forked from Mirrors/openclonk
143 lines
3.7 KiB
C++
143 lines
3.7 KiB
C++
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#include "C4Include.h"
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#include "C4FoWAmbient.h"
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namespace
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{
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template<typename IFT>
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double AmbientForPix(int x0, int y0, int R, const IFT& ift)
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{
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double d = 0.;
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for(int y = y0 - R; y <= y0 + R; ++y)
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{
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for(int x = x0 - R; x <= x0 + R; ++x)
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{
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const double l2 = (x - x0) * (x - x0) + (y - y0) * (y - y0);
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if(l2 > R*R || ift(x, y)) continue;
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if(x == x0 && y == y0)
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{
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// Central pixel, this corresponds to the integral
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// for a round pixel with the same area as a square pixel
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d += 2 * sqrt(M_PI);
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}
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else
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{
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// Non-central pixel; assume same weight over the full
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// pixel.
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d += 1. / sqrt(l2);
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}
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}
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}
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return d;
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}
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// Everything is sky, independent of the landscape
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// This is used to obtain the normalization factor
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struct IFTFull {
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IFTFull() {}
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bool operator()(int x, int y) const { return false; }
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};
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struct IFTZoom {
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IFTZoom(const C4Landscape& landscape, double sx, double sy):
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Landscape(landscape), sx(sx), sy(sy) {}
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// Returns whether zoomed coordinate is IFT or not
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bool operator()(int x, int y) const
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{
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// Landscape coordinates
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const int lx = static_cast<int>((x + 0.5) * sx);
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const int ly = static_cast<int>((y + 0.5) * sy);
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// IFT check
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//return (Landscape.GetPix(lx, ly) & IFT) != 0;
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return Landscape.GetPix(lx, ly) != 0;
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}
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const C4Landscape& Landscape;
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const double sx;
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const double sy;
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};
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} // anonymous namespace
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C4FoWAmbient::C4FoWAmbient()
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: Tex(0), SizeX(0), SizeY(0), LandscapeX(0), LandscapeY(0)
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{
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}
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C4FoWAmbient::~C4FoWAmbient()
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{
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Clear();
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}
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void C4FoWAmbient::Clear()
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{
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if(Tex != 0) glDeleteTextures(1, &Tex);
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Tex = 0;
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SizeX = SizeY = 0;
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LandscapeX = LandscapeY = 0;
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}
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void C4FoWAmbient::CreateFromLandscape(const C4Landscape& landscape, double resolution, double radius, double full_coverage)
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{
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// Clear old map
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if(Tex != 0) Clear();
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// Number of zoomed pixels
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LandscapeX = landscape.Width;
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LandscapeY = landscape.Height;
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SizeX = Min<unsigned int>(static_cast<unsigned int>(ceil(LandscapeX / resolution)), pDraw->MaxTexSize);
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SizeY = Min<unsigned int>(static_cast<unsigned int>(ceil(LandscapeY / resolution)), pDraw->MaxTexSize);
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// Factor to go from zoomed to landscape coordinates
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const double zoom_x = static_cast<double>(landscape.Width) / (float)(SizeX);
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const double zoom_y = static_cast<double>(landscape.Height) / (float)(SizeY);
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// Zoomed radius
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const double R = (radius / sqrt(zoom_x * zoom_y) + 0.5);
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// Normalization factor with the full circle
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// The analytic result is 2*R*M_PI, and this number is typically close to it
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const double norm = AmbientForPix(0, 0, R, IFTFull()) * full_coverage;
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// Create the ambient map
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IFTZoom iftZoom(landscape, zoom_x, zoom_y);
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float* ambient = new float[SizeX * SizeY];
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for(unsigned int y = 0; y < SizeY; ++y)
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{
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for(unsigned int x = 0; x < SizeX; ++x)
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{
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ambient[y * SizeX + x] = Min(AmbientForPix(x, y, R, iftZoom) / norm, 1.0);
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}
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}
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#if 0
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CSurface8 debug(SizeX, SizeY);
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for(unsigned int y = 0; y < SizeY; ++y)
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{
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for(unsigned int x = 0; x < SizeX; ++x)
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{
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debug.SetPix(x, y, int(ambient[y * SizeX + x] * 255. + 0.5));
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CStdPalette pal;
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for(int i = 0; i < 256; ++i)
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pal.Colors[i] = i + (i << 8) + (i << 16);
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debug.Save("Ambient.bmp", &pal);
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}
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}
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#endif
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// Store it in a GL texture
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glGenTextures(1, &Tex);
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glBindTexture(GL_TEXTURE_2D, Tex);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
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glTexImage2D(GL_TEXTURE_2D, 0, 1, SizeX, SizeY, 0, GL_RED, GL_FLOAT, ambient);
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delete[] ambient;
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LogF("Created %ux%u ambient map", SizeX, SizeY);
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}
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