87 lines
2.7 KiB
C++
87 lines
2.7 KiB
C++
#include "Texture.h"
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void gj::Texture::Draw(Colorbuffer& fb) const {
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const int32_t w = static_cast<int32_t>(fb.width());
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const int32_t h = static_cast<int32_t>(fb.height());
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const int32_t srcw = static_cast<int32_t>(src_.width());
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const int32_t srch = static_cast<int32_t>(src_.height());
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/* dst coordinate */
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vec3 p[4] = {
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{ -1, 1, 1 },
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{ -1, -1, 1 },
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{ 1, -1, 1 },
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{ 1, 1, 1 },
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};
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for (size_t i = 0; i < 4; ++i) {
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p[i] = ::linalg::mul(mat_, p[i]);
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}
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const double pl = std::min({p[0].x, p[1].x, p[2].x, p[3].x})-.1;
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const double pr = std::max({p[0].x, p[1].x, p[2].x, p[3].x})+.1;
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const double pu = std::max({p[0].y, p[1].y, p[2].y, p[3].y})+.1;
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const double pb = std::min({p[0].y, p[1].y, p[2].y, p[3].y})-.1;
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const double pw = pr - pl;
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const double ph = pu - pb;
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const int32_t pli = static_cast<int32_t>((pl + 1) / 2 * w);
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const int32_t pri = static_cast<int32_t>((pr + 1) / 2 * w);
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const int32_t pui = static_cast<int32_t>((pu + 1) / 2 * h);
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const int32_t pbi = static_cast<int32_t>((pb + 1) / 2 * h);
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const int32_t pwi = pri - pli;
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const int32_t phi = pui - pbi;
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/* src coordinate */
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vec3 q[4] = {
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{ pl, pu, 1 },
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{ pl, pb, 1 },
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{ pr, pb, 1 },
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{ pr, pu, 1 },
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};
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for (size_t i = 0; i < 4; ++i) {
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q[i] = ::linalg::mul(invmat_, q[i]);
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}
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const double ql = std::min({q[0].x, q[1].x, q[2].x, q[3].x});
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const double qr = std::max({q[0].x, q[1].x, q[2].x, q[3].x});
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const double qu = std::max({q[0].y, q[1].y, q[2].y, q[3].y});
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const double qb = std::min({q[0].y, q[1].y, q[2].y, q[3].y});
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const double qldx = q[0].x - q[1].x;
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const double qrdx = q[3].x - q[2].x;
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const double qldy = q[0].y - q[1].y;
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const double qrdy = q[3].y - q[2].y;
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/* blit with transformation */
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const float* src = src_.ptr();
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float* dst = fb.ptr();
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for (int32_t y = 0; y <= phi; ++y) {
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const double yfr = y*1. / phi;
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const double lxf = qldx * yfr + q[1].x;
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const double rxf = qrdx * yfr + q[2].x;
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const double ax = (rxf - lxf) / pwi;
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const double lyf = qldy * yfr + q[1].y;
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const double ryf = qrdy * yfr + q[2].y;
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const double ay = (ryf - lyf) / pwi;
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for (int32_t x = 0; x <= pwi; ++x) {
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const double xf = lxf + ax*x;
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const double yf = lyf + ay*x;
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if (std::abs(xf) > 1 || std::abs(yf) > 1) continue;
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int32_t srcx = static_cast<int32_t>((xf+1)/2 * srcw);
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int32_t srcy = static_cast<int32_t>((yf+1)/2 * srch);
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if (srcx >= srcw) srcx = srcw - 1;
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if (srcy >= srch) srcy = srch - 1;
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const int32_t dstx = pli + x;
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const int32_t dsty = (h-pui) + y;
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if (dstx < 0 || w <= dstx) continue;
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if (dsty < 0 || h <= dsty) continue;
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dst[dstx + w*dsty] += src[srcx + srcw*srcy] * alpha_;
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}
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}
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} |