r_lightning.c

   1
   2 #include "quakedef.h"
   3 #include "image.h"
   4
   5 cvar_t r_lightningbeam_thickness = {CVAR_SAVE, "r_lightningbeam_thickness", "8", "thickness of the lightning beam effect"};
   6 cvar_t r_lightningbeam_scroll = {CVAR_SAVE, "r_lightningbeam_scroll", "5", "speed of texture scrolling on the lightning beam effect"};
   7 cvar_t r_lightningbeam_repeatdistance = {CVAR_SAVE, "r_lightningbeam_repeatdistance", "128", "how far to stretch the texture along the lightning beam effect"};
   8 cvar_t r_lightningbeam_color_red = {CVAR_SAVE, "r_lightningbeam_color_red", "1", "color of the lightning beam effect"};
   9 cvar_t r_lightningbeam_color_green = {CVAR_SAVE, "r_lightningbeam_color_green", "1", "color of the lightning beam effect"};
  10 cvar_t r_lightningbeam_color_blue = {CVAR_SAVE, "r_lightningbeam_color_blue", "1", "color of the lightning beam effect"};
  11 cvar_t r_lightningbeam_qmbtexture = {CVAR_SAVE, "r_lightningbeam_qmbtexture", "0", "load the qmb textures/particles/lightning.pcx texture instead of generating one, can look better"};
  12
  13 static texture_t cl_beams_externaltexture;
  14 static texture_t cl_beams_builtintexture;
  15
  16 static void r_lightningbeams_start(void)
  17 {
  18         memset(&cl_beams_externaltexture, 0, sizeof(cl_beams_externaltexture));
  19         memset(&cl_beams_builtintexture, 0, sizeof(cl_beams_builtintexture));
  20 }
  21
  22 static void CL_Beams_SetupExternalTexture(void)
  23 {
  24         if (Mod_LoadTextureFromQ3Shader(&cl_beams_externaltexture, "textures/particles/lightning", false, false, TEXF_ALPHA | TEXF_FORCELINEAR))
  25                 cl_beams_externaltexture.basematerialflags = cl_beams_externaltexture.currentmaterialflags = MATERIALFLAG_WALL | MATERIALFLAG_ADD | MATERIALFLAG_BLENDED | MATERIALFLAG_NOCULLFACE;
  26         else
  27                 Cvar_SetValueQuick(&r_lightningbeam_qmbtexture, false);
  28 }
  29
  30 static void CL_Beams_SetupBuiltinTexture(void)
  31 {
  32         // beam direction is horizontal in the lightning texture
  33         int texwidth = 128;
  34         int texheight = 64;
  35         float r, g, b, intensity, thickness = texheight * 0.25f, border = thickness + 2.0f, ithickness = 1.0f / thickness, center, n;
  36         int x, y;
  37         unsigned char *data;
  38         skinframe_t *skinframe;
  39         float centersamples[17][2];
  40
  41         // make a repeating noise pattern for the beam path
  42         for (x = 0; x < 16; x++)
  43         {
  44                 centersamples[x][0] = lhrandom(border, texheight - border);
  45                 centersamples[x][1] = lhrandom(0.2f, 1.00f);
  46         }
  47         centersamples[16][0] = centersamples[0][0];
  48         centersamples[16][1] = centersamples[0][1];
  49
  50         data = (unsigned char *)Mem_Alloc(tempmempool, texwidth * texheight * 4);
  51
  52         // iterate by columns and draw the entire column of pixels
  53         for (x = 0; x < texwidth; x++)
  54         {
  55                 r = x * 16.0f / texwidth;
  56                 y = (int)r;
  57                 g = r - y;
  58                 center = centersamples[y][0] * (1.0f - g) + centersamples[y+1][0] * g;
  59                 n = centersamples[y][1] * (1.0f - g) + centersamples[y + 1][1] * g;
  60                 for (y = 0; y < texheight; y++)
  61                 {
  62                         intensity = 1.0f - fabs((y - center) * ithickness);
  63                         if (intensity > 0)
  64                         {
  65                                 intensity = pow(intensity * n, 2);
  66                                 r = intensity * 1.000f * 255.0f;
  67                                 g = intensity * 2.000f * 255.0f;
  68                                 b = intensity * 4.000f * 255.0f;
  69                                 data[(y * texwidth + x) * 4 + 2] = (unsigned char)(bound(0, r, 255));
  70                                 data[(y * texwidth + x) * 4 + 1] = (unsigned char)(bound(0, g, 255));
  71                                 data[(y * texwidth + x) * 4 + 0] = (unsigned char)(bound(0, b, 255));
  72                         }
  73                         else
  74                                 intensity = 0.0f;
  75                         data[(y * texwidth + x) * 4 + 3] = (unsigned char)255;
  76                 }
  77         }
  78
  79         skinframe = R_SkinFrame_LoadInternalBGRA("lightningbeam", TEXF_FORCELINEAR, data, texwidth, texheight, false);
  80         Mod_LoadCustomMaterial(&cl_beams_builtintexture, "cl_beams_builtintexture", 0, MATERIALFLAG_WALL | MATERIALFLAG_ADD | MATERIALFLAG_BLENDED | MATERIALFLAG_NOCULLFACE, skinframe);
  81         Mem_Free(data);
  82 }
  83
  84 static void r_lightningbeams_shutdown(void)
  85 {
  86         memset(&cl_beams_externaltexture, 0, sizeof(cl_beams_externaltexture));
  87         memset(&cl_beams_builtintexture, 0, sizeof(cl_beams_builtintexture));
  88 }
  89
  90 static void r_lightningbeams_newmap(void)
  91 {
  92         if (cl_beams_externaltexture.currentskinframe)
  93                 R_SkinFrame_MarkUsed(cl_beams_externaltexture.currentskinframe);
  94         if (cl_beams_builtintexture.currentskinframe)
  95                 R_SkinFrame_MarkUsed(cl_beams_builtintexture.currentskinframe);
  96 }
  97
  98 void R_LightningBeams_Init(void)
  99 {
 100         Cvar_RegisterVariable(&r_lightningbeam_thickness);
 101         Cvar_RegisterVariable(&r_lightningbeam_scroll);
 102         Cvar_RegisterVariable(&r_lightningbeam_repeatdistance);
 103         Cvar_RegisterVariable(&r_lightningbeam_color_red);
 104         Cvar_RegisterVariable(&r_lightningbeam_color_green);
 105         Cvar_RegisterVariable(&r_lightningbeam_color_blue);
 106         Cvar_RegisterVariable(&r_lightningbeam_qmbtexture);
 107         R_RegisterModule("R_LightningBeams", r_lightningbeams_start, r_lightningbeams_shutdown, r_lightningbeams_newmap, NULL, NULL);
 108 }
 109
 110 static void CL_Beam_AddQuad(dp_model_t *mod, msurface_t *surf, const vec3_t start, const vec3_t end, const vec3_t offset, float t1, float t2)
 111 {
 112         int e0, e1, e2, e3;
 113         vec3_t n;
 114         vec3_t dir;
 115         float c[4];
 116
 117         Vector4Set(c, r_lightningbeam_color_red.value, r_lightningbeam_color_green.value, r_lightningbeam_color_blue.value, 1.0f);
 118
 119         VectorSubtract(end, start, dir);
 120         CrossProduct(dir, offset, n);
 121         VectorNormalize(n);
 122
 123         e0 = Mod_Mesh_IndexForVertex(mod, surf, start[0] + offset[0], start[1] + offset[1], start[2] + offset[2], n[0], n[1], n[2], t1, 0, 0, 0, c[0], c[1], c[2], c[3]);
 124         e1 = Mod_Mesh_IndexForVertex(mod, surf, start[0] - offset[0], start[1] - offset[1], start[2] - offset[2], n[0], n[1], n[2], t1, 1, 0, 0, c[0], c[1], c[2], c[3]);
 125         e2 = Mod_Mesh_IndexForVertex(mod, surf, end[0] - offset[0], end[1] - offset[1], end[2] - offset[2], n[0], n[1], n[2], t2, 1, 0, 0, c[0], c[1], c[2], c[3]);
 126         e3 = Mod_Mesh_IndexForVertex(mod, surf, end[0] + offset[0], end[1] + offset[1], end[2] + offset[2], n[0], n[1], n[2], t2, 0, 0, 0, c[0], c[1], c[2], c[3]);
 127         Mod_Mesh_AddTriangle(mod, surf, e0, e1, e2);
 128         Mod_Mesh_AddTriangle(mod, surf, e0, e2, e3);
 129 }
 130
 131 void CL_Beam_AddPolygons(const beam_t *b)
 132 {
 133         vec3_t beamdir, right, up, offset, start, end;
 134         vec_t beamscroll = r_refdef.scene.time * -r_lightningbeam_scroll.value;
 135         vec_t beamrepeatscale = 1.0f / r_lightningbeam_repeatdistance.value;
 136         float length, t1, t2;
 137         dp_model_t *mod;
 138         msurface_t *surf;
 139
 140         if (r_lightningbeam_qmbtexture.integer && cl_beams_externaltexture.currentskinframe == NULL)
 141                 CL_Beams_SetupExternalTexture();
 142         if (!r_lightningbeam_qmbtexture.integer && cl_beams_builtintexture.currentskinframe == NULL)
 143                 CL_Beams_SetupBuiltinTexture();
 144
 145         // calculate beam direction (beamdir) vector and beam length
 146         // get difference vector
 147         CL_Beam_CalculatePositions(b, start, end);
 148         VectorSubtract(end, start, beamdir);
 149         // find length of difference vector
 150         length = sqrt(DotProduct(beamdir, beamdir));
 151         // calculate scale to make beamdir a unit vector (normalized)
 152         t1 = 1.0f / length;
 153         // scale beamdir so it is now normalized
 154         VectorScale(beamdir, t1, beamdir);
 155
 156         // calculate up vector such that it points toward viewer, and rotates around the beamdir
 157         // get direction from start of beam to viewer
 158         VectorSubtract(r_refdef.view.origin, start, up);
 159         // remove the portion of the vector that moves along the beam
 160         // (this leaves only a vector pointing directly away from the beam)
 161         t1 = -DotProduct(up, beamdir);
 162         VectorMA(up, t1, beamdir, up);
 163         // generate right vector from forward and up, the result is unnormalized
 164         CrossProduct(beamdir, up, right);
 165         // now normalize the right vector and up vector
 166         VectorNormalize(right);
 167         VectorNormalize(up);
 168
 169         // calculate T coordinate scrolling (start and end texcoord along the beam)
 170         t1 = beamscroll;
 171         t1 = t1 - (int)t1;
 172         t2 = t1 + beamrepeatscale * length;
 173
 174         // the beam is 3 polygons in this configuration:
 175         //  *   2
 176         //   * *
 177         // 1*****
 178         //   * *
 179         //  *   3
 180         // they are showing different portions of the beam texture, creating an
 181         // illusion of a beam that appears to curl around in 3D space
 182         // (and realize that the whole polygon assembly orients itself to face
 183         //  the viewer)
 184
 185         mod = &cl_meshentitymodels[MESH_PARTICLES];
 186         surf = Mod_Mesh_AddSurface(mod, r_lightningbeam_qmbtexture.integer ? &cl_beams_externaltexture : &cl_beams_builtintexture);
 187         // polygon 1
 188         VectorM(r_lightningbeam_thickness.value, right, offset);
 189         CL_Beam_AddQuad(mod, surf, start, end, offset, t1, t2);
 190         // polygon 2
 191         VectorMAM(r_lightningbeam_thickness.value * 0.70710681f, right, r_lightningbeam_thickness.value * 0.70710681f, up, offset);
 192         CL_Beam_AddQuad(mod, surf, start, end, offset, t1 + 0.33f, t2 + 0.33f);
 193         // polygon 3
 194         VectorMAM(r_lightningbeam_thickness.value * 0.70710681f, right, r_lightningbeam_thickness.value * -0.70710681f, up, offset);
 195         CL_Beam_AddQuad(mod, surf, start, end, offset, t1 + 0.66f, t2 + 0.66f);
 196 }