw; u3 *= (float)tw; v1 *= (float)th; v2 *= (float)th; v3 *= (float)th; int x, y; float y2y1 = y2 - y1; float y3y1 = y3 - y1; float y3y2 = y3 - y2; /* Compute slopes, making sure we don't divide by zero */ /* (in this case, we don't need the value anyway) */ /* FIXME : only compute needed slopes */ float sl12 = ((float)x2 - x1) / (y2y1 == 0 ? 1 : y2y1); float sl13 = ((float)x3 - x1) / (y3y1 == 0 ? 1 : y3y1); float sl23 = ((float)x3 - x2) / (y3y2 == 0 ? 1 : y3y2); float usl12 = (u2 - u1) / (y2y1 == 0 ? 1 : y2y1); float usl13 = (u3 - u1) / (y3y1 == 0 ? 1 : y3y1); float usl23 = (u3 - u2) / (y3y2 == 0 ? 1 : y3y2); float vsl12 = (v2 - v1) / (y2y1 == 0 ? 1 : y2y1); float vsl13 = (v3 - v1) / (y3y1 == 0 ? 1 : y3y1); float vsl23 = (v3 - v2) / (y3y2 == 0 ? 1 : y3y2); float xa = (float)x1, xb = (float)x1; float ua = u1, ub = u1; float va = v1, vb = v1; float u, v; int s = 0; /* Top */ for (y = y1; y < y2; y++) { if (xb < xa) { SWAP_F(xb, xa); SWAP_F(sl13, sl12); SWAP_F(ua, ub); SWAP_F(va, vb); SWAP_F(usl13, usl12); SWAP_F(vsl13, vsl12); s = 1; } float tus = (ub - ua) / (xb - xa); float tvs = (vb - va) / (xb - xa); v = va; u = ua; /* scanline */ for (x = xa; x < xb; x++) { u += tus; v += tvs; /* FIXME: use caca_get_canvas_attrs / caca_get_canvas_chars */ uint32_t attr = caca_get_attr(tex, u, v); uint32_t c = caca_get_char(tex, u, v); caca_set_attr(cv, attr); caca_put_char(cv, x, y, c); } xa += sl13; xb += sl12; ua += usl13; va += vsl13; ub += usl12; vb += vsl12; } if (s) { SWAP_F(xb, xa); SWAP_F(sl13, sl12); SWAP_F(ua, ub); SWAP_F(va, vb); SWAP_F(usl13, usl12); SWAP_F(vsl13, vsl12); } /* Bottom */ xb = (float)x2; /* These variables are set by 'top' routine and are in an incorrect state if we only draw the bottom part */ if (y1 == y2) { ua = u1; ub = u2; va = v1; vb = v2; } for (y = y2; y < y3; y++) { if (xb <= xa) { SWAP_F(xb, xa); SWAP_F(sl13, sl23); SWAP_F(ua, ub); SWAP_F(va, vb); SWAP_F(usl13, usl23); SWAP_F(vsl13, vsl23); } float tus = (ub - ua) / ((float)xb - xa); float tvs = (vb - va) / ((float)xb - xa); u = ua; v = va; /* scanline */ for (x = xa; x < xb; x++) { u += tus; v += tvs; /* FIXME, can be heavily optimised */ uint32_t attr = caca_get_attr(tex, u, v); uint32_t c = caca_get_char(tex, u, v); caca_set_attr(cv, attr); caca_put_char(cv, x, y, c); } xa += sl13; xb += sl23; ua += usl13; va += vsl13; ub += usl23; vb += vsl23; } caca_set_attr(cv, savedattr); return 0; } /** \brief Fill a triangle on the canvas using an arbitrary-sized texture. * * This function fails if one or both the canvas are missing * * \param cv The handle to the libcaca canvas. * \param coords The coordinates of the triangle (3{x,y}) * \param tex The handle of the canvas texture. * \param uv The coordinates of the texture (3{u,v}) * \return This function return 0 if ok, -1 if canvas or texture are missing. */ int caca_fill_triangle_textured(caca_canvas_t * cv, int coords[6], caca_canvas_t * tex, float uv[6]) { return caca_fill_triangle_textured_l(cv, coords[0], coords[1], coords[2], coords[3], coords[4], coords[5], tex, uv[0], uv[1], uv[2], uv[3], uv[4], uv[5]); } /* * XXX: The following functions are aliases. */ int cucul_draw_triangle(cucul_canvas_t *, int, int, int, int, int, int, uint32_t) CACA_ALIAS(caca_draw_triangle); int cucul_draw_thin_triangle(cucul_canvas_t *, int, int, int, int, int, int) CACA_ALIAS(caca_draw_thin_triangle); int cucul_fill_triangle(cucul_canvas_t *, int, int, int, int, int, int, uint32_t) CACA_ALIAS(caca_fill_triangle);